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SYNOPSIS OF BIOLOGICAL DAT: ON Ï 114EAM
_ramis brama (Linnaeus, 1758)
Prepared by
T. Backiel and J. Zawisza
F FOOD AND AGRICULTII a' ORGANIZATION OF THE UNITED NATIONSRome, 1968
4- p
FAO Fisheries Synopsis No. 36 FRi/b JO(Distribution restricted) SAST - A. brama 1,40(02),001,02
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OF FISHERIES
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FAO Fisheries Synopsis No. 36(Distribution restricted)
FRi/S36SAST A. brama 1 40(02),001,02
SYNOP$IS OF BIOLOGICAL DATA ON THE BREA
Abramis brama (L.)
Prepared by
T. BACKIEL and J. ZAWISZA
Inland Fisheries InstitutePoland
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONSRome, February 1968
This synopsis of biological data on the bream has been prepared to fulfil theProgram of Work established at the Second Session of EIFAC, Paris, May 1962.
The authors have the pleasure of acknowledging the cooperation of Dr. M. Gasowska,Zoological Institute, Pol.Ac.Sci., who helped in writing chapters 1 and 2, andDr. J. Grabda, Center for Combating Fish Diseases, Olsztyn, who prepared section 3.35.Special thanks should go to the persons listed below who have supplied valuable data,not published elsewhere, summarized in Tables XXII and XXVII.
Mr, K. Apostolski,Mr, J. Dahl,Dr, W. Einsele,
Dr, Entz Bela,Mr. A.B. Hofstede,Prof. M. Huet,Dr, L. Ivanov,Mr, K. W. Jensen,Mr, E.D. LeCren,Dr, H. Mann,Mr, H.V. Mentzel,Mr, K.A. Pyefinch,Mr, I. SassersonMr. V. Sjbblom
9
Dr. F.W. Tesch,Mr, P. Tombleson,Mr, E.D. Toner,Dr, W.B. Ziemiankowski,
Distribution
AuthorFAO Department of FisheriesFAO Regional Fisheries OfficersRegional Fisheries Councils and CommissionsSelector 2
PREPARATION OF IhiS SYNOPSIS
Fisheries Institute of S.R. Macedonia, YugoslaviaDenmarks Fiskeri - og Havundersgelser, DenmarkBundesinstitut fUr Gewasserforschung und Fischereiwirtschaft,AustriaBiologisches Forschungsinstitut, HungaryInland Fisheries Inspection, NetherlandsStation des Recherches des Eaux et Forats, BelgiumInstitut za Rybarstvo i Rybna Promyshlennost, BulgariaFisheries Research Officer, NorwayFreshwater Biological Association, EnglandBundesforschungsanstalt fUr Fischerei, Hamburg, F.R. GermanyInstitut fUr Binnenfischerei, Berlin, D.R. GermanyFreshwater Fisheries Laboratory, ScotlandInstitute Freshwater Research, SwedenBureau of Fisheries Investigations, FinlandBiologische Anstalt, Helgoland, F.R. Germany"Angling Times", Peterborough, EnglandFisheries Division, EireStatiunea Experimentala Stuficola Delta Dunarii,
RoUmania
Our appreciation of Mr. and Mrs. W. Rumszewicz's translation must be expressed.
We also extend aur thanks to Dr. D.I. Williamson of the Marine Biological Station,.Port Erin, Isle of Man, for his help in the technical editing.
"Current Bibliography" entry
Backiel, T. & J. Zawisza 13-6F084(1968)
FAO Fish.Synops., (36): pagevar.Synopsis of biological data on thebream Abramis brama (L.)
Taxonomy. Morphology. Distribution.Life history. Population structure.Exploitation. Management. Culture.
FRi/S 6 Abramis brama
CONTENTS
Page No,
1 IDENTITY 1:1
1.1 Nomenclature :1
1:11 Valid names :1
1:12 Objective synonymy :1
1.2 Taxonomy :1
1.21 Affinities :1
1.22 Taxonomic status, :1
1.23 Subspecies :5
1.24 Standard common names, vernacular names :5
1.3 Morphology :7
1.31 External morphology :7
1.32 Cytomorphology :7
1.33 Protein specificity :7
2 DISTRIBUTION 2:1
2.1 Total area sl
2.2 Differential distribution :1
2.21 Spawn, larvae and juveniles :1
2022 Adults :1
2.3 Determinants of distribution :1
2.4 Hybridization tl2.41 Hybrids :1
2.42 Influence of natural hybridization in ecology and morphology*
3 BIONOMICS AND LIFE HISTORY 3:1
3.1 Reproduction :1
3.11 Sexuality
3.12 Maturity :1
3.13 Mating :1
3.14 Fertilization
3.15 Gonads :1
3.16 Spawning :4
3.17 Spawn :9
ii FRi/S36 Abramis brama
3.2 Pre-adult phase 3:9
3.21 Embryonio phase :9
3.22 Larval phase :13
3,23 Adolescent phase :18
3.3 Adult phase, mature fish :18
3.31 Longevity :18
3.32 Hardiness :22
3.33 Competitors :22
3.34 Predators :22
3.35 Parasites, diseases, injuries and abnormalities :22
3.4 Nutrition and growth :29
3.41 Feeding :29
3.42 Food :31
3.43 Growth rate :31
3.44 Metabolism :46
3.5 Behaviour :46
3.51 Migrations and local movements :46
3.52 Schooling ':46
3.53 Responses to stimuli :46
4 POPUIATION 4:1
4.1 Structure :1
4.11 Sex ratio :1
4.12 Age composition :1
4.13 Size composition :1
4.2 Abundance and density :6
4.21 Average abundance :6
4.22 Changes in abundance :6
4.23 Average density s8
4.24 Changes in density :8
4.3 Natality and recruitment :10
4.31 Reproduction rater :10
4.32 Factors affecting reproduction :10
4.33 Recruitment :10
FRi/S36 Abramis brama
404 Mortality and morbidity 4:10
4.41 Mortality rates :10
4.42 Factors causing or affecting mortality :14
4.43 Factors affecting morbidity :14
4.44 Relation of morbidity to mortality rates*
4.5 Dynamics of population (as a whole) :14
406 The population in.the community and the ecosystem :15
5 EXPLOITATION 5:1
5.1 Fishing equipment :1
5.11 Gears :1
5.12 Boats :1
5.2 Fishing areas :1
5.21 General geographic distribution :1
5.22 Geographic ranges :1
5.23 Depth ranges :1
5.24 Conditions of the grounds :1
5.3 Fishing seasons :4
5.31 General pattern of season(s) :4
5.32 Dates of beginning, peak and end of.season(s) :4
5.33 Variation in date or duration of season :4
5.4 Fishing operations and results :4
5.41 Effort and intensity :4
5.42 Selectivity :4
5.43 Catches :4
6 PROTECTION AND MANAGIWTINT 6:1
6.1Re., ......a.:_z_Ltorle.'sltne_aspres1 :1
6.11 Limitation or reduction of total catch :1
6.12 Protection of portions of populations :1
6.2 Control or alternation of physical features of the environment :1
6.21 Regulation of flow :1
6.22 Control of water levels :1
6.23 Control of erosion and silting :1
6.24 Fishways at artificial and natural obstructions :1
6.25 Fish screens 6:1
6.26 Improvement of spawning grounds sl
6.27 Habitat improvement*
6.3 Control or alteration of chemical features of the environment :4
6.31 Water pollution control 24
6.32 Salinity control :4
6.33 Artificial fertilization of waters*
6.4 Control or alteration of the biological features of the environment :4
6.41 Control of aquatic vegetation*
6.42 Introduction of fish foods, (plant, invertebrate, forage fishes) :4
6.43 Control of parasites and diseases :4
6.44 Control of predation and competition
6.45 Population manipulation :4
6.5. Artificial stocking 24
6.51 Maintenance stocking :4
6.52 Transplantation and introduction :4
7 POND FISH CULTURE 7:1
7.1 Procurement of stock
7.2 Genetic selection of stocks
7.3 Spawning
7.4 Holding of stock
7.5 Pond management
7.6 Foods and feeding*
7.7 Disease and parasite control
7.8 Harvest
7.9 Transport
8 REFERENCES
*
FRi/S36 Abramis brama
:1
:1
:1
8:1
As no information was available to the author, these items have been omitted from the text.
FRi S36 Abramis'brama
1 ILONTITY
1.1 Nomenclature
1.11 Valid names
Cyprinus brama Linnaeus, 1758,Systema Naturae, 10th Ed.
Abramis brama (Linnaeus): Cuvier, 1817,Regne Anim., II
1.12 Objective synonymy
There are no junior objective synonyms ofthe name.
Abramis brama (L). An objective synonym of oneof its subspecies is given in section 1.23.
1.2 Taxonomy
1.21 Affinitiesauprageneric
Phylum VertebrataSubphylum CraniataSuperolass Gnathostomat4Series PiscesClass TeleostomiSubclass ActinopterygiiOrder CypriniformesSuborder CyprinoideiFamily Cyprinidae
Generic
Abramis Cuvier, 1817
The generio comept adopted here is that ofBerg(1949).
Body laterally strongly compressed. Pha-ryngeal teeth in one row 5-5, sporadically 6-5or 5-6, their crowns compressed and oblique witha groove on the masticating surface. A scale-less keel on the belly; a scaleless furrow a-long the edge of the back, from head to dorsalfin; no keel behind the dorsal fin. Dorsal finbegins behind the vertical line drawn from thebase of ventral fins, ray formula D III 8-10;anal fin long, begins before a vertical linedrawn from the end of the dorsal fin, ray for-mula A III 15-44. Scales strongly attached to
the skin. Lateral line slightly convex ven-trally, without sharp curves. Mouth small, up-per jaw protromtile.
According to Berg(194, this genus containsthe four species: A. brama sapa (PallasA. ballerus (L.) anT A. melanopSHeckel. How-ever Karaman 1924 (in Berg, 1949; in Drenski,1951) put the last species in the genus Vimba;if this is done, the generic definition shouldbe modified toAnal fin III 21-44.
SpecificAbramis brama (Linnaeus, 1758) (Fig. 1)
Type locality: Gulf of Finland
Diagnosis: Fin formula D III 9(10),A III (23) 24-30; L.1. 49-60; gillrakerCount 17-25, vertebral count 38-46. BodYdeep, maximum height 35-40 percent of stan-dard length. (Tables I and II).
Subjective synonymy
Gyprinus iarens Linnaeus, 1758, placed insynonymy in Siebold (1863) as description ofyoung specimens.
Abramis microlepidotus Agassiz, 1835, and
Abramis argyreus Agassiz, 1835, both placedin synonymy in Siebold (1863); reasons dis-cussed.
Abramis vetula, Heckel, 1835, placed in syno-nymy in Siebold (1863) and Blanchard (1880);reasons discussed.
Abramis gehini Blanchard, 1880, placed insynonymy in Moreau (1881) as a "variety" of A.brama.
Key to the species of Abramis simplified(from Berg, 1949).
1 (6) Anal fin more than 20 soft rays.
2 (3) Anal fin less than 30 soft rays. La-teral line less than 60 scales ...
A.brama (L)
3 (2) Anal fin more than 30 soft rays.
4 (5) Lateral line less than 60 scales ...
A.sap (Pall.)
5 (4) Lateral line more than 60 scales ...A. ballerus (L.)
6 (1) Anal fin 20 or less soft rays.
7 (8) Dorsal fin usually 9-10 soft rays ...hybrid of bream and roach
8 (7) Dorsal fin usually 8 soft rays. BalkanPeninsula ... A. melanops Heckel.
1.22 Taxonomic status
This is a well defined species by morpho-logical as well as by breeding data (cf. hy-brids, section 2.4). It seems to be polytypic.No published analysis of this subject is avail-able.
1:1
1:2
4*,
Figure 1. The bream, Abramis brama (Linnaeus).
FRi S Abram brama
Kitai Lake, Danube
Estuary
Figures in brackets refer to one case only.
Table I
Meristic features of the subspecies of Abramis brama
Abramis brama brama (Linnaeus, 1758)
Fin D
Fin A
lateral line
gill-rakers
vertebrae
range
mean
rango
mean
range
mean
range
mean
range
4mean
authors, regions
III 9(10
III (23)24-30
27.4
51-60
55.2
19-24
22.5
(44)45-46
45.0
Berg (1949)
22-28
25.1
52-57(59)
54.2
(22)23-25
23.6
(43)44-45
44.1
Gulf of Finland
Markun
(1929)
III (8)9(10)
9III (22)23-27(28)
24-9
50-58
54.1
17-25
19.8
41-44
44.0
Pskovskoe Lake
Potapova (1954)
III (8)9-10
9.5
-23.4
52.5
20-27
23.5
44.0
Sjamozero
Pavl
ov(1956)
III
99
-25.7
54.9
25.2male
44.5
Dnepr River
Klimova, after Berg
III
8-10
9.3 III (22)23-27(28)
25.1 (49)50-57
53.3
21-25
22.2female
23.27
(41)42-45
43.05
(1949)
YaskjXrvi
Zhukov (1958)
10-12
26-32
49-57
0Nemen River
42-45
0Ladiges (1960)
Nordmark
III
99
III
23-28
51-56
43-45
Bauch (1963)
III
8-10
9.0 III
23-29
25.7 (50)51-57
53.86
21-25
23.12
43-45
44.46
GermaPY
Gasowska (MS)
Vistula River
III
9-10
9.1 III
23-28
25.7
Abramis brama orientalis Berg, 1949
26.0
(42)43-44
43.4
Markun (1929)
(49)50-55(56)
52.3
(20,21,22)
23-30
Aral Sea
25.9
53.45
25.22
44.5
Shaposhnikova (1948)
Volga River
Abramis brama danubi i Pavlov, 1 956
III
9-10
111/23,24/ 25-28
25.8
50-56
52.7
18-26
22.5
38-43
40.5
Pavl
ov(1956)
Yalpukh Lake, Danube
Estuary
III
99
111/24/ 25-26
25.5
52-55(56)
I53.2
20-26
22.9
Pavl
ov(1956)
1:4 FR1/S36 Abramis brama
Table II
Morphometrio charaoters of Abramis brama (L.), expressed as percentages of standard length;values in upper AW773i males, in lower row for females
(After niaposhnikova, 1948, and Pavlov, 1956)
Features
Abramis brama Abramis bramaAbramis brama danubiiPavlov
Yalpukh Lake(males and females combined)
brama (L.)
Gulf of Finland
Berg
Aral Sea
Depth of bodY 37.00 38.84 34.7737.62 39.58
Depth of caudal 9.68 10.72 9.79peduncle 9.56 10.36
Antedorsal 56.63 58.62 56.57distance 58.28 58.50
Distance P - V 24.13 22.96 22.5724.95 24.30
Length of P 19.37 21.08 20.3119.04 20.14
Base of D 12.54 13.54 13.3012.28 13.25
Height of D 20.05 26.16 22.4320.56 24.92
Length of head 21.37 22.20 21.7621.38 22.06
Length of 15.19 13.52 13.72caudal peduncle 15.14 13.68
FRi/S36 Abramis brama
1.23 Subspecies
Abramis brama orientalis Berg, 1949.
Synonym (objective): Abramis brama bergiGrib and Vernidub, 1935, placed in synonymy inBerg (1949) as nomen preocupatum.
Type locality: Aral Sea.
It occurs in the basins of the Caspianand Aral Seas.
Abramis brama danubii Pavlov, 1956.
Type locality: Yalpukh Lake and KitaiLake in the Danube Estuary.
It occurs in the Danube Estuary. Balon(1961, 1962, 1964), Banarescu (1964) andPacdk (1962) used the name of this subspeciesfor the bream of the Danube River.
1:5
The statistical analysis of bream'scharacters applied by Pavlov (1956) mayraise reservations. He used Pravdin's (1939)methods, but, on the criteria of Mayr,Linsley and Uainger (1953), a number offeatures cannot be considered differentenough to be subspecific (Gasowska, MB).
For subspecific characteristics seeTables I and II.
1.24 Standard common names,vernacular names
1:6 FRi S36 Abramis brama
Country
Table III
Standard common and vernacular names
(After Antipa, 1909, Steininann, 1948, and others)
Standard common names Vernacular names
Austria Brachsen Brasse, Scheibpleinzen
Belgium Brème
Bulgaria Platika Diverika
Czechoslovakia Cejn velkS. Plesk4c vysokl,
Denmark Brasen
England Bream
Finland Lahna
France Br4me commune Brame, Bramme, Brasem
Greece Lestia Lestika
Germany Bracksen Blei, Brassen, Breitling
Hungary Dév4r Keszeg Durda
Netherlands Bley
Norway Brasme Brase
Poland Leszcz
Roumania Platica Platicuta, Carjanca, Carjencuta,
Albitura, Ciabac, Lest
Sweden Brazen
Switzerland Brachsmen Steibrachse, Blei, Breiteln,
Braese, Blagge
Cormontant, Platton,
Bracsele
Turkey Ciapac balac
U.S.S.R. Leshch Tsebák, Liashch, Laskir(in Russian)
ni/S36 Abramis brama
1.3 Morphology
1.31 External morphologY
Some morphological data are given inTable II.
Geographic variation small(Shaposhnikova, 1948).
Morphological changos with growth: injuvenile and adolescent phases length/depthratio decreases with growth. Quantitativedata not available (of. section 3.2).
1:7
1.32 Cytomorphology
Lieder (1954) studied chromosomes ofroach (Rutilus rutilus) and of the hybridroach x bream (male): since the hybrid hada similar chromosome count (2n = 52) to theroach he concluded Ihat bream also had 52diploid chromosomes.
1.33 Protein specificity
Schumann (1959) made use of electro-phoresie to study haemoglobins of some fishspecies including bream. He found thatbream Hi° was dual and that the migrationvelocity of Hb fractions was specific.
2 DISTRIBUTION
2.1 Total area
Bream occurs in fresh and brackishwaters of Europe, off the northwestern partof Asia Minor and in the drainage areas ofCaspian and Aral Seas. (Berg 1949;Banaresou, 1964; Stephanidis, 1937;Ladiges, 1960; NUmann, 1962). The naturaldistribution area has been enlarged east-wards by transp/antation (see section 6.52)Fig. 2.
2.2 Differential distribution
2.21 Spawn, larvae and juveniles
Demersal eggs, adhesive, deposited onhydrophytes in shallow waters, mostly at thedepths of 20-80 cm. (for detail seo section3.16).
Larvae remain in shallow water neartheir hatching place. When they are about20 mm, juveniles start feeding at the bottomand move away from the shore. At that time(June and July) A. brama orientalis startsits downstream runs to brackish waters (cf.section 3.22).
2.22 Adults
Feeding individuals remain dispersed atthe bottom, far from shores. Before winterthey gather in schools. Early in springA. brama orientalis and the bream of the Seaof Azov begin their spawning migration upstream(cf. sections 3.5 and 5.31).
2.3 Determinants of distribution
The lethal temperature for southernbream is 33-34°C (Shkorbatov, 1964). Forlarvae, 2 weeks old, raised in aquaria at30°C, the lethal temperature was 37-39°C(Horoszewicz, unpublished.data). Duringembryonic development the temperature of28-31°0 proved to be lethal (of. section3.21). Alabaster (1964) recorded 50 percentsurvival for 1000 min at 30.2°C and 100 minat 31.8°0, (Backiel) in bream acclimatized at20°C.
Oxygen. Lethal oxygen contents are1.8 - 1.9 mg 02/1 for larvae (Kuznetsova,1958) and 5 mg 02/1 for embryos (Iurovitskii,1961). In the case of mature bream, accor-ding to Privanev and Koroleva (1953,) it is0.3 mg 02/1 at a temperature of 20°C.Alabaster and Robertson (1961) observed pro-nounced restlessness among bream at an oxygencontent of 1-1.5 mg/l.
Salinity. The highest salinity atwhich bream occur in the Sea of Azov is'12.9°/oo (Karpevich, 1955). Bream eggs canbe fertilized in the Aral Sea at a salinityof 10.2°/oo (cf. section 3.21).
Water flow. .Bream are not found in therivers with strong currents (Backie/, 1956;Berg 1949; Shaposhnikoya, 1950). Aslanova(1952) found that bream 24-35 cm long couldresist a current of 16 cm/seo for up to 3 h30 minutes when immature but only up to 30minutes when fully mature.
It seems that the natural distributionof bream is limited by the conditions neces-sary for their reproduction and embryonicdevelopment: maximum temperature not higherthan 28°C, high oxygen content, salinity upto 2.8%oand up to 10%o in the case of theA.b. orientalis, gentle water flow.
2.4 Hybridization
2.41 Hybrids
- frequency of hybridization; specieswith which hybridization occurs; methods ofhybridization.
Rutilus rutilus (L.) x Abramis brama (L.)
This cross was described by Heckel asAbramis leuckartii; junior synonyms areAbramis heckelii Selys Longthamps, 1842,and Leuciscus buggenhagii (Valenciennes,1844 (NikoliUkin, 1952). Siebold (1863)named this cross Abramidopsis leuckartii(Heckel) but he was aware that it was ahybrid of the roach and bream. Berg (1949)desoribed it as a cross and gave itscharacteristics. NikoliUkin (1952) thorough-ly examined specimens of this hybrid fromnatural waters and from artificialfertilization.
Characteristics: D 111(1V) 9-10(II),AligiV?) (13)14-20, P I 15-16, V II 8,C 19, L.1 44-55 P4aryngeal teeth in
5-6one or two rows, vertebrae.usually 41-44.Keel complete or only half of it is present.Females preponderate over males among sexu,-ally mature individuals (Nikoliukin, 1952).
Abramis brama (L.) xScardinius isylhaphthalmus (L.)
Nikoliukin (1952) stated that Long-champs found the above cross in ponds in1887. Regan (1908) described this hybrid
FRi/S36 Abramis brama 2.1
Figure 2. Geographical distribution of bream (after Banaresou, 1960,supplemented by data in Niimann, 1962, and Ladiges, 1960dotted line).
22 FRi/S36 Abramis brema
from 12 individuals from Ireland and England.Nikoliukin (1952) reared specimens of thiscross to an age of five years. Thecharacteristic features given by him aresimilar to those described by Longchampsand Regan.
Characteristicss externally the hybridresembles something between the rudd andbream. D III (7)8-9(10), A III(IT) 15-18,L.1 45-51 11 vertebrae 41-43, pharyngeal
4 5--teeth usually in two rows.
Blicca bjoerkna (L.) x Abramis brama (L.)
According to Nikoliukin (1952) thishybrid was described by Knaute in 1896.Nikoliukin (1952) raised individuals fromartificial fertilization until they were 5years old. Zhúkov (1958) obtained onespecimen from the Nemen River. Accordingto Nikoliukin (1952) the characteristics ofthe hybrid are: D 8(9), A (20) 21-25, L.14853, gill rakers 18-22, vertebrae 43,pharyngeal teeth 1.5-5.1. In contrast tothe bream, there is no scaleless furrow onthe back.
Alburnus alburnus (L.) xAbramis brama (L.)
Specimens obtained by Nikoliukin (1952)from artificial fertilizations survived forup to two years. This hybrid can hardly bedistinguished from that of
A. alburnus x Mace bjoerkna.
Nikoliukin (1952) also crossed thebream with Gobio gobio (L.), Tinca tinca (L.),C rinus carpio (L.) and Carassius carassius
but in each case either the embryos orlarvae did not survive. He also unsuccess-fully crossed the bream with Perca fluviatilis(L.), Lucioperca lucioperca (L.) and Acerinacernua (L.).
FR11536 Abramis brama 2:3
FRi/S36 Abramis brama
3 BIONOMICS AND LIFE HISTORY
3.1 Reproduction
3.11 Sexuality.
The bream is heterosexual. No informa-tion on hermaphroditism, even as an anomaly,is available. Sexual dimorphism of the seceondary sexual characters is weak: pearl or-gans of males can be distinct in autumn (Ol-iva, 1952), and males have longer pairedfins (Vladykov, 1931, quoted by Oliva, 1952).On the spawning grounds, males can be distin-guished by colour, spawning tubercles and in-jured fine, especially the dorsal fin (Fabri-cius, 1951).
