Based on the data collected from New Ferry Wharf, Sassoon Dock and exploratory survey of MFV Saraswati on the Northwest coast of India, the growth, mortality, population and stock parameters of Saurida tumbil is reported in the present communication. The Von Bertalanffy growth function (GF) parameters for growth on length were found to be L∞=49.8 cm, K=0.96/year, t0 = -.141 year. The length at recruitment (lr) is 80 mm. (tr=.167 year) while the length at first capture (lc) for the commercial trawl fishery is 100 mm (tc=0.25 year). The annual fishing mortality coefficient (F) for 1983-85 was 0.43, the natural mortality coefficient (M) was 1.33 and the exploitation ratio (E) was 0.25. The yield per recruit (Y/R) attained the maximum of 54.99 g at F=1.091 for E=0.45 for the present tc at 0.25 year. The annual total stock (P) and standing stock (P) in the exploitation portion at the inshore grounds to a depth of about 50 m were estimated to be 12,811 tons and 6,034 tons respectively. The average annual yield of 2,635 tons at the present F=0.439 (E=0.247) was less than the maximum sustainable yield (MSY) for 3,331 tons attainable from the inshore grounds at E=0.45

Devaraj, M.

George, J.P.

Gulati, D.K.

Aquatic Commons

Journal of the Indian Fisheries Association 
24, 1994 (Proc. Nat. Symp. Aquacrops), 41-49 
41 
ASSESSMENT OF SAURIDA TUMBIL (BLOCH) STOCK IN THE 
NORTHWEST CONTINENTAL SHELF WATER OF INDIA 
D.K. GULATI, M. DEVARAJ AND J.P. GEORGE 
Central Institute of Fisheries Education, (Deemed University), 
Versova, Mumbai - 400 061 
ABSTRACT 
Based on the data collected from New Ferry Wharf, Sassoon Dock 
and exploratory survey of MFV Saraswati on the Northwest coast of 
India, the growth, mortality, population and stock parameters of 
Saurida tumbil is reported in the present communication. The Von 
Bertalanