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ICLARM's Activitiesin
TropicalStockAssessment:1979-1984,and Beyond
In March 1977, shortly after ICLARMcommenced in Manila, its
Program Advi-sory Committee fonnulated the guidingprinciples for
the Resource Developmentand ManagementProgram,which is one ofthe
four program areasof ICLARM (theothers are Aquaculture, Traditional
Fish-eries and Education and Training.) Theseemphasized research as
the basis formanaging tropical multispecies fisheriesand were
translated into a more detailed
research program by D. Pauly during a2-month consultancy at
ICLARM in1978 which laid the foundations forICLARM's activities in
fish stock assess-
ment and management.
Daniel Pauly
The ResearchProgram 1979 to 1983
From June 1979 to February 1982,the Program was staffed only by
D. Paulyand emphasiswason the in-house develop-ment of appropriate
researchmethodolo-gies,particularly on microcomputer-basedmethods
for the analysis of length-fre-quency data. Additionally, time
wasspent on organizing a workshop on trop-ical multispecies stocks,
which wouldexamine the models used to asse!iSsuch
stocks, and prepare a set of recommenda-tions for future
research.
July 1984
D. PAULYand
J. L. MUNRO
The researchon microcomputer-basedmethods yielded its first
major result inmid-1980 When the ELEFAN I (Elec-tronic LEngth
Frequency ANalysis) mi.crocompu ter program, a radically
newapproach for the estimation of growthparameters from
length-frequency datawas completed and first described in theICLARM
Newsletter.
By the end of 1983 an integrated suiteof ELEF AN programs was
available:
ELEFAN 0: for the creation and mainte-nance of IDesfor use with
the ELEFANsystem
ELEFAN I: for the estimation of growthparameters from
length-frequency data
ELEFAN II: for estimation of total mor-tality from a
length-converted catchcurve, and for the derivation of
seasonalpatterns of recruitment
ELEFAN III: for performing two differenttypes of
length-structured Virtual Popu-lation Analysis using monthly
catchinformation and length-frequency datafrom the fIShery,and
ELEFAN IV: for estimation of naturalmortality from catch
length-composi-tion data and the select\on curve(s)of the
fIShinggear(s).
These programs, including user's in-struction and BASIC
listings, which havebeen extensively revised, are now beingprepared
for publication in book fonn,along with computational examples.
TheELEFAN I and II programs, accordingto the results of a recent
survey, are beingused by over40 users in over 20 coun-tries. Some
15 reports and papers havebeen published based on the
ELEFANprograms (not counting those producedat ICLARM) with a
similar number inpreparation. Also, several scientists, nota-bly A.
MacCall(NMFS, La JOllil,U.S.A.),J.G. Beddington (Univ. of York,
U.K.)and J. Majkowski (CSIRO, Australia)have initiated simulation
studies onELEFAN I, II and III with the purpose
Reprinted from ICLARMNewsletter 7(3): 7-11.
of assessing, using rigorous criteria, thevarious properties of
these programs, andtheir suitability for routine application.
These developments, as well as theincreasing realization by the
staff ofvarious fisheries laboratories throughoutthe world of the
need to reassess andamplify work on length-based methods,led in
1983 to the concept of an "Inter.national Conference on the Theory
andApplication of Length-Based Fish StockAssessment Methods",
initially plannedbetween ICLARM and the Kuwait Insti-
tute of Scientific Research. The proceed-ings of this conference
(February 1985)
John Munro
sponsored by FAO and the Instituto diTecnologia della Pesca e
del Pescato, inSicily, Italy, should serve for years tocome as a
basic reference on length-frequency analysisand
length-basedstockassessment in both tropical and
temperatewaters.
Length-frequency analysis, however, isnot the only area of stock
assessment forwhich microcomputers can be used. For
7
s.mondouxText BoxPauly, D. and J.L. Munro. 1984. ICLARM's
activies in tropical stock assessment: 1979-1984, and beyond.
ICLARM Newsletter 7(3):7-9
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example, the filing and manipulation ofdata obtained during
small to medium re-sources surveys and ecosystem modellingrepresent
other areas where microcom-puters can be used with great
advantage.ICLARM initiatives on these topics
Seasonally oscillating growth curve, as "stimatedby ELEFAN
I.