3.12 Maturity.
The following data supplement Table IV.Differences in the age at which first matu-rity is reached can be considerable. In theCaspian Sea, 85 - 100 percent of four-yearold bream are mature, in the Sea of Azov 52percent of four-year old, 32 percent offive-year-old and 14 percent of six-year-oldbream are maturing for the first time (Domen-tova, 1952a, 1955). On the other hand, im-mature bream of ten years or older have beenfound by Neubauer (1926) and Peozalska (1963)in the Szczecin Firth (Lagoon) and by Ostrou-mov (1956) in the Ribinskoe Reservoir. Thereare considerable differences in the length ofthe sexual activity period. Driagin (1952)quotes the data of Tereshchenko concerningthe Volga Delta (Caspian Sea) where malobream older than eight years and females of12 years appear to be sterile, whereas ac-cording to Potapova (1954) female bream of20-26 years from the lakes of the Karelo-Finnish SSR are still sexually active, andin the Volga (Shaposhnikova, 1948) 13-year-old males and 16-year-old females showed nosigns of sterility. A male bream of the KamaRiver (Griazeva, 1936) could still spawn atthe age of 15 years.
The bream of the southernmost waters(the Dnepr Delta, Volvi Lake, Fertö Lake)mature earliest, i.e. at the age of three-four years. In the remaining area no clear-cut regularity could be observed. The matu-ring period ranges from three to ten years,and, according to numerous observations,males frequently reach maturity one year ear-lier than females.
The geographic position and climate donot influence'pronouncedly the size at whichmaturity is reached. The data of Table IVdo not confirm the assumption of Laskar(1948) that the climate affects the size atwhich bream reach maturity. In the AralSea, according to Merezova (1952), two popu-
lations of bream occur together and reachmaturity at the same age, but they differconsiderably in size.
The bream of the Aral Sea transferredto Lake Balkhash (Kazakh SSR) reaches matu-rity at the same age as in its native watersalthough the fish are much smaller (Pet-kevich, 1953; Ivanov and Pechenikova, 1960).
Geyer (1939) pointed out the inter-dependence of growth rate and maturity. Hewas of the opinion that, under conditions ofrapid growth, males and females mature atthe same time, and one year later ihan inlakes where growth is slow. On the con-trarY, ShaPoehnikova (1948) linked earliermaturity with faster growth in the firstyears of life. These differences resultlargely from regional variations, as statedby Wundsch (1939), who confirmed the fin-dings of Geyer (1939) for the lakes studiedby him.
Though the age ef sexual maturity va-ries from 3 to 10 years, the length at whichmaturity is reached is less diversified andlies between 14 cm and 30 cm ratio 1 : 2).Perhaps, as suggested by Alm 1959), matu-rity is affected by "physiological age",which is determined by absolute age andgrowth rate. Zemskaia (1958) expressed asimilar opinion.
3.13 Mating.
Male and female bream spawn repeatedlywith different partners. Mating is there-fore promiscuous.
3.14 Fertilization.
Fertilization is external. At a tem-perature of 19-21°C sperm motility lastsfor eight minutes in fresh water andfor 10-13 minutes in brackish water (,8.6-10.1e). (Data for bream of Aral Sea, Gos-teeva, 1957). According to DziekoAska(1958), sperm motility lasts for 45-75 se-conds in the Vistula Lagoon.
3.15 Gonads.
The quantity of eggs produced annuallyby one female may differ considerably andit depends mainly on body size. Berg (1949)reported 941,000 eggs as the highest fecun-dity of the bream; according to Bauch(1963) the lowest is 2,000. Different fec-undities are recórded for different diet-riots: for the middle reaches of the Don,the range is 98,000-713,000 and the average218,000 eggs per female (Syrovatskaia,1949); for the middle reaches of the Volga,401500-654,000, average 176,500 (Shapoehnik-ova, 1948); .for the Aral Sea, 92,000-
at1
Table IV
Age and size at first maturity
Brean from
ag
(Years)
standard
lengthl/
(cm)
Approximate
weight
(gran)
Growth
ratela/ Author
too
cr.
males
females
males
females
-
Norfolk Broads, England
River Welland, England
Grosser Planer Seo, Germany
Vierer See
Oberer Ausgrabensee
Mügel See
Langer See
Ammersee
Simssee
Lake Volvi, Greece
Lake Fertö, Hungary
Danube, Czechoslovakia
Danube Delta
Toften, Sweden
Hjdlmaren, Sweden
Yxtasjon, Sweden
Haderslev-Dam, Denmark
Tuusula, Finland
Vistula Lagoon, Poland
Szczecin Firth, Poland
Goldopiwo Lake, Poland
Aral, USSR
(4)6
7 (5)6
(4)5
6 6 8 7-8
2-3
(2)3
2-4
6-7
8 6-10
7 (3)5
(5)6
(5)6
6 (3)4
5
(4)6
7 6 (4)6
7 6 8 7-8
3 (3)4
3-4
6-7
8 6-10
8-10
(4)6
(5)6
6 7 (4)5
2/(22)24
30
25
(13)16
(18)20
(15)
25
30
14 (16)
12-22
25
25
16-20
19 9 28
(22)28
25
25
23
17-23
(l8)24
30 25
(13)16
20 (15)
25
30
16
20-24
23-26
25
25 16-20
20-21
12
30 (23)30
28
28
- 500
250
100
160
120
- - - - - - 5-12
400
400
300
400
average
average
good
good
poor
poor
poor
good
good
good
good
good
good
average
poor
poor
poor
good
good
good
good
Hartley, 1947
Leeming, 1963
Geyer, 1939
Geyer, 1939
Geyer, 1939
Wundech, 1939
Wundsch, 1939
Laskar, 1948
Laskar, 1948
Laskar, 1948
Geyer and Mann, 1939
Balon, 1963
Pavlov, 1956
Alm, 1919
Alm, 1917
Alm, 1922, in Laskar, 1948
Otterström, 1932, in Geyer
1939a
JRrnefelt, 1921
Filuk, 1962
Przalska, 1963
Inland Fish. Inst., Poland
(unpublished)
Morozova, 1952
1960
2/Figures in brackets give the youngest age and the smallest length of sexually mature bream.
The remaining figures
give the age and size when a considerable part of the population reaches sexual maturity.
2/The length of Norfolk Broads bream is fork length, while for other water bodies it is standard length.
When
calculating standard length (lo) from total length (it) the ratiolcilt
m0.78 - 0.80 has been accepted (Bauch, 1963).
Growth rate scale is according to Geyer (1939).
..4./
When no data on length and body weight wereavailable, publications on the growth rate of breaM in a given water body
were nado use of.
Azov, USSR
4-5
4-5
30
30
500
good
Dementeva, 1955
limen Lake, USSR
66-7
26
27
400
good
Morozova, 1952
Volga, USSR
(5)
6-7
7-8
(22)28
30
good
Shaposhnikova, 1948
Rybinsk Reservoir, USSR
(7)9
(7)10
30
30
500
average
Ostroumov, 1956
Poddubnyi, 1960
Caspian Sea, USSR
(3)4
(3)4
(19)23
(20)24
good
Dementeva, 1952a
Siamozero, Karel SSR
7-8
8-9
27-30
600-900
Potapova, 1954
Niukozero, Karel SSR
8-10
28-30
600-800
Potapova, 1954
Ubinskoe, Novosibirskaia
obl.
5-6
average
Petkevich, 1953
Balkhash, Kazakhstan
(3)5
average
Ivanov and Pechnikova,
338,500, average 205,000 (Morozova, 1952);for the lakes of the Karelo-Finnish SSR,25,000-501,500 (Potapova, 1954); for LakeMamry, Poland, 45,000-520,000 (authors' ma-terial).
Taking into account a small number ofstudies and differences in the methods ap-plied, the data concerning the average fe-cundity of weight classes, as presented inFig. 3, should be treated as tentative.
The number of eggs per gram of bodyweight and the relative weight of gonadsare presented in Table V. Attention isdrawn to the great variability of the re-lative weight of female gonads from thesame body of water, e.g. from 10 to 23.8percent for the Aral Sea. After spawningthis index diminishes'in the case of fe-males to 2.2 - 2.3 percent (Morozova, 1952).Seasonal changes in gonads were studied byButskaia (1955) and Shilov (1962).
The quantity of eggs which remain inthe ovaries after spawning is inconsider-able; according to Dementeva (1952a) it is1.4 percent.
The potential quantity of eggs whichcould be produced by one female depends onthe duration of its sexual activity and itsrate of growth. Fiom data referring to themiddle reaches of the Volga (Shaposhnikova,19 ),it appears that a female which maturesat the age of six years, weighing 680 g,may spawn for the last time at the age of16 and a weight of 4,380g; such a fishcould produce about 2.5 million eggs duringthese 10 years. Shpet (1964) gives an ab-solute potential fecundity of one pair ofbream during nine years of life as 6 x 105pairs of progeny.
Griazeva (1936) carried out a histolo-gical analysis of changes occuring in breamgonads.
3.16 Spawning.
Some orientative data concerning thespawning of bream are presented in Table VI.
In most water bodies bream spawn onlyonce a year, but there are populations knownin which females spawn twice or even threetimes (Papadopol, 1963). In the spawningperiod, the avaries contain eggs of two orthree different sizes. (Driagin, 1949;Morozova, 1952; Syrovatskaia, 1949; Sych,
1955). Quantities of small eggs found inbream from the Aral Sea and River Don makeup 30 and 32 percent respectively of thetotal number of eggs.
FRi/S36 Abramis brama
Repeated spawning can occur in thewhole population or in paA of it. Accor-ding to Zakharova (1955) females with twoegg fractions occasionally occur in theRybinskoe Reservoir. In Lake limen onlyseven percent spawn repeatedly but in theDon and in the Danube Delta the great majo-rity of females spawn more than once a year.The fact should be stressed that repeatedspawning occurs more frequently among thesemi-migratory populations which spawn inthe areas inundated by spring floods.
In the water bodies where female breamspawn only once a year, the population mayoften be divided into groups which spawn atvarious times; sometimos these groups arerelated to the size of the spawners. Accor-ding to arnefelt (1921) younger and smallerbream spawn first in Lake Tuusula, while ac-cording to Pciczalska (1963) bigger and olderindividuals spawn first in the Szczecin La-goon. In several water bodies the periodsat which particular spawning groups appearare regular enough to have local namesgiven . by fishermen, e.g. in Lake limen(Driagin, 1949), in Szczecin Lagoon (Neu-baur, 1926). They are often connected withphenological observations. According toBernatowicz (1962) the first period ofspawning in Mazurian Lakes coincides withfull blooming of apple trees (Malus domes-ticaYand lilac (Syringa vulgalIT)T- the se-cond period begins with the flowering ofStratiotes aloides.
Males are ready to spawn first and theyremain longer on the spawning grounds; theyare therefore in a majority in the.spawningschools (P9czalska, 1963; Shaposhnikova,1948; and others).
Table VI also shows the spawning sea-son. The data refer to different years ofobservation, and the season can differ bytwo-three weeks in successive years, depen-ding on the weather.
The main factor influencing the begin-ning and course of spawning is temperature.Driagin (1949) stated 12-13°C to be thelowest temperature, at which bream haveobserved to spawn. The corresponding highesttemperature is 2700, recorded in the Aral Sea(Shaposhnikova, 1948). The most commonly re-ported spawning temperature is 16-180C. Asudden cooling may stop spawning (Zakharova,1955). During warm and calm weather, breanspawn in masses in a short time (two-threedays); under bad conditiuns spawning lastslonger. The maximum water level reached inspring and the time when it occurs are im-portant factors influencing tne populationsof estuaries, rivers and retention r000r-voirs. Those factors affect the area of the
PRi S36 Abramis brama
Number of eggs
per femalethousands
500
400
300
200
100
o
.0
a
Average for Mamry Lake Poland (Inl.Fish Inst.)
Szczetin.Firth (Lagoon) Peczalska (1963)
Volga, Shaposnikova (1949)
Sea of Aral. Marcum° (1952)
A Rybirisk Reservoir, Sergeev et all.(1955)
Danube delta Papadopal (1959)
SOO 1000 2000 3000 4000 vveight,Tam
Figure 3. Fecundity of bream in relation toindividual weight.
Table V
Number of eggs per gram of body weight and gonad weight as percentage of body weight
in some bream stocks
o. ON
Stock from
No of eggs
Gonad weight, percent
Author
average
range
Females
Males
average
range
average
range
A/Spawning once a season
Volga River
125
102-
156
-age:
6-7
102-
105
Shaposhnikova
(194
8)
_ age: 12-14
151-
156
Szczecin Lagoon
150-
200
13.3
-19.
42.
8Peczalska
(196
3)
Lake Mamry
b/Spawning repeated
150
140-
170
authors' data
Dnepr
River
113
97-1
38Velikokhatko,
(194
7)
Danube delta
246
21Papadopol
(196
2, 1
963)
Aral Spa
260
16.8
.10
.0-2
3.8
3.4
2.4-
4.6
Morozova
(195
2)
Lake limen
8.4-
16.8
2.0-
3.9
Driagin
(194
9)
Water body
Aral Sea, USSR
Caspian Sea, USSR
Don River lower course, USSR
Dnepr River lower course, USSR
Volga River middle course, USSR
Siamozero, Karelo-Finnish
ASSR
Ilmen Lake, USSR
Volgogradski Reservoir, USSR
Rybinekoe Reservoir, USSR
Glubokoe Lake, USSR
Harsz Lake, Poland
Mazurian Lakes, Poland
Vistula River, Poland
Vistula Firth, Poland
Szczecin Firth, Poland
Holstein Lakes, Germany
Tuusula Lake, Finland
Norfolk Broads, 7ngland
Malären Lake, Sweden
No of
Repeated
spaw-
spawning
ning
groups
-+
Table VI
Data on bream spawning
Beginning
Spawning
of
Temfg.rure
duration
spawning
(days)
Author
Morozova, 1952
Dementeva, 1952a
Syrovatskaia, 1949
Velikokhatko, (1947)
Shaposhnikova, 1948
Shaposhnikova, 1948
Driagin, 1949;
Ponedelko, 1958
Elizarova, 1962
Zakharova, 1955
Dmitreva, 1960
Pliszka, 1953a
Bernatowicz, 1955, 1962
Sych, 1955
Dziekofiska, 1956
Zukowski, 1962;
Peczalska, 1963
Geyer, 1939
JErnefelt, 1921
Hartley, 1947
Svardson, 1949;
Fabricius, 1951
few
15.IV
15
120
few
17-20
320.IV
15
40-45
2-3
25.IV
10-18
20-25
110.V
12-18
4-6
310.VI
15-20
320.1V
12
40
5.V
8-15
25
120.V
12.5-15
14
21-2.VI
17-18
14
25.V
16-18
3-4
210.V
16
30
210.V
17-20
20
1-10.V
18
45
3-4
25.IV
15-17
30
26.V
14
25.VI
18
10
5.VI
5.VI-10.VI
14.5-18
3:8 FRi S36 Abramis brama,mm.E.arazz.===mmamsramov wwww.c...mao.
spawning ground and the spawning season e.g./in the Volga (Shaposhnikova, 1948), in theVistula (Sych, 1955), in the Rybinskoe Reser-voir (Zakharova, 1955; Elizarova, 1962).
According to the observations of Sych(1955), spawning lasts day and night, beco-ming more intensive at ni.ght. Fabricius(1951) and Svardson (1949) observed breamspawning in Lake MElaren by day. Accordingto Shaposhnikova (1948), most intensive breamspawning lasted from 10.00 to 11.00 and aftera break at noon from 16.00 to 17.00 hours.
- Location and type of spawning ground.
Bream deposit eggs in sheltered places,where the water is either still or the cur-rent is weak. Depths at which eggs havebeen found vary from 9 cm (Sych, 1955, Vistu-;la) to 3-3.5 m (Driagin, 1949) and even 17 min the Kakhovskoe Retention Reservoir (Belyi,1962). The most common spawning depths arefrcm 20 to 80 cm (Shaposhnikova, 1948; ZukoW-ski, 1962; Zakharova, 1955). When bream spawnat various times in the same body of water,the earliest spawning takes place on shallowgrounds, and later spawnings are on deepergrounds (Driagin, 1949); the temperature ofthe water is probably important. Sych (1955)observed that during calm weather eggs arelaid at the minimum depth (9 cm), when thereare waves they are laid at a greater depth(30 cm). One body of water can have bothshallow and deep spawning grounds (Driaeln,1949; Morozova, 1952; Dziekoziska, 1956).
There is considerable variation in theareas of different spawning grounds. Sha7poshnikova (1948) described particular spawn-ing areas in the Volga as occupying about100 m2; Pliszka (1953a)reported a spawningarea of 0.5 ha in 'a lake of 200 ha; Zakha-rove (1955) stated the area of a spawningground in the Rybinskoe Reservoir to be'about 50 ha. In many Mazurian lakes fisher-men know the maimspawning grounds which arerelatively constant (Pliszka, 1953a)and thesame is true of the Szczecin Lagoon (Pgczal-ska, 1963). In retention reseryoirs, riversand estuaries, where bream spawn on inun-dated areas, the locality and size of thespawnine ground are changeable and they de-pend en the hydrometeorological conditions(Zakharova, 1955; Morozova, 1952; Demen-.teva, 1952a, and others).
The breaM is a"generatively phytophilousspecies'; a term applied' by Kryzhanovskii(1949); its eggs adhere and develop onplants. The plant substratum may be quitediverse: flooded land plants, the remainsof the previous year's aquatic vegetation,tree leaVes, stems and roots of emergentplants, algae (Cladophora), submereed hydro-
phytes. From among the latter the follo-wing are often mentioned: Myriophyllum112., Chars. Stratiotes aloides, Elodea2E., etc. In the Vistula, Sych (1955) foundthe eggs of bream on Rorippa amphibia, Buto-mus umbellatus, Sagittaria sapittifolia andGlyceria aeuatica. Bream eggs are depositedalso on "artificial" spawning grounds, wherethe branches of conifers are used as a sub-stratum (cf. section 6.26).
The spawning of bream may coincide withthe spawning of other species of fish. Inthe Szczecin Lagoon a part of the bream pop-ulation spawns on the same breeding groundsand simultaneously with Blicca bgrkna (L.).The eggs of bream, pike-perch and ruff werefound at the sane time on the artificialspawning grounds in the Don delta.
At time of spawning, bream are alert.and shy. A splash of an oar or voicesfrighten them away, and they swim to deeperwater (Shaposhnikova, 1948).
According to lake fishermen, breamspawn in great masses during calm weather.The spawning is stormy; the fish splash wa-ter with their tails, making characteristicnoises which can be heard from afar. Thewater of the spawning ground is turbid andvegetation torn out by the fish can be seen.
According to Svgrdson (1949) and Fabri-clue (1951), who observed the spawning ofbream in Lake Malaren, the spawning groundconsista of a number of plots occupied bybig males which are on the move. Theirmovements attract females and scare awaymales. The male defends its territory andwhen another male appears there is intensivesplashing. According to Svgrdson one terri-tory is about 5 m2; Faloricius observedsmaller territories. Males did not abandontheir territories during the whole time ofobservatien (8 h.).
' The data of Zakharova (1955) suggestthat the spawning of bream may follow asimilar course in other water bodies. Inthe Rybinskoe Reservoir she found bream eggsdeposited in patches, each covering about1 m2 and containing about 1,200 eggs. Thefact should_be stressed. however, that eggsare often not evenly distributed (Shaposhni-kova, 1948; Pliezka, 1953a) and their greatquantities suggest that many fish may spawnin the same area. Thus according to Potapo-va (1954) from 60,000 - 2,300,000 eggs werefound on 1 m2 in Lake Vygozero. In the ViB-tula Lagoon, Dziekoriska (1956) found 30,000- 738,000 eggs per m2 on the shallowspawning grounds and, on the average, 2,000
eCCs Per m2 on the deep grounds. In Lake
FRi S 6 Abramis brama
Harsz, Pliszka (1953a) found 20,000 -400,000 eggs per m'e
3.17 Spawn.
The polyplasmatic eggs show variousshades of yellow and contain littleperivitelline space. The diameter of a matureegg is 1.62 - 1.82 mm, without membrane it is0.97 - 1.30 mm. The blastodiso is from0.325 to 1.30 mm high depending on the stageof development, in width it almost equals thediamter of the yolk sac. The membrane istransparent, and thé filaments whioh attachthe egg to the substratum are minute andthinly spread. The egg membrane isdelicate and it breaks easily(Kryzhanovakii, 1949). Other authors givethe egg size as follows: Driagin (1949):1.3 - 1.9 mm, ay. 1.5 mm, after swelling ay.2.1 mm s Morozova (1952): 0.9 - 1.2 mm, ay.1.0 mm; Sych (1955): ay. 1.3 mm.
The average weight of a bream egg variesbetween different populations from 0.75 -1.35 mg. The differenoes in average weightof eggs of particular females may amount to100 percent. Maximum egg weight of 1.25 gwas found in females seven years old;younger and smaller females as well asolder and heavier ones had lighter eggs(Privol'nev,1964).
The biochemistry of bream eggs andspawners has been studied by Maliarevskaiaand Birger (1965).
3.2 Pre-adult hase
3.21 Embryonic phase.
Developmental stages of bream eggs arepresented in Fig. 4. The rate of embryonicdevelopment depends clearly on temperature(Table VII). Kryzhanovskii (1949) statedthat the incubation period lasts from 3 -13 days and data from other works are inagreement with this.
A temperature of 28°C was found to belethal during oleavags and it caused heavylosses at other stages of development, 24°Cwas responsible for heavy losses duringcleavage and before hatching, 10 - 18°C gavesimilar results to the control (14 - 15°C),and the temperature of 600 caused considerablelosses only at cleavage (Volodin, 1960).The same author quotes the lethal temperaturefor the developing bream eggs from the DonRiver as 29 - 31°C. DziekoAska (1958) tookdeveloping bream eggs from the VistulaLagoon at five defined developmental stagesand placed them in water of 35, 32, 8 and4°C for 5 minutes. At the temperature of
3:9
35°C all eggs, irrespective of the develop-mental stage, perished, while at 32°C and4°C, 10 - 20 percent of eggs survived.At the temperature of 8°C the results weresimilar as in the control at 1700.
- Oxygen.
Acoording to Iurovitskii andRosnichenko (1961) the critical oxygencontent for bream egg development at 1500 is5 mill. At 3 mg/1 losses were 100 percent,at 5 mg/1 they amounted to 11 percent andthere were 67 percent of abnormallydeveloping embryos. At the control at10 mg/1 the losses were 7 percent and7 percent of eMbryos were developedabnormally. -According to Kuznetsova (1958)the critical oxygen content is 1.9 mg/l.
- Salinity.
Morozova (1952) and Gosteeva (1957)reported that in the Aral Sea, some breamspawning grounds, far from the shore and4 - 5 m deep, show a salinity of 9 - 10%o.Under experimental conditions (Gosteevap1954, 1957) bream eggs from the Aral Seadeveloped normally at a salinity of 10.12%o.At 11.5 - 11.6 %o the development wasabnormal, at 11.7 %/0o embryos perished at thebeginning of segmentation and at 12 %Gli thedevelopment stopped at the blastula stage.Changes in salinity from 5.4 - lo.%o did notimpair the development.
The survival of Bream embryos atdifferent salinities is also given by Cherfas(1956) after Konovalov:
Bream eggs from the Sea of Azov:
Bream eggs from the brackish water ofthe Vistula Lagoon, do not develop at sucha high salinity. Fertilization could becarried out only at 2.8 %o but fertilizedova could develop at a salinity of 5.6 5o.
CO2 is harmfb1 to the eggs of breamonly at the conoentration of 50 mg/1 orgreater (Volodin, 1960).
Salinity (50) 0 2.7 4.5 5.4
Survival (%) 60.1 52.3 21.5 15.1
Bream eggs from the Aral Seas
Salinity (50) 0 4.3 5.7 7.1 10.2
Survival (%) 88.4 86.3 80.0 67.3 38.4
1L4.
1 5
lo
11
12
Figure 4. Embryonic development of bream,after Kryzhanovskii (1949).
_-AVOZAVIFx.w"'"
3:10 FRi/S36 Abramis brama
arm
Explanation of Fig. 4
1/ Stage of two blastomeres; age 1 h 5 mm, yolk sac diameter 0.97 mm.
2/ Stage of four blastomeres, from above; age 1 h 27 min.
3/ Eight blastomeres, from above; age 1 h 48 min.
4/ Two superimposed drawings of the same egg, at the stage of eight blastomeres(age 1 h 48 min.)
and at the stage of early morula (age 4 h 5 mm),
5/ Two superimposed drawings of the same egg at the age of 4 h 5 min and 5 h 55 min.
6/ Transitional stage between morula and blastula; age 6 h, temperature 22°C.
7/ Blastula; age 6 h 30 mm, temperature 22oC.
8/ Beginning of gastrulation; age 8 h 15 mm, temperature 22°C.
9/ End of gastrulation, blastopore still partially open; age 16 h 40 mm, temperature 19.9°C.
10/ Blastopore closed but still visible; age 2 days 3 hrs, temperature about 16°C.
11/ Cephalic mesoderm still linked with body mesoderm; age 21 h, temperature 20.8°C.
12/ Cephalic mesoderm rudiment separated from body mesoderm, the latter beginning to divici-J
segments; age 2 days 17 h, temperature about 16°C.
13/ Three segments: rudiments of eyes and KUpffer's vesicle visible (the latter is situated in
the future eleventh segment); age 22 h 40 mm, temperature 20.8°C.
14/ 8 segments; age 24 h 18 mm, temperature 21°C.
15/ 12 segments: encephalomeres and ear vesicles can be seen; age 26 h 40 min.
16/ 15 segments: gall bladder differentiating, Kupffer's vesicle has increased in size and its
location now corresponds to that of 12 segment; age 28 h 10 min.
17/ 18 segments: the location of Kupffer's vesicle corresponds to that of 24th segment; age 29
h 40 min.
18/ 20 segments; elongated head, encephalomeres have disappeared, Kupffer's vesicle has moved
towards caudal kidney and its location corresponds to that of 27th segment, embryo moves
slightly.
19/ 22 segments: Kupffer's vesicle is very small, its location corresponds to that of 31st seg-
ment; age 31 h 40 mm, temperature 20.4°C.
20/ 35 segments (9 segments in the tail): gall bladder pearshaped, otoliths visible in ear ve-
sicles; age 42 h 24 mm, temperature 19.4°C.
21/ 17 segments in tail; heart starts beating, beginning of blood circulation; age 48 h, tem-
perature 20°C.
FRi/536 Abramis brama 311
19°C
20-22°C
230C
Table VII
Number of "degreehours" of embryonal development,
from fertilization to hatching
2950
1300
2600
1501
1430-1890
2208
Kryzhanovskii, 1949
Pliszka, 1953a
Shaposhnikova, 1948
Dziekotska, 1956
Kryzhanovskii, 1949
Dementeva, 1952a
3:12_ FRi S36 Abramis brama
Temperature No of degreehours Source
FRi/536 Abramis brama
Developing bream eggs can withstandshort (60 minute) periods of exposure tothe air (without water). This does notdisturb the process of development butirregularities during hatching must be men-tioned (DziekoAska, 1958).
The percentage of fertilization ofbream eggs on the natural spawning groundsis high (Dria:gin, 1949; Dmitreva, 1960).Pliszka (1953a) reported 98 - 100 percentfertilization in Lake Harsz, of which 70 -90 percent hatched. Sych (1955) estimatedthe fertilization on the Vistula spawninggrounds to be 91.2 - 96.7 percent and the
losses to be 65%. Zakharova (1955) des-cribed the losses on the spawning grounds ofthe Rybinskoe Reservoir as 32 percent,Dziekoxiska (1956) estimated the losses in theVistula Lagoon, depending on the character ofthe spawning ground, to be 6.8 - 19.6 per-cent. Potapova (1954) reported that 75 - 90percent of eggs are fertilized in Karelo-Finnish lakes.
Different causes are responsible forlosses in bream eggs on natural spawninggrounds.. According to Dmitreva (1960) andauthors quoted by Zakharova (1955) and Gos-teeva (1957), they are (a) oxygen deficiencyin poor water circulation, caused by de-caying organic matter or, at night, by plantrespiration; this can check the developmentof eggs deposited on the bottom, on vege-tation near the bottom, or on decayingleaves (shallow inshore grounds of the VolgaDelta,Aral Sea); (b) eggs not fertilized;
drying out due to a fall in water levelrivers, retention reservoirs); (d) infec-
tion with the mould Saprolegnia; (e) pre-dation by invertebrates and fishes. Zakha-rova (1955) found up to 400 bream eggs perfish in perch caught on a spawning ground,and Gosteeva (1957) mentions Pungitius pun-gitius L. as a predator. It seems that fishcan cause considerable losses in bream eggs.In the lower reaches of the Don River,Mikheev and Meisner (1954) observed breameggs deposited on artificial grounds, wherepike-perch had spawned earlier. The breameggs viere protected by the male pike-perch.On those spawning grounds the losses inbream eggs were very small when comparedwith those on natural spawning grounds.
- Mode of hatching.
Glands oontaining a substance whichweakens the egg membrane can be found on thehead and back of the embryo. They are con-spicuous and full in larvae taken from theegg-capsule before hatching (Kryzhanovskii,1949). From bigger eggs hatch bigger larvae,from 4.57 to 5.30 mm, (Dmitreva, 1960).
3.22 Larval phase.
General features of development. Thepost-embrionic development of the bream hasbeen worked out in detail in a number of pa-pers from the A. N. Severtsov Research In-stitute of Animal Morphology in Moscow (Vas-netsov, 1948; Vasnetsov et al. 1957;Brome:evo, 1960, 1960a; Dmitreva, 1960;Kryzhanovskii, 1949; Sablina, 1960).
Those works distinguish a number ofdevelopmental stages in the pre-and post-larval phases. These stages are illust-rated in Fig. 5, and a summarised descrip-tion is given in the accompanying expla-nation.
The rate of development depends on tem-perature, hence the rate of development maychange, but in principle the course of larvaldevelopment is similar in lake bream, estua-rine bream (semi-migratory) and in those ofretention reservoirs (Dmitreva, 1960; Ere-meeva, 1960, 1960a). The main difference isin the fact that at stage G, bream in estu-aries, such as the deltas of the Volga, Donand Kuban, gather in schools and begin theirmigration towards the sea.
According to Vladimirov (1964), morta-lity at this phase resulting from hereditaryfactors may be very high and may differgreatly between the progeny of different fe-
-
males. His experiments lasted 30 days, un-der good environmental and feeding con-ditions; mortality among the progeny of 60percent of the females was less than 20 per-cent, but among the progeny uf 12 percent of'females it was 90-100 percent. Vladimirovobserved the highest mortality of larvae onthe 13th - 15th and 20th - 23rd days afterhatching. Larvae shorter than the meanlength perished. Abnormalities of the ali-mentary tract were the cause of losses. Theresults of breeding bream in ponds for thepurpose of stocking (Nikolskii, 1955) showthat at low densities, i.e. 200,000 pike-perch eggs and about 1.5 million bream eggsper 1 ha, the mortality of bream amounted to95 percent in 60 days, and when the densitywas 2 - 3 times greater it rose to 98.5 -99.6 percent in 30 days. In Poland, infish-ponds near lakes where bream larvaewere raised together with tench, the morta-lity of the bream amounted to 99 percent in90 days, but the survivors grew excellently,and on average they measured 7.5 am andweighed 4 g after three months, i.e. 2 - 3times higher gain than in the adjaoent lakes.
According to Berg et al. (1949) frogssometimos do considerable damage to breamlarvae.
3:13
3:14 FRi S36 Abramis brama
E
Figure 5. Stages of bream development (after Dmitreva, 1960).See explanation on following page.
FRi/S36 Abramis brama
Stage Length Age(mm) (days)
Explanation to Fig. 5 (after Vasnetsov et al.,,1957,
and Dmitreva, 1960)
Structure
B 5.2-6.4 3-4 Filled air bladder. Yolk sao small.
Tail fin develops from larval fin.
Mouth inferior, not completely clo-
sing. Mombranous gill cover leaves
last three gill arches uncovered.
Chorda straight. Pectoral fin bases
vertical. Intestine resembles a
straight tube.
.4-7.5C1 6 3 Yolk disappears. Chorda straight.
Dorsal and anal fins develop. Nesen-
chyme concentration can be'seen in
caudal fin.
Behaviour, Food
Stay near shore, in vegeta-
tion. Swim obliquely,
head upwards. Feed on yolk
and small sluggish organ-
isms such as rotifers and
their eggs.
Swim well and fast, chasing
food. Feed on rotifers, di-
atoms, nauplfi, copepodids
and email copepods.
Al 4.5-5.3 3 Yolk sao pear-shaped, head slightly Larvae motionless,
bent down. Body surrounded with lar- attached to vegetation or
val fin. Mouth inferior, immobile. resting on bottom. Feed
Eyes slightly pigmented. Pectoral only on yolk.
fin bases horizontal. Rudimentary
gill cover. Glutinous glands under
eyes for attachment of larva.
A2 up to 6 2-3 Yolk sao cigar-shaped. Head straight.
Mouth inferior, lower jaw movable.
Pectoral fin bases oblique. Mem-
branous gill cover reaching first
gill arch only. Few melanophores on
yolk sao.
3:16 FRi/536 Abramis brama
C2
D1 8.6-10 3 Anterior cavity of air bladder fills
with air. Posterior chorda end
bending slightly upward. Tail almost
homocercal. Bony fin rays in tail
fin. Mesenchymal rays in dorsal and
anal fins. Operculum still
membranous, not covering last two
arches. Mouth slightly
protractile.
D2 10-13.5 4 Bony finrays developed in dorsal and
anal fins. Tail homocercal. Caudal
fin forked. Ventral fins developed
as two horizontal folds without fin-
rays.
E 13.5-16
7.5-8.6 3 Chorda end bent sli tly upward,
cartilaginous bypural beneath it.
Heteroceroal tail. Mesenchyma
concentration in dorsal and anal fin
lobes. Membranous gill cover leaves
last three gill arches uncovered.
4 Bony finrays developed in all fins.
Olfactory cavity resembles figure
of eight, septum starts forming.
First two intestinal ansae
developed. Gills covered.
Stay near shore (depth
0.5m), in surface layer of
water; agile. Feed on
rotifers, nauplii and
copepodids.
Stay among plants. Feed on
small copepods, Cladocera,
rotifers and diatoms.
Stay near shore in
vegetation. Feed on large
Cyclops and on rotifers and
diatoms.
Stay a little further from
shore. 'Feed on zooplankton
and periphyton.
. 3
FRi/S36 Abramis brama3:17
16-20 7 Scales develop. Preanal fin lobe
disappeare. Body height increases.
Upper profile line almost straight,
lower one convex. Finrays start
branching. Olfaotory oavity double,
although septum not complete.
Stay far from shore, in
places without vegetation,
not shallower than 1.5 m;
swim in upper water layers,
feeding on zooplankton
(large Daphnia, Cyclops,
rotifers, larvae of
Chironomidae).
20 Whole body covered with scales. Stay at bottom, feed on
Mouth semiinferior. Two nostrils. larvae of Chironomidae,
Seoond pair of intestinal ansae larger zooplankton,, green
developed. algae and diatoms.
At a temperature of 17 20°C, the yolksao resorbs between the sixth and eighth day,and the larvae then start feeding on minuteorganisms. The information on feeding habitsis summarized in Table VIII.
A concentration of food organisms of500 per liter provides good feedingconditions for larvae at stage C1 (lo = 7 mm,weight 1.5 mg) according to the experimentsof Panov (1960). Zheltenkova (1964) statesthat 227 275 organisms/liter is asufficient food concentration. A planktonbiomasa of 30 40 mg/liters, i.e. about1,000 organisms/liter, secure proper feedingconditions for bream larvae at stage D2(length 12 mm, weight 15 mg) aocording toPanov (1960). Karzinkin (1952) gives thefollowing data on the amount of food eaten bylarvae in a day:
16dayold, weighing 7.7 mg:101.9 percent of body weight,
32day-old, weighing 38.8 mg:57.0 percent of body weight,
48dayold, weighing 85.0 mg:35.0 percent of body weight.
Larvae were fed on tiny Cladocera in aquaria.
Growth.
Body length reached in the first yearof life is exemplified by the followingdata: (Table IX).
Shaposhnikova (1948) expressed theopinion that the growth of juvenile breamresponds readily to a number of factors andtherefore it may be different in particularparts of a bigger water body and inparticular years. This is illustrated byher data in the table IX, showing'widelydifferent growth rates for different parteof the Ural and Dresna rivers.
3.23 Adolescent phase.
Depending on the population, theadolescent phase lasts from two to eight years(Table IV).
The basic period of development andorganogenesis ends at the length of 75107 mm (Sablina, 1960). The bream'attainsits final body shape when longer than 14 cm(Vasnetsov, 1948).
Predators.
Bream is seldom eaten in largequantities by predatory fish. (Table X). Thedata of Domanevskii (1964), Hartley (1947),
Filuk (1962a), Ivanova (1956, 1960),Makkoveeva (1956), Vashchenko (1958),Romanova (1956) and Balagurova (1963) confirmthe small proportion of bream in the food ofpredatory fish, apart from those exceptionaloases where no buffer species are availableand bream is practically the only availablefood for the predators (cf. Dziekotska,1954). Bream are also eaten by some birds,such as grebes (Podicens sp.), diversColymbus sp.), herons and oormorants.Authors' material).
Bream longer than 20 cm are attackedrarely and only by big predatory fish.Although detailed information is not available,it seems that, exoept in the larval phase,predation is rarely a factor controlling thedensity of bream. In Polish lakes, wherepredatory fish are protected and common, nodecrease in the abundance of adolescent breamhas been observed. (Authors° material).
Parasites can probably affect the sum.-vival of bream in the adolescent phase (of.section 3.35).
3.3 Adult yhase, mature fish
3.31 Longevity.
SegestrUle (1933) published a photographof a scale of a 32yearold female bream fromHajka FOrd, Finland. It was 50.4 cm lo andweighed 2.4 kg. Potapova (1954) found 26yearold bream. A 23yearold female breamfrom Lake Sniardwy, Poland, weighed 5.2 kgand its lo was 57 cm. The oldest breamfound during archeological excavations inCentral Russia was 20yearsold (Levedev,1961). Bigger bream and probably the olderones have been caught in Central and NorthernEurope. Berg (1949) reported that a breamweighing 11.5 kg was caught in Lake Vestjarvi,Finland. Wundsch (1939) quoted dataaccording to which bream of German waters canbe heavier than 10 kg.
Maximum age is not older than 15 yearsin the case of the poPulations of thesouthernMost areas of the distribution ofthe species (Berg, 1949; Dementeva, 1952;Balon, 1961, 1963). NtImann (1962) reportedthat he caught bream up to 2 kg in Spence,an Anatolian lake, Turkey.
The interdependence between longevityand growth rate is not clear. Semimigratorybream of the estuaries of the Caspian, Azovand Aral Seas are characterized by a fastgrowth rate and a short life cycle, but atthe same time an ecological variety of aslow growing bream with a short life cYclealso occurs in the Aral Sea, (Morozova, 1952).
3:18 FR1/S36 Abramis brama
FRi/S36 Abramis brama 3:19
Table VIII
Bream diet in the first year of life
Water body Size or ageof fish
Main food Author
Volga 6 days Phytoplankton Pankratova, 1948
10-11 days Small Cladocera and
Copepoda found in
aggregntions
2-3.7 cm Tendipedidae and
zooplankton
Tsimlanskoe 4 cm Zooplankton: Bosmina, Lapitskaia, 1958Reservoir
Daphnia, Moina, Cyclops
4.1-6 cm Forms found at the
bottom: Alona ap.
Pleuroxus, Rarpacticidae
Mazurian 1.8-4.8 am Littoral forms of Pliszka and Dziekoliska,Lakes(Poland) Cladocera 1953a
2.3-2.9 cm Cladomax,.a Copepoda, Leszozpiski, 1963
Nematocera puppae
Lake Bolshoi Age 0+ 60 percent Alona affinis, Bogatova, 1963Ivan (North.)USSR3 12 percent Bosmina sp.
Water body Date
Table IX
Body length of bream in the first year of life
Lengthmm
Weight Author
Tsimlanskoe Reservoir Sept.1953 92.0 15.0 Ginzburg, 1958
'Tsimlanskoe Reservoir Sept.1954 86.1 12.6 Ginzburg, 1958
Tsimlanskoe Reservoir Sept.1955 64.4 4.7. Domanevskii, 1958
Vistula River Oct.1952-1955 25.0 Backiel and Bontemps, 1958
Mazurian Lakes autumn 32.0-37.0 0.5-0.8 Zawisza, 1953
Ural River August 29.0-59.0 Shaposhnikova, 1948
Desna River August 16.0-40.0 Shaposhnikova, 1948
3320 FR1/536 Abramis brama
Percentage of
Bream as
Bream as
_
Water body
Predator
Season
predators
percentage
Percentage
with bream
of total food
of no. of
in stomachs
by weight
fish in
stomachs
Table X
Predation on bream
Size of
bream
most fre-
quently
found
(cm)
In 2 out of 6
places studied,
no bream in
pike-perch and
skeatfish
Bream
abundant
Bream very
abundant
Vistula River
Pike
3
(middle reaches)Perch
2
Pike-perch
4
Skeatfish
6
Aspius aspius
2
Chub
3
2-12
Remarks
Author
Baimov, 1963
Antosiak, 1963,
1963a
Dziekofiska, 1954
Domanevskii
1958a
u.)
1\3
Aral Sea
Pike-perch
1.4-13.7
Mazurian lakes
of common type
Perch
summer
1.5
4-10
winter
3.9
4-10
Pike
summer
1.4
2-10
winter
5.0
5-10
Mazurian lakes
Pike-perch
summer and
of pond-type
autumn
66.0
winter
12.5
6-21
spring
20.0
Horoszewicz, 1964
Bream
abundant
winter
2.4
Tsimlanskoe
Pike
SUMMer
38.0
Reservoir
3:22
The growth rate of bream has beendetermined for several hundred Polish lakes,Z. Marciak, unpublished data), but no relationcan be established between the longevity of apopulation and its growth rate.
It is almost a rule thatfemales aremore numerous in older yearclasses of bream(of. section 4.41).
3.32 Hardiness.
Wunder (1936) reported that at anexigen content of 2 2.5 mg/1 bream showthe firstaigns of aspyxia and at 0.4 0.5mg/1 they begin to die. Similar resultswere obtained by Privollnev and Koroleve(1953). Lethal temPeratures for southernbream arei33 34°C, for northern bream theyare less than 30°C (Shkorbatov, 1964).
3.33 Competitore.
Reproduction.
Peczalska (1963) mentioned commonspawning grounds of bream and white breamin the Szczecin Lagoon. In the Don Deltabream spawned together with pikeperch andthe males of the latter protected the eggsof both species (Mikheev and Meissner, 1954).Sukhoivan (1959) reported similarobservations. The hybrids described (cf.section 2.4) suagest that breaM can spawntogether with a number of.other species offish, thus competition for spawning groundsoannot be excluded.
Competitors for food.
In lakes and rivers ruff, eel, whitebream, roach, carp, Chondrostoma nasua andtench show common food items with bream(Aristovekaia, 1954; Bogatova, 1963;Podarueva, 1960: Wundsch, 1939; Pliszkaand Dziekotska, 1953; Neuhaus, 1934).In the Azov, Aral and Caspian Seas, the foodof bream is similar to that of Neogobiusfluviatilis (Pallas), N. melanostomus(Pallas), Rutilus rutilus paspius (Yakovlev),Percarina demidoffi maeotica Kuznetzov,Aspius aspius, wild carp, Abramis sapa (L.)and Barbus brachycephalus (ra3TITA7r) (Berget al., 1949; Shornin, 1952). The lattercalculated and compared a number ofquantitative indexes referring to thecompetition for food among the fish of theCaspian Sea (cf. section 4.6).
Vasneteov (1948) was convinced that thestronaest competition between bream, wildcarp and roach may take place when theystart to feed on benthos (bream about 25 mmlong). The older year classes of thosespecies have their own speoifio feeding
grounds and the oompetition for food occursonly in poorly differentiated water bodiescontaining not enough food.
Karzinkin (1952) gave a number of dataon the availability of Tendipendidae larvaeas food for a number of fish species. Theseobservations suggest that under similarconditions carp, crucian carp, tench andruff are superior to bream in finding food.
3.34 Predators.
Predators were discussed in section3.23. Large bream are rarely preyed uponby fishes; big fisheating birds attackthem when on the spawning grounds (Berget al., 1949).
3.35 Parasites, diseases,Injuries andabnormalities.
Parasitic diseases.
Ichthyophthiriosis
A disease caused by Ichthyophthiriusmultifillis Fouquet, 1876, (Protozoa,Ciliate).
A cosmopolitan parasite occurring innumerous fish species, including bream.The vegetative form of the parasite (up to1 mm in diameter) is found under the gillepithelium and under the epidermis on thefins but also on the entire surface of thefish body. On heavily infested fish thereare found small, whitish nodules. Theparasite couses an inflammation of the skin,increased mucus secretion, peeling of theSkin, and in more advanced cases even death.The parasite is dangerous to fish of allages but especially so to fingerlings(Amlaoher, 1961; Markevich, 1951;Schaperclaus, 1954).
Control.
Best results are obtained by keepingthe infected fish for some time in a troughwith a strong current of water, whiohwashes off the parasites from the skin andalso from the bottom of the trough. Athorough disinfection of the pond erradicatesthe invasive stages of the parasiteaccumulated on the bottom.
Bucephalosie
A disease caused by an invasion ofmetacercariae of the family Bucephalidae(Trematoda). In Europe and Asia twospecies of this family are found in bream:Ducephalus polymorphus Baer, 1827, andRhipidocotyle illense (Ziegler, 1883).
PRi/S36 Abramis brama
FRi/S36 Abramis brama 3:23
Sexually mature forms of the parasite arefound in the intestine of predatory fieh(Esox lucius L., Lucioperca lucioperca L.,Perca fluviatilis L. and Acerina cernua L.).Cercariae develop in mussZT(Elo andAnodonta), metacercariae are usually foundunder the gill epithelium, in the eyes, sub-cutaneous tissue and in muscles of variousspecies of Cyprinidae.
Pathogenic effects of both the speciesdepend on their localization in the fishbody. Kozicka (1958) reported fin damage,skin hyperaemia and even large wounds on thebody, in bream infested with Ehipidocotyleillense. According to Kozicka metacercariae,by pressure on the blood vessels, causecirculatory disturbances. The resultingblood oongestion may result in atrophy ofparticular parts of the organs.
The presence of matacercariae in theeyes may cause blindness. Grabda and Grabda(1961) observed a massive invasion ofBucephalus polymorphus metacercariae in theeye cornea (some 500 larvae in one eye)causing cloudiness of the cornea and anincrease in the amount of fluid in theinterior chamber of the eye and exophthalmus.
Parasites pathogenic both to fry andto older bream.
Caryophyllaeosis
A disease caused by Caryophyllaeuslal .ceps (Pallas, 1781) (Cestoda,Caryophyllaeidae), a parasite of Cyrpinidae,extremely common in bream.
The parasite is common all over Europeand also in the Asiatio part of the USSR.The adult tapeworm is found in the fish'sintestine and its larvae develop in the bodycavity of various species of Tubificidae.
