Document 11856993
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NOT TO BE CITED WITHOUT PRIOR REFERENCE TO THE AUTHORS
C.M. 1998/0:21
Deepwater fish and fisheries
International Council for the
Exploration of the Sea
Growth study of white and black anglerfish (Lophius piscatorius Linnaeus,
1758; L. budegassa Spinola 1807) based on annual sampling in the southern
stock (ICES Divisions VIlle and IXa)
by
J. Landa', P. Pereda', R. Duarte2 and M. Azevedo 2
jorge.landa@slieo.es pilar.pereda@st.ieo.es rduarte@ipimar.pt mazevedo@ipimar.pt
1 Instituto Espailol de Oceanografia. PO Box 240. 39080 Santander. Spain
'Instituto de Investiga9ao das Pescas e do Mar, Avenida de Brasilia, 1400 Lisboa. Portugal.
--
ABSTRACT
The growth study of Anglerfish Lophius piscatorius and L. budegassa is presented for the southern
stock (ICES Divisions VInc and IXa). It is the first time that growth of this species has been studied
throughout a one year period. Samples were obtained between July 1996 and June 1997 from
commercial landings and research surveys (IPlMAR and lEO). The sampling program was established
by the EC Study Project 95/038 "Biological Studies of Demersal Fish". A total of 844 and 1049
individuals ranging from 14 cm to 140 em and from 5 cm to 93 cm in length were aged for L.
piscatorius and L. budegassa. respectively. Ageing was based on growth ring counts of transversal
sections of the illicium (first dorsal fm ray). Age length keys are presented by quarter with the observed
mean length at age and mean weights at age. Estimation of the von BertalanffY growth parameters by
sex and for combined sexes is performed. The obtained growth parameters are for L. piscatorius
females: Linf= 140.50 cm, k = 0.08 year", to = 0.09 year; for males: Linf= 110.50 cm, k = 0.11 year",
to = 0.26 year and for combined sexes: Linf= 140.50 cm, k = 0.08 year", to = 0.23 year. For L.
budegassa females: Linf= 110.10 cm, k = 0.08 year", to = 0.39 year; for males: Linf= 72.90 cm, k =
0.13 year'I, to = 0.36 year and for combined sexes: Linf= 132.40 cm, k = 0.06 year", to = 0.04 year.
The discussion of these results and the comparison with previous studies is made.
Keywords: Age length keys, ageing, anglemsh, growth, illicium, Lophius budegassa. Lophius
piscatorius, monkfish.
INTRODUCTION
The two species of monkfish (Lophius piscatorius and L. budegassa) in the southern stock
(ICES Divisions VIIIc and IXa) are an important component of the by-catches of the
European fisheries of both bottom trawl and artisanal fisheries. The mean armual catch of L.
piscatorius and L. budegassa in these divisions over the last five years have reached 2247 and
1876 tonnes, respectively (Anon, 1997). The exploitation assessment of the northern stock
(ICES Divisions VIIIa,b and Subarea VII) and southern stock (ICES Divisions VIIIc and IXa)
(Figure 1) of this species are made armua1ly within the ICES Working Group on the
'<.:,
Assessment of Southern Shelf Demersal Stocks. While age-length keys are available from 1987
for the northern stock (Anon., 1997) and can be used to obtain age composition of catches, the
basis of analytical techniques of assessment, they are not available for either species of
southern stock monkfish (L.budegassa and L. piscatorius).
Growth of these species has been studied in other areas (Fulton, 1902; Guillou and Njock,
1978; Tsimenidis and Ondrias, 1980; Dupouyand Kergoat, 1985; Dupouy et al. 1986; Crozier,
1989; Peronnet et al. 1992) using otoliths and tra,nsversal. sections of illicia as anatomical
pieces for age determination. The only studies on growth of this species in the southern stock
are those of Azevedo, 1992; Duarte et al., 1997 and Landa and Pereda, 1997. Azevedo (1992)
estimated, for the first time, growth parameters for the southern stocks of L.budegassa and L.
piscatorius for both sexes combined using Shepherd's Robust Length Composition Analysis,
SRLCA (Shepherd, 1987). Growth parameters for L.budegassa and L. piscatorius were
estimated for the 1993 Working Group based on the mean lengths at age observed in direct
reading of illicia and identification of modes in the length frequency distribution found in
surveys. From these parameters an attempt was made to estimate age compositions of the
catches by slicing length compositions (Anon., 1994). Duarte et al. (1997) and Landa and
Pereda (1997) studied growth based on mean lengths at age derived from direct reading of
transversal sections of illicia and identification of modes in the length composition from
research surveys. Nevertheless, the reading technique was not validated for the different age
readers of the southern stock of these species. In 1997 a workshop was held on age
determination of both species of monkfish, in which the two countries (Spain and Portugal)
responsible for monkfish age reading for the southern stock participated together for the first
time. The estimations ofthe readers from the two countries were' compared and validated, and
reading criteria were established. Asa result, this paper presents a first annual study of the
growthofboth species in the southern stock. Growth in each quarter is shown separately and
differences between sexes are presented. A attempt is made to improve the knowledge of the
growth' of this species and to apply analytical methods for the first time to assess the state of
exploitation of the southern stock.
Data were collected by the sampling program established for the EC Study Project 951038
"Biological Studies ofDemersaI Fish" (Azevedo and Duarte, 1998; Landa and Pereda, 1998).
MATERIAL AND METHODS
Sampling
Individual age was determined by growth ring counts on transversal sections of the first dorsal
fin ray (illicium) according to the ageing workshop held in Lorient (Dupouy, 1997). Age was
determined for a total of 844 and 1049 illicia of L. piscatorius and L. budegassa respectively,
collected between 1 July 1996 and 30 June 1997 in Spanish and Portuguese waters (ICES
Divisions VInc and IXa). Most of the illicia come from specimens landed by the Spanish and
Portuguese commercial fleets which operate in waters of the area of the study and from
specimens collected in research surveys carried out in the same period.
In each quarterly period it was ensured that a minimum of three illicia were collected for each 1
em length class, attempting to cover the whole length range of the species. Lengths were
2
,,
measured to the lower cm. Table 1 shows the number of illicia and length range covered in
each quarter for each sex.
Illicia
Mounting and slicing of illicia was carried out following the methodology described by Duarte
et al. (1997). Age readings were made by two readers using a binocular microscope (100 X)
under reflected light. A video monitor was connected to the microscope to facilitate and
validate observations between the two readers. The interpretation of growth rings followed the
criteria adopted in the Workshop on anglerfish age determination (Dupouy, 1997).
Growth parameters
Growth parameters were estimated from individual lengths at age, for which a fit was made of
the real age of each specimen. This real age of each specimen was estimated as a function of
the season of capture. To do so the proportional part of the year (month) in which it was
caught was added to the age estimated by reading the illicia. With this adjustment, the
differences in the "Sampling periods, which might introduce an element of error into the
estimation of growth parameters, are minimized.
The theoretical growth model to which individual data are fitted is the VOn Bertalanffy growth
equation (1938).
Lt = length at age class t.
Lin/= maximum length the species can reach.
k = instantaneous growth coefficient.
t= age.
to = point at which the Von Bertalanffy curve intersects the ahcisas axis.
Growth parameters were estimated by using algorithms for least-squares regression. The
values 0 f Lin! for L. piscatorius estimated automatically by the statistical pro gramme are quite
different from what was observed experimentally. With the aim of choosing values of Lin!
which fit the lengths at age estimated better than those offered automatically by the statistical
programme, the value for Lin! as the greatest length observed during the period of samplings in
the study area, was taken. Considering that practically all of the specimens over 11 0 cm are
females, their growth parameters were also estimated by taking Lin! as the maximum length
observed in unsexed specimens in the sampling period (140.5 cm).
RESULTS
Age-length keys
Tables 2a-h present the combined length-age keys for both sexes for each quarter studied,
showing the number of specimens studied by length class and the total by age class. The annual
length-age keys of males, females and combined sexes are presented in Table 2i-n. These
combined length-age keys include the ages ofunsexed specimens mainly from specimens which
had been totally gutted when landed and from very young indeterminate specimens. The range
3
- -------,- - - - -
._--------------".. _ - - - - - - - - -
of lengths and ages of each quarterly length-age key differs as a function ofthe number of
specimens collected for each quarter. Differences also appear in the ranges of the keys
depending on sex.
Mean lengtb at age
Table 3 shows the annual values of the observed mean lengths at age by quarter for combined
sexes. A successive progression is .observed in the values of mean lengths throughout the
quarters,. more patently in yo ung ages than in old.
Of all the age classes used in the estimation of mean lengths at age, some include only a few
specimens. Generally these were poorly represented age classes: older ages or ages
corresponding to quarters with few sampled specimens. Other age classes, although they had a
greater number of specimens, did not have specimens throughout the entire length range
corresponding to that age, as did the young. age classes, which are not totally accessible. to the
gear. Thus, ages 0 and 1 are not commonly present. in commercial landings, which generally
include specimens from age 2.
Table 4 shows annual mean lengths, standard deviations and number at age by sex and for
sexes combined. Figure 2 presents the annual values for each sex. The observed mean length at
age for males is similar to that of females to age 2 for L. piscatorius and to age 7 for L.
budegassa. Thereafter, males are smaller than females at the same age. Very few males older
than 13 years and very few females older than 16 years are observed in either species.
Practically all unsexed specimens over 13 years are females.
In both species, the mean lengths of females are expected to increase with age, which is
observed to age 10. Nevertheless, in ages 11, 12 and over this continued increase is not so
clearly and regularly observed. This is due to lower sampling levels, higher standard deviation
and lower ageing (Figure 2).
Mean weigbt at age
TablesS and 6 show the annual values of the observed mean total weight and gutted weight at
age by quarter for combined sexes. As in the case of mean lengths, mean weights also show a
progressive increase through the .quarters, more easily seen in the first ages than in older ones.
Tables 7 and 8 show annual mean weights, standard deviations and number of specimens at age
by sex and for sexes combined. Figures 3 and 4 present the annual values for each sex. From
age 10 and 11 onwards, the mean weight increase is lower than expected. As to mean lengths
at age, it is due to a lower sampling levels, a higher standard deviation and a lower ageing.
Growtb parameters
Annual growth parameters of the von BertalanffY growth curve were estimated for each sex
and for sexes combined using all observations (Table 9). The growth curves are shown in
Figure 5.·
4
DISCUSSION
Age-length keys
This is the first time that annual age-length keys by sex and both sexes combined have been
presented, together with quarterly keys for a full year. The range of lengths and ages of both
species are well represented. The dispersion of the length ranges of older ages in the keys by
sex is due to the slowing down of growth at these ages. In the combined keys, the effect is
duplicated on adding the dispersion of males to that of females. Very large specimens of L.
piscatorius which appear in greater abundance in the combined key of the first quarter mostly
correspond to large mature females (Duarte et al., 1998).
Mean length at age
It must be considered that the extremes of the length range and, therefore, of ages are difficult
to sample. Thus, fOr L. piscatorius no specimens of age class 0 are found, and so the value of
its mean length could not be estimated. Age class 0 of L.budegassa and age class 1 of L.
piscatorius are not Jiill.y recruited to the gear and the values of their mean lengths are probably
overestimated as they are mostly made up of specimens larger than those found in these
classes. Furthermore, in specimens less than 15 cm it is difficult to distinguish sex, and so
young ages of each sex have biased values for their mean lengths. Older ages of each sex are
composed of a very small numbers of specimens, and as ages have a wide range of lengths, the
values of their mean lengths are highly variable.
The progression in the values of mean lengths throughout the quarters, more patently observed
in young ages than in old ones, is due to the length range and variability within each age being
greater and the number of specimens lower. This is due in turn to the slowing down of growth
and to the lower abundance of large specimens.
The results in this paper once more reinforce the different growth pattern by sex, females
attaining greater body length. This differential growth by sex, with higher mean lengths at age
and longevity in females, may be generated by the distinct maintenance metabolism of the two
sexes (Pauly, 1994). This differential growth and longevity are outstanding features of other
species, such as Pleuronectiform fish, which, like both species of the genus Lophius, are also
found in a habitat in direct contact with the bottom, which may be related in some way. Both
species have a different age of first maturity as a function of sex, with males reaching maturity
between approximately 2 and 3 years befure females in both species (Afonso-Dias and Hislop,
1996; Duarte et al., 1998). This earlier start of spawning in males, with its consequently
greater metabolic consumption may be the cause of the higher natural mortality in males which
limits their longevidad (Pauly, 1994). Nevertheless, these natural causes of the higher mortality
of males may not be the only ones. Beverton (1964) suggested that males are more accessible than
females in the English North Sea plaice fishery, especially at spawning time. Rijnsdrop (1993)
showed that fishing mortality is determined also by the increase in males' vulnerability during the
spawning period. The differential sex ratio found throughout the year in L. piscatorius, with
higher abundance of males in the first months of the year (Duarte et al., 1998) may make them
subject to greater fishing mortality in this season owing to their greater vulnerability.
Additionally, the scarcity of females in catches in the same season, due to their lower presence
in the area, makes them less vulnerables, thus increasing the differences in fishing mo rtality
between the two sexes. This leads to the consideration that the differences in longevity may be due
5
not only to natural mortality (M), as in Scott and Scott (1988) and Cardenas (1996), but also to
differential fishery mortality (F).
Mean weight at age
The reasons for the mean weight increase lower than expected from age 10 and 11 onwards
are the same as those referred to for mean lengths.
From weight data it is seen that standard deviation is greater at age for total weight than for
gutted weight, probably asa consequence of stomach content and gonad development in the
former.
Growth parameters
Regarding sexes combined, including extra individuals for which sex information was not
available, the Lin/ estimate is rather higher than expected. The growth curve for sexes
combined was expected to be between the female and male growth curves, which is not
observed in this estimation (Figure 5) due to the weight of some males in the curve adjustment
and the curve of sexes combined greatly influencing large sized indeterminate specimens,
almost all females.
On the other hand, Lin/of this study is higher than the previous estimate, owing to the greater
coverage of the length range, and consequently age range, in this case particularly large, than
in previous studies. The expected mean length at ages 1 and 2 given by the estimated growth
parameters are lower than observed mean lengths (Table 10), possibly. due to observed lengths
being somewhat overestirnateddue to the inclusion of specimens larger than the length range
at age. The length range and, consequently, age range decisively influence the estimation of the
parameters of the growth curve.
If we compare the growth parameters of L. piscatorius, we see that Azevedo (1992) presents
faster growth than the remaining authors in the two hypotheses suggested. Her samples come .
from landings of the commercial fleet and the length range of the species is not fully
represented in the first ages. This absence of samples in young ages may have influenced the
differences found. in parameters in comparison with the rest of the authors; With respect to the
other papers, it must be considered that the age ranges studied to the present are lower than
those presented in the present study. Thus, the ages studied by Duarte et al. (1997) are up to 8
years, and up to 12 years in that presented by Landa and Pereda (1997), against the 24 years
estimated in the present work. On the other hand, the inverse relationship between Lin/ and k
also influences the comparison of both parameters. Thus, when similar values of Lin/are
estimated, although there are some differences in mean lengths, the variations in the values ofk
are minimal. For this reason the growth parameters estimated by the different authors who
have studied this species in thesouthem stock are, in general, quite similar. It is observed that
for both sexes combined and for Lin/to have values between 120 and 140 cm, the value of k
varies between 0.08 and 0.11. It may, therefore, be more useful to compare mean lengths than
the growth parameters themselves. Table 10 shows that the values for mean lengths of L.
piscatorius obtained in the presentpaperaresimilarto those estimated by Duarteet aL (1997)
in the same area of study. In the paper by Landa and Pereda (1997), while mean lengths of the
first ages are similar, some differences exist in older ages. This is probably due to the use ofa
binocular microscope in that work (40 X) for illicia reading, which possibly prevented the
6
differentiation of certain annual rings in the older ages. Following the Ageing Workshop in
1997 the use of 100 X magnification was established for illicia reading, thereby enabling the
distinction of all the rings. Thus, using the same reading technique, the values of mean lengths
in the present work are practically the same as those presented in the Ageing Workshop of
1997, with the exception of the first ages, in which differences were observed, probably due to
the narrow length range taken in the Workshop and to the variability in interpretation.
The growth parameters of L. budegassa estimated in the present work show certain differences
with respect to those estimated by Duarte et al. (1997). Lin/is greater and the value of k lower
than in the previous study. These differences are mainly due to the greater age range with
which the parameters have been estimated in the present paper. This means that the value 0 f
Lin/ is greater and that k diminishes. If we look at the mean lengths at age, we see,
nevertheless, that there are no great differences between the values observed in both papers,
only the value of one 'year of age approximately.
ACKNOWLEDGEMENTS
'.
Thanks are extended to Maria Sainza and Joaquin Barrado for their assistance in illicium
sampling and the preparation of the material. Also to Paulino Lucio, liiaki Quincoces, Marina
SanturtUn, Jesus Martinez and Susana Arego for their suggestions on the use of instruments
for the preparation of the material.
REFERENCES
Afonso-Dias, LP. and Hislop, J.R.G., 1996. The reproduction of anglerfish Lophius
piscatorius Linnaeus from the north-west coast of Scotland. Journal of Fish Biology 49
(Supplement A), 18-39.
Anon, 1994. Report of the Working Group on the Assessment of Southern Shelf Demersal
Stocks. ICES CM 1994/Assess :3, 447 pp.
Anon, 1997. Report of the Working Group on the Assessment of Southern Shelf Demersal
Stocks. ICES CM 1997/Assess :5, 617 pp.
Azevedo, M., 1992. Update of monkfish Portuguese catch statistics. Working paper presented
to the 1992 meeting of the ICES Working Group on the assessment of Southern shelf
demersal stocks 8-17 September 1992. Copenhague, IPlMAR (mirneo), 14 pp.
Azevedo, M. and Duarte, R., 1998. Black Anglerfish from ICES Divisions VIIIc and IXa. In:
Biological Studies of Demersal Fish. Final report to the Commission of European
Communities (Study contract 95/038) Ed. P. Pereda. 38 pp
BertalanflY, L. von., [938. A quantitative theory of organic growth (inquiries on
growth laws II). Hum. BioL, 10: 181-213.
Beverton, R.I.H. 1964. Differential catchability of male and female plaice in the North Sea and
its effect on estimates of stock abundance. Rapp. P.v. Reun. Cons. Int.Explor. Mer 155, 1037
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112.
Cardenas, E. 1996. The fernales ratio by length as .an indicator of sexual differences ,in
mortality at ages 8+ of Greenland halIbut (Reinhardtius hippoglossoides). NAFO SCR Doc.
N° 96/35 N2710, 10 pp.
Crozier, W.W., 1989. Age and growth of angler-fish (Lophius piscatorius L.) in the North
Irish Sea.. Fish. Res., 7:267-278 ..
Duarte, R., Azevedo, M., Landa, J.. and Pereda, P. 1998. Reproduction of black andwhite
anglerfish (Lophius budegassa, L. piscatorius) in the southern stock (ICES Divisions VIlle
and IXa). ICES C.M.1998/0:23, 21 pp.
Duarte, R., Azevedo, M. and Pereda, P., 1997. Study on the growth of southern bla(;k
monkfish and white monkfish stocks. ICES Journal of Marine Science, 54: 866-874.
Dupouy, H. and Kergoat B., 1985. Donnees sur la croissance de !a baudroie blanche (Lophius
piscatorius) des cotes franr,:aises de l'Atlantique (Divisions CIEM VIl et VIII).- I.C.E.S. Com
C.M. 1985/G: 36: 22p.
Dupouy, H., Pajot, R. and Kergoat, B., 1986. Etude de la. croissance des baudroies, Lophius
piscatorius et L. budegassa, de VAtlantique Nord-Est obtenue a partir de l'illicium. Rev .. Trav.
Inst. Peches marit., 48: 107-131.
Dupouy, H. 1997. International Ageing Workshop on European Monkfish. Lorient, 25-28
June 1991 and 9-11 July 1997. IFREMER 1997.
Fulton, W.T., 1902. The distnbution,growth and food ofthe angler (Lophius piscatorius L.).
Rep. Fish. Bd, Scotland, 21, Part III: 186-199, 1 tab!.
Guillou, A. and Njock, I. C., 1978. Analyse de !apeche dans les ports de !a cote Atlantique
franr,:aise de 1961 a 1975 et des incidences du chalutage sur les stocks des principales especes
concernees par cette activite dans les mers adjacentes . Rev. Trav. Inst. Peches marit., 42 (l y
2): 17-164.
Landa, I. and Pereda, P., 1997. Growth of white monkfish (Lophius piscatorius, L.) in the
Northern Spanish continental shelf (ICES Divisions VIllc and IXa). ICES C.M. 1997/CC:07.
Landa, I. and Pereda, P., 1998. White Anglerfish from ICES Divisions VIllc and IXa. In:
Biological Studies. of Demersal Fish. Final report to the Commission of European
Communities (Study contract 95/038)Ed. P. Pereda.. 37 pp
Pauly, D., 1994. On the sex of fish and the gender of:scientists: essays in fisheries science. Fish
and Fisheries series. Chapman and Hall, London: 1-264.
Peronnet, Y., Dupouy, H., Rivoalen, J.I. and Kergoat, B., 1992. Methods of ageing based on
caudal fin-rays for megrim (Lepidorhombus wiffiagonis) and on sections of illicium for
anglerfishes (Lophius piscatorius and L.budeg). CoUoq; NatL ORSTOMIINRA. Boudy
(France) 4-6 marzo 1991.
8
Rijnsdorp, A.D., 1993. Selection differentials in male and female North Sea plaice and changes
in maduration and fecundity. In: Stokes TK, McGlade 1M, Law R (ed). The explotation of
evolving resources. Springer Verlag, Berlin: 19-36.
Scott, W.B. and Scott, M.G. 1988. Atlantic fish of Canada. Can. Bull. Fish. Aquat. Sci. 219:
731 pp.
Shepherd, J. G., 1987. A weakly parametric method for the analysis of length composition
data. In Length-based methods in fisheries research. Ed. by D. Pauly and G. P. Morgan.
ICLARM Com. Proc., 13, Manila.
Tsimenidis, N. CH. and Ondrias, J.CH., 1980. Growth studies on the angler fishes Lophius
piscatorius 1. 1758 and Lophius budegassa Spinola, 1807 in Greek waters. Thalassographica,
Volume 3, N° 2.
-.
9
.Table 1. Number and range ofillicia readings for each sex and for combined sexes.
L. piscatorius
Period
1996 (Q. 3) Total number
Min. Length (em)
Max. Length (em)
Males
41
16
97
Females
42
23
95
Combined
164
16
112
1996 (Q. 4) Total number
Min. Length (em)
Max. Length (em)
89
86
89
15
112
239
14
119
1997 (Q. I) Total number
Min. Length (em)
Max. Length (em)
85
19
110
85
22
122
235
19
140
1997 (Q. 2) Total number
Min. Length (em)
Max. Length (em)
77
23
87
93
20
126
206
20
126
Total number
Min. Length (em)
Max. Length (em)
292
16
110
309
15
126
844
14
140
Period
1996 (Q. 3) Total number
Min. Length (em)
Max. Length (em)
Males
70
15
58
Females
80
15
78
Combined
178
7
78
1996 (Q. 4) Total number
Min. Length (em)
Max. Length (em)
64
17
67
74
16
85
221
5
85
1997 (Q. I) Total number
Min. Length (em)
Max. Length (em)
96
15
60
139
20
89
329
1997 (Q. 2) Total number
Min. Length (em)
Max. Length (em)
118
18
57
104
17
82
321
Total
348
15
67
397
15
89
1049
5
93
18
~
Total
L. budegassa
Total number
Min. Length (em)
Max. Length (em)
Il
93
Il
88
Table 2a
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'n,
,'no
'n,
,.,
,.,
, ,,
,
Table 2c
,
,
,,
,
,
,
,,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,,
,
,
,
,
,
,
,
,
,
,
,
~
,
,
,
,
,
,
,
,
,
,
,
,
,
I
,
,,
,
,
,
,
,
,
,
,
,
,
,
,
,
, ,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,,
,
,
,
,,
,
,
,
,
,
,
,
,
,
,
,
, ,
,, ,
Table 2d
_.
'"'"
'"
'"'" ,
""
"'
n,
--,
,~
,
"
,
,
,
,
"
,
"
,
"
11.5
~,
~,
'"
...••
~,
n .•
,
,
,
,
,
,
,
,
,,
,
,,
,,
,
,
,
,,
,
,
D.'
l1.5
~.
n,
•..
M.'
••
n .•
••
0.'
~,
41.5
,,
~.
~.
"'
0.'
0.'
su
'"
2'
,
,,,
,,
,
...••".g.,
-
••
'"
,,
,,,
,,
,,
,
,
,, ,
,
,,, ,,
,
, ,
,,
, ,, ,,,
,, ,, ,
, , ,
, ,,, ,
,,
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••
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••
0.'
••
""m.
71,5
"...
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".
n .•
"'.
"'.
no
~
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•
"""..
.,
""
~,
...
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,
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,,
,,,
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,,,
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,,
,,, I
,
,,,
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,, I
,
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0.'
.....
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••
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'7.~
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"",
,
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,
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,,,
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,
,
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=.
,
...
,'M'
...
101.5
,''''.
,
,
,~.
107.5
,
,
,
,,.,
105.5
,
,
,
,
,
,
,
"0.5
I
",,5
.
112.5
",,5.5
Il.U
1115
,
,'no
•
,n,
,n,
,
.,..
.n.
.,,'
.,.
""
,no
1JotS I
,:as
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,g.
,,,.
,
,
,
127.5
,
,
,
,
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,
,
11115
l1!U
..
,
,
,
I1:U
,,,,.
I·
,•
,,,
,,
,,,
,,, 1
,
,
,
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.
,
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,
,
,
,
i
,
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1:».5
•
,
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,
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,,
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,
I
Table 2h
combined _
L /Judt QJStl. '991
Lion
a
1
3
2
4
•
5
S.5
8.S
7.S
8.S
9.S
10.5
7
,
,
8
rn
10
"
11
,
13
17
18
19
20
Total
21
,
I
11.5
12.5
13.5
14.5
15.5
1
1
,
16.S
17.5
IS.S
19.5
I
20.5
I
21.5
22.S
I
23.5
24.5
25.5
26.5
i
1
3
4
2
3
4
1
1
3
4
3
3
8
I
1
I
I
2
3
2
S
1
•,
•
26.5
29.5
30.'
31.5
32.S
33.5
34.5
35.5
,
1
2
7
4
3
-
7
7
,
I
7
3
2
3
S
S
1
8
8
10
8
7
8
1
38.'
37.5
38.'
39.5
1
3
4
1
1
1
4
,•,
I
S
S
,
2
41.5
5
1
42'
43.5
1
3
3
3
....,
S
3
7
1
47.5
•,
•
1
•
44.'
45.,
S
5
4
4
4
4
4
4
49.5
1.5
2.'
2
1
2
2
1
1
1
4
4
4
3
1
I
".S
55.5
...,
,
,
S
5
1
4
.,
SO.5
60'.5
62.5
83.5
".5
4
1
1
1
1
4
3
7.'
59,5 I·
1
4
3
S
5
,
1
2
2
S
10
8
7
3
3
1
8
4
3
5
1
1
2
1
65.5
3
".5
67.5 i
.,
I
1
1
3
,
8
:
1
8
2
1
2
89.5
70.S
I
71.S
72.5
1
a
,
2
14.5
2
2
2
75.5
I
a
,
711.'
,.,.,
,,
1
2
1
I
82.5
...,
,
I
85.5 I
,
,
I
,
,
I
66.5 I
I
I
87.5 ;
,
88.5 I
I
I
I
:
I
I
I
I
,
I
I
'1
I
27
43
·22
20
. 33
... "
I
I
I
I
I
27 I
15
I
:
I
I
8
15
1
I
8
1
a
I
3
I
,
2
1
,
,I
I
,;
I
1
I
91.5 I
I
,:
I
I
1
1
I
I
9O.S
2
3
3
3
1
I
B9.S .
,
,
1
,
,
I
2
3
63.5
,a
,
,
I
1
1
au
,
1
a
OO.S
4
4
3
7
I
I
4
I
77.5
1
8
2.
2
3
4
73.5
76.S
.
3
4O.S
.,
.,.,
.,
...
3
27.5
92.5 I
93.5
94.5 I
95.S I
Total '
18
15
14
,
,
,
I
I
I
;
I
I
I
,
I
321
;
...
Table 2i
Table 2k
.,
Table 21
L bud
flU.
Lt em
5.5
'.5
7.5
'.5
9.5
0
Annual. mala
,
,
•
3
2
,
7
9
"
I
."
A
11
I
I
,
" " " " " " "
I
"
Total
,
I
,
10.5
20
"
'1,5
12.5
I
I
13.5
14.5
15,5
18.5
I
3
11.5
2
7
18.5
3
2
,
3
21.S
22.5
23.5
24.5
25.5
26.5
·
i
, ,
,,
",, ,
,, ,
,•
19.5
2<l.5
3
2
7
5
I
•.
9
5
"7
2
27.5
28.5
•
31.5
32.S
33.5
"•
,,
3
2
I
,
34.'
35.5
88.'
31.5
36.5
39.'
<0.'
9
I
1\
30.'
,
,
,,
I
29.5
,
11
,
7
7
,
•••
•,,
I
I
2
3
•
,• ,
, ,,,
, •
••
,
I
I
I
]
I
41.S
.
42.5
43.5
I
1
I
I
,....
"
,.
2
3
,
6
I
7
2
49.5
2
1
S
3
2
S
2
51.5
I
,2
52'
5>5
54.'
5S.5
56.5
57.S
56.'
14
12
,
I
2
]
SO.,
..
12
1B
I
,• ,
•, ,
,
•
I
48.5
47,S
48.'
11
2
,
]
,."
1
11.
•
3
7
I
2
I
2
2
I
,
,t
2
I
I
1
3
I
I
I
59.5
I
,
60.5
,,,
61.5
..
11
t
I
I
I
63.5
64.5
65.5
i
t
68.5
I
69.S
"'.5
71.5
72.5
73.5
,
I
,
74.5
75.5
I
,
78.5
79.5 I
80.5
,
I
,
03.5
".5
,
85,5
I
,
,
,
I
I
88.5
I
,
I
I
,
I
62.5
I
I
97.S
I
,
,
,
,
,
92.5
93.5
".5
95.5 ,
,i
,
I
I
I
I
I
I
I
I
I
18
,
,
I
,
I
" '" "
I
I
I
I
I
30
..
I
I
,
56 I
,
,
,
,
I
I
I
,
I
I
,
I
I
,
2.
I
I
5
5
t
I
I
I
,
,
. i
,
I
,
,
I
I
I
I
I
,
,
I
I
,
,
,
"
,
i
I
90,5 i
91.5 ,
T,""
I
i
!l1.S
I
I
76.5
77.5
69.5
,
,
I
67.5
".5
t
I
66.5
I
I
,
I
I
,I
,I
....
Table 3. Observed mean length (ML), standard deviation (SD) and number (n) at age for combined sexes by
quarter.
L. piscatorius
Ag. (years)
1st Quarter
4 tl1 Quarter
JrdQuarter
ML (em)
SD (em)
n
ML (em)
SD (em)
n
3
6
ML (em)
SD (em)
n
19.00
2.96
26
28.94
3.52
18
24.17
2.71
2""Quarter
SD( em)
n
25.39
1.59
I
9
31.63
38.56
3.1'
3.17
16
ML (em)
o
18.50
2.16
2
28.00
2.57
3
4
34.00
1.98
12
35.74
3.25
17
31.86
1.77
9
11
20.50
40.65
3.01
41.86
3.80
22
38.ll
3.89
24
8
5
46.61
1.66
II
9
48.35
2.90
13
45.31
4.00
16
46.10
2.15
15
6
5J.43
3.94
15
53.69
3.47
16
52.94
3.28
27
52.36
3.68
21
7
60.37
4.00
23
60.36
4.43
22
60.50
3.71
9
57.90
3.88
15
8
66.41
71.50
3.57
22
67.50
4.92
18
66.85
6.12
20
66.31
5.10
31
2.85
17
73.20
3.98
4.50
19
73.87
17
82.00
5.24
78.55
19
81.13
II
6.52
14
89.90
4.40
20
85.19
5.89
6.82
'.59
5.82
19
4.34
20
24
70.03
79.32
86.64
16
88.50
5.56
5.75
4.15
II
9
10
12
91.67
4.71
6
93.39
4.58
9
89.07
6.ll
14
90.10
13
92.17
2.87
3
95.25
1.48
4
92.75
5.20
16
95.68
I.
105.50
105.50
5.10
3
99.50
7.07
3
98.00
2./8
15
86.50
99.30
5.23
5
101.83
3.30
16
112.50
105.38
4.11
97.50
115.50
3.00
8
2
1
4
103.50
17
121.50
..
112.50
4.60
5
18
110.50
19
114.25
1.50
7.66
118.50
2.16
3
6.87
4
22
120.25
124.50
4.00
23
138.00
2.50
2
2
24
134.50
20
114.00
2
21
16
15
II
•3
I
108.83
3.68
110.00
3.50
3
2
107.50
126.50
25
Total
164
239
235
206
L. budegassa
JrdQuarter
4"Quarter
I"Quarter
Ag. (years)
ML (em)
SD (em)
n
ML (em)
SD (em)
n
a
7.7
0.6
3
6.5
2.1
2
2
ML (em)
2"'Quarter
SD (em)
n
15
11.2
1.3
9
II
1.3
7
II
16.1
2.1
16
17.5
2.2
17
16.2
1.3
ML (em)
SD(em)
n
II
3
21.9
1.6
16
25.6
1.5
9
21.1
1.8
25
22.3
2.5
27
4
28.4
3.3
21
28.9
2.4
12
26.3
1.8
28
28.3
2.5
43
5
6
36.5
4.6
24
32
2.2
15
31.8
2.3
22
32.2
2
22
44.2
4.4
21
37.3
1.7
II
36
2
23
l7.3
2.8
20
12
42.1
4.7
33
2.6
26
51.5
6.8
48
7
44.8
2.6
13
41
2.4
10
40.2
8
46.7
2.1
3
44.7
3.3
II
44.5
9
54.2
3.8
13
50.7
4.8
12
49.3
3.6
29
58.1
5.6
52
10
58.5
5.4
16
54.8
7.2
22
57.5
5.5
29
64.3
5.6
27
II
58.8
3.4
15
60.6
4.5
20
60.3
4.3
JJ
70.8
l.4
15
12
58
o
2
60.6
6.2
35
66.2
5.3
12
74.5
1.1
8
13
63.5
9.2
2
69.1
7.2
14
69.6
4.5
19
79
2.6
15
14
70
74.8
7.3
14
73.9
4.5
11
77
15
73
64
8.5
3
74.8
4.3
10
84.3
2.9
6
16
74
80
5
3
78.4
3.7
12
85
1.7
3
17
78
80.3
1.5
3
79.7
3.3
10
82
4
6
84.5
4.8
4
18
19
80
20
87
21
Total
93
178
221
I
1
329
321
Table 4. Observed annual mean length (ML). standard deviation (SD) and number (n) at age for each sex and for
combined sexes.
L. piscatorius
Females
Males
Age (y=<)
ML (em)
Combined sexes
SO (em)
n
ML (em)
SO (em)
n
ML(cm)
SO (em)
n
2.56
3.52
2.81
3.07
2.68
11
19.58
26.30
34.92
40.60
47.15
2.25
3.54
2.99
3.69
3.15
12
20
19
34
19
20
26
29
26
19.00
27.02
33.73
39.75
46.50
2.86
3.52
3.17
3.92
3.16
30
42
48
75
53
3.44
3.43
5.23
4.09
4.27
4.13
3.06
3.00
34
32
43
39
18
10
7
2
53.90
60.71
68.22
75.06
79.95
89.02
90.17
92.10
97.00
98.17
102.25
104.50
113.50
2.99
3.87
5.23
4.54
4.36
4.23
53.03
59.85
66.69
72.18
80.36
87.69
90.66
93.94
101.14
98.72
105.90
110.68
110.17
112.90
117.50
120.25
125.17
138.00
134.50
3.59
4.21
5.01
4.34
5.54
6.11
5.75
4.63
5.80
6.23
4.32
6.12
2.87
7.36
3.21
6.87
3.40
2.50
79
69
91
75
76
63
44
34
o
2
3
4
5
6
20.50
27.60
32.24
37.85
44.87
. 51.56
7
8
57.81
65.50
71.37
76.44
79.40
83.93
85.50
9
10
11
12
13
14
15
16
17
18
19
20
21
90.50
97.50
5.45
3.41
4.97
0.94
4.09
0.00
35
19
29
18
29
23
15
10
4
3
4
0.00
101.50
117.00
120.50
126.50
110.50
22
4.50
2.00
2
2
0.00
1
23
24
25
Total
9
10
11
3
5
6
4
3
2
844
309
292
11
L budegassa
Females
Males
Age (year.;)
ML (em)
SO (em)
n
ML(em)
SO(cm)
Combined sexes
n
o
ML (em)
SO (em)
n
7.20
1.30
5
11.09
1.21
18
2
16.81
1.17
16
18.64
2.10
11
16.63
2.01
48
3
22.57
2.22
47
22.40
2.44
22
22.19
2.36
77
4
28.34
2.40
48
27.46
2.69
49
27.86
2.67
104
5
33.34
3.86
37
33.31
3.62
42
33.32
3.64
83
6
39.29
4.14
30
38.91
4.96
39
38.83
4.51
75
3.49
18
42.14
3.88
68
7.36
18
48.42
6.33
88
7
42.75
2.74
46
40.36
8
45.27
2.62
56
50.32
9
49.49
3.06
37
56.12
6.08
45
54.39
6.21
106
10
51.13
20
59.13
5.57
39
58.98
6.90
94
11
55.90
2.78
. 1.88
5
60.38
4.58
44
61.98
5.77
83
12
59.00
7.38
5
60.55
6.52
21
63.64
7.33
57
13
57.00
69.82
7.45
22
72.04
6.89
50
14
72.13
8.47
5.96
27
74.40
4.72
9
5
74.33
15
75.95
8.05
20
16
77.88
3.68
8
79.47
4.34
19
3
79.71
2.89
14
17
77.67
18
78.00
82.00
4.00
6
19
89.00
83.60
4.62
5
1.53
20
87.00
21
93.00
Total
348
397
1049
Table 5. Observed mean total weight (MWt); standard deviation (SO) and number (n) at age for combined Sexes by
quarter.
L. piscatorius
2M Quarter
15tQuarter
4" Quarter
3"'Quarter
Age (years) MWt(g)
SOlg)
n
MWt(g)
SO (g)
n
4Q
3
6
12
13
9
15
23
22
120
388
697
1095
1632
2204
3090
4251
5325
7386
9564
10663
11216
15103
53
125
176
281
275
395
638
870
812
1304
1322
1498
500
2123
26
18
17
22
13
16
22
18
20
24
20
9
4
3
18112
2111
5
18735
704
2
MWtlg)
SOls)
n
234
501
851
1383
2132
3117
4192
4732
6590
8315
9402
10507
12895
12747
15046
19497
17158
19088
20956
22017
24165
32339
30031
75
81
9
11
24
16
27
9
20
19
19
16
14
16
3
5
MWt(g)
SO (g)
n
-19
150
203
187
407
531
878
946
1414
1509
1653
1312
738
1172
1
9
8
16
15
21
15
J1
19
16
13
15
11
4
3
1491
1438
3
2
0
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
116
371
636
1063
1550
2311
3260
4258
5235
7058
9133
10637
10754
15749
8957
18903
12587
92
103
228
163
487
631
645
579
1125
1943
1638
944
17
17
14
6
3
..