8
:r:....Zo::E:
included the commissioning of a systemof programs in Microsoft
BASIC for thefiling, maintenance and analysis of fishresources
survey data, and the prepara-tion of shorter programs for
variouspurposes, some of which are includedin program compilations
to be publishedby FAO.
Throughout, the emphasis has beento show that virtually all
aspects oftropical fish stock assessment can behandled with
relatively cheap micro.computers and programmablecalculators,and
that such hardware, judiciouslyused, can magnify immensely the
outputof a fisheries laboratory, with a cost:benefit ratio much
h~er than that ofa large computer or research vessels.
A manual by D. Pauly containing30 fully documented programs
forHP 67/97 and HP 41C calculators, hasalso been published. It
embodies theessential parts of the multitude of pub-lished methods
and models used toassess fish stocks, with emphasis onthose
approaches that have limited datarequirements and can be applied to
trop-ical stocks. The book demonstrates thatprogrammable
calculators are sufficientto implement most models used to
assesssingle-species stocks with program list-ings and computed
examples, for whichcomplete keystroke sequences are given.
Participation in various conferencesand training courses in
1980-1983, espe-cially the ICLARM/CSIRO conferenceon the Theory and
ManagementofTropi-cal Fisheries in January 1981 and theFAO/DANIDA
Training Courses in FishStock Assessment confirmed the needfor
simple, robust methods for use whendata are scarce, and for a wide
dissemina-tion of such methods throughout theintertropical belt,
where fishery scientistsoften work in isolation, and generallyhave
inadequate access to appropriatescientific literature.
The microcomputer- and calculator-based methods mentioned above,
plusa number of "paper-and-pencil" methodsalso developed at ICLARM,
do fulmlthe criteria of being rather simple, robustand easily
applicable to tropical stocks.
The problems linked to the dissemina-tion of these methods to
the people whoneed them was effectively tackled byestablishing the
Network of TropicalFisheries Scientists, which has now over
300 members in 65 countries, all linkedby Fishbyte, the
Network's newsletter.
The Network of Tropical FisheriesScientists, which is presently
partlysupported by the FAO/DANIDA FishStock Assessment Training
Project allowsfor improved communication betweenindividual members,
and also enhancesthe identification of groups of scientistsat
institutions in various countries whoare interested in setting up
"countrymodules" within the framework of theother major project,
the "Management-Oriented Fisheries Research Project",also initiated
in 1982. There have beenfour such modules to date:
. a Philippine module, with theCollege of Fisheries of the
Univer-sity of the Philippines, concernedwith the relationship
between mon-soon wind patterns and the recruit-ment of Philippine
fishes (projectnow concluded with two scientificpapers
produced);
. an Indonesian module, with theMarine Fisheries Research
Institutein Jakarta in which a microcomputerand ELEFAN programs
supplied byICLARM are being used to analyzethe large amount of
length-fre-quency data collected in the lastfew decades by
Indonesian fisheriesbiologists;
. a Peruvian module, with the Insti-tuto del Mar del Peru and
morerecently the German Agency forTechnical Cooperation as
coopera-ting institutions, in which theELEFAN programs are being
usedto derive monthly recruitment esti-mates, never before
available, forthe period 1953 to 1982 from thelarge database
available on thePeruvian anchovy and its ecosystem;
. a Zambian module which isassessingthe state of the country's
majorpelagic and demersal fisheries byanalyzing accumulated catch
andeffort statistics and length-frequen-cy data. Most of this work
will beaccomplished on a microcomputingsystem supplied by ICLARM,
andit includes a visit by a Zambianscientist to ICLARM
headquartersin Manila to become familiar withthe analytical
techniques.
The country modules of the
"Manage-numt-OrientedFisheriesResearchProject"
ICLARM Newsletter
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have several objectives. Foremost is thetraining of fishery
scientists in the inter-pretation of fishery data. They willprovide
the basis for future in-countrytraining of additional workers, for
im-provement of university curricula andfor interaction with
fisheries administra-tion. Thus, the capabilitiesof
participatingcountries in fisheries management shouldbe improved
through better dialoguebetween biologists and managers, andbetween
the fisheries departments ofgovernments and universities.