A heavy invasion of the parasite causesan inflammation of the intestine. Theintestine may be blocked by numeroue tape-worms and heavy mortality may result. Theheaviest infestation occurs in April-May.The intensity of the invation increaseswith the age of the fish. According toSchilperolaus (1954), the degree ofinfestation inc.:eases markedly from thefifth year onward, when the bream starts tofeed at the bottom.
- Control.
Intensive oatches of bream with theonset of the disease.
Ligulosis
A disease caused by plerocerooids ofthe tapeworms (Cestoda, Ligulidae), Ligula
intestinalis (L.) and Digramma interrupta(Rud., 1810), living in the body cavity offish. The first intermediate hosts of theparasite are copepods (Cyclops strenuus,Diaptomus gracilis and others), in whosebody cavity develop larvae of the procercoidtype which are infectious to fish. Thedevelopment of the larvae (plerocercoidae)in the body cavity of fish takes about 12 .-
14 months (Dubinina, 1957). At this timethe parasite attains the length of an adulttapeworm, the gonads develop but there isno egg production as yet. Sexually maturetapeworms are found in the intestine of suchpiscivorous birds as gulls, grabes, wildducks and others. The final host may bealso the domestic duck. (E. Grabda, 1951).In the intestine of birds, Liomla maturesin about two days and begins to produceeggs.
The parasites are very common in Europeand the Asiatic part of the USSR in manyspecies of Cyrpinidae, the main host beingthe bream. In many lakes the extent of theinfection exceeds 50 percent. Single tape-worms are usually found, but sometimes afew or even some dozen are present in thebody cavity of a single fish. Adult plero-cercoids attain 1 m length and 1.5 cm width.A mixed simultaneous invasion of bothspecies of cestode is sometimes encountered.
Ligulosis is most often found in palm,sized bream. A000rding to SchMperclaus(1954) the heaviest infestation is foundamong bream undw17.5 am. According toZawisza (M.S.), the highest percentage ofinfestation is found in bream aged 4 - 5years, which corresponds to the length of20 - 24 cm. Dubinina (1957)reports thatbream aged 1+ to 3+ are subject to theheaviest infestation. After the fish havestarted bottom feeding the incidencedecreases.
Ligulosis causes heavy losses amongfish. Reshetnikova (1959) estimated theannual losses in the Tsimlanskoe Reservoirat 1,200 tons.
A heavy invasion is manifested byflatulence. This often results in bursting ofthe abdominal oavity and the parasites dropinto the water. Infested fish becomelanguid and may easily be attacked bypredators. In ligulosis there is observeda substantial decrease in fat content offish muscles, a chronic: peritonitis, andfrequently there is a serum exudate in thebody cavity. The internal organs of thefish are damaged owing to the pressureexerted by the parasites. The developmentof gonads is inhibited (Willer, 1912).According to Kerr (1948), infested fishshow hypophysis changes and disturbances
3:24
in the secretion of gonadotropio hormones,which results in a decreased fecundity.The investigations of Koshsva (1957)showed a lowering of the haemoglobincontent and an increased blood sedimentationrate among infested bream. A slowing downof growth and a reduction in weight ofbream infested with Digramma interruptawas found by Reshetnikova (1965).
Affected bream show low survival intanks and during shipment.
Control.
Intensive °etches of infested fishand checking of the stocking material.
Ergasilosis
A disease caused by Ergasilus sieboldiNordmann, 1832 (Crustacea: Copepoda parasitios), a gill parasite of numerous speciesof fresh water fish, frequently found inbream.
The parasite is very common in thelakes of Europe and Asia. The larvalstages of the parasite develop outside thefish body, in water. Only the females areparasi tic.
E.sieboldi injures the gillepithelium of the fish and causesrespiratory difficulties. Heavilyinfested fish die of asphyxia, especiallyduring summer heat. An emaciation of thefish is frequently observed. The intensityof the invasion is generally milder inbream than in Tinca tinca, the latter beingthe main host. As many as five hundredparasites have been reported on the gillsof a single fish (Gnadeberg, 1948).
Control: an examination of thestocking material aswell as intensivecatches with the onset of the disease.Neuhaus (1929) recommended intensivecatches during the winter season, when nojumenile forms of the parasite are foundin the water, thus the females of E.sieboldi hibernating on the gills of fishare eradicated along with the fish.
Tracheliastosis
A disease caused by the parasiticcopepod Tracheliastes maculatus Kollar,1836 (Crustacea: Copepods parasitioa).
Only females which attach to thescales of fish, are known to be parasitio.Males unkown.
FRi S36 Abramis brama
T.maculatus is found in Europe, mainlyon bréam, less frequently on other membersof the family Cyrpinidae. It damagesscales at the place of attachment andcauses dermatitis, local at first and thendiffuse. If the fish is heavily infestedand the disease is more advanced, woundsform at the places of attachment. Thesemay become portals of secondary infectionthrough bacteria or fungi. Dermatitis isaocompanied by a profuse mucus secretion.The disease causes strong emaciation offish resulting in death (Grabda and Grabda,1957). According to Geyer (1939a), breamranging from 14 17 cm in length are mostfrequently subject to infestation. Grabdaand Grabda (1957) found the heaviestinfestation among fish over 20 cm lt. Theintensity of the invasion amounts frequentlyto 100 percent. Usually only singleparasites are found on a fish. When theinvasion is heavy several parasites may bepresent.
Control.
There are no means of eradicating theparasites themselves. They can be controlledthrough usual management-practices, i.e. thecontrol of stocking material and intensivecatches of bream to thin the stock and todiminish the possibility of contactcontamination.
Table XI summarizes data concerningthe common parasites of bream.
Infectious diseases.
Bream septicemia
An infectious disease manifested byan inflammation of the skin accompanied incongestions and haemorrhages. Frequentlythere are local swellings of the skin due toserum exudate in scale pockets. On theskin there may form lesions, sometimesreaching deep into the muscles. The gillsare usually pale, sometimes there is pro-trusion of the eyeballs. Internal anato-mioropathalogio changes: serum fluid inthe body cavity, a congestion of theintestine, liver, and swim bladder, necrosisof the kidneys.
The investigations of Flemming (1954)proved that in the initial phase of thedisease there is an increase in the numberof leucocytes of the blood. Among themthere are numerous granulocytes. In moreseriously affected fish complete destructionof erythrocytes is observed.
11036 Abramis brama
Table XI
More frequently occuring parasites of the bream, Abramis brama (L).
No. Species of parasite
1. Cryptobia abramidis(Brumpt, 1906)
Myxidium pfeifferiAuerbach, 1908
Myxobolus oviformisThélohan, 1882
4, myxobolus exiguusThdlohan, 1895
5. Myxobolus m(IlleriBateohli, 1882
6. Myxobolus oycloidesGurley, 1893
7. Chilodonella cypriniTkoroff, 1902)
8. Iohthyophthiriusmultifiliis
Fouquet, 1876
9. Daotylogyrus auricu-latus(N771.mann, 1832)
10. Dactylogyrus cornuLinstow, 1878
FoUnd in
Protozoa
blood
Distributionarea
Europe
gial-bladder Europe, Asia
gills, Europe, Asiamuscles, (Siberia)viscera
gills, in- Europetestine,kidney
skin, gills, Europe, Asiakidneys (Siberia)
gills EUTOpe
... 2
Authors
Markevich, 1951; Koshe-va, 1957; Bykhovskii,1962
Markevich, 1951; Bogda-nova, 1957; Baryshevaand Bauer, 1957
Wegener, 1909; Marke-vich, 1951; Akhmerov andBogdanova, 1957; Bykhov-skii, 1962
Wegener, 1909; Markovich1951; Kogteva, 1957;Grabda and Grabda, 1961;Bykhovskii, 1962
Markevioh, 1951; Bogdan-ova, 1957; Kogteva,1957; Grabda and Orabda,1961, and others
gills Europe, Asia Markovich, 1951; Prost,(Kazakhstan) 1957, 1959; Bogdanova,
1957; Vojték, 1959;Margaritov, 1959; Byk-hovskii, 1962; Agapova,1962
Markovich, 1951; Bogdan-ova, 1957; Paoak, 1962;Bykhovskii, 1962; Luckyand Dyk, 1964
viscera Europe Wegener, 1909; Marke-vich, 1951; Orabda andGrabda, 1961
gills, skin Europe Kozicka, 1951; Marke-vich, 1951; Bogdanova,1957
skin, gills Europe Kozicka, 1951, 1959;Markevioh, 1951; Bogda-nova, 1957; Paoak, 1962
Monogenoides
1960; Bykhovskii, 1962;
000 3
3:26 PRi/S36 Abramis brama
11. Dactylogyrue falcatus gills Purope, Kaz-akhstan
Markevich, 1951; Prost,1957, 19591., Bogdanova,1957; Vojtgk, 1959;
(Wedl, 1857)
Agapova, 1962, Bykhov-'Ail, 1962
12. Dactylogyrus crucifer gills Europe Markevich, 1951; Bogda,nova, 1957; Bykhovskii,1962; Lucky and Dyk,1964
Wagoner, 1857
13. Dactylogyrus sphyrna gills Europe Markevichi 1951; Prost,1957, 1959; Bogdanova,1957; Bykhovekii, 1962;
Linstow, 1878
Lucky and Dyk, 1964
14. Daotylogyrue wunderi gills Europe,Kazakhstan
Markevich, 1951; Bogda,nova, 1957; Kogteva,1957; Vojték, 1959;
Bykhovskii, 1931
Agapova, 1962; Bykhov-skii, 1962
15. Dactzl_cg.orf_:_us zandti gills Europe Markovich, 1951; Prost,1957, 1959; Bogdanova,1957; Margaritov, 1959;
Bykhovskii, 1933
Vojtgk, 1959
16. Gyrodactylus parvicopula gills Europe, Kaz-akhstan
Prost, 1957; Bogdanova,1957; Margaritov, 1959;Bykhovskii, 1933Agapova, 1962; Bykhov-skii, 1962
17. Gyrodactylue medius gills Europe,North Asia,Kazkhstan
Markevich, 1951; Agapo-va, 1960; Lucky and Dyk,1964
Kathariner, 1893
18. Diplozoon paradoxum gills Europe, Asia Markevich, 1951; Ko-Nordmann, 1832 (Siberia,
Kazakhstan)zicka, 1951, 1953; Prost1957, 1959; Vojtgk,1959; Margaritov, 1959;Pacak, 1962; Agapova,
Trematoda Digenea
Lucky and Dyk, 1964
19. Bucephalue polymorphus gills,eyes,skin
Europe,Asia
Markevioh, 1951; Ko-zicka, 1951; Grabda andGrabda, 1961; Bogdanova,1957; Vojt8k, 1959; Ag-apova, 1960; Bykhovskii,1962
Baer, 1827, larva
20. Rhipidocotyle illense skin,gills, fins
Poland Kozicka, 1953, 1958, 1959Ziegler, 1883, larva
21. Phyllodistomum folium urinary Europe Markovich, 1951; Koshe-(Olfers, 1916) bladder, ur-
etersva, 1957; Vojtkova,1959; Bykhovskii, 1962
FRi/S36 Abramis brama 3:27
Phyllodistomum elongatumNybelin, 1926
lphaerostomum bramas-(Mdller, 1776) -------
Asymphylodora imitans(MUhling, 1898)
piplostomum clavatumNordmann, 1832, larva
Diplostomum spathaceum(Rudolphi, 1819) larva
Posthodiplostomum outico-laTgordmann, 1832) larva
Apóphallus muhlingi(Jagerskield, 1899)larva
Metagonimus yokogawaiKatsurada, 1912, larva
Caryophylleus laticeps(Pallas, 1781)
Caryophyllaeides fornica(Schneider, 1902)
Ligula intestinalis(L., 1758) larva
vitreousbody of oye
eye lens
skin, fins,gills
gills, fina
scales, fine,gills
Cestoda
intestine
intestine
body cavity
Purope, Asia(Kazakhstan)
Europe, Asia(Kazakhstan)
%rope
Europe
USSR,Czechoslo-vakia
Europe,Asia,(Siberia,(Kazakhstan)
Europe,Asia
Europe
Markevich, 1951; Bary-sheva and Bauer, 1957;Akhmerov and Bogdanova,1957; Vojtkova, 1959;Bykhovskii, 1962
Markovich, 1951; Ko-zicka, 1951, 1959; Grab-da and Grabda, 1961; Pa-oak, 1962; Bykhovskii,1962, and others
Markovich, 1951; Ko-zicka, 1951; Vojték,1959; Wierzbicka, 1964;Bykhovskii, 1962
Markovich, 1951; Ko-zicka, 1953, 1958; Bog-danova, 1957; Vojtkova,1959; Agapova, 1958;Grabda and Grabda, 1961;Bykhovskii, 1962
Markovich, 1951; Ko-zicka, 1951, 1953, 1959;Bogdanova, 1957; Engel-brecht, 1958; Grabda andGrabda, 1961, and others
Kozioka, 1953, 1958;Grabda and Grabda, 1961;Paoak, 1962; Bogdanova,1957, and others
Markovich, 1951; Vojtók,1959; Bykhovskii, 1962
Vojtgk, 1959; Zitman,1960; Bykhovskii, 1962
Markovich, 1951; Janis-zewska, 1954; Kozicka,1953, 1959; Engelbreoht,1958; Agapova, 1960;Pacak, 1962, and others
Kozicka, 1959; Pacak,1962; Bykhovskii, 1962
Markovich, 1951; Ko-zioka, 1958; Dubinina,1957; Willer, 1912;Paoak, 1962; Kosheva,1957, and others
4
urinary Europe, Asiabladder
intestine Europe
intestine Europe
33, liisramma interrupta-(Nudo1p1i,1810), larva
Proteocephalr torulosueTBatsch, 178
Rhaphidascaris acus(Bloch, 1779) larva
Philometra ovata(Zeder, 1803)
Philometra abdominalisNybelin, 1928
Neochinorh nchusrutiliTIVID7r, 1780)
Acanthooe halusanguillaeTgaller, 1780)
42. Caligus lacustrisSteenstrup et Lütken,1861
Wematoda
viscera Europe
body cavity Europe,Asiatic USSR
Acanthocephala
gills, skin
Crustacea arasitica
41. Ergasilus sieboldi gills Europe, AsiaNorAmann, 1832
Europe, Asia(basins ofthe Baltic,Black, Cas-pian and Ar-al Seas)
Kosheva, 1957; Dubinina,1957; Bykhovskii, 1962
Markevich, 1951; Kosh-eva, 1957; Grabda andGrabda, 1961; Pacak,1962, and others
Markevich, 1951; Scha-perclaus, 1954; Dyk,1961; Bykhovskii, 1962,and others
Bykhovskii, 1962; Aga-pova, 1962
Markevich, 1951; Bykhov-skii, 1962
Van Cleave and Lynch,1950; Grabda and Grabda,1961; Bykhovskii, 1962,and others
Kozioka, 1951, 1953; Pa-oak, 1962; Lucky and Dyk,1964; Bykhovskii, 1962,and others
Kozicka4 1953, 1959; Pa-cak, 1962; Bykhovskii,1962, and others
Neuhaus, 1929; Markevioh,1956, Orabda and Orabda,1961; J. Grabda, 1962;Schlperclaus, 1954; Pa-cak, 1962, and others
Markevich, 1956; Kozikow-ska 1957; J. Grabda,1962; Bykhovskii, 1962and others
Schaperolaus, 1954; Mar-kevich, 1956; Kozikowska,1957; Orabda and Orabda,1957; J. Grabda, 1962;Bykhovskii, 1962, andothers
Bogdanova, 1957; Stammer,1959; Pacak, 1962; Bykh-ovskii, 1962, and others
3:28 FRi/S36 Abramis brama
intestine Northern ho-larctic re-gion
intestino Holarctioregion
40. Acanthocephalus luoii(Müller, 1776) intestine Europe
43. Tracheliastes maculatus skin Central andKollar, 1835 East Europe
44. Argulus foliaceus skin, mouth Europe, AsiaLinnaeus, 1758) cavity, gills
Europe,mainly EastEurope
Europe
body cavity
intestino
Europe, Ka,zakhstan
body cavity
From the affected bream, Schaperclaus(1954) isolated Pseudomonas punctata (Syn.Aeromonas punctata). The disease is quitecommon in Germany and Poland.
It is frequently found together withcarp saepticemia (Abdominal dropsy).Although it has not been established thatit is caused by the same germ as in carp,utmost precautions should be taken whenstocking lakes with the latter species.
Focal li uefactive necrosis
An enzootic disease of bream found inPoland (Waluga, 1962; Niewolak, 1961).
The disease occurs among lake breamweighing approximately 1 kg, in summer(August - September). Weakened fish swimupside down near the surface. On the bodyof the fish there are found tumors of asoft consistency.
Histopathologic symptoms: a lique-factive necrosis of the skin and muscles,focal necrosis of the liver, spleen andkidney, fatty degeneration of the liver,peeling of the intestinal epithelium.In extreme cases there is a completenecrosis and loss of the caudal part of thefish (Waluga, 1962).
These changes are irreversible andusually lethal.
From the affected bream there has beenisolated Pseudomonas chlororaphis (Guignardet Sauvagea(Niewolak, 1961).
- Diseases of unknown etiology.
Epithelioma
In the initial phase of the diseasethere is a proliferation of the epithelialcells in the form of soft, whitish patcheswhich eventually harden. The disease mayaffect the gills, oausing their degeneration,or the skin. When the patches cover largeportions of the surface of the fieh body thefish become emaciated, the growth isretarded and death may eventually result.
Epithelioma is a disease common amongoarp. In bream the symptoms were observedby Schaperclaus (1954) in Germany, byLiaiman (1949) in the USSR, in Poland byJ. Grabda, (unpublished observation). Inolder bream the disease is found sporadically.
The etiology of the disease is notsuffioiently known.
- Poisoning.
Water pollution by industrial wastescontaining phenol.
Phenol poisoning causes disturbances ofthe circulatory system (congestions,haemorrhages), necrobiotio changes in thecells resulting in a destruction of thecytoplasm and nucleus, the presence of fociof coagulative necrosis. Phenol affects thecentral nervous system oausing abnormalitiesof respiration, motion and piiaientation - thebream become pale. Death results fromrespiratory paralysis (mors per asphyxiam) orfrom paralysis of the heart (mors persyncopem) (Waluga,f1966).
Low concentrations of phenol, althoughnot lethal to fish, cause changes in theperipheral blood of fish, characterized byan increase in the number of non-typical andjuvenile forms of blood corpuscles and adestruction of morphotio elements of blood(Waluga, 1966a).
3.4 Nutrition and growth
3.41 Feeding.
According to Laskar (1948), in lakes,younger bream feed by day and the older onesby day and night. Kogan (1963) andNebolsina (1962), after studying the dailyfeeding rhythm of bream in retentionreservoirs, came to the conclusion that theyfeed exclusively by daylight. Feeding ismost intensive from 11.00 to 13.00 and thenfrom 15.00 to 19.00 hours if the temperatureis higher than 27°C.
Tendipedidae preponderate in the foodwhen the light is strong, and Molluscs atdusk. Younger year classes feed in thelittoral zone, the older ones in the sub-littoral and profundal regions of lakes(Laskar, 1948; Plistka, 1953). Feedingplaces depend on the limnologioal characterof the water body (Table XII, and Plistka andDziekoliska 1953, 1953a). In the Vistula,bream feed in muddy places' at greater depths,where the current is weak (Plistka eta].,,1951).
Poddubnyi (1959) reported that, in theRybinskoe Reservoir, one-to-two-year-oldbream feed inshore, two-to-three-year-oldson the newly inundated areas, and olderbream mainly in the former river bed; breamschools were observed on rich feeding grounds,while, at the same time, single fish or smallgroups were feeding on the poorer ones.
The mouth of an adult bream is semi-inferior; it makes a long snout directeddownward, at an anglo with the long axis ofthe body. The gill covers have strongmuscles, which give the mouth considerablesucking power (Eremeeva, 1948, in Vasnetsov,1948).
FRi/S36 Abramis brama 3:29
Tapypini
Tanytarsini
Polypedilus
Bathophilus
Sublittoral
Grosser.
eutroph
Limnochir.
Plumosus
-Profundal
very good
low middle
P1Bner
Cryptochiro -
nomus
Tanypini
Tapytarsini
Polypedilus
Bathophilus
Sublittoral
good-
high-
Kleiner
eutroph
Limnochir.
Plumosue
-Profundal
very good
very high
Plfter
Cryptochiro-
nomus
Tanypini
middle-
Vierersee
eutroph
++
4+(not always)
Plumosus
Profundal
low
high
middle low
eutroph
44+
+Plumosus
Profundal
low
(rarely
high)
Mfiggelsee
Table XII
Feeding grounds of bream in some German lakes (after Laskar,
1948
)o
Tendipedidae
Feeding
Lake type
Abundance
of bream
in food,
forms of:
ground of
mature
bream
Growth
Catch
Lakes
(Examples)
Sublittoral
Profundal
Tanytarsus
oligotroph
and other littoral forms
Littoral
sublittoral
very good
low
Bodensee
According to Wunder (1936), the breamuses mainly its taste when looking for food;according to Kogan1969 sight is mostimportant. Disler 1948 proved that thesense organs of the lateral line may behelpfUl in finding food.
'Bream can search for food in the uppermud layer only. According to Karzinkin(1952), bream 11.5 cm long can penetrate mudlayers up to 5 cm thick, 16 am fish up to9 cm. Karzinkin (1952) is of the opinionthat old bream (6 years old) can find theirfood even under a 15 cm mud layer. Changesin nutrition in older year classes of bream ofthe Caspian Sea are presented in Fig. 6, inthose of Central European lakes in Fig. 7.Many authors agree with the general rulo thatas bream grow older they move to deeperfeeding grounds and feed on bigger organisms.
A"typical pattern of feeding aotivityis shown in Fig. 8 (after Hartley, 1947).The data of Laskar (1948) for German lakes,Pliszka (1953, 19538) for Polish lakes andMorozova (1952) for the Aral Sea suggestthat bream, feed most intensively frOm Juneto August. According to Pliszka et al.(1951), however, in the Vistula there aretwo feeding maximatin November and May, andtwo minima, in'January.and'July; the laiteris connected with the level of water; feedingis intensive at a low water level.
The data of Hartley (1947), Laskar(1941, 1948), Pliszka (1951, 1953, 1953a)and Nebolsina (1962) suggest that there isa drop in the feeding intensity both duringthe spawning season and in winter. Theobservations of Ziemiankowski and Cristea(1961) suggest that bream feed at a
temperature of 0.5°C, but in the GorkiReservoir Zhiteneva (1960) noticed thatfeeding stopped in October at a temperatureof 4 5 C and in 1958 bream stopgedfeeding at a temperature of 8 9 C.
- Abstention from feeding.
During the epawning season breamhardly feed (Morozova, 1252; Pliezka etal., 1951). Ivlev (1955) studied theeffect of starvation upon the biologicalreactions in fish. The data (Fig. 9) referto bream weightz 0.32 g. Starvationclearly diminished the resistance to waterpollution (phenol) and infection withmould (Saprolegnia).
3.42 Food.
Data on bream food are numerous..Laskar (1948), Shorygin (1952), Aristovskaia(1954) and Pankratova (1948) made lists ofappropriate references. Table XIII and
Fig. 7 show the most important foodcomponents of bream.
Many authors confirm the pattern offood oomposition (Egereva, 1962; Volgin andVertinin, 1964, and others already quoted).
Annual changes in food compositionwere observed in lakes (Pliszka, 1953,19538) and brackish waters (Shorygin, 1952).It is believed that they reflect changes inavailability of food animals. Thisexplanation may be applied to differencesin the food of bream in diverse biotopes,and in various years in reservoirs(Aristovskaia, 1954; Ivanova, 1960;Kogan, 1958; Zhiteneva, 1960.)