164
Total
253
352
37J
544
1124
904
1508
1830
1837
1699
2462
1855
1575
1440
3415
1098
3543
2206
1667
8
2
4
3
4
2
2
1
152
278
519
894
1453
2084
2755
4031
5416
7051
8955
9416
11070
11792
13139
IJ710
15812
16283
15236
21418
23960
235
239
206
L. budegassa
3~Quarter
AgelYears) MWt(g)
0
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Total
9
38
76
173
363
838
1246
IJ65
1342
2315
2800
2946
4830
41.bQuarter
1" Quarter
SO (g)
n
MWt(~)
SO(~)
n
3
28
24
46
161
296
297
188
115
666
716
437
3
9
16
16
18
24
19
IJ
3
7
9
7
5
23
92
259
403
498
806
1096
1341
1852
1745
3252
2967
4614
6213
3
9
38
41
111
105
147
303
386
461
183
966
1013
1636
2277
2
7
17
9
12
14
10
10
10
9
11
10
19
8
5
9083
10000
2240
3
2588
2
5120
6652
SOlg)
n
67
153
277
517
722
961
1344
1780
2530
3521
3966
5261
5560
4380
6400
28
42
67
IJ4
144
114
243
318
911
793
1086
1222
1038
4
17
25
20
21
11
20
18
11
13
4
7
3
MWt(g)
SOlg)
n
65
85
182
168
243
724
1347
1103
1591
877
682
26
41
21
19
30
JJ
24
161
349
548
832
1059
1722
3079
4286
6027
6020
7046
7480
JJ
9
J
2
5
9500
I
7450
7025
148
2"'Quarter
MWt(g)
157
I
4278
2
179
225
Table 6. Observed mean gutted weight (MWg), standard deviation (SO) and number (n) alage for combined sexes
by quarter.
L. piscalOrius
3n1 Quarter
Ag. (Y""') MWg (g)
4tllQuarter
n
MWg(g)
SO (g)
32
3
6
12
13
9
15
23
22
17
17
14
6
3
99
323
582
916
1368
1850
2597
3578
4486
6231
8076
9008
9478
12778
44
105
147
236
231
333
. 538
735
687
1105
1121
1271
425
1804
18
20
24
20
9
4
3
15335
1795
5
15865
598
2
"
0
2
3
4
5
6
7
8
9
10
II
12
13
14
IS
16
17
18
19
20
21
22
23
24
25
96
302
512
848
1229
1818
2549
3314
4059
5443
7010
8143
8233
11975
6880
14326
9609
7J
82
179
127
376
484
493
441
851
1465
1230
710
164
TolBI
2nriQuarter
l"'Quarter
So(g)
26
18
17
22
13
16
Z2
MWg(g)
SD(g)
n
194
419
718
1173
1819
2674
3612
4083
5713
7231
8189
9165
11280
11148
11187
17148
15064
16787
18449
19400
21317
28640
26569
63
68
216
303
322
473
982
791
1327
1:612
1622
1503
2180
1643
1397
1284
9
24
16
27
9
20
19
19
16
14
16
3
5
8
2
3040
980
3163
1972
1497
4
3
4
2
2
239
11
MWg(g)
125
229
U9
739
1201
1723
2278
3334
4480
5833
7408
7790
9158
9756
10870
11343
13083
11472
12606
17723
SO (g)
n
41
124
168
155
9
8
16
15
21
15
3I
19
16
13
15
11
4
3
I
3
2
I
337
439
726
782
1170
1249
1368
1086
611
970
1234
1190
19828
235
206
L. budegassa
SD(~)
n
MWg(g)
4_th Quarter
(g)
7
24
62
145
316
702
1119
1178
1195
2081
2398
2572
2
10
·22
28
113
236
295
207
70
633
540
328
3
7
16
16
18
24
19
13
3
7
8
6
3940
1895
2
4
20
71
220
323
408
679
758
1101
2205
1479
2860
2242
3127
4679
2
7
26
33
73
81
117
106
359
431
135
948
492
1040
2265
3"Quarter
Age (Y""') MWg (g)
0
I
2
3
4
5
6
7
8
9
10
II
12
13
14
IS
16
17
18
19
20
21
TolBI
so
tllQuarter
n
2
7
13
9
12
14
9
7
5
2
4
5
13
;
3
MWg(g)
SO (g)
n
MWg(g)
122
212
351
32
45
40
9
11
2
1348
1498
1659
3083
123
282
235
141
9
13
4
2
4249
4671
605
590
2
3
145
303
449
719
936
1417
2089
3410
4314
5663
5809
2J>iQuarter
SD(g)
n
59
64
117
137
224
505
606
1035
970
23
32
20
19
3I
31
15
6
682
4
2
3875
5325
4609
6340
8885
144
110
58
184
Table 7. Observed annual mean total weight (MWt), standard deviation (SD) and number (n) at age for each
sex and for combined sexes.
£. piscatoriUS
Age (years) MWt(g)
Males
SD(g)
n
MWt(g)
II
20
19
34
19
34
129
302
658
1013
1535
2239
3150
4413
5757
6879
9326
9707
10251
Fornal..
SD(g)
Combined sexes
n
MWt(g)
SD(g)
n
12
20
26
29
26
35
19
29
18
29
23
15
10
4
3
4
1
1
122
327
602
961
1481
2150
3034
4133
5146
7000
8971
9840
10840
13397
12530
15202
17295
16963
18354
20373
21898
24376
32126
29841
52
120
163
270
284
411
611
896
886
1389
1708
1759
1507
2164
2136
1693
2626
1247
3289
1579
3512
1852
1651
30
42
48
75
53
79
69
91
75
76
63
44
34
0
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17.
18
19
20
21
22
23
24
25
153
353
534
835
1336
1976
2717
3884
4902
5941
6600
7683
8091
53
118
133
189
223
367
455
878
790
955
951
800
794
l2
43
39
18
10
7
2
llnO
12252
13813
14636
18518
9459
",
11656
41
124
163
257
286
352
573
990
983
1048
1230
1664
llOI
1709
337
1519
13046
20270
21976
25219
16554
2213
1038
292
Total
2
2
II
9
10
II
3
5
6
4
3
2
844
309
L. budegassa
Males
Age (years) MWt(g)
0
1
2
3
4
5
6
7
8
9
10
II
12
13
14
15
16
17
18
19
20
21
Total
83
175
351
618
894
1159
1350
1813
1825
2670
2813
2470
SD(g)
14
60
113
261
288
251
261
265
234
184
955
n
16
46
46
37
29
44
49
28
18
2
5
321
MWt(g)
113
175
327
627
920
1010
2059
2967
3544
3585
3278
5481
5703
4750
9017
6652
7450
10050
Fornalcs
SD(g)
34
68
107
241
307
267
867
1307
1095
1215
1226
1601
1818
523
2351
Combined sexes
n
II
22
47
41
38
18
17
39
22
29
18
18
7
2
3
335
MWt(g)
SD(g)
n
7
31
82
175
340
620
909
1110
1532
2485
2770
3545
3371
5392
6136
4750
8630
8326
7450
7025
3
22
33
62
109
249
292
260
577
1158
1191
1173
1313
1626
1793
523
2023
2367
5
17
37
68
96
79
69
64
66
67
4278
2
40
33
25
22
9
2
5
2
1
709
Table 8. Observed annual mean gutted weight (MWg), standard deviation (SO) and nwnber (n) at age for each
sex and for combined sexes.