The country modules should alsohelp determine the basic
informationrequirements for stock assessment andfisheries
management in {'articipatingcountries and produce
well-documentedreviews of the various fisheries inves-tigated as
well as original studies ontropical fish population dynamics.
Other training activities have includednational training courses
in the Philip-pines to international training courses,such as the
FAO/DANIDA coursesmentioned above, and from supervisingM.Sc.
students to assisting numerousc9lleagueson extended visits to
ICLARM.
Additionally, reports and books ranging.from the "Theory and
Management of
Research assistant Deng Palomares at computer analyzing data for
the Tropical Fish Stock Assess-ment Project and Management-Oriented
Fisheries Research Project-Peru module.
Tropical Fisheries" (D. Pauly and G.Murphy, eds.) to "Caribbean
Coral ReefFishery Resources" (J.L. Munro, ed.),and to a series of
reports on the fisheriesof San Miguel Bay in the Philippines,have
provided well documented examplesof the theory and practice of
tropical fishstock assessment. They are now used as abasis for
parts of the FAO/DANIDAFishStock Assessment Training Project.
Someare listed on the n.extpage.
1984 and Beyond
The various methodological advancesoutlined above, particularly
the calculatorand microcomputer-based approacheshave led to a
situation very different fromthat prevailing a decade ago when
theauthors, working on a variety of fisheriesprojects had
difficulty in identifyingstraightforward methods which couldbe
applied to the data which had beengathered. In fact the situation
has almostreversed itself, and there is now an urgentneed to
accelerate the dissemination ofthe new methodologies that have
emergedin the last decade.
For this reason, much of ICLARM'sfuture activities in stock
assessment willconsist of dissemination of
appropriatemethodologies, organizingtrainingcourses,
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helpingwith the development of curricula,and training scientists
through stays atICLARM.
Future ICLARM research, as far itcan be now anticipated, will
concentrateon three major areas: assessment ofspecific resources,
recruitment problemsand comparative studies of the growthand
mortality of fish and aquatic inver-tebrates.
Feedback
The continued relevanceofICLARM\work in stock assessment depends
criti-cally on feedback by colleagues;we hopethat this essay will
encourage colleaguesto write, and to comment on how tomake our work
and theirs more effective.
We believe that one way that this canbe achieved is by
increasing the mem-bership in the Network of Tropical Fish-eries
Scientists. Membership, which isfree and includes subscription to
Fish-byte and other benefits, is personal(not institutional) and
readers who are,or wish to be, actively involved in stockassessment
and management are en-couraged to seek nomination by writingto the
Director, Resource Developmentand Management Program, ICLARM,MCC
P.O. Box 1501, Makati, MetroManila,Philippines. 8
9
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Pauly, D. 1979. Theory and managementof tropical multispecies
stocks: areview with emphasison the SoutheastAsian demersal
fisheries. ICLARMStUdies and Reviews No.1, 35 p.
Pauly, D. 1980. Reply to Dr. BarryGoldman's letter on
"Biological Over-fishing of Tropical Stocks", ICLARMNewsletter
2(3). ICLARM Newsletter3(2): p. 22.*
Pauly, D. and N. David. 1980. A BASICprogram for the objective
extractionof growth parameters from length-frequency data.
I.C.E.S.C.M.1980/D:7Statistics Cttee. 14 p.*
Pauly, D. 1980. A new methodology forrapidly acquiring basic
information ontropical fish stocks: growth, mortalityand
stock-recruitment relationships,p. 154-172. In S. Saila and P.
Roedel(eds.) Stock assessment for tropicalsmall-scale fisheries.
Proc. Intern.Workshop, 19-21 Sept. 1979, Univ.Rhode Island. Intern.
Center Mar.Res. Development, 198 p.*
Pauly, D. and J. Ingles. 1981. Aspects ofthe growth and
mortality of exploitedcoral reef fishes, p. 89-98. In E.Gomez, C.E.
Birkeland, R.W. Budde-meier, R.E. Johannes, J.A. Marsh, Jr.and R.T.
Tsuda (eds.) Proceedingsof the Fourth International CoralReef
Symposium, Manila, Philippines.Vol. 1.*
Pauly, D. and J.L. Munro. 1982. On thedevelopment and
disseminationof newmethodologies for tropical stock assess-ments,
p. 79-87 (Annex 3). In Indo-Pacific Fishery Commission (IPFC)
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Fisheries, University of the Philippinesin the Visayas, Diliman,
Quezon City,International Center for LivingAquaticResources
Management, Manila, andthe United Nations University,
Tokyo,Japan.