Detritus, or mineral particles fromthe bottom, are almost always found inbream feeding on demersal fauna. They maymake up to 80 - 90 percent of the contentaof the digestive tract by weight (Bogntova,1963; Shorygin, 1952). Gomazkov (1959) andAnanitchev (1959) discuss detritus as asource of food for bream. They concludethat detritus cannot be sufficient food forbrean although it contains comparativelylarge amounts of vitamin B12. The partplayed by bacteria is not clear.
The daily food intake (as percentageof body weight) is 19.5 percent in ponds,38.4 percent in aquaria for email breamand 5 9 percent for big ones. The annualfood requirement is the body weight times15 (Zheltenkova, 1964).
Karzinkin (1952) found in experimentsthat one-year-old bream had a daily foodintake of 5.7 percent of body weight inJune, 10.1 percent in July and 6.6 percentin August. During 92 days the bream ate16.5 times its weight at the beginning ofthe experiment.
Kogan (1963) estimated the daily foodintake of bream in the Tsymlanskoe Reservoiras 2.5 3 percent of the body weight duringsummer. Nebolsina (1962) obtained a similarresult of 2.5 peroent for the bream of theVolgograd Reservoir. Shorygin (1952)reported the daily intdke to be 7.4 percentin the oase of bream aced one-plus in LakeGlubokoe; the annual intake was equal.to15 times the body weight.
3.43 Growth rate.
The growth in length and body weightof many bream populations has beenestablished during the last 50 years. Mostdata were obtained from scale reading and
FR1/S36 Abramis brama 3:31
100
90-
80-
70-
60
50
40-
30-
20-
10-
0 5 15 20 25 30 35 40body length cm
Figure 6. Food composition of Caspian bream,changing with growth (afterShorygin, 1952).
3:32 FRi 536 Abramis brama
Fi/s36 Abramis brama 3:33
ut
OroBer Planer Lake
IV VI
Oberer Ausgraben Lake
VII
VII XII-XIV Age groups
Crustocea
other food organismsfitorol and sublitoral
OEM Procl2dius c7.gm Tendlpes sp
Figure 7. Food composition of bream from two eutrophio lakes(after Laskar, 1948).
IV VI
3s34 FRi/536 Abramis brama
100
90
80
70
60
50
40
30
20
10
./.
I I III IV V VI vr 111 IX XXI XII III IV V VI VI VII IX X XI XI
1939 1940
Figure 8. Variation in feeding activity in the course of the years 1939 and
1940. Percentage of fish containing food (after Hartley, 1947).
0,9
0,8
0,7
0,6
0,5*:6
0,4
0,3
0,2
0,1
o
Time to SO percent.mortality days
30 50'' 70 90 110 130 150
0 10,0 20,0 30,0 40,0Loss in individual weight,percent
Figure 9. Loso in weight (solid lino) and time to50 peroent mortality (broken line) inbream in relation to the "feeding level"expressed as proportion of maintenanoefood ration (after Ivlev, 1955).
FR1/836 Abramis brama 3:35
3:36 FRi/S36 Abramis brama
Table XIII
Food of bream
Water body Food components Remarks Author
Northern Cumacea, Corophiidae Shorygin, 1952
Caspian Sea Adacna (69 percent by weight)
Tendipedidae, Polychaeta
Gammaridae, Mysidae
Monodacna, Oligochaeta
Volga River Tendipedidae, Oligochaeta Pankratova, 1948
Corophiidae
Vistula River Tendipedidae, Oligochaeta Pliszka et al., 1951
Tipulidae
Danube Delta Tendipedidae bream Botnariuc and Spataru,1963
floodedareas
Nematode, Copepoda 6.2-37.5cm long
delta itself Tendipedidae, Mollusca
Ivankov Tendipes sp. up to 94 percent summer Zhiteneva, 1958
Reservoir Mollusca 10-61.8 percent food
Oligochaeta 10-76 percent
Volgograd Tendipedidae, Oligochaeta Nebolsina, 1962
Reservoir Mollusca
Gorky Zooplankton 33 percent in Zhiteneva, 1960
Reservoir 1957; in other years
Tendipedidae, Oligochaeta,
Mollusca
Tsymlianskoe Tendipedidae, Oligochaeta Kogan, 1958, 1963
Reservoir Mollusca
back calculations and they should betreated with caution. Numerous data onthe growth rate of bream in European waterscan be found in the works of Balon (1962),Bauch (1963), Berg (1949), Geyer (1930,Hartley (1947), Karpifiska-Walufi (1961),Segestrále (1932, 1933), Shaposhnikova(1948) and Wundsch (1939).
Table XIV presents some available datato show differences in growth rate of bream.It is possible to distinguish two principaltypes of bream growth. The first isrepresented in Fig. 10 by the curve of thegrowth rate of bream in the Ural River deltaand the Sea of Azov; in these cases, a highgrowth rate during the first 3 - 4 years isfollowed by a pronounced slowdown at the timeof attaining sexual maturity. The secondtype of growth rate is shown in Fig. 10 bythe data referring to Lake Tuurula, Gr.Plbner See and averages for Polish andGerman lakes; here the growth rate isapproximately uniform, and there is noslowing down after sexual maturity isreached. This type of growth is commonin the water bodies of Central and NorthernEurope.
Vasnetsov (1934) regarded the firsttype as representative of bream. Hedefined the relative growth index or "growthcharacteristic" as
log lt - log lt_i
i.e. the difference between log of lengthat age t and log of length at age t 1,
times length at age t 1. He consideredthe growth of bream to show two periods inmost cases: the first, or juvenile, withrapid growth, and the second, after sexualmaturity is reached, with low rate ofgrowth. The data of Fig. 11 give thevalues for the "growth characteristic"index for three bream populations ofvarious growth rates. Sharp differencesin the index can be observed most frequentlyin the populations from the southernmostareas of the species distribution (Balon,1963).
The relation of weight to age ispresented in Table XV for three breampopulations. For length/weight relation,.ship, Hartley (1947) gave the formulas
3.296W 7: 0.0065 L
for fork length of bream from English waters.Fig. 12 presents a relationship between body
weight and length for bream from LakeGodopiwo, Poland, after Karpifiska-Walug(1961), and data referring to a number ofother water bodies. These show a similartrend, although they represent extremelywidely separated populations with differentgrowth rates. This confirms the opinion ofGeyer (1939) and Wundsch (1939) on a closecorrelation between body length and weightin bream, irrespective of growth rate.
The Fulton condition index does notshow any greater differences in the case ofpopulations from different lakes and ofdiverse growth rate. For instance,according to Savina et al. (1964) the Fultonindex for seven lakes situated in the north-western part of the USSR varies from 1.73in Lake Tiosto to 1.90 in Lake Ilmen.Shaposhnikova (1948) gave the Fulton indexas 2.20 for the Volga, the highest valuebeing for three-year-olds, 1.8 - 2.4 forLake Itkml, 2.00 - 2.21 for the Dneper delta.Other authors give similar values for breamfrom a number of water bodies, (inShaposhnikova, 1948). Starvation formsare, however, also known among bream, whenbody proportions and'condition deviate fromthe mean (Ullmann and Mann, 1957).
No correlation has been found betweengrowth rate of bream and limnological trpeof lake (Zawisza, 1961). Wundsch (1939stated that when comparing the growth rateof different populations of European breamit was impossible to find any dependenceon the geographic position or climaticconditions. Shaposhnikova (1948) alsoreported that the.geographic position of awater body and climatic conditions arerather secondary factors, the effects ofwhich may be alleviated by food abundance.The growth rate in different areas isshown in Fig. 13, from the work ofShaposhnikova (1948), supplemented by datafrom other authors.
The following classification of growthrate of bream follows JErnefelt (1921),Geyer (1939 and Wundsch (1939):
FRi/536 Abramis brama $237
0.4343 t -1
3:38 11/036 Abramis brama
Finnish lakes
German lakes
Polish lakes
Azov Sea
Caspian Sea
In addition, a class of "very good" growthrate has been introduced, after Shaposh-nikova (1948), to denote those populationswhich reach the length of 31.5 am at the ageof five-to-six years and the weight of 1 kgand body length of 37 cm at the age of six-to-eight years. Such growth rates have beenobservad not only in estuaries and brackishwaters of southeastern Europe but also in theBodensee (Haakh 1929, in WUndsch, 1939), theVistula Lagoon (Filuk, 1957) and among survi-vors in smaller lakes after winter-kill (Kar-piAska-INalud, 1961).
A number of authors, from Järnefelt
Temperature
Combination of factors
Food abundance, combination
of factors
Food availability, length
of growing season
Abundance of bream and food
availability
(1921) to Laskar (1948), have drawn attentionto the dependence of growth rate upon thequality and quantity of food. This is verynoticeable in retention reservoirs during thefirst period of their existenoe (Elizarova,1962; Iliina, 19601 Márketova, 1958;Shaposhnikova, 1948). But in lakes no olear-cut correlation between the abundance of theprofundal fauna food and the growth rate Ofbream can be established if other factors arenot taken into consideration (Wiandsch, 1939;Karpiriska-Walud, 1961; Zawisza, 1961).
Some other opinions concerning growthrelations may be summarized as follows:
Segestrgle, 1932
Geybr, 1939
KarpiAska-Walud, 1961,
Zawisza, 1961
Dementeva, 1955
Zemskaia, 1958, 1961
Age (years) at whichRate of standard (total length weight of 1 kg andgrowth at age 9 ( standard length of
37 cm aro reached
good 31.5 (37.5) before 11
medium 25 - 31.5 (30 - 37.5) before 14
poor less than 25 (30 ) after 14
Stock in: Factors affecting growth: Author:
1111/536 Abramis brama
Liengthite *f.rni
SO
60
3$
,C.Malsolealr
/30 ri iflor /2$
d .gew 3/
20
se //IS
.0* 3416---4
10 5 o 0fa'
XV
Figure 10. Growth in length of bream from some waters:1. Ural River, 2. Sea of Azov, 3. GrössePlöner Lake, 4. Average from 244 lakei ofPoland, 5. Average from 36 lakes of NorthernGermany, 6. Tuusula Lake, Finland.
XX AO*grou
3:39man .¢1,2*
Table XIV
Growth of bream (standard length) (cm)
Age group
IIII
IIV
VV
IV
IIV
III
IXX
XI
XII
XII
IX
IVX
VX
VI
XV
II X
VII
I X
IXAuthor Remarks
Lakes
Madingley Lake,7.63
England
Bodensee,
Switzerland-
Germany
Gr. Plöner,
5.1
Germany
Ob.Ausgrabensee4.9
Mfiggelsee
Average from
4.7
36 North German
lakes
Havgardsjön,
5.9
Sweden
Hg1maren,
2.9
Sweden
Onkamo,
5.2
Finland
Tuusula,
2.2
Finland
Average from
4.8
14 Mazurian
Lakes, Poland
Odwin, Poland
4.8
Wadag, Poland
4.3
inin Du;y, Po1.5.7
limen, USSR
6.5
Itkul, USSR
Samoziero,
3.4
Karelia
Ladoga, USSR
6.5
Rivers
Vistula near
5.6
Warsaw
Vltava near
6.2
Praha
12.77
15.8
8.9
8.2
7.8
11.6
6.1
9.6
4.1
8.6
11.5
6.3
10.2
12.0
6.9
9.8
9.8
10.3
14.0
19.5
13.3
10.3
11.0
11.7
16.7
9.1
14.8
6.0
11.6
18.0
8.9
15.2
16.8
22.5
9.6
13.7
13.6
14.6
21.4
24.1
20.0
12.9
13.3
14.8
22.0
12.2
18.8
7.8
15.0
23.8
11.4
20.3
21.3
29.0
13.6
18.0
17.1
16.5
25.33
30.1 32.8
21.3 27.4
14.7 16.0
16.6 17.8
18.0 20.4
26.3 29.3
15.0 17.4
22.4 25.9
9.8 11.8
17.9 20.5
14.0 16.0
24.6 28.5
25.2 29.0
33.2 38.0
16.2 22.5
23.8 27.7
20.0 23.3
21.4 25.0
38.7
31.8
18.0
19.4
23.6
32.1
20.0
30.0
13.9
23.5
19.2
33.4
32.7
40.5
24.9
29.0
27.5
39.9
32.8
21.2
20.8
25.9
34.5
22.3
33.5
15.9
27.5
22.4
37.3
36.1
44.0
26.5
32.0
30.5
42.4
35.0
23.3
23.2
28.8
37.3
24.7
36.0
18.5
24.0
39.8
39.1
47.0
29.5
33.6
33.3
43.7
40.7
27.2
24.7
32.8
39.0
26.8
39.3
20.5
25.7
41.5
41.8
52.5
32.6
37.8
35.8
45.8
45.9
31.4
35.2
40.7
29.6
42.3
22.0
28.0
43.3
44.2
34.9
40.0
38.5
47.0
48.0
35.5
35.2
42.8
31.8
44.2
23.7
30.5
46.0
37.3
48.6
35.5
44.1
32.2
25.2
32.9
47.7
38.9
27.9
42.5
44.5
30.5
43.1
32.5
45.0
35.5
48.8 50.9
Hartley (1947)
total length
Haakh (1929) in
Wundsoh (1939)
Geyer (1939)
Geyer (1939)
Wundsch (1939)
Bauch (1963)
Alm (1920 in
Wundsch (1939)
Alm (1917) in
Wundsch (1939)
arnefelt (1921)
Jarnefelt.(1920
Karpifiaka-Waltie
(1961)
(After winter-kil
(Data of Inland
(Fisheries Inst..
(Poland
Berg (1949)
Berg et al.(1949)
Balagurova (1963)
Balagurova (1963)
Zawisza (1951)
Oliva (1958) in
Balon (1963)
cr.
Danube near
5.3
10.6
16.7 20.8 23.9 26.9 29.4 31.7 33.1 35.5 39.5
Xedvedovo
Danube delta 11.2
18.4
24.7 29.7 34.2
Dne
per,
8.1
14.9
21.5 27.6 32.7 35.8 38.1 39.9
middle course
Dneper delta
8.6
16.4
25.2 30.3 34.7 38.6 41.2 44.6
Niemen,
USS
R6.7
13.6
20.8 26.9 32.1 36.4 40.3 45.2
Volga near
4.6
9.3
14.1 19.3 24.3 28.4 31.8 35.0 37.2
Kuybyshev
Ural delta
7.6
19.7
27.8 31.6 33.6 37.4 38.5 40.0
Reservoirs
Ryb
insk
4.8
9.2
13.0 16.8 20.2 23.5 26.2 28.6 31.3 33.6 35.4 37.3 39.0 42.0
Reservoir
Volgograd
14.0
18.7 24.9 29.8 33.3 37.3 41.0
Reservoir
Psko
vReserv. 6.2
11.6
16.7 21.6 25.829.4 32.8 35.6 37.8 39.6 41.5 43.5 45.1
Brackish waters
Aral Sea
9.2
16.1
22.1 26.8 30.0 32.3 34.7
Cas
pian
Sea
7.1
16.1
22.4 26.2 28.9 31.4 34.6 37.5
Azov Sea
8.0
18.0
26.0 29.0 32.0 35.0 38.0 40.0 42.0 43.0
Vistula Firth
17.1
21.8 26.0 30.5 32.4 34.5 36.7 38.5 46.5 43.0 45.2 47.0 48.7
(Lag
oon)
Baltic,
4.8
11.0
14.1 17.6
21.0
23.0 26.1 30.5 33.6 37.0 37.8 38.8
Arkona
Rom
man
g,s-
2.5
5.7
Pelli
nge
Balon (1963)
U!
Papadopol (1960)
in Balan (1963)
Belyi (1948) in
Balan (1963)
Belyi p949 in
Balan
1963
Zhukov (1958) in
Balan (1963)
Shaposhnikova
(1948)
Berg (1949)
Ostroumov (1955)
Elizarova (1962)
Berg (1949)
Berg et al.(1949)
Dementeva in
Shorygin (1952)
Timofeev (1964)
Filuk (1957)
total length
Bauch (1963)
9.0 11.8 14.2 16.2 18.3 19.6 21.8 23.4 25.1 27.0 28.3 30.0 31.6 33.0 34.4 35.4 36.9 Segestrgle (1933)
XIII
XIV
XV
xvi
XVII
Table XV
Dxam les of slow, medium and fast growth of bream
Age group
11
IV
VVI
VII
VIII
IX
XXI
XII
Lakes
Tuusula
length
2.2
4.1
6.0
7.8
9.8
11.8
13.9
15.9
18.5
20.5
22.0
23.7
(cm)
(Jarnefelt,
1921
)weight
(0)
5.2
11.5
6512
2.5
168.
221
7.2
304.
534
303
Gr.Plöner.
length
5.1
8.9
13.3
20.0
21.3
27.4
31.8
32.8
35.0
40.)
45.9
48.0
(cm
)(Geyer,
1939
)weight
(g)
12.5
40.
5 17
0.0
225.
051
0.0
700
800
980
1500
2400
2850
Itkul
Berg.et
length
eni)
22.5
29.0
33.2
38.0
40.5
44.0
47.0
52.5
21.9
weight
250
595
880
1310
1700
1960
2600
3700
049)
(g)
25.2
27.9
30.5
32.5
35.
2
375
475
P575
683
950
1111/S36 Abramis brama 3:43
Growth index
6
7
6
L.
3
2
1
Figure 11. Vasnetsov's growth index: (1n 1t in lt_i)1. Ural River, 2. Tuusula Lake both from Vasnetsov(1934), 3. Charzykowo Lake (Stangenberg, 1950)calculated by Baba (1963).
2500
2000
1500
1000
500
100
-- Goldopiwo Lake Poland
2 A ItkuUlake USSR, Syberia
3 Tuusula Lake Finland
I. a Sea of Azov
S Gr Plöner Lake, N. Germany
a
o
Figure 12. Length/weight relationship in bream
45 SO Standoidiengsb,crn
3:44 FRi/536 Abramis brama
16 15 20 25 30 0
Figure 13.
Growth ratee of bream in the area of its natural distribution.
Circles
from Shaposhnikova
(194
8)Triangles
some data from Table XIV.
3.44 Metabolism.
The available data are presented inTable XVI and Figs. 14 and 15.
Kuznetsova (1958) studied the oxygenrequirement of bream from fertilization ofegg until the larvae attained a weight of2 g. According to Vinberg (1956) a roughestimate of the standard metabolism ofbream at 20°C can be obtained from theformula:
(11/ 02 mi/b/ = 0.3 w0.8
orQ2/calories/da3/= 36 w0.8
where "w" is weight in grams.
No data on active metabolism has beenfound.
3.5 Behaviour
3.51 Migrations and local movements
Bream from the estuaries of Black,Caspian and Azov Seas have been described assemimigratory. The spawning and wintergrounds of those populations are in the lowerreaches and deltas of large rivers, whiletheir feeding grounds are in brackish seaareas. Consequently two periods of massmigration are observed: spring and autumn.The spring migration of the Caspian breambegins with the melting of ice on the sea.The first group of bream start their up-stream migration at the beginning of April,while the second and larger run lasting for15 30 days begins when the water of theriver reaches the temperature of 80C.
After spawning, bream return to the seaand disperse to feed. They school at theend of July and in August. The autumnmigration in the northern part of the CaspianSea begins in August and reaches its peak inOctober. Bream spend the winter in thedeeper parts of rivers, not far from theplaces where they discharge themselves intothe sea (Dementeva, 1952a; Berg in Berg etal., 1949).
Only a part of the bream population ofthe Aral Sea spawn in rivers, while the restspawn in the areas surrounding river mouths.In March April bream ap ar in coastalareas to breed. After spawning, bream moveto marine feeding grounds and return to theshore in September October. In Decemberbream aggregate near the Syr and Amur-DariaRivers (Morozova, 1252). Velikokhatko(1941, in Berg 1949) distinguishes two formsof Dneper bream: a "winter" form whichmigrates up to 100 upstream and "spring",fish which occur in the lower reaches of the
river. The runs of the "winter" form beginin autumn, at the end of September and inOctober,'and they last all through the winter.The "spring" form is not so numerous as the"winter".one and starts its migration inspring. Young bream reaohing the length of25 30 mm swim seaward.
The results of tagging carried out inGerman rivers and in the middle Vistula(Pliszka, 1951) prove' that most of thepopulation does not migrate for longdistances. Similarly, the observations ofSakowicz and Baokiel (1953), on the migrationsof fish along canals linking lakes with densebream populations, did not reveal any olearcut migratory trends.
Within particular lakes, however, thereoccur local migrations which in some degreeresemble those of semimigratory bream ofthe NorthEuropean big river estuaries.Driagin (1949) describe& the spawningmigration of bream from Lake Pakovsko, USSR,to adjacent rivers. .Tagging was carried outin Lake Sniardwy, Poland, (unpublished dataof the Inland Fisheries Institute in Olsztyn)on a spawning ground where they were veryabundant. Tagged fish were caught on feedinggrounds over the'whole lake in summe4 andthey were found on a thering ground inwinter, when 40 tons of bream were taken inone seine haul.
3.52 Schooling.
Bream school in early stages of their.development (Vesnetsov et al., 1957) afterreaching the length of ITmm (Paiusova,.1961).These schools or aggregations, known also as"elementary populations" (Lebedev, 1946),differ in individual size, size distribution,condition factor and degree of infestationwith metacercariae. Paiusova (1961) observedseparate aggregations of young bream for twoweeks. The behaviour of those bream was notobserved. Observations on bream in anaquarium suggest that they school whenexcited and they scatter for feeding.Ohlmer and Schwarzkopf (1959) proved that theswimming velocity of bream studiedindividually increases with their length,from 0.66 m/sec. when they are 12 16 emlong to 0.90 m/seo at the length of 24-28 am.Bream, when studied in a school, swam 0.650.68 m/seo irrespective of their length'(cf. also section 3.51).
3.53 Responses to stimuli.
Bream are able to seo light of wave-length 400-710 mg, their greatest sensitivitylying between 600 and 630 mp. At dusk theyare most sensitive to rays of 540 mg. Thenumber of pictures a bream can distinguishin one sec is 55 (Radakov and Protasov, 1964).
3: 6 FRi S36 Abramis brama
Table XVIRespiration rate of bream
weight(days) 0 consumption AuthorAge (g)2
Embryo
Larvae
0.655 mg/h/g
mm3/h/10 larvae
Kuznetsova,1958
Nikiforov,1953
20 0.080 0.84
25 0.100 0.38
30 0:120 0.42
45 0.210 0.42
60 0.200 0.42
Older bream at to = 20oO mg/h/g Ivanova,1939
38.7 0.177 in Vinberg,1956
69.5 0.165
102.9 0.114
3:47FRi/S36 Abramis.brama
Figure 14. Metabolio rate of bream and temperature(from Vinberg, 1956, after Bogdanovaand Streloova, 1953).
FRi 336 Abramis bram
FRi/836 Abilimis brama 3:42
11112.49.041 elreppplepl
2 4 6 8 10
Oxygen content, mg / liter
Figure 15. Respiration rate of bream and oxygen contentof environment at 20°C (from Vinberg, 1956).
The reaotion to light changes with age.Privolnev (1956a) found that bream youngerthan 15 days shun strong light, from the15th to the 20th day-of their life they gotmore photophilous, and they a in avoidlight when they are 40 days old.
A positive rheotaxis wee observed byAslanova (1952) among bream 4.5 - 5.5long, when the water current was 3.32 opfsec.Bream aged two-to-six years, which were24 - 35 am long, took an upstream positionin flow rates of 4.54 - 8.46 cm/sec.
A drop in the oxygen content of waterto 1 or 1.5 mgil caused bream to leave thatplace and search for another where theoxygen content was higher (Alabaster andRobertson, 1961). Privolnev (quoted byVinberg, 1956) observed restlessness amonebream at an oxygen content as high as2-2.5 mg/l.
Bream of the southern region of itsdistribution avoid salinities higher than12.9 %o (Karpevich, 1955).