L. piscatorius
.Females
Males
Age(years) MWg(g)
SO(g)
n
MWg(g) . SO (g)
n
Combined sexes
MWg(g) SO (g)
n
0
2
)
4
5
6
7
8
9
10
II
12
Il
14
15
16
17
18
19
20
21
22
23
24
25
123
287
438
692
1116
1664
2302
))14
4201
5110
5689
6642
7002
43
98
III
160
190
315
393
764
691
838
835
705
700
II
20
19
34
19
34
32
43
39
18
10
7
2
8210
10158
110
258
563
866
1314
1917
2699
3782
4935
5898
7998
8326
8792
10226
10510
11852
12558
15893
35
106
140
220
245
302
492
850
843
899
1056
1428
946
1468
290
1105
17399
18864
21651
1901
892
12
20
26
29
26
35
19
29
18
29
23
15
10
4
3
4
11395
14526
Total
2
2
98
265
488
782
1206
1754
2479
3381
4214
5739
7363
8080
8904
11014
10299
12505
14234
11960
15110
16779
18041
20091
26509
24615
42
98
113
221
232
337
502
736
729
1144
1408
1450
1243
1787
1763
1398
2170
1030
2719
"1306
2906
1533
1368
II
9
10
II
3
5
6
4
3
2
I
309
292
30
42
48
75
53
79
69
91
75
76
63
44
34
844
L. budegassa
. Females
Males
"so(years) MW~(g)
SO (g)
n
MWg(g)
SO (g)
49
73
79
143
216
181
209
202
19
23
145
260
466
669
762
1848
2056
2991
3793
3501
5289
4671
60
66
142
119
224
628
693
1173
815
1972
1001
590
7208
1756
n
Combined sexes
'MWg(g) SO (g)
n
0
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Total
115
298
414
763
1012
1225
1561
1550
II
10
26
33
17
6
14
8
5
3
6
3
119
280
440
719
959
1381
1785
2373
3793
3501
5289
4671
53
72
115
117
238
436
542
1142
815
1972
1001
590
43
22
19
33
44
31
14
5
3
6
3
)
7208
1756
3
IJ
20
II
9
7
II
6340
8885
145
32
6340
8885
115
260
Table 9. Annual von Bertalanffy growth parameters for each sex and combined sexes.
L. piscalorius
Sex
males
females
combined
Lin/(ern)
110.500
140.500
140.500
k{year· l )
10
0.108
0.081
0.080
.z
n
0.945
0.970
0.958
292
309
844
(year)
0.255
0.089
0.232
Lt min (ern) Lt max (ern) Age min (y) Age max (y)
16
15
14
110
126
140
I
I
I
21
22
24
L. budegassa
Sex
Lin/(ern) k (year· l )
males
females
combined
72.900
110.100
132.400
0.125
0.Q75
0.056
10
(year)
0.360
0.397
0.039
r
,
0.963
0.950
0.959
n
348
397
1049
Lt min (ern) Lt max (ern) Age min (y) Age max (y)
15
15
5
67
89
93
2
2
0
13
19
21
------------
----
Table lOa. Annual mean lengths at age and von BertalanfiY growth parameters for combined sexes.
L. piscalorius
Lin!
k
Present work
Present work
expected
140.500
observed
10
0.080
0.232
Age (years)
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
10.5
ll.5
12.5
13.5
14.5
15.5
16.5
17.5
18.5
19.5
20.5
21.5
22.5
23.5
24.5
25.5
ML(em)
13.55
23.31
32.32
40.63
48.31
55.40
61.94
67.98
73.56
78.70
83.45
87.84
91.89
95.62
99.07
102.26
105.20
107.91
llM2
ll2.73
114.87
116.84
ll8.66
120.34
121.89
ML (em)
19.00
27.02 .
33.73
39.75
46.50
53.03
59.85
66.69
72.18
80.36
87.69
90.66
93.94
. 101.14
98.72
105.90
llO.68
llO.17
112.90
ll7.50
120.25
125.17
138.00
134.50
Workshop
(1997)
observed
ML (em)
9.10
18.10
26.80
35.10
43.10
50.70
58.00
65.00
71.70
78.20
84.30
Duarte et at.
(1997)
observed
121.54
0.102
0.032
ML(em)
17.50
30.10
36.50
42.90
50.50
58.00
64.60
71.50
Landa & Pereda
(1997)
observed
132,05
0.11
0.66
ML (em)
18.85
30.94
37.75
43.97
53.61
63.21
69.72
79.17
86.03
102.50
97.70
102.50
Table lOb. Annual mean lengths at age and von Bertalanffir gtowth parameters for combined sexes.
L. budegassa
Present work Present work
observed
to
expected
132.400
0.056
0.039
Age (years)
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
10.5
1l.5
12.5
13.5
14.5
15.5
16.5
17.5
18.5 .
19.5
20.5
21.5
ML(em)
6.90
13.80
20.20
26.30
32.10
37.60
42.70
47.60
52.20
56.60
60.70
64.60
68.30
71.80
75.10
78.20
81.20
84.00
86.60
89.10
91.50
ML (em)
11.09
16.63
22.19
27.86
33.32
38.83
42.14
48.42
54.39
58.98
61.98
63.64
72.04
74.33
75.95
79.47
79.71
82.00
83.60
87.00
93.00
Lin!
k
Workshop
( 1997)
observed
ML(em)
4.30
11.00
17.50
23.60
29.40
35.00
40.20
45.20
50.00
54.50
58.90
63.00
66.90
70.60
Duarte et al.
(1997)
observed
101.700
0.080
-0.200
ML (em)
9.30
16.40
23.00
29.00
34.60
39.80
44.50
48.90
53.00
56.70
60.20
63.40
66.30
69.00
71.60
73.90
....--------
'H-
'6'
1-10"
~'.f
.
..-...... '.
57"
55°
i----.'
..-.-------
,
....
....
.J""
Figure 1..-\nglertish stocks geographical areas:' northern stocks (ICES Divisions vlIb-k and vlIIa.b):
l!I southern stocks (ICES Divisions YlIIc and IXa).
Figure 2a: Mean total length at age.
L. piscalorius
males
ego
.:;
130
120
110
100
90
80
70
60
50
40
30
20
10
0
•
•
. ;,- i: !:
.• !. ...
.1 ~
.:L
... '"-
