FARWEST: An international research programme (1990- 93) for the Northwestern Mediterranean demersal fisheries Farrugio H. Dynamique des populations marines Zaragoza : CIHEAM Cahiers Options Méditerranéennes; n. 10 1995

Dynamique des populations marines Zaragoza : CIHEAM

Cahiers Options Méditerranéennes; n. 10 1995

pages 53-67

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: (1990-93)

Henri FARRUGIO

IFREMER, 1 rue Jean Vilar,

-

^{Sete, France}

the have been done at a national

level in the field of assessment and management of

the last decade it has be noted a tendency to implement "analytical" methods of modelling of the exploited stocks, mainly population analysis

models. The techniques of simulation of the

hypothetical of exploitation also in the

These techniques allow to cancel part of the handicaps linked

the stocks che between and use was at a

1990).

the scientists have from the Atlantic that if

some biological exploitation are often

not

known, this should not

obstacle to assess a sensitivity

analysis techniques allow to study the impact of such and quantification, in

the of Also, the lack of long of annual

catches and length data should not a applying the

analytical techniques a good idea of the dynamics.

These analyses can which need only few

-

^{or at least}

only one

-

^of sampling of the catches. Finally it that it was possible to perform VPA on ages kngah of some meditenanean stocks exploited with gears aad to analyse the

Some mehdobgical on sampling also

been donc previously. of such that it was possible to obtain, via a sustained action in time, good data about the fishing activities ni the

This conceptual evolution have led in 1989 to the setting up of a

an attempt to solve the question of the of the &ta collecting and at a 1990 to 1993, a

Spain scientists belonging to 8

of the mast of the to the Tuscan

(fig 1).

This 4 (known the code

was aimed at the out of a common methodology the study of some

of the most topics in the Spanish and following

achieved the 4 of

-

the setting up of a common &ta base on catches, efforts and biological information,

-

the improvement of the knowledge of demographic and biological characteristics

-

a general reflexion about the methods and technics to be created a 4 adapted fitture some demersal andpelagic fuh sto& of major economic value,

common assessments and managements of the western mediterranean jìsheries.

-

an improvement of the knowledge biological parameters, fleets dynamics, fishing

-

an approach of the modelling of some of the most characteristic problems regarding the

-

some preliminary predictive studies about the effects of changes in fuhing patterns

-

^an improvement of the knowledge about economical characteristics of the fisheries efforts and capacities,

demersal fiheries the countries associated in the project,

(assessment of stocks, sensitivity analysis, simulation of selectivity).

sector.

The objective is

et a1.,1991,1994) and in

1.

of the

of the

The final two

main kinds of files :

-

a common wded fleets,

files can also of

-

^contain and biological

samplings. Some of them "exhaustive data files" aimed at the stocking of the global catches and fishing efforfs, and of

of of of "sampling data

at the stocking of non equipments of the boats, catch samples

of the in 3+

on The

scheme of of the base been built using the

fundamental concepts

The has used tool a basis the

biological and explaitation aspects.

collection of at

caught by the hake merluccius), sole

(Solea vulgaris), sea bass l a b r a ) , (Sparus auratus) and

k k t e u s antennatus. it is one

of of

The been

of 1990 to the end of to the seasons and the species, the biological monthly samplings took place in

board of

also

which where carried in the of of the

audies.

The data base been also not) of

in

of dynamics, the data base has also been fed with

.of fleets

of stock assessments, essentially by using

example the and ANACO models

cohort of exploited stocks,

aimed at

Fig. 1. programme geographic coverage

of thc studied.

sanlpling points

0

di Scicnzc dell'Ambicnte e dcl di

Grupo dc dc dc Cicncias

dc Français dc dc la

di Zoologia d i Gcnova

Arcas cikd in the text : a: sca b: gulf of c: Alicanlc d: Valencia e: Cataluña sea' g: gulf of Lions h: sea i: sea.

veral computer programs have been set up, aimed firstly at the facilitation of stocking and sorting operations and secondly at the interfacing between the data base and the assessment modelling programs (mainly the one).

The complete process, from basic data to assessment results can schematized as shown in fig. 2 below :

- > { F I

errors

I <

I

?