Munro, J .L., editor. 1983. Caribbeancoral reef fishery
resources. ICLARMStudies and Reviews7,276 p.
Munro, J.L. 1983. A cost effective dataacquisition system for
assessment andmanagement of tropical multispecies,multigear
fisheries. Fishbyte 1(1):7-12.*
Pauly, D. and I. Tsukayama. 1983. Onthe seasonal growth, monthly
recruit-ment and monthly biomass of thePeruvian anchoveta from 1961
to1979, p. 987-1004. In G.D. Sharp andJ. Csirke (eds.) Proceedings
of theexpert consultation to examine changesin abundance and
species compositionof neuritic fish resources. San Jose,Costa Rica,
18-29 April 1983, FAOFish. Rep. No. 291, Vol. 3.*
Munro, J.L. 1984. Estimation of naturalmortality rates from
selectivity andcatch length-frequency data. Fish-byte 2(1):
11-14.*
Munro, J.L. and I.R. Smith. 1984.Managementstrategies for
multispeciescomplexes in artisanal fisheries. Proc.Gulf and
Caribbean Fish. Inst., 36.*
Pauly, D. 1984. Fish population dynam-ics in tropical waters: a
manual foruse with programmable calculators.ICLARM Studies and
Reviews 8,325 p.
10
Selected Publications on
TropicaL Stock Assessment fromICLARM's Resource Development
and Management Program1979-1984
Single copies of articles followed by an asteriskare available
free of charge from the address atthe foot of p. 9. The others may
be purchasedfrom ICLARM or its overseas distributors.
See p. 11 for ordering procedure.
Report of the Third Session of theStanding Committee on
ResourceResearch and Development. Sydney,Australia. April-May 1982.
FAO FishRep. 275. 135 p.*
Pauly, D. and G.I. Murphy, editors.1982. Theory and management
oftropical fisheries. ICLARM Confer-ence Proceedings 9, 360 p.
Inter-national Center for Living AquaticResources
Management,Manila,Philip-pines and Division of Fisheries Re-search,
Commonwealth Scientific andIndustrial Research Organisation,
Cro-nulla, Australia.
Pauly, D. and A.N. Mines, editors. 1982.Small-scale fisheries of
San MiguelBay, Philippines: biology and stockassessment. ICLARM
Technical Re-ports 7, 124 p. Institute of FisheriesDevelopment and
Research, Collegeof
ICLARM Newsletter
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Introducinga New
ManualforFisheriesScience:"FishStockAssessmentinTropicalWaters:A
Manualfor Use
with ProgrammableCalculators"
Fish population dynamics in tropical waters: a manual for use
with programmable calculators. D.Pauly. 1984. ICLARM Studies and
Reviews 8, 325 p. US$14.00 surface, $17.50 airmail (paper);$25.00
surface, $29.50 airmail (cloth); 30 preprogrammed HP 67/97 cards,
$10.00. Peso price:P200 (paper); P250 (cloth).
This manual challenges the widely-held notion that fish stock
assessment,being based on mathematical models,should remain
accessibleonly to a mino-rity of scientists working in the
researchinstitutions of developed countries.
Starting with explicit defmitions ofeven the simplest concept,
this book pre-sents a variety of methods for stock assess-ment, all
of which have been tested fortheir applicability to tropical
fish.
The methods selected cover the fol-lowing areas: length/weight
relationships,
mesh selection, fish growth, mortality,population size
estimation by variousmethods (e.g., tagging, virtual
populationanalysis), yield-per-recruit
assessments,stock-recruitment relationships, surplus-yield models,
fish population increase andaspects of multispecies stocks and
fish-eries. Emphasis was given to methodsbased on length-frequency
and other datathat are readily collected from
tropicalfisheries.
The full program listings and userinstructions of thirty
programs for usewith HP 67/97 programmable calculators
July 1984
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are included, whilethe translation.of theseprograms for use with
other types of cal.culators, espeCiallyHP 4] and TI 59, isdiscussed
in an appendix. Sixty compu-tational examples including complete
key-stroke sequencesare provided to illustratethe methods presented
in the text. Theseexamples are drawn exclusivelyfrom sub-tropical
and tropical stocks and fisheries.