According to Lenkiewicz (1964), Youngbream of 6-10 cm, studied in November andaoclimatized for one-to-five days at7-8°C, showed a preference for water oftemperature 9-19°C (avera 13.75°C); but
when acclimatized at the temperature of14-25°0 they preferred a higher tem rature,
from 13-24°C (average 18.9°C). Bream bredin an aquarium at room temperature for 6months showd a preferenoe for temperaturesfrom 26° to 28°0 (Roroszewicz, unpublisheddata).
The bream is sensitive to direoteleotrio current of field intensity equal to0.66 V (Bodrova and Kraiukhin, 1959). Atthe intensity of 3.64 V eleotronaroosistakes place. The reaction to alternatingcurrent (Shentiakov, 1964) begins with fintwitching at about 0.46 - 0.77 V, head-to-tail voltage ("Gestaltspannung" in German,denoted by UR).
As the electrio field strength grows,the twitching of fins inoreases, there arebody jerks, uneasy swimming around, thensudden swimming for long distanoes andconvulsive movements of the body. Shook ortautening of fins and the whole body,twitching and at last complete immobilitytake place at UR o 2 to 3.5 V, depending onthe body length, at the water resistanoe3035 Ohm/am.
3:50 FRi S36 Abramis brama
FRi 536 Abramis brama
4 POPULATION
4.1 Structure
4.11 Sex ratio
Available data are presented in TableXVII. In the oatohable populations femalesusually predominate. It may be assumedthat the same is true of the population as awhole owing to the greater mortality ratoamong males (Alm, 1959). In older agegroups the proportion of females keeps in-oreasing.
During the spawning season far moremales are taken and up to 80 percent werereoorded by Shaposhnikova (1948). This isbecause males remain longer on the spawninggrounds (of. section 3.16). In bream ag-gregations observed in the Sea of Azov,called "elementary populations" by Lebedev(1946), the sex ratio varied widely, rangingfrom 48 to 80 pereent of females. To sumup the available datas
the ratio among young bream is closeto 1 : 1;
the number of males declines fasterthan that of females as bream grow older;females predominate in older age groups;
in the spawning aggregations usuallyfemales predominate before spawning whereasmales are more numerous during spawning;
in feeding aggregations the ratiovaries.
4.12 Age composition
Table XVIII exemplifies age compositionin bream catches. Populations from northernwaters (Siamozero) are composed of more agegroups than those from southern waters.
The composition of a population variesfrom year to year, particularly in heavilyexploited populations (e.g. Caspian Sea)owing to considerable variations in theabundance of different generations (Fig. 16).
Age at first capture is frequently two-to-three years (Table XVIII). In the lakesof northern Poland it is five-to-six years.
The average aae of bream caught in thenorthern Caspian Sea (LUkashov, 1961) was
4.5 in the years 1937 - '48 and 3.6 in the
years 1953-' 58. In the Sea of Azov itranged from 4.5 to 5.5 in 1939-'47.
The most abundant age groups of breamcaught in northern waters are:
'Siamozero 7 - 12 years
Vistula Lagoon 3- 8 years
Vistula River 4- 6 years
Lakes of Northern Poland 6 - 10 years
In the Danube estuary 76 percent of thebream caught are two years old (Popescu,1958),
The age composition in the populationscaught varies in the course of a year, asshown in Table XVIII for the Caspian Sea.In spring, older individuals are usually ta-ken in spawning aggregations.
Age at maturity - cf. section 3.12
Maximum age - cf. section 3.31
4.13 Size composition
The composition of bream populations inlength groups are illustrated by the data efDementeva (1955), for catches with a gearcalled "lampara" in the Sea of Azov. Thecatches comprise individuals ranging from5 to 51 am in length (Fig. 17). The varia-tions in the size composition are in agree-ment with the variations in age composition(cf. section 4.12), so that bream 7 cm longdominated in the Sea of Azov in 1948, whilebream 27-35 am long were predominant in 1952.In commercial catches from various waters thelength of bream was as followsz
Nogat River 28 - 57 cm body length(Vistula estuary) (Badkiel unpublished)
Vistula Lagoon 15 - 60 cm total length(Filuk, 1957)
Elbe River 22 - 57 cm total length(Bauch, 1958)
21 - 38 cm total lengthDanube estuary(Popescu, 1958)
Size at first capture: cf. section 6.12.
The average lengths of bream caught invarious waters vary, due to differences inthe abundance of generations, variations ingrowth and also exploitation.
In 1929-'39 the average length of breamcaught in the Volga Delta ranged from 24.5 -31 cm (Dementeva, 1952) due to variations inthe abundance of generations. A decrease inthe average length of bream caught today, ascompared with bream caught during the MiddleAges and in prehistoric times, has been ex-plained by changos in the methods and inten-
Danube River,Czechoslo-vakia
Volga estuary
Volga estuary
Volga estuaryand Azov Sea'
TABLE XVIISex ratio in bream populations
special collec-tion
young breamcatch, age 1 and2
spawning popula-tion in autumn
commercial catch,age group:
3
456
78
abt 50.0
abt 50.0
53.0
Balon,1963
Berg,1949
Berg,1949
Dementeva,1952
LocalityData
obtained fromPercent of
femalesAuthor
Szczecin commercial catch 63.8 Pecza1ska,1963Firth, 1956-1959Poland
SzczecinFirth
commercialcatch, agegroup:
P9cza1ska,1963
2 43.33 55.94 70.5
5 59.76 61.67 60.08 65.0
9 64.010 70.0
11-15 78.'7
German lakes abt 50.0 Wundsch,1939
Vistula RiverPoland
commercial catchage group:
Zawisza,1951
3 46.04 39.05 48.5
6-10 55.5
42 FR1/S36 Abramis brama
28.6
45.364.078.2
87.5100.0
Table XVIII
Age c.,mposition of bream in catches
ercent
*Note that the total catch increased rapidly:
1953
-00.2 ton;
1954 -
6.00 ton;
1959
-120.90 ton
Locality
oups
t-;
Author
a2
34
79
10
11
12
13
141 15
16
17
18
19
Lake SiamozeA), Ka-
relia, USSR
Vistula Lagoon, Po-
land
Vistula Estuary,
Poland
Elle River,
middle course, Germany
Danube River, Czecho-
slovakia
Vesolovskoe Reservoir
on Don River, USSR
*J
1953
1954
1959
Southern Aral Sea
1939
1947
Estuary of Terek Ri-
ver, Western Caspian
Sea, USSR1947
Northern Caspian Sea
1933 autumn
1934 spring
1935 autumn
1936 spring
1951 spring
1951 autumn
Lake lasa, Turkmen
SSR
0.2
7.0
2.7
3.6
25.5
1.0
2.4
0.2
0.3
7.7
10.0
0.4
25.1
0.8
39.9
62.7
64.8
22.0
5.5
71.2
91.0
8.2.0
2.3
0.8
13.8
49.1
40.0
0.2
14.1
0.6
5.1
6.8
20.5
8.3
67.0
52.9
2.0
17.2
6.2
13.9
13.7
25.2
12.1
11.1
31.0
0.2
9.1
4.0
24.5
24.5
11.4
0.7
9.0
36.7
56.3
10.1
0.4
2.0
81.5
72.4.
64.5
25.6
19.0
2.4
10.2
49.9
25.5
8.4
4.5
31.7
1.1
0.6
2.5
1.4
6.5
4.4
7.8
8.8
21.9
28.8
7.3
0.3
709
1.2
0.1
1.1
0.9
13.9
6.7
15.8
8.5
3.6
0.1
1.5
0.1
0.6
0.4
25.9
6.0
2.5
3.4
2.7
0.3
0.8
0.7
16.9
3.7
2.2
3.4
1.6
0.3
0.3
8.1
2.1
0.6
0.9
6.2
0.9
1.9
0.5
4.6
0.7
0.5
5.9
0.1
0.5
2.2
0.1
2.5 1.9 0.5 0.2 Balagurova, 1963
a ti J-. e
Filuk,1957
a 1 wBackiel,(unpublished)
Bauch,1958
Balon,1963
Kruglova,1961
Berwa1d,1956
Demin,1962
Dementeva,1952
Berdichevskii,1961
Nikolskii,1953
1042
rfl Sim1943
IJ Lamm.2 3 e0 0 7 0 0 10
Age
Figure 16. Age oomposition of bream oatehes in VolgaEstuary (after Dementeva, 1952),
Age
2 3 4 S$7 SI1931
20
1932
ÍL1033
I
1034
:21I1935
rma
1930
PRi S36 Abramis brama
FRi 536 Abramis brama
20
10
20
10
20
10 1949
i ' ' 2135.2933 37 6.1.41:
20
10
SIZE COMPOSITION OF BREAMIN AZOV SEA
(after Dementeva 1955)
117 ?I 15 19 23 27 31 35 39 43 47 cm
Figure 17. Size composition of bream in Azov Sea(after Dementeva, 1955).
1952
20
10
sity of exploitation. So, for example, ex-cavations from the first eight centuriesA.D. revealed that the average length ofbream from Lake Pskovskoe was 39.6 am,whereas the average for 1951 is 33.1 cm.Excavations in the vicinity of Lake limenfrom VII to IX centuries A.D. revealed theaverage length to be 42.4 am; today it is30.5 am (Nikolskii, 1958). Similar tenden-cies have been observed in bream from theSea of Azov (Nikolskii, 1958), the averagelength being:
5,000 years ago, about 36.0 am
According to Tsepkin (1964), 'bream ave-raging from 28.9 to 29.5 am mere caught in.the VI - XI centuries A.D., in the estuarYof the Amu.7Daria River, where it enters theSea of Aral. It must be stressed that 5,000years ago bream comprised only two percentof all catches, whereas today they amount tosome 39 percent.
Size at maturity cf. section 3.21.
In lakes, adult bream inhabit deeperregions. In the shallow coastal waters oflakes only young :bream, about 4 cm long, arefound, and these occur only in small numberseven in the vicinity of spawning grounds(Backiel, 1953). In running water, largerbream avoid shallow places. They move todeeper waters within one month of hatching(Backiel, 1958).
The same applies to the Volga (Demen-teva, 1952a; Tanasiichuk, 1952, 1959), andto the Amu-Daria and Syr-Daria (Berg, 1949)where young bream move to deeper water andto the brackish water of the estuary. Asearly as July, bream about 2 cm long havebeen found in brackish waters (Dementeva,1952a; Paiusova, 1961; Tanasiichuk, 1952).The data concerning the age distributipn inautumn and spring catches in the Northern
1947 1948 1949 1950 1951
18 13 12 10 10
96 130 40 40 66
Caspian Sea (Table XVIII) ehaw'differencesin bream size in various places and seasons,connected with spewning migration.
According to Berg (1949) the maximumweight of bream is 11.55 kg. Toner (perso-nal communication) reported that a 5.3 kgbream has been caught in Ireland. Bauch(1958) gave 8 kg as the maximum weight inthe Elbe River. Lebedev (1961) mentionedthe length of 74 cm as the maximum forbream, (cf. section 3.31).
4.2 Abundance and density
4.21 Average abundance
No information is available on any at-tempt to estimate the abundance of bream bytagging or from data on fishing effort andcatch. Karpevich (1955) estimated the so-called "Promyslovyi zapas" (available cam-
_
'mercial stock) of more than three-year-oldbream of the Sea of Azov to be 39.4 million_ _
:fishes in 1947 and 47.7 million fishes inA949-'50. The areas where bream gccured were17,000 - 18,000 km2 and 10,000 km' respeo-tively. Therefore it is possible to calcu-late that average numbers of bream older thanthree years were 22 per hain 1947 and 48 per,ha in 1949 and 1950.
4.22 Changes in abundance
Changes in abundance caused by hydro-graphic and other conditions were studied inthe Sea of Azov by Maiskii (1955). He esta-blished the area where bream were present,and then the relative density was found invarious places of that area by means ofcatches made with a net called "lampara",which can take fish from 5-50 cm long. Thenumbers of fish caught are an index of rela-tive abundance, acCbiding to the author. Theresults were as follows:
in 1925 " 34.3 am" 1929 " 31.0 cm" 1955 " 29.4 am
Year 1937 1940 1946
Area wherebream werefound(thousand km2)
22 20 15
Relative abun-dance(million fish)
161 62 120
4:6 PRi/536 Abramis brama
A shrinkage of the area of occurrence,and consequently a drop in abundance, werecaused, according to Karpevich (1955) andMaiskii (1955), by an increase in the sali-nity of the Sea of Azov, as a result of flowregulation of the Don River where retentionreservoirs have 'breen built.
Tanasiichuk (1952), Dementeva (1952a)and Koblitskaia (1961) have pointed to thedependence of the abundance of young breamon the water level of the Volga delta. Ahigh, although not disastrous, water levellasting for 12-15 days during bream spawning,and egg and larval development and then alowering of the water leve/ favour the deve-lopment of a numerous generation. Romany-chova (1958) noticed a similar correlationbetween the strength of year-Classes in theAral Sea and the water level in the Amu-Daria,River. His suggested explanation is that.a_high ,water_levelmakes bream more difficultto caich and therefore more bream reach thespawning grounds.
Changes in hydrological conditions andan increase in the water area resulting fromthe building of retention reservoirs gene-rally cause a,rise in the abundance of bream,both in absolute and relative numbers(WUndsch, 1949; Badkiel, Kossakowski andRudnicki, 1956; Alkolskii, 1948; Sebentsovand Meisner, Mikheev, 1953; Vasilev, 1956).
The following four reservoirs may serveas an examples
Reservo ir
In all these water bodies the catches ofbream increased with the lapse of years.
Year of fisheryexploitation
Pape (1952) drew attention to the un-desirable effects of river bed correctionupon the population of bream. He was con-vinced that a drop in catches (mainly bream)in the Elbe from an average of 56.6 kshilaabetween 1896 and 1928 to 18.5 kg fish/ha wascaused largely by cutting-off or destroyinglentic environments and by pollution. Bauch(1958) was of a similar opinion. Hydro-graphic conditions should be accepted,therefore, as one of the most important fac-tors influencing the abundance of bream.
Nikolskii (1954) drew attention to theeffects of climatic changes and stated that5,000 years ago bream were the main fish inthe catches in the drainage basin of theWhite Sea; and now they are caught there innegligible amounts. The retreat of breamfrom those waters is connected with coolingdown of the climate.
- Biotic factors.
Competition for food is mentioned as animportant factor but no reliable data areavailable (cf. section 3.33). Tanasiichuk(1952) stated that a decrease in the popu-lation of Blicca bjarkná L. in the Volgadelta favours a better survival of bream.
Predation on bream is inconsiderableand cannot really affect the changes inabundance (cf. section 3.34).
An invasion of parasites can have se-
Percentage in catches
Möhne, to 12th year very lowWestfalen(highland) 12th - 14th. years up to 8.3 percent
gtmuch6w, 1st -, 4th years 1.0 percentSlask, Poland(lowland) 13th - 20th years 75.0 - 90.0 percent
Kutuluk, 1st - 5th years considerable amounts ofMiddle-Volga, youngUSSR(lowland) 8th - 10th years 34.0 - 42.0 per cent----- o o m ------ o o o o o ......... o o o o o o oRybinskoe,USSR(lowland)
FRi/536 Abramis brama 4:7
1945 9,5 percent
1951 35.8 percent
4:8 FRi 536 Abramie brama
rious effects (cf. section 3.35).
- Effects of exploitation.
A break in bream exploitation in thegroup of "Siamozero" lakes in 1940-'42caused an increase in the abundance of 1941-'43 generations (Balagurova, 1963). An in-crease in brean catches in Polish lakes du-ring the years 1958-65 was partly due togreater legal sizes and stocking (Zawisza, inBackiel, 1965).
According to Dahl (personal communi-cation), brean in Danish lakes is underfishedand therefore numerous. Hofstede (personalcommunication) is of a similar opinion con-cerning Dutch waters.
The importance of exploitation in thechanges in the abundance of fish, includingbream, is commonly accepted.
4.23 Average density.
From the.data quoted by Karpevich (1955)it has been calculated that in the Sea ofAzov there were 22 individuals/ha in 1947 and
48 individuals older than three years in 1949-150. The average yield was 6.6 kg/ha (TableXIX).
Data presented in the table show diffe-rences in the average density of a breampopulation. The intensity of catches is notknown, and therefore water bodies exploitedin a similar way for a long time have beenselected. Thus it may be assumed that dif-ferences between catches result from dif-ferences in population density.
The differences are even more distinctwhen a group of 238 lakes exploited in Po-land is taken into consideration (Leopold,data Inland Fisheries Institute). This ape-cies was not taken at all in three of thelakea, and the amount of bream caught in theremaining lakes was as follows: In 27 lakes
(11.3 percent) less than 1 kg/ha; in 26lakes (10.9 percent) 10-20 kg/ha; in 3 lakesit was higher than 20 kg/ha, the maximumyield being 27 kg/ha; in the remaining lakes(76.5 percent) the yield was between 1 and 10kg/ha. The average yield per ha, which to acertain decree supplies information on the
density of bream, does not depend on the areaof a lake (Leopold, personal communication).
4.24 Chances in density
Catches per unit of fishing effort withvarious types of gear are very diverse inthe lakes of Northern Poland. Average valueeare presented in Table XXIV (Section 5.41).
The catches near the Volga delta in theCaspian Sea per 100 gill nets are given byDementeva (1952); they vary with the region:
Region Western Central Eastern
kg/100 nets 0.9-2.2 3.7-23.4 in single casesup to 5.0
In the Volga delta, the farther from the seathe lower catches per unit of fishing effortwere reported, e.g. in 1937:
Delta region Lower Central Upper
kg per 218.52 44.61 6.69Seine haul
Tanasiichuk (1952) included the results ofcatches made with a fry trawl in the NorthernCaspian Sea and information on salinity:
The few examples mentioned above illustratethe enormous variability in the bream popu-lation density in fresh and brackish waters.
Seasonal variation of available stock isshown in Table XXIII. This variation is a
Salinity No. of Bream per hour
o
trawling
903
10512
10633
2364
2105
2656
2517
3758
239
610
12111
10612
2413
714
o15
o16
Table XIXAmount of bream caught per ha of some water bodies
Water bodyBream inkg/ha
Percentage ofbream in total
catchAuthor
Sea of Azov 6.6 9.1 Bervald,1952
North-Cas pian 4.1 13.0 Bervald,1952
Aral Sea 1.8 36.0 Bervald,1952
Siamozero,Karelia,USSR
Ijssel Lake,
0.2- 0.3
1.5 3.0
Balagurovap/963
Hofstede, pers.comm.Netherlands
North.-easternGerman lakes:
Griminitz(data for 2 years)
11.8-24.3 58.0-72.9 Tesch,1955
Mügelsee(2 years)
12.0 30.0 Tesch,1955
Sacrowersee(6 years) 0.3-7.7 1.7-50.6 Tesch,1955
Tallensee(3 years) 3.7-15.0 6.5-18.4 Tesch,1955
Polish lakes:
Average for allin 1950-1964
4.73 19.25 Leopold, pers.comm.(Dpt.Economics,InlandFish.Inst.)
minimum (1957) 3.14 17.55
maximum (1952) 6.79 23.87
FR11536 Abramis brama 419
4:10 FRi/536 Abramis brama
result of winter or spawning aggregations.
4.3 Natality and recruitment
4.31 Reproduction rato
Zemskaia (1961) estimated annual eggproduction rates for the bream of the VolgaDelta (Fig. 18). She multiplied an averagefecundity by the number of females probablyreaching the spawning grounds. Numbers ofeggs deposited varied from 520 to 3,962 mil-lion million in 1936-'49.
For eurvival in embryonio and larvalphases see sections 3.21 and 3.22.
- Forecasting of potential yields.
An estimate of the density of youngfish, made during their seaward runs in theVolga delta by Tanasiichuk (1952), has beenusedto forecast the relative abundanoe of year clas-ses in batches (Dementeva, 1952; Dementeva,1952a; ,Zemskaia, 1961). There is a directrelation between the number of young breamcaught during one hour trawling and yearclass strength calculated by the Derzhavinmethod, as shown by the approximate formula:
Ni
Nb
ai OrNi aab b
axoNb
where: ax, ab are number of young per one
hour of trawling in the years x and b, Niand Nb are year class strengths in the yearsx and b.
As seen from Fig. 19, such calculationsmay contain considerable errors. It shouldbe mentioned that the correlation between thedensity of young and the year class strengthwas close in 1931-'38, the correlation coef-ficient being 0.91 (Monastyrski, 1952).
4.32 Factors affecting reproduction
The water level in the estuaries of theVolga and Amu-Daria affects decisively thenumber of larvae hatched (cf. section 4.2).A sudden lowering of the water level in theriver after spawning causes drying out ofeggs (cf. sections 3.21, 3.22).
The amount of food available for larvaeand young fish is mentioned as the main factorinfluencing the brood strength (Zemskaia,1964 Dementeva, 1955; Nikolskii, 1953; andsections 3.22, 3.35). According to Karpevich(1955), the survival of four-day-old breamlarvas in the Sea of Azov, in water of sali-nity 0 - 7.5 %40 and temperature of 17°C, wasreasonably high and it did not depend on
salinity; an increase in salinity above7.5%o caused increased mortality. A similarresistamos was shown by 11-day-old larvae tosalinities of up to 7.5o.
4.33 Recruitment
Monastyrskii (1952) proposed to dividethe spawning population into two parts onthe absence or presence of spawning marks onscales:(a) fishes spawning for the firsttime and (b) those repeating their spawnings.The spawning population of bream in the in-land seas of the southern USSR is the mainobject of exploitation. Therefore fish whichhave not yet spawned are to a certain degreerecruitment to the fishable stock. The agedistribution of that part of population isshown by data referring to the bream of theNorthern Caspian Sea (Table XX). In thecatchable stock of Caspian bream, the rela-tive numbers of recruits defined as abovevaried frbm 42.2 to 87.7 percent, dependingon brood strength, in the period 1933-'39.Relative numbers of recruits can be higherin lightly exploited populations. Varia-tions in the growth rate of bream and resul-ting changes in the average age at whioh sex-ualAaturity is reached affect the recruit-ment rato (cf. sections 3.12 and 3.43).
Recruitment may proceed during the en-tire growing season or only in the warmerperiod. Fig. 18 shows the ratio of eggs de-posited by bream in the Vblga delta to thedensity of young fish. As can be seen, thereis no simple.correlation. In our opinion itis very characteristic that maximum numbersof young fish developed from eggs depositedin numbers below the average (see year clas-ses 1941, 1942), and this suggests a relationresembling Ricker's reproduction curves. Ac-cording to Dementeva (1952) the number ofspawnere, and hence the quantity of eggslaid, has little bearing on recruitment.
4.4 Mortality and morbidity
4.41 Mortality rates
Average annual mortality caused byfishing and natural factors was estimated forthe postrecruitment phases of the North-Cas-pian bream (Lukaskov, 1961) (cf. section4.5). Balon (1963) from one sample of 256individuals, estimated total mortality ofbream older than four years to be 65 percentannually. It follows from the age composi-tion (section 4.12) that among older acegroups, particularly in the northern waterbodies, total mortality is less than 50 per-cent. Tiurin (1962) estimated the survivalof the Lake Ilmon bream using Baranov's me-thod. The method assumes that if, in a givensample, maximum age is represented by one in-
FRi S36 Abramis brama 411
Year
TABLE XXAge composition Percentage of Northern Caspian bream migrating
for spawning for the first time a.fter Dementeva.1952),Age years)
2 3 4 5
1933 25.8 45.3 27.5 0.9
1934 0.2 91.2 8.4 0.2
1935 2.8 94.1 3.1
1936 2.4 45.9 51.7
1937 3.5 46.6 36.3 9.8 3.8
1938 0.9 28.3 66.0 2.5 0.7
1939 80.3 17.0 2.7
4:12 FRO36 Abramis brama
'41
'49
'4.2
'48
'38
'40 '44
46.
'37
Potential reproduction rate , 10" eggs.
Figure 18. Relative abundanoe of young bream in the VolgaEstuary against potential number of eggsdeposited in the same year (data from Zemskaia,1961).