1

>

I I

l-

II

I

f o r

I -

-

2.1 Growth of merluccius)

it is well known that

of

usable pieces) is This

of of the

of to

to

stock assessments. The of this of

existing computation models to the available Sets of &ta and to

k e n done:

-

the same set of data

(same arca),

-

of

areas).

where by sexes,

sampled at landing in

-

Splitting in of a smoothing on

in er al.,

the et al., 1988), using inputs these

2

-

Assessment of the same sets of data,

1 of

-

^et al., 1990)

1991 data.

-

et al., for

in the Gulf of the

used estimahg paramedess. of

she growth rates of of life.

A model also been established, taking into account sizes

of some 20 for 1 40 cm

than 50 of life females, and maximum sizes 110

discounting the concept of the existence of a hake.

also been applied to

(Alicante, Spain). The by

vessels al Santa

application of

on files,

of the VBGF

Of the

to goWh

of

& 1979) methods the analysis of

cm hasized on the identification of annual is a goal t0

S

^of

57

2.1.2.

Gulf of to than one

could think to

that mean is 16 cm at the end of the of life. The

The of 1.18 obtained by means of modal length- high estimates, showing the

The of

Finally, a set of

of the spccies, the fitting of to

conditions of of to of the daily

otolilhs

For 1, 0.4 have h e n

as convenient; the global stock assessments i t has to use the sexes; for the Guif of it is best

f i t

and to values which do a suitabk

on thesc of the Von

to be used as population dynamics analyses on the of

S p a n , z i g u r .

.

^T

Tyrrhen.

both sexes

I I

.48 49.8 - 2 8

-.O44

emales es

k t o k t o

5 5 . 0

Tab. 1.- , Span.Med = Spanish = Gulf of Lions,

f.igur..p=

sea continental shelf, Ligur.S =

sea continental slope,

Ligur.T= total, Tynhen. = Tyrrhenian

22. Growth of (Arkfew anfennutus)

2.2.1. and methods

of of

is to the change of

moulting. So

techniques to of

ages. Size re on the catches have been

splitted by sex and weightcd by

f

^{catches in}

...). of and

2.2.2.

by a consensus have

been met on a set of to be used

stock assessments on this species (tab. 2).

es

O P GENOA

~

Tab. 2.- clristeus antennatus

2.3 OF

CASE OF to attempt the modelling of

l

2.3.1.

As of not long enough to

achieve classic of the case-studies

So the use of the model and has

been adopted. This modcl was specially built by the to

by ages

or state on so

that it is not suitable of these

a! the moment).

From the catch

(VPA)

tools of he can

VPA in exrensu, based on (F)

analysis of the of

a change of due to changes in

applicable to the study of

The also sense

may be can be size to

age The outputs of file to be onto a

l of ^gears.

59

k e n use on

sets of data have been used in to

of assessments based on lenght

have been done listed in table 2.

I I

G u l f

&

+ +

BASS SEA

G u l f G u l f G u l f o f

2.3.2.1.

Using the data on period 1988-1992, an analysis

Y/R) of the Spanish "hvant" in

of state of this stock to be

an exploitation scheme with

subsisting

This is

of the Y/R

to was

of

of this stock.

at of the

and models have to this 13

significant between the by the two methods.

For the of

surmuletus)

of

1980

-

1991, have been used two specific

pseudocohorts on which VPA and Yield per analyses were performed

with

the

60

inadequacy of the is applied. A

shown that using a (60mm) will in a significant of both

spccics yields and biomasses.

in a of and

populations status has been done using VPA and calculations. This

used the data catches on islands.

Exploitation pattern lightly one from The mean lengths and ages

in level is

assessments have shown a biological all

A on thc sea

coming both 13 out 1990 to 1993 and samplings at

landing. nlodcl on (1990,91,92) and on an

this The two to the same about

the state of this stock (i.e. hcavy exploitation). was shown that of the

rcsufrs by taking into account the bio-ecological

obscwations which h a w bccn donc on the last 25

basin the 1992

hakc by of uscd by the been uscd

to somc VPA and to one

have shown a heavily biological with a low age

and a values of the two bccn

shown, but in both a s e s low if to the

A of of hake in two non-adjacent of

Cataluna, Spain) has been performed

using the 1990-1992 these two

computations have been done both on lengths and ages

of in the

project The to

and Catalan that the hake can be

as the two

the Gulf of Lions, the exploitation of the hake stock is and typcs of Some analyses of its dynamics have bccn

and to the biological

was studied, as well as the These analyses have shown that, a biologicaí point of view, this stock can as heavily exploited. Another

is the evidcncc t h d mainly small individuals (i.e. have a gears

-

^{such as} gillnets and longlines

-

An assessment of the same stock has been 1988-1991, using two methods of population analysis based on