PreprogrammlJd cards for HP 67/97can be purchased from ICLARM
alongwith the book, which includes a pagewithholders for 30
cards.
A supplement to this book will also beavailable from ICLARM,
which providescomplete translations of the original list-ings for
HP 67/97 for use with HP 41 Ccalculators. These translations,
preparedby J.M. Vakily and D. Pauly, make fulluse of the advanced
capabilities of theHP 41 C.
Altogether, this manual and the cal.culator programs which go
with it shouldmake fish stock assessment much easierfor its
practitioners than has been thecase to date.
This latter feature should also allow .for use of this manual as
a teaching tool,both in the context of shorter-termtraining courses
for fisheries officersand in universities, where it can serveas
background to courses in populationdynamics. .
Enquirers in the U.S.A. should orderdirectly from our exclusive
distributor there, ,International Scholarly Book Services, Inc.,
.P.O. Box 1632, Beaverton, Oregon 97075.to whom payment should be
directed usingthe airmail price. Persons in Canada andCentral and
South America may also findISBS a convenient source.
Indian readers can avail of the surfaceprice in rupee equivalent
from PioneerPublishers, D/9 Vanshree, L.T. Road,Borivli (West),
Bombay 400 092, India.
Enquirerselsewhereshouldaddressorders "and payment (payable to
ICLARM) in US$by check (from U.S.-based banks only),international
money order, bankdraft orUNESCO coupons to The Editor, ICLARM,MCC
P.O. Box 1501, Makati, Metro Manila,Philippines.
11
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Fisheries biologists trained at ICLARMin the use of the
ELEFANprograms and othermethods for tropical.stock assessment
(April 1980 to June 1984).
Visitor Dates of visitInstitution
Mr. J. Ingles
Mr. R. Regalado
Dr. Yap Siaw-Yang
Mr. Paul Dalzell
Dr. Sann Aung
Mr. Mohd Zaki Mohd Said
Mr. Mohd Azmi Ambak
Mr. G. Tampubolon
Mr. L. Pinto
Dr. K. Sivasubramaniam
Mr. Abdul Rehman AbdulGhaffar
Mr. Aye Pyo
Ms. Anette Juinio
Ms. Chan-Eng Heng
Mr. Liew Hock Chark
Mr. R. Matipa
Ms. A.S. CabanbanMs. E. Cortes-ZaragozaMr. I.D. MangaoangMr.
C.R. PagdilaoMr. N.A. Navaluna andMs. D.P. Tandog
College of Fisheries, Univer-
sity of the Philippines
Bureau of Fisheries andAquatic Resources,Research Division,
Manila
Dept. of Zoology, Universiti
Malaya, Kuala Lumpur
Division of Fisheries, Kavieng,
Papua New Guinea
Sea Fisheries Survey and Re-search Unit, Rangoon,Burma
Faculty of Fisheries and MarineScience, Univ. PertanianMalaysia,
Kuala Lumpur
Faculty of Fisheries and MarineScience, Univ. PertanianMalaysia,
Kuala Lumpur
Balai Pengem~ngan Penang-kapan, lkan, Semarang,Indonesia
Department of Biology, De LaSalle University, Manila
Bay of Bengal Programme,Colombo, Sri Lanka
Kuwait Institute of ScientificResearch, Kuwait
Sea Fisheries Survey and Re-search Unit, Rangoon,Burma
Marine Sciences Center, Univer-
sity of the Philippines,Manila
Faculty of Fisheries and MarineScience, Univ. PertanianMalaysia,
Kuala Lumpur
Faculty of Fisheries and MarineScience, Univ. PertanianMalaysia,
Kuala Lumpur
Department of Fisheries,
Chilanga, Zambia
}
M.Sc. students, University ofthe Philippines, Manila
April 1980 to March 1982
Sept. 1980 to March 1982
May-June 1981
Sept. 1982
June-Oct.1983
Nov. 1983
Nov. 1983
Nov.-Dec. 1983
Dec. 1983
February 1984
February-April 1984
April-May 1984
May 1984
June 1984
June 1984
June 1984
Various dates