'36
'45
Fai/S36 Abramis brama 4:13
Number of young bream per 1 hqur trawling (special trawl)
Figure 19, Year olass strength in the oatohable stock of breamin the Volga Estuary against relative abundanoe ofyoung of the same year olass (Data from Dementeva,1952, for 1931-1935, and Zemskaia, 1961, for 19361949).
.61 cc
t ;51..fil -
VI
7.1 o..x"
L. 0o oo 17;
),-
0
'37 '32
'35..49133 '1:7
,
43
14.5
,
38
'34
'36
146
'48
140.
'44
'41
'42.
OD 2d0 350 4100
.0
500-'31
oo
u
dividual then annual survival is a functionof maximum a and the size of the sample.Tiurin's sample contained.260 bream in agegroups from 2 to 11, from which he estimatedthe total mortality rate to be 40 percent.His estimate of fishing mortality as 22 per-cent seems to be not very convinoing.
Cherfas (1956) quoted Dementeva'sestimate that the proportion of eggs_whicheventually gave rise to caught fish in thecase of NorthCaspian bream varied from0.0006 to 0.0220, or from 6 to 220 fish werecaught per 10,000 eg laid.
These data show variatiOns in mortalityrates. As can be seen in Fig. 18, there is aconsiderable variation in survival in thefirst year, but a more consistent survivalrata in later years of life is suggested byFig. 19. The osoillation of the fishingreturn coefficient, expreseed by Zemskaia(1961) in arbitrary units, ranged from 0.01to 0.18 (ratio 1 3 18).
4.42 Factors causing oraffecting mortality.
Predation by fish is a factor whichusually has little influence on the survivalof young bream (cf. seotion 3.23). When thedensity of young bream is great, however,competitors or predatory fishea may affectthe survival rate (cf. seetion 6.44).
4.43 Factors affecting morbiditycf. section 3.35.
4.5
Lukashov (1961), in a very short paper,attempted to apply a mathematical model tothe exploited bream population in the northernpart of the Caspian Sea. The survival ratewas estimated after taking into account theyearclass composition of the populationfished, during two periods of varyingintensity of exploitation, i.e. in period I:1937-48, period II: 1953-58. The totalmortality rabo in period I was 0.55 and inperiod II ib was 0.80. He estimated fishingand natural mortalities, without describingthe method in detail, as follows:
Natural mortality Fishing mortality
Period I 0.15 0.40
Period_ II 0.15 0.65
Growth rate parameters to the Bertalanffy'sformula k(tt0))
lt.. L..(1 e
were estimated as:
Lee = 42 cm
k = 0.233
to = 0.62 years
Fr the weight/length relation
Woo= 0.0215 . L3eo
the maximum weight was calculated to be1,593 grams.
In calculating yield per recruit thefollowing values have been accepted:
M (natural mortality coefficient) = 0.165
t (age at recruitment) = 2 years
to (age at first capture) = 3 years
ti,(maximum age) = 20 years
Lukashov 1961) was convinced thatincreasing to age at first capture) by oneyear and diminishing the intensity of fishing(F) could result in a three or fourfoldincrease in yield.
Many Soviet ichthyologists (monastyrskii,1952; DementeVa, 1952; Nikolskii, 1950,1953; Dementeva et al., 1961, and others)view fish population dynamics in a differentway, emphasizing the connections betweendynamic parameters and environmentalconditions and the community, and looking forcausality. The latter has been mentionedabove (sections 4.2, 4.39 4.4). According tothose authors the size of a populationdepends mainly on the "feeding base" (thearea and richness of feeding grounds) andalso on spawning conditions. Monastyrskii(1952) explained variations in the abundanceof a bream population in the region of theVc1c delta as resulting from the changes inthose factors and in the conditions underwhich young fish live in winter. He stressedthe faot that looking for one factorresponsible for variations in abundance doesnot solve the problem.
Nikolskii (1950) pointed to the relation-ship between food, growth rate and age ofsexual'maturity, and stated that the strengthof fish yearolasses depends on the aboverelationship. For the bream of the VolgaDelta region, Zemskaia (1961) found apositive oorrelation between the food supplyindex and the growth rate of bream in the3rd, 4th and 5th years of life.
4:14 FRi/S36 Abramis brama
FR1/S36 Abramis brama
Factors responsible for variations inabundance may be different in diverse environ-ments. Thus, e.g. changes in the abundance ofbream in the Sea of Azov and the Don Deltaare connected with variationain salinity(Karpevioh, 1955). The water level osoilla-tion in the deltas of the Volga and AmuDariaare of great importance (Tanasiiohlik, 1952;Romanycheva,.1958). Water level was also heldresponsible for variations in the yearclassstrengths of bream of the Rybinskoe Reservoir(Ostroumov, 1956).
Numerous authors have drawn attention toexploitation as the main factor controllingabundance (Berdichevskii, 1961; Nikolskii,1958; Tsepkin, 1964; Zawisza, 1961;Lukashov, 1961).
4.6 Thejulatiou inand the ecosystem
The bream is a generatively stagno-philous freshwater species, living also inbrackish waters of a salinity up to 10 %o(of. sections 2.1 and 3.21). In bigger river ,it ocours in the middle and lower reaches (e.g.in the Rhine, Elbe, Danube, Vistulai Don,Volga). When the current °fa river is strong,as e.g. in the Amu,-Daria, it occurs only in itsdelta (Shaposhnikova, 1950). In small rivers,even those with very week currents, bream arefound in negligible quantities .(Backiel, 1964).When a river is divided into zones, the breamis recognized to be a characteristic speciesof oertain physical conditions (Borne, 1877,and Nowioki, 1882, according to Starmach, 1956;Rust, 1949; Bauch, 1963). According to Huet(1949), a brean zone oomprises those riverstretches of slope less than 1 in 2,000 andwhich are from 5 m to 300 m wide; accordingto Starmach (1956), a bream zone comprisesriver stretches of slope between one in 800and one in 10,000 and 15 200 m wide. Bauch(1963) defined that zone in a different way,namely: besides bream and white bream thereare found numerous species which also occur inthe lakes of the German Lowlands includingsporadically Barbus barbus; the bottom is sandyand muddy; lotio environment with abundantvegetation, the banks overgrown with TyphaandlarIgmites.
The fishery olassification of the lakesin Germany, Poland and USSR also accepts thebream as a characteristic species (Bauch,1963; Sákowicz, 1952; Cherfas, 1956).
Among bream lakes, Bauch (1963)distinguished four subtypes which differ incertain environmental properties and inquantities and sizes of bream most oftenoaught (Table XXI). Cherfas (1956) definedbream lakes in the USSR as those which are nottoo deep, with a well developed littoral region,abundant vegetation and a very muddy bottom.During winter and summer, oxygen exhaustionoften occurs in the deeper layers of water.
4:1
Two subLypes have been distinguished: amelt-bream lakes and bleákbream lakes, accordingto which of these two species is abundant inthe pelagio zone of a lake.
In the bream lakes of Poland, from 17 to23 fish species are found, but roach, breamand bleak predominate (Zawisza in Baokiel,1965).
It should be stressed that the fisheryclassification of lakes as described abovehas not resulted from an analysis of certainproperties of water bodies and the co-existence of fish species in those waterbodies, and therefore it ought to be lookedupon as a working conception. It has beenmentioned here since it is very common.
According to limnological typology,bream lakes are bmezotrophio and eutrophio.
The bream population position in the eco-system is determined by their abundance, food,prodatore feeding on bream, and parasites,some of which have a complex life cycle (of.section 3.35). The abundance of bream in manywaters can be comparatively great (cf. section4.2) and therefore it may be concluded thattheir part in the ecosystems of lakes and somebraokish waters is considerable.
After studying the food of fish of theNorthern Caspian Sea, Shorygin (1952) etatedthat bream feed mainly on Cumacea (more than25%.of daily intake) and that Cumaces are alsothe main food of some Gobiidae (Fig. 20). Acomplete list of organisms on which bream feedshows that many of its items are taken by al-most all the fish species, but the coincidenceis strongest in case of some Gobiidae andDiorinus.a_ax.k.i.o and less, although still con-siderable with Rutilus rutilus 222E1E2. andAcipenseridao. Taking into account. the area offish occurrence in the Northern Caspian Sea,the biomasa of fish and that of food organisms,Shorygin (1952: 203) established the relativeintensity of competition for food between thebream and other fish species (in arbitraryunits) as follows:
Neogobius fluviatilis pallasi, 144Benthophilus macrocephalus 32Rutilus rutilus sespkLe. 29Neo obius melanostomus 21Acipenser stellatus 16Acipenser gUldenstUdti 8Lucio erca lucioperca 6
The food of the carp is similar to that ofthe bream, but, since the two fish occur indifferent regions, they do not compete. Infresh waters, the composition of fish speciesand food is different (cf. section 3.4), butthe bream is a demersal fish in these waterstoo.
Predatory fish attaoks upon bream areinconsiderable (of. seotion 3.32).
Transparency in summer
Oxygen content in sum,
MA
T
H S occurrence in sum-
2mer
BottoM fauna in sommer
Depth
Shape of lake basin
Area
Vegetaticn along
shores
Fish
Fishery yield
.Subtypes
1 -
5 m
insufficient at the
bottom
not present
0-12 m, abundant'Ten-
dires
15 - 30 m
with relief
more than
500ha
abundant
Coregonus lavare tus
Brean, heavier than
1,5 kg, numerous
Rjach - very numerous
Eel-- rather numerous
Pike, tench, big perch
20 -
50kg/ha
Table XXI
Characteristics of brean lakes after Bauch (1963)
frequent under the met -
alimnion
in the deepest places
poor;
7-10m, very
abundant 12
- 3
5 m
with relief
less than 500 ha (fre-
quently channel-like)
Coregonus, usually not
found
Bream 1-1.5 kg quite
abundant
Roach - numerous
Eel - rather numerous
Pike - rather numerous
Tench - numerous
Perch - rather numerous
Pike - perch present
when transparency is
1.)
mBrean 20 -
50percent
1.5
- 5
m
insufficient at the
bottom
0.8 - 2 m
insufficient in the
hypolimnion
-frequent in the hypo-
limnion
comparatively abun-
dant m; 2
5m in places
without relief
submerged - compara-
tively dense
no Coregonus
numerous smaller
bream
Roach - not always
nunerous
Eel,- usually nume
rous
Pike - numerous
Tench - moderately
Pike-perch - big
IV
2 -
5 m
not found at the bottom
-always present
Soyomya - larvae
Tubifex - few
Tendipe didae
6-25 m (depending on sise,
usually deep) -
submerged
- very poor
no Coregonus
small bream, not very
numerous
Roach - small
Pike - moderately numerous
Tench - usually none
Eel -
Pike - perch - none
Perch - small, usually too
numerous
Alosa broshnikoviagrochanica
A.br. brashnikovi
A.saposhnikovi
Figure 20. Food interrelations among fishes in NorthernCaspian Sea. Arrowsdirected towards prey. Areas of circles relative biomass ofgroups indicated. The figure includes only food items whichconstitute not less than 25 percent in food of a fish species(after Shorygin, 1952).
4:17FRi/336 Abramis brama
FRi S36 Abramis brama
5 EXPLOITATION
5.1 Fishing equipment
5.11 Gears.
Various types of fishing gear, adapted tolocal conditions and to the behaviour ofbream, are used in commercial fishing. Inlarge water basins (Sea of Azov, Caspian andAral Seas, large retention reservoirs of theUSSR) trawls are mainly used but seines,pound nets and gill nets are also employed.Winter seines, for fishing under ice, areused on ice-covered lakes. In summer, beachseines and various set nets are used.
In Polish lakes, so-called bream gillnets, mesh size 60-90 mm, height 2.5 - 3.0 m,length 40-45 or 90 m, are used. Best fishingresults with this gear are óbtained in Apriland in October and November. In the AralSea, from 40 to 50 percent of bream arecaught with gill nets (mesh size 60-75 mm),from 30 to 35 peroent with seines and from10 to 15 percent with fyke nets (Bervald,1956). In the Rybinskoe Reservoir, gillnets, mesh size 50 to 90 mm, as well astrawls and seines, smallest mesh size 6 mm,
are used (Ostroumov, 1956).
In large rivers, usually river seineswithout bag are used (lower Danube, Vistula)fyke nets and drifting gill nets, lessfrequently river seines with bag (TableXXII).
In the Rybinskoe and Tsimlanskoe reser-voirs, successful attempts have been made tocatch bream with a trawl, the lead line ofwhich was equipped with a system ofelectrodes supplied with alternating current(Shentiakov, 1964).
5.12 Boats.
Various fishing craft, ranging fromsimple rowing boats or boats with an out-board motor (lakes, rivers) to trawlers ordrifters (e.g. Sea of Azov, Caspian Sea) areused, according to the type of fishing gear.
5.2 Fishing areas
5.21 General geographiodistribution.
Bream are taken almost everywhere theyoccur (of. seotion 2.1), although oommercialcatches are made only in regions of theirgreater concentrations. The richest breamfishing grounds are situated in the southernseas of the USSR (Table XXII and XXVI), andin the brackish waters of the South-oasternBaltio.
.Exploitation and its intensity invarious waters also depend upon whetherpeople consider bream as a savoury fish, asdo the fishermen of Northern Germany (Bauch,1963), people in the USSR (Berg et al., 1949)and country people in Hungary (Entz, personalcommunication). It is considered as acoarse fish by Danish people (Dahl, personalcommunication), and Dutch people (Hofstede,personal communication), and as of littlevalue in Sweden (Sasserson, personalcommunication). Bream is believed tocompete with other highly valued species inDanish lakes and in the Netherlands.
5.22 Geographic, ranges.
See sections 5.21 and 5.43
5.23k Depth ranges.
Adult bream are demersal fish. In lakes,however, they have not been taken by bottomfishing at a depth of over 40 m. Breamfishing grounds in brackish waters usuallydo not go beyond the 12 %o isohaline, i.e.they do not reach any great depth.
5.24 Conditions of the grounds.
An increase in salinity in the Sea ofAzov has affected the abundance of bream(Karpevioh, 1955). The construction ofretention reservoirs has resulted in newfisheries having conditions different fromthose existing in the river, e.g. theRybinskoe Reservoir on the upper Volga, whin.,trawls are used in fishing; this gear wasformerly limited to the sea (Ostroumov,1956).
River pollution'in Central Europe hasaffected fishing grounds, e.g. the Elbe(Bauch, 1958). A decline in abundance wasnoted, and the meat of bream (and of otherspeoies) acquired an unpleasant "ohemioal"flavour and this in turn caused a decline indemand. In the middle Vistula and lowerOdra, fish developed the flavour of phenol orits derivatives.
Variations in the abundance in certainregions and the resulting variations in theimportance of certain fishing grounds arealso related to changes of climate over longperiods of time. Nikolskii (1954) found that5,000 years ago bream was the mainconstituent of all catches in the White Seadrainage area. Today only single individualsare taken. Thus the conditions on thefishing grounds are subjeot to rapid changesdue to the activities of man, whereas thechanges resulting from variations of climateare slow.
Country
Denmark
Norway
Sweden
Finland
Netherlands
Belgium
Franco
Ireland
Great Britain:
Yugoslavia
Greece
Bulgaria
Kind of
exploitation
commercial
no exploitation
little commercial
commercial, no
sport
commercial;
very
little sport fishing
(released when caught)
sport only
v.little sport fish-
ing
little sport occa-
sionally during
closed seasons for
salmonids
sport fishing common
in lowland rivers of
"%gland (Northern
Ireland: little com-
mercial)
little commercial
no information
commercial, of little
significance
Summary on data
equipment
otter trawls,
seines, pound and
hoop nets
winter seines gill
- and fyke nets
gill nets, seines,
in fyke nets with
eel
hook and rod
rod and line
rod and line
(gill nets)
river seine
fyke nets
TABLE XXII
on bream fisheries by countries
loisEing
main areas
lakes (the largest
lake Arres/S)
brackish waters,
lakes
lake Yssel
rivers
rivers (Danube, Drava
Sara, Tisa)
Danube, coastal lakes
main season
spring
September
to March
Utilisation,
other remarks
coarse fish,
fish meal, v.
little export of
fish over 1.5 kg
price appr. 28
percent that of
pikes
import.food fish
cJoarse fish, not
consumed
not appreciated
for consumption
not consumed
not appreciated
no market value
2
Authority
p.c.?ci
V.Sjöblom,p.c.
A.E.Hofstede,p.c.
M.Huet,p.c.
R.Vibert,p.c.
E.D.Toner,p.c.
E.D.LeCren,p.c;
P.Tombleson,p.c.
K.Apostolski,p.c;
Disalov,
1964
L.Ivanov,p.c.
k.71
1
K.W.Jensen,p.c.
brackish water in the
Baltic, some lakes
May to June
and winter
coarse fish,
little consump-
tion, v.low
J.Sasserson,p.c.
Roumania
Turkey
Germany
Austria
Poland
Hungary
USSR
little commercial and
little sport
commercial (little
with nther fishes)
commercial and
sport
commercial more in
lakes, sport more in
rivers (ox-baw lakes)
commercial and sport
Czechoslovakia little commercial,
almost no sport
fishing
commercial;
as
sport fish not ap-
preciated
commecial (large
scale) and sport
seines and
fyke nets
water and sead
seines, gill nets,
fyke nets
gill nets in lakes
fyke nets.in riv-
ers and rod and
line
winter seines
beach seines, gill
nets, fyke nets
seines, fyke nets
in spring
Danube estuary and
proximate lakes
northern and central
lakes
Firths of Vistula and
Odra, northern lakes
anule (low lakes)
seines, fyke nets Balaton lake, Danube
in rivers
seines, trawls,
orth Caspian, Azov,
gill nets, pound
south Aral, big res-
nets
ervoirs, big north-
western lakes
xi p.c. means personal communication
Winter and
spring
winter,
early
spring and
autumn
spring and
autumn
spring and
autumn
second grade
food fish
large specimens
appreciated
sold at a med-
ium price,
large speci-
mens appreci-
ated
appreciated as
food fish by
country people,
mostly pres-
erved (tinnea)
food fish,
large specimens
appreciated
W.B.Ziemiankowski,
p.c; Popescu,1958
1Umann,1962
Ladiges,1960
Bauch,1963
Tesch,p.c;
Menzel,p.c.
W.Einsele,p.c.
authors
E.K.Balon,p.c.
B.Entz,p.c.
Nikolskii,1954;
Berg et al-,1949;
Dementeva,1952a.
5.1.4 FRi S36 Abramis brama
5.3 Fishing seasons. _
General.pattern of season(s)
The general distribution pattern ofcommercial catches throughout the year isvery much the same in various regions (TableXXII). Most bream are taken at the time ofspawning aggregations in spring, or in winter(in freezing lakes). In the warmest period,i.e. at a time of intensive food intake aswell as great dispersion of fish, the catchesare very small. A few examples are given inTable XXIII, A'
5.32 Dates of beginning, peak andend of season(s)
Cf. Tables XXII and XXIII.
5.33 Variation in date or durationof season
According to Dementeva (1952a) a coolspring retards the spawning migration ofbrean to the Volga estuary, thus shiftingthe peak of catches (Romanycheva, 1958).
In lakes, winter catches depend on thedate on which a sufficiently thick ice coverforms. The duration of the fishing season inturn depends on winter weather. The lakes ofnorthwest Poland frequently fail to freezeand therefore do not permit the use of winterseines.
5.4 Fishing operations and results
5.41 Effort and intensity
It is difficult to estimate the fishingeffort in a bream fishery since, in lakes,bream are caught under conditions that varyfrequently, and they are usually caught to-gether with several other species. Dábrowski
al. (1964) and Leopold and NowakM1964,1964a1964b, 1964e) made an analysis of caltches inlakes and established, among other data, theaverage (annual) yield of fish caught pergear per day (Table XXIV). The authorsstress, however, that yield per gear per dayvaries widely throughout the year and withthe locality. It can serve only as a cómpari-son for a large number of data.
Catch per h has been accepted as an ef-fort unit when catching young fish with aspecially designed fry trawl in the CaspianSea and in the Aral Sea (cf. section 4.24).
5.42 Selectivity
Baranov (1948, page 207) stated that the
optimum mesh size (a) of bream gill nets isgiven by a 0.2 Lo or a = 7,d,i7- where Lois body length in cm and w is weight offish in gram.
The availabls_data_on the selectivity ofSome fishing gear in re/ation to the size of!bream are presented in Table XXV.- In TableXXIV it is worth noticing that the catch ofbream varied with the use of different typesef fishing gear, constituting a larger orsmaller percentage of all fish landed. Thisdepends on the distribution of bream in water',bodies and on the fishing technique used.Usually, however,'seines and trawls catchSmaller fish than other nets. .
In the Rybinskoe and Tsimlanskoe reten-tion reservoirs an alternating electric cur-rent has been applied to trawls (a system ofelectrodes at ca. 230 v placed along the leadline, to prevent the fish escaping the trawl).This device was used in selective fishing:the average weight of bream caught with theselective trawl exceeded the average weight ofbream taken with a usual trawl by 22 percentin the Tsimlanskoe and by 58 percent in thegybinskoe Reservoirs (Shentiakov, 1964).
5.43 Catches
The available data on commercial breamcatches are presented in Table XXVI. In eomecountries bream catches are recorded togetherwith the catches of other fresh water species(partially in the Netherlands and Denmark).
In most countries bream is caught byanglers and in some exclusively so. Theamounts of bream caught by anglers may beconsiderable; e.g. in Belgium, annual ang-lers' catches are estimated to be 37 tons(Huet, personal communication in 1963). Ac-cording to Ramler (1949), the ratio of com-mercial to sport catches varied from 1 : 1 to1 t 11 in Lake Sacrower, near Berlin, in 19231948.
Similarly around Warsaw, Poland, theratio of anglers' catches to commercialcatches has been estimated by tagging, as about 1 i 1.
The number of bream caught by anglersmakes an estimate of the total catch in thewhole region of their exploitation difficult.From commercial catches only, Table XXVI, thetotal annual yield amounts to about 70,000tons, and 80 percent of this quantity comesfrom the fishing grounds of the Caspian, Azovand Aral Seas.
greatest part caught in April, May, June
great peak in May and second in October or November
peaks in spring and late autumn
spring 60-90 percent
Bervald,1956
M.Leopold,p.o.
Filuk,1962
Poozalska, 1963
Dementeva,1952a
spring 60 - 70 percent
Demonteva,1955
Balagurova,1963
Vis tula Firth
Szczecin Firth
Northern Caspian
Azov Sea
Lake complex
"Siamozero",
Xarelia,USSR
Table XXIII
Seasonal distribution of bream catches (percent of total annual catch
Area
Calendar month
II
III
IV
VVI
VII
VIII
°IX
XII
Don estuary
Azov Sea near
Kuban estuary
0.8
1.6
8.0
4.4
21.4
16.8
33.4
13.6
22.6
40.9
7.7
13.7
0.2
0.8
0.3
0.7
0.8
2.2
1.3
2.7
2.9
1.8
6.0
0.8
Aral Sea
23.0
63.0
4.0
10.0
Lakes in Poland
(1950-1964)
9.4
14.0
11.6
4.1
10.7
8.5
4.0
5.4
6.1
8.3
11.1
6.8
Authority
Berg,1949
5:6 FRi/S36 Abramis brama
Table XXIVBream fishing with various gears in Polish lakes
(Data from DOrowski et al., 1964; Leopold and Nowaki'1964, 1964a, 1964b,. 1964c)
GearFishingseason
Size classof lakes
(ha)
Catch of breamas percentageof total catch
Total averagecatch per
gear per day(kg)
No. 0flakesconsi=dered
Winter seine January= up to 100 28.02 245.4with.bag April 100 500 41.83 323.3 108
500 and more 28.38 500.6
Summer seine July- up to 80 22.32 157.5with bag December 80 500 19.57 177.9 206
500 and more 6.56 252.3
Fyke nets March up to 100 6.73 1.36with'rings October 100 500 15.07 1.78 10137-80 cm 500 and more 10.03 1.52
Fyke nets(traps)height ay.