The of been a methodolgical point of

ones to the level of exploitation of hake. The

two methods give quite similar rcsdts and mean biomass. The

fishing martaiity mte on juveniles is

and for the biomass/mcan an level

of exploitation but not so high to bc 2.3.2.2.

-which is only fished at sea- the sea bass, the sea

of the main species of small-scale and

fleets in the Gulf of Lions. The on the 1986, 1987, 1991 and 1992 catch

to thcsc activitics to build a diagnosis of

61

the stocks of

period,

on and on the possible

of an of the of of fleets.

Thc havc shown that thc stocks can bc as biologically hcavily cxploitcd. They stay at low bionlass lcvcls but is to any

of Thc most of the to the

which hcavity on thc small-scaìe

of thc resulted in in yield

the fleets.

The evolution of the fishing of Aristeus antennutus on the Catalan

coast has also of The exploited

as wcll the mean size of

1983-1991; to this species has

in

of 0.5 fcmalcs and 0.8

This shows that thc fishing on this spccics is closc to the optimum.

A of A . utrfetrnatus Catalonia and Valcncia has also bccn donc.

An annua1 of by analyscd a 6 (1983-1989)

using LCA and Sonx rtnalyscs in to gct a of the

status of the stock. Scnsitivity of K A and

studicd in to evaluate the cffcct of The stocks

not t o bc far from the stcady state and a

hcncc it was possible to use LCA. The vs level closc to

not they yield.

The status of Gamba by in

adjacent zones and been

using VPA and analyses. The that is close to the

biological not show evidence of

2.3.2.3. of the stocks

l

The pol?ulatjon

aimed at the of the feasibility of a to analytical

stock assessments in

beyond this some

about the status of some stocks a biological

point of view we can state that we

diagnoses of biological full exploitation, This

situation seems to be the of both the conditions of the exploited populations and the to them. limitatcs today's catchcs

to WC

that if to a (and one) was

on thc past, such an

into a of biological of The situation

Seems to to at the

moment.

2.4. Studies gear selectivity

bcen achieved to obtain additional data which on the possible cffccts of changes in mesh sizes on the age composition of the stocks. The data of

of sea have some

among which have to be noticed the use of

of the these mixed

fisheries it can bc cxpcctcd that

62

studies on by

new aimed at selectivity evaluations by the

method, took place on local fishing boats in

(Spain) between and The data collcctcd, especially on

hake, of

and cumes assessed.

of bcen to compile all these

and to discuss about the methodologics, the of the

of on

3.

The of an

to in thc economical field to

This has been done stating that the methodological fundamcnts of totally applicable to

basic objective of this of the was not to analyscs but to imagine

a databaqe which will contain the clcmcnts to establish the managcmcnt

at the main efficiency all of the systcm". fact, it to a whole, bccause fishing is linked to

take an placc.

to the main of the database which includcs mainly eco-biological and of the files which could the economical of the bcen defincd. They consist mainly in two types of and,fleets and socio-cconomical data. of this (especially the technical one) was yct includcd in of

common database but at a step of

easily be eliminated, as the between do not poscs any technical

a encoding

of of the socio-

economical This methodology has been tcstcd on the Andaluz fishing the files

have been fed and data and sonic cxamplcs of

have bcen 4.

of b c c n u c to analyzc thc of

the hakc unit of of in two of thc

the Gulf of basin. in

the hake cpue (kg/day) have bcen to be thc of thc combination of thc following (hp), fishing fishing zonc and tinlc of (month). With

to a distinction was t o thc opening of the mouth.

into two and to d c t c n i n c thc

of the cpue a modcl has bcen used.

