On the Phenology of North Sea IchthyoplanktonWulf Greve*#, Sabine Prinage*, Heike Zidowitz*, Jutta Nast# and Frank Reiners#

*German Centre for Marine Biodiversity Research (FIS) and # Federal Agency for Shipping and Hydrography of Germany (BSH) , Notkestr. 85, D-22607 Hamburg, Germany

Phenology is the study of the timing of recurrent synchronised biological processes

Spawning, plankton blooms, animal migrationsare examples for such seasonal events

Phenology requires many years of frequent observations

These are available from the only off-shore North Seaisland Helgoland

Mean SST April to June [°C]

Sta

rt o

f s

ea

so

n o

f ju

ve

nile

Ple

uro

bra

ch

ia p

ileu

s

[K

W]

7576

77

78

79

80

81

8283

84

85

8687

88

89

90

91

9293

94

10

12

14

16

18

20

22

24

26

6,5 7,5 8,5 9,5 10,5 11,5 12,5

Mean SSZT April to June [°C]

En

d o

f s

ais

on

of

zoe

a-l

arv

ae

of

Callia

nassa s

ub

terr

an

ea

[KW

]

838485

86

87

90

91

9394

195

205

215

225

235

245

255

6,5 7,5 8,5 9,5 10,5 11,5 12,5

Correlation coefficient r= -0,88

Correlation coefficient r= -0,80

Correlation coefficient r= -0,95 Correlation coefficient r= -0,78

START OF SEASON

Correlation coefficient r= -0,78

Mean SST June to July [°C]

En

d o

f S

ea

so

n o

f

No

cti

luca s

cin

tillan

s [

KW

]

75

76

77

78

79

80

81

82

83

84

85 86

87

88

89

90

91

92

93

94

25

27

29

31

33

35

12,4 12,8 13,2 13,6 14,0 14,4 14,8 15,2 END OF SEASON

Correlation coefficient r= -0,78

A B

Example: Timing of the start of season in apple blossom in a cold (A) and a warm (B) year, from DWD, unpublished

PHENOLOGY IS AN ESTABLISHED TERRESTRIAL MANAGEMENT TOOL

The physiologically important relative temperature variance in winter exceeds the summer values

The example: annual dynamics of the larvae of the common sole

Solea solea

The definition of phenophases:

10 w

eeks

-3

-2

-1

0

1

2

3

19

75

19

76

19

77

19

78

19

79

19

80

19

81

19

82

19

83

19

84

19

85

19

86

19

87

19

88

19

89

19

90

19

91

19

92

19

93

19

94

19

95

19

96

19

97

19

98

19

99

20

00

year

°C

The spawning period of fish is determinedby the preceding winter temperatures

The deviation of winter temperatures from the long term mean

Phenology of North Sea Ichthyoplankton

correlation coefficient R2

name of species(english name)

range fromstart to endof season(weeks)

range ofmiddle

of season(weeks)

numer ofyears

measured>0 ind. * m-3

start ofseason

middle ofseason

end ofseason

Agonus cataphractus(Hooknose)

5 - 14 8 - 11 7 0,184 0,506 0,421

Ammodytes marinus(Lesser sand-eel)

4 - 14 6 - 10 7 0,195 0,387 0,246

Ammodytes tobianus(Small sandeel)

14 - 44 14 - 40 6 0,411 0,004 0,056

Arnoglossus laterna(Scaldfish)

24 - 33 26 - 33 6 0,849 0,935 0,751

Buglossidium luteum(Solenette)

22 - 35 23 - 32 7 0,419 0,368 0,702

Callionymus sp.(Dragonet)

19 - 28 23 - 28 6 0,884 0,471 0,318

Clupea harengus(Atlantic herring)

1 - 48 1 - 47 7 0,129 0,114 0,472

Ctenolabrus rupestris(Goldsinny-wrasse)

27 - 34 27 - 32 6 0,517 0,670 0,625

Gadus morhua(Atlantic cod)

3 - 19 7 - 17 7 0,034 0,655 0,827

Gobiidae ge. sp. 19 - 35 22 - 31 7 0,400 0,248 0,384Hyperoplus lanceolatus(Great sandeel)

17 - 44 25 - 39 6 0,647 0,432 0,579

Limanda limanda(Dab)

10 - 26 14 - 23 7 0,452 0,398 0,536

Liparis sp.(Striped seasnail)

5 - 26 15 - 25 7 0,681 0,595 0,311

Merlangius merlangus(Whiting)

6 - 28 9 - 23 7 0,156 0,412 0,579

Micrenophrys lilljeborgi(Norway bullhead)

6 - 27 6 - 25 5 0,971 0,941 0,902

Myoxocephalus scorpius(Shorthorn sculpin)

4 - 16 7 - 11 7 0,103 0,283 0,000

Pholis gunnellus(Rock gunnel)

2 - 14 6 - 13 7 0,562 0,731 0,053

Platichthys flesus(Flounder)

10 - 21 11 - 19 7 0,473 0,486 0,432

Pleuronectes platessa(European plaice)

3 - 18 10 - 15 6 0,671 0,723 0,370

Scomber scombrus(Atlantic mackerel)

24 - 32 25 - 30 6 0,271 0,332 0,440

Solea solea(Common sole)

13 - 32 18 - 28 7 0,670 0,760 0,714

Sprattus sprattus(European sprat)

16 - 39 21 - 26 7 0,055 0,011 0,007

Taurulus bubalis(Longspined bullhead)

8 - 26 9 - 25 7 0,660 0,501 0,483

Trachurus trachurus(Atlantic horse mackerel) 24 - 32 25 - 30 7 0,650 0,863 0,668

Triglidae gen. sp. 23 - 36 25 - 36 7 0,086 0,006 0,026

Table 1

Operative prognosis on the phenology of North Sea plankton

is available under:www.senckenberg.de/dzmb/plankton

Summary:

- phenology is applicable in marine ecology

- climatic effect recognition and prediction are supported

- marine monitoring has to consider quanititative and phenological variance

- as in terrestrial phenology a marine phenological observation system will have to include the participation of volunteer observationists and phenological observation sites (e.g. W.M.O. phenological gardens)

Expectation:

- phenology will become a standard method in marine research