March-September
up to 10001000 and more
15.1923.98
1.931.72 44
100 am
Gill nets,mesh 30-50mm
April-Decemler
Mamry lakecomplex(10,000 ha)
lees than 3.1 2.44
other lakes less than 1700 3.26 21
FRi 536 Abramis brama
TABLE XXVSelectivity of some gear in bream fishin
Gear (water body) mesh size fish caught Authority
Seine towed byboatbeach seinetrammel nets
mostly 20-35 am
20-35 cm
35-45 cmFiluk,1957
gill nets 60 mm 30-74 Filuk,1962(Vistula Firth)
Trawl and seine cod end 6 mm - 2-17 years oldnets 50-90 mm 6-18 years old Ostroumov, 1956
(Rybinskoe Reser-voir)
percent of fish under 18 cmGill nets in 28 100 Berdichevskii,1959autumn 1956 and 35 73-90.2spring 1957 38 70.4-93.8
43 15.1-54.8(Northern 50 0-1.3Caspian)
Seines and trawls average body length Berg/1949
nets24.2-36.2 cm32.9-37.9 cm
(NorthernCaspian)
Country Catch estimate per annum
Coarse fish: total 800-)1,100 ton (1955-63),bream is the most abundant. (see editor's note)
Freshwater: total 2,700- 4,b00 ton 1956-59,bream 100- 200 ton (1956-60),Brackish water: bream 126 ton (1961)(e.g. in Lake Aspen, bream 15 percent of 10ton).
Bream 3,300- 4,500 ton, which is 5-1 of total freshwater fish yield.
Lake Ijssel: total 10,400-15,800 ton (1955-62),lar ,= bream and roach 400-710 ton;"immature fish" 7,600-10,800 ton, includessmall bream.Other waters: 250-300 ton.
Bream not more than 5% of total freshwatercatch.Danube: 595 ton (1963).
Danube: 154 kg-48 ton, average 12.6 ton
(1925-58)Coastal lakes: average 2.7 ton.
Authority
Denmark
Sweden
'Finland
Netherlands
Yugoslavia
Bulgaria
Hungary
Roumania
Germany West
Germany East
Poland
Tabla XXVI (Sheet I)Bream catches
Bream, average for all commercial waters01,600ton,-Wliich is to 55 percent of total catch-
Danube estuary: ca 200 to 400 ton (1962-1964),which is 2-3.8 percent of total catch.Danube: 457 ton (1963).Other waters: about same as Danube.
Total freshwater: ca. 10,500 ton; Bream, perchetc 10,100 ton.
Total freshwater: 3,200- 4,100 ton (1960-1964),Bream 900- 1,400 ton
Lakes: total 5,400- 7.000 ton (1956-60),Bream: 1.3-1.4 th ton.Rivers: total 800- 1,200 ton (1956-61),Bream 0.3 t'a t(m.Szczecin Firth: bream 745 ton (1948-50)Vistula Firth: bream 300-400 ton (1948-60)
FRi S36 Abramis brama
Dahl,p.c.
Yearbook*
Sasserson,p.c.
V.SOblom,p.o,
Hofstede,p.c.
K.Apostolski,p.c.
Disalov, 1964
Ivanov,p.c.
Entz,p.c.
Ziemiankowski,p.c.
Disalov,1964Popescu,1958
Yearbook*
Menzel,p.c.
Pecza1ska,1963Filuk,1962
Table XXVI (Sheet II)Bream catches
Country Catch estimate per annum Authority
USSR Freshwater: total 420,000-489,000 ton (1956-61) Yearbook*bream 46,400- 56,300 ton
Bream catch (1936-39) Nikolskii, 1954Caspian Sea: 47,600-105,300 tonSea of Azov (inclu-ding very littlefrom Black Sea): 17,800- 47,100 tonAral Sea: 9,800- 16,700 ton'Gulf of Finland: 30- 460 tonNorthwestern Lakes: 830- 17,400 tonOnega and LadogaLakes: 220- 360 tonLake Pskovskoe-Cud-skoe: 300- 700 tonLake IImen: 1,300- 3,100 ton
*/ Yearbook of Fishery Statistics, Production, 1961, Vol.XIV, FAO
PRi 536 Abramis brama 5:9
FRi 336 Abramis brama
6 PROTECTION AD MANAGEMENT
6.1 Reatorivemeasuree.6.11 Limitation or reduction of
total catch.
Limitation on efficiency. No data areavailable on limitations other than thosepresented in Table XXVII. Equally no limita-tions has been imposed on the number offishing units.
- Quota limitation.
Fishing was prohibited in some of therecently constructed retenfion reservoirs inthe USSR (Sebentsov et al., 1953). In somePolish retention reservoirs there arequantitative restrictions on fish taken withnets, bream included. This measure appliesto reservoirs heavily exploited by anglers.
6.12 Protection of portionsof populations.
Closed areas, season, legal sises, etc.are presented in Table XXVII,
Rescue action of fry in the estuaries ofthe Volga, Ural, Dneper, Amu-Daria Riversincludes bream (Cherfas, 1956). The aim ofthis action is to rescue fry remaining inshallow basins which lose their connectionwith the adjacent river as the water levelfalls. Young fish are rescued in two ways:(i) when the bottom of the cut-off basinis above the low water level of the river, acanal connecting the latter with the basin isdug and the young fish are released with thewater; (ii) when the bottom of the cut-offbasin is beneath the water level in the river,young fish are caught with fine meshed netsand transferred to the river.
In both cases the number of the rescuedfish is estimated. In 1948 in the USSR,8,272.4 million young fish were rescued, andthe percentage of bream amounted to 15.3 per-cent (Cherfas, 1950); in 1953 2,422.7million were rescued, including 579.6 million(16.9 percent) bream (Cherfas, 1956).
6.2 Control or alternation of physicalfeatu-as of the environment
6.21 Regulation of flow.
In many countries the construction ofdams to regulate the flow of water in rivershas led to changos in the population ofbream. This has been mentioned in sections4.22 and 5.2.
The regulation of flow resulting fromthe construction of a dam on the Don Riveraffected the abundance of bream in the Sea
6:1
of Azov (Karpevich, 1955). In rivers afterthe construction of a dam the breampopulation increased (Nikolskii, 1948;Backiel et al., 1956; Wundsch, 1949).
6.22 Control of water levels.
The construct'ion of dams alters thewater level. The effects are the same asthose mentioned above.
6.23 Control of erosion andsilting.
That, too, is achieved by building dame.
6.24 Fishways at artificial andnatural obstructions.
Although bream use the fishwaysconstructed at the dams, this is of minorimportance (Sakowicz and Zarnecki, 1954).
6.25 Fish screens.
No screens specially adapted for breamhave been devised. The Soviet electricscreens .of the E RZ U - 1 type (Strakhov andNusenbaum, 1959) are used at dams, to directfish into the fishways, and in front ofirrigation canals, to disoouraga young fishfrom ascending these canals. The screensare up to 85 percent effective. Bream arealso protected by them.
6.26 Improvement of spawninggrounds.
In the construction of artificialspawning grounds, use has been made of thefact that bream spawn on branehes of ooni-ferous treee placed in lakes (Mikheev, 1951;Sukhovan, 1959). Floating spawning groundshave also been used, consisting of bunches ofconiferous tree. twigs or bulrush (Scirpus)attached every 30-40 cm to ropes hanging30-40 cm apart from a floating wooden frame.Mikheev (1951) advised the use of this typeof spawning ground in reservoirs ofoscillating water level, e.g. retention re-servoirs. But Antipova et al. (1954) foundthat bream did not use such spawning groundsin the Rybinskoe Reservoir, in spite of un-favourable conditions on natural spawninggrounds. Dudin (1954) sharply criticizedthis method, drawing attention, among otherthings, to the considerable cost and lossesin eggs. Trials in Poland with floatingartificial spawning grounds have also notbeen very succeseftl.
Mention should be mad4 here of themeasures taken on the so-called "poimennyeosera", ox-bow lakes in the Volga delta.These are flooded during high water in springand they serve as the spawning grounds ofbream and other fish (Suvorov, 1948;Sukhoverkhov, 1948). Improvement is possible
Coun r
Denmark
General remarks
Finland
Nether-
lands
Belgium
France
Ireland
England
Yugo-
slavia
Bulgaria
Roumania
Germany.
West
lakes overpopula-
ted, considered
competitor, inter),
sive fishing recom-
mended.
oonsidered impor-
tant, fishing is
regulated by law.
intensive fishing,
including small
fish, recommended.
of little impor-
tance
of little impor-
tance
considered impor-
tant
Le :l size
no
35 am total
length
12inch
in some Re-
publics
20 am from
eye to end
of tail
25 to 32 am
(in various
parts of
country)
TABLE XXIil
Proteotion and mana.zment in bream fisheries
'Closed seasons
--Closed areas
Other measures
no
no
1 April to 31 May
(for all fishes)
end March tO mid-
June
2 months in spring
15March to
15June
May (Danube fi-
sheries)
May (Danube fi-
sheries)
4to 6 weeks in
spring, dates dep-
ending upon local
conditions
netting is pro-
hibited in in-
land waters
no
no
some sport fish-
ing associations
prescribe length
limits
noStOCkiflL
AuthorIt
transfered
to several
lakes with
success.
no
Dahl, P.C.
V. Sjöblom, p.o.
Hofstede, p.c.
Huet, P.C.
Vibert, p.c.
Toner, p.c.
Tombleson, p.c.
Apostolski, p.c.
Ivanav, p.c.
1
Ziemiankowski, p.c.
Tesoh, p.c.
coa
no
no
Germany
East
Austria
25 cm
established by lo
cal authorities
spawning time, va-
rying in different
regions
as in case of
closed season
Menzel, p.c.
Poland
protected and regu 25 cm in
15 March to 30 Ap socalled pro
local restric
usually
authors
lated
State Fish
ril all kinds of
tected spawning tions such as
transfer
Farms, 500g movable gears pro grounds estab
catch limit, no
from one
in lake fi
sheries, 30
cm in Szcze
cin Firth
hibited
lished by local
fish authori
ties
seining etc.
lake to
another
Czecho
slovakia
25 cm
16 March to 15
June
E. K. Baba, p.c.
Hungary
50 gram
15 April to 15
May
commercial fi
shing prohibi-
ted-in the 100
m wide belt al-
ong the shore
of Balaton Lake
Entz, p.c.
USSR
considered impor
tant food fish,
fishery regulated
18 cm
no
no
rescue action
(see text)
both main
tenance and
transplan-
tation (see
text)
Berdichevski, 1961
(and many others)
by construction of a sluice in the canallinking a lake with the river and securinga high water level from spring to the end ofAugust or the beginning of September. Sucha sluice prevents spawners from swimming intothe spawning ground but desirable species maybe released in the lake. In the middle ofAugust, 196 kg of fry, weighing on avera1,6 g, was obtained from 1,000 bream spawnersreleased in 95 ha of lake. Sukhoverkhov (1948)reported that with careful management 300-400kg/ha of carp and bream fingerlings can beobtained from such lakes.
6.3 Control or alteration of chemicalfeatures of the environment
6.31 Water pollution control.
Water pollution control exists in allcountries where bream occur (EconomicCommission for Europe, 1962).
This water pollution control is notcarried out from the point of view of thebream,s demands only but the criteria ofsurface water purity are good enough to thepopulatiens of this species.
6.32 Salinity control.
In spite of the fact that an increase insalinity limits the occurrence of bream (cf.section 4.2 - the Sea of Azov), not much canbe done to prevent the undesirable effects ofthese changes.
6.4 Control or alteration of the bio-eFj2f'thlo'calfeatiue
6.42 Introduction of fish foods(plant, invertebrate, foragefishes).
Invertebrates are being introduced in theUSSR. They are not exclusively organismspresent in the natural food of bream but theyare accepted as food by bream (Karpevich andBokova, 1963, 1961; Karpevich and Lokshina, 1965),
6.43 Control of parasites anddiseases - cf. section 3.35.
6.44 Control of predation andcompetition.
In the USSR attempte have been made toregulate the species composition of spawners inox-bow lakes which have sluices and are periodi-cally flooded (Irinarkhov and Tokarev, 1949).Regulation has consisted in preventing preda-tory fishes and less valuable species fromentering those ox-bow lakes; carp, bream andCaspian roach (R.rutilus caspius) were lookedupon as valuabl7 species. Changos in fryspecies composition were as follows: in thespawning grounds under control 59.4-83.5 per-cent of fieh were valuable while the respect-
ive figures were 20.5-67.8 percent on un-controlled spawning grounds. Neverthelessthis method has been criticized (Kuznetsova,1950) since the production of fry on thecontrolled spawning grounds proved to belower than on the uncontrolled ones.Kuznetsova (1950) does not attack the basioidea but she stresses the technical diffi-culties, laborious control of species compo-sition of spawners and inconsiderable effects.
6.45 Population manipulation (cf.sections 6.1 and 6.5).
6.5 Artificial stocking
6.51 Maintenance stocking.
In the USSR some river deltas arestocked with bream fry reared in the so-called spawning and breeding farms (Cherfas,1956). Those farms have ponds lying in hol-lows separated from the river bed by naturalelevations or by dams with sluices. Suchreservoirs are flooded during high water inthe river or by means of pumps. Young fishwhen two months old are usually released byemptying the pond into the river. Theirnumbers are estimated(see section 7). Stockingwith bream eggs was done in the USSR tostrengthen the population in recentlycons cted retention reservoirs (Mikheevand Meisner, 1954)0
Such reservoirs were stocked with"spawners, too. Recommendations have beenmade to release one female and one-to-twomales per one ha (Bizaiev, 1952; Mikheev andProkhorova, 1952).
The transfer of two-to-three year oldbream from lakes having an abundant popula-tion to lakes and retention reservoirs witha small bream population is common in Poland.Some such transfers have been successful.Wundsch (1949) mentions the stocking ofGerman retention reservoirs with bream.
6.52 Transplantationand introduction.
Bream have been introduced into numerousSibirian waters (Table XXVIII). These worksare being continued on a big scale in theUSSR, e.g. in 1960-61 Abramis brama orientaliswas introduced into eight lakes and two re-tention reservoirs and in 1962 into more than30 lakes and four reservoirs; in most casesspawners were released (Karpevich and Bokova,1961, 1963; Karpevich and Lokshina, 1965).
The bream is being introduced into thosewater bodies within its natural geographicdistribution where it did not previously occur,e.g. to some lakes of Finland (SOblom, p.o.1965) and Poland. It can be stated that itsintroduction into the lakes within itsnatural occurrence area and its acclimatiza-tion in Sibirian waters have been successful.
6:4 FRi/S36 Abramis brama
Locality
Ponds andlakes in theIset Riversystem (nearSverdlovsk,West Siberia)
Lake Ubinskoe(near Novosi-birsk, WestSiberia)
Lake Zajsan(East Kazakh.SSR)
Lake Balkash(East Kazakh.SSR)
Lake nearBaikal Lake
TABLE XXVIII
Acclimatization of bream
1863
1929
1949
1949
1954
spawners
spawners
spawners
spawners
Successful, invadedsome sectors ofmiddle Irtysh river
In 1950 estimatedstock abt. 300 ton ofyoung bream, in 1951 -30-40 percent of totalcatch
Spawning and fry ob-served in many placesafter 2 years
1958 commercial cat-ohes about 1.5 ton pertrawl
young observed in manyplaces in 1955-57
Cherfas, 1956;Burmakin, 1963
Petkevich, 1954;Tikhii, 1954;Volgin and Vertinin,1964
Goriunova and Serov,1954
Goriunova and Serov,
1954;Ivanov and Pecheni-kova, 1960
Askhaev, 1958
Year of Stage offirst in-troduction
fish in-troduced
Results Authority
FRi S36 Abramis brama 61
FRi/836 Abramis brama
(Mrugasiewicz, 1931). At present bream arereared in ponds near lakes. Similarattempts have been made in Roumania(Ziemiankowski, personal communication).
Young fish (bream, carp and eventuallyothers) are reared in ponds until the middleor end of August,.then released into a riverby letting out water through a sluice orsimilar arrangement. Fishes released arecounted (Cherfas, 1956:275; Kozhin andLetichevskii, 1953).
7.5 Pond management
Ponds of 50-500 ha in area are filled inspring, at the time of high water in theadjacent river. These ponds are withoutwater from about the beginning of Septemberuntil the spring. The importance of earlyflooding is stressed, since food organismscan then develop.
Emergent plants overgrowing ponds andtheir control are a serious problem (Kozhinand Letichevakii, 1953). To secure suitablespawning conditions, grasses should be sownin autumn (Letichevskii, 1965).
7.7 Disease and parasite control
The spawners (of bream and otherspecies) should be carefUlly examined and allindividuals either injured or having externalparasites ought to be discarded (Cherfas,1956). Apart from that, the drying out ofponds should be looked upon as a means ofcontrolling diseases and parasites.
7.8 Harvest
Some data on the yields obtained by thefarms of this type are presented in TableXXIX.
7.9 Transport
Live,eggs deposited on a substratum ofconiferous-tree branches have beentransported in the USSRUikheev and Meisner,1954). Eggs on,chopped branches of coni-ferous trees were put into impermeable card-board hoxes and the twigs were interlaid withwet naPkins. After 8.5 h of transportationthe eggs werein good condition.
In Poland, young bream for stocking areusually transported in autumn in tanks,trucks or lorries with tarpaulin and barrels.From 20-50 kg of fish is put per 1,000 litersof water, depending on the time required fortransportation.
7 POND FISH CULTURE
Bream have not been reared in ponds untilreaching marketable size. Nevertheless, therearing of young fish has much in common withpond fish culture.
-7.1 Procurement of stock
Bream spawners are caught in the watersadjacent to a fish farm during their spawningmigration in the spring (in May) (Cherfas,1956; Syrkov, 1953; Kozhin and Letichevakii,
1953).
7.2 Genetic selection of stocks
Genetic selection of stocks has not beenattempted.
7.3 Spawning
Bream spawners are released in a pondhaving proper spawning conditions, usuallytogether with carp spawners and occasionallyalso with Caspian roach spawners (Rutilusrutilus caspius Jak.) and pike-perch spawners(Syrkov, 1953; .Nikolskii, 1955). The sexratio among spawners should be 1 a 1 (Kozhinand Letichevskii, 1953) and 5-11 females arereleased per ha. The number of spawning fishreleased depends on the quantitative relationof fish species, female fecundity and the sur-vival rates of young fish (Cherfas, 1956).According to Kozhin and Letichevskii (1955),survival was between 3.34 and 8.5 percent fromfertilization of the eggs until the fish weretwo-to-three months old.
When necessary, artificial spawning isused (e.g. when there is no suitable sub-merged vegetation to induce. natural spawning).The fertilization is carried out by the drymethod (Russian method). The eggs are thenplaced on a substratum of coniferous treebranches or their adhesiveness is removed bymixing with river mud for one h. (Cherfas,1956:119; Vernidub, 1953).
Eggs, on a substratum or after un-sticking, are put into hatching boxes whichare submerged in a pond or river. Green'sor Chalikov's apparatus sets are used;these are cases, some or all walls of whichare made of fine-meshed netting.
7.4 Roldin of stock
The so-called spawning and breeding farmscover an area of about 7,000 ha in the Volgadelta (Syrkov, 1253; Letichevskii, 1965,cf. section 6.51). There are also farms inthe deltas of the Don, Kuban and Kura Rivers(Syrkov, 1953). Attempts to rear young breamwere made in Poland before World War II
Marketable live bream are rarely trans-ported. Privollnev (1956) advised in suchcases the use of the same appliance as whentransporting carp, providing that only 72percent of carp weight is carried; e.g. ina railway wagon (car) provided with tanks of24,000 liters capacity and an appropriate
system of aeration the following quantitiesof bream can be transported for two-to-threedays:
watertemperature (°C): 0-2 2-5 5-10 106-15 15-20
tons of fish(bream): 7.2 6.5 5.8 4.3 2.9
72 FRi/S36 Abramis brama
Year No offarms
Table XXIX
Harvest from spawning-breeding Farms in Vol Estuary
(after Syrkov, 1953 selected data)
Total area(ha)
1946 5 1454 46.9 41.4 420
1948 7 1874 62.7 83.8 14.2 318
1951 10 4052 215.7 267.9 6.7 160
7:3FRi S36 Abramis brama
No of fish harvested, millions HarvestCarp Bream Other species (kg per ha)
FRi/S 6 Abramis brama 8:1
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9 Efforts to charaoterize the feed relation and feed conditions in lake Tafty for1953a fry. (Polish, En and Ru summary). Rocz.Nauk rol., 67:209-21
Pliszka, F., et al., Investigation into the food and feeding habits of fish in the river Vistula.1951 (Polish, En summary). Rocz.Nauk rol., 57:205-35
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Pravdin1939
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FRi/S36 Abramis brama
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SES OF FISHERIES BIOLOGICAL DATA
This is one of a series of documents issued by FAO, CSIRO and USFWS concerning speciesand stocks of aquatic organisms of present or potential economic interest. The primary purposeof the series is to make existing information readily available to fishery scientists accordingto a standard pattern, and by so doing also to draw attention to gaps in knowledge. It is hopedthat synopses in the series will be useful to other scientists initiating investigations of thespecies concerned or of related ones, as a means of exchange of knowledge among thosealready working on the species, and as the basis for comparative study of fisheries resources.They will be brought up to date from time to time as further information becomes availableeither as revisions of the entire document or their specific chapters.
The relevant series of documents are:
FAO Fisheries Synopsis No. FR/S(replacing, as from 1.1.63 FAO Fisheries Biology Synopsis)and FB/S
CSIRO Fisheries Synopsis No. DFO/S
Synopses in these series are compiled according to a standard outline described in Flb/S1Rev. 1 (1965).
FAO, CSIRO and USFWS are working to secure the co-operation of other organizations andof individual scientists in drafting synopses on species about which they have knowledge, andwelcome offers of help in this task. Additions and corrections to synopses already issued willalso be most welcome. Comments including suggestions for the expansion of the outline andrequests for information should be addressed to the co-ordinator of this work and editor ofthe FAO series:
A. Ben-TuviaFishery Resources and Exploitation DivisionMarine Biology and Environment Branch
Food and Agriculture Organizationof the United NationsVia delle Terme di Caracalla
00100 Rome, Italy
Consolidated lists of species or groups covered by synopses issued to date or in preparationwill be issued from time to time. Requests for copies of synopses should be addressed to theissuing organization.
The following synopses in this series have been issued since January 1966:
SSR/F526 Synopsis on the biology of the jack mackerel (Trachurus(FR/S86) trachurus). (Published as U.S. Fish and Wildlife Service Special
Scientific Report - Fisheries No. 526)
FR i/S30 Synopsis of biological data on the pike Esox lucius (Linnaeus)1758. Provisional version
FR/S31.1 Synopsis of biological data on common carp Cyprinus carpio(Linnaeus) 1758 (Asia and the Far East). Provisional version
FR/S31.2 Synopsis of biological data on common carp Cyprinus carpio(Linnaeus) 1758 (Near East and Europe). Provisional version
FR/S32 Synopsis of biological data on cat's Cat/a catla (Hamilton) 1822.Provisional version
FRm/S34 Synopsis of biological data on the blue whiting Micromesistiuspoutassou (Risso) 1810. Provisional version
FRm/S35 Synopsis of biological data on the West African croakers Pseudo-tolithus typus, P. senegalensis and P. elongatus
FRm/S33 Synopsis of biological data on the Norway pout TrisopterusRev. 1 esmarkii (Nilsson) 1855
FR i/S36 Synopsis of biological data on the bream Abramis brama (L.)
April 1966
April 1966
May 1966
May 1966
May 1966
September 1966
October 1966
January 1968
February 1968
M1169608/4.681E111750