The daily mcan catch, vcsscl and month, showcd a high with to thc to of this study, the expcctcd hakc yicld vcsscl mainly dcpcnds on the time of and fishing zone and, to a on the vcsscl

of

withthe mcntionncd,

of hake in this area has been

in and

have been of abundance of

a of the it can be some

conclusions, that

of out up to now,

of the dynamics of exploited populations, does not

allows to to of the national bodies.

be based on full knowledge of the system and shouid

out concept.

of one of the

in of the typology of

lead to the dcfinition of well individualized units of exploitation and managemcnt.

Thc of thcsc analyses and an of the

quality of the statistics in a of species, an

of thc knowlcdgc on the biological (age, on the

Studies on

and also to be as well as thc

of the mechanisms of biomosscs fluctuations in space and time. Still at thc fundamental lcvel, tbc

to explain the to and

those of the fleets' dynamics bccome of too.

such a of

databases will be of a of the situation as a whole.

a socio-cconomic point of of the

evolution of the investments and the capital, of seems indispensable.

The also

-

^extending

-

of

and of only

sketchy knowledge is available.

64

FARRUGIO, H., F. ALVAREZ, J. LLEONART and DE RANIERI.- 1991. Study for assessment and management of fisheries in the western mediterranean, part 1. €€C-FAR MA 1-232 Final report 454 p.

FARRUGIO, H., ALVAREZ, J. LLEONART, DE RANIERI, RELlNl A. RUIZ MOLINA.- 1994.

Study for assessment and management of fisheries in the western mediterranean, part 2. EEC- FAR MA 3-621 Final report 417 p.

FOURNIER, D.A., J.R. SIBERT, J. MAJKOWSKI and J. HAMPTON.- 1990. MULTIFAN a likehood-based method for estimating growth parameters and age composition from multiple length frequency data sets illustrated using data for southern bluefish tuna (Thunnus maccoyid. Can. J. Fish.

Aquaf. Sci., 47 (2): 301 -31 7.

GAYANILO ir, F.C., M. SORIANO and D. PAULY.

-

^1988. A draft guide to the compleat ELEFAN.

Software2, ICLARM, p.

GRIFFITHS, (ed.).- Rapport du groupe de travail ad hoc sur l'aménagement des stocks en M&ilerranée Occidentale. in Rapp. Consultation Technique du CGPM sur Ilévaluation des stocks dans tes divisions statistiques Baléares et Golfe du Lion. FAO rapport sur les pêches, 447.

Rome, 1997: 57-59.

LLEONART, J J. 1992. VIT, Programa de analisis de pesquerias. Inf. Techn. Sci. Mar., 168-1691 116 p.

MACDONALD P.D.M. and PITCHER T.J.- (1979). Age-groups from size frequency data: a versatile and effrcent method of analysing distribution mixtures. Journal of the Fisheries Research Board of 987-1 001.

MESNIL,

-

1989. Computer programs for fish stock assessment. ANACO : Software for the analysis of catch data by age group on IBM PC and compatibles. FAO Fish. Tech. Pap., 101 (Suppl. 3): 73 PP.

SAILA, and PRAGER.

-

1988. Basic fishery science programs. A

compendium

of microcomputer programs and manual of operation. Elsevier, Dev. Aquacult. Fish.

Sci.

,

1 8: 231

ALDEBERT Y., RECASENS L., LLEONART J.-1994. Analysis of gear interactions in a hake fishery: the case of the Gulf of Lions (NW Mediterranean). Scientia Marina, 57(4): 207-217.

ALDEBERT Y., RECASENS L.-1994. Growth of hake in the Gulf of Lions: an appraisal of the studies canied out the 'growth working group" of the FARWEST2 MA3-621 programme. in Farrugio et' al.-1994. Study for assessment and management of fisheries in the western mediterranean, part 2. EEC-FAR MA 3-621 Final report. 45-55.

ALDEBERT Y., RECASENS L.-1994. Methods of approach for stack assessment of hake in the Gulf of Lions (Northwestern Mediterranean). id.: 141-149.

ALEMANY F., OLIVER P., REiiONES 1994. Growth of hake of the Balearic islands stock. id.: 40-44.

BlAGl F.,DE RANIERI S., VIVA 1994. Analysis of the growth of Merluccius meduccius (l.) in the northern tyrrhenian sea id.: 68-78.

65

CASTILLO CABEZAS M., RUIZ BRAVO G. & RUIZ MOLINA A.- Management of fisheries:

CASTILLO CABEZAS M., RUIZ BRAVO G. & RUIZ MOUNAA- Socioeconomic information system DEMESTRE M., LLEONART J.- 1994. Population dy'hamics of Aristeus antennatus (decapoda:

proposal for a methodology of investigation. id.:

for fisheries: application to the Andalucia Mediterranean areamid.:

dendrobmchiata) in the northwestern mediterranean. id.:

DEMESTRE M., CARBONELL A., M A R T I N E Z - W P.- Analysis of the exploited population of Aristeus antennatus (Risso, in three adjacent zones n the Spanish Mediterranean. id.:

DEMESTRE M., MARTIN Optimum exploitation of a demersal resource in the Western Mediterranean: the fishery of the deep water shrimp Aristeus antennatus (Risso, id.:

DEMESTRE M., CARBONELL k- Growth of the shrimp Aristeus antennarus: results of the FARWEST programme working group. id.:

FARRUGIO LE CORRE VAUD0 Population dynamics of sea bass, sea bream and sole exploited the French multigears demersal fishery in the Gulf of Lions (Northwesterm Meditemmar$. id.:

GARCIA-RODRIGUE2 Determination of the growth parameters using length frequencies:

application to the Mediterranean hake (Merluccius merluccius) Santa Pola bay (Spain). id.:

GARCIA-RODRIGUE2 M., RECASENS L,- Assessment of the hake (Merluccius merluccius) population in the Levante zone (Murcia-Valencia) of the Spanish Mediterranean area. id.:

GIL-DE-SOLA SIMARRO L.- Trawl selectivity in the Western Mediterranean and Adriatic sea fisheries. id.:

GIL-DE-SOU SIMARRO GAZA M.- Distribution of hake ,(Merluccius merluccius) in the Alborran sea. id.: 250-257.

LE G., P. MARTIN, M. GARCIA-RODRIGUEZ, B. REALE, and C. VIVA- The Northwestern mediterranean "FARWEST" Catches and efforts database. id.: 310-360.

LEONART J.- VITMAN: computer program for managing frequency distributions. id.:

LLEONART J.- VITSEL: computer program to prepare files for simulating selectivity changes. id.:

MARTIN REALE B., RECASENS L, SBRANA Comparative analysis of the trawling exploitation of Merluccius merluccius in two non adjacent zones of the Western Mediterranean.

MARTIN P., VIVA C.- Analysis of the variations of the Merluccius merluccius catch per unit of effort (cpue) in two areas of the Northwestern Mediterranean. id.:

MORALES-NIN B., ALDEBERT Y.- Growth and birthdate distribution of juvenile Merluccius merluccius in the Gulf of Lions (NW Mediterranean) determined by otolith microstructure and length frequency distribution. id.:

id.:

66

OUVER P.- Catch fluctuations in a trawl fishery analysis of fluctuations observed in the trawl fleet OUVER P., REilONES MASSUTI E.- Analysis of the exploitation of hake in Majorca id.:

OUVER P., MASSUTI E., REirONES A cornDarison of results obtained bv mean a cohort landings of the Balearic islands. id.:

analysis applied to a thirteen years series and to various annual iseudocohörts. id.:

ORSI RELlNl L., FIORENTINO F., RELlNl ZAMBONI A.- An attempt to evaluate ligurian hake RAMOS F., BARO J., CAMIñAS J.A.- Artisanal fisheries resource mapping in the Spanish REALE DE RANIERI S.- FARSOFT (FARwest SOFTware): computer program for the

REALE B., SBRANA M., VIVA Analysis of the exploitation of Merluccius merluccius by two RECASENS L.,GARCIA M.,MASSUTI E.,OLIVER P,,REiiONES Population dynamics of hake SBRANA SARTOR P.- Selectivity of an "Italian' trawl net in the Southern Tuscan arcipelago. id.:

resources, with notes on the biology and dynamics of Merlucuus. id.:

Mediterranean region: methodological aspects. id.:

management of the FARWEST database files. id.:

different types of trawl in the Northern Tyrrhenian sea. id.:

(Merluccius merluccius) in the Spanish Mediterranean fisheries. id.:

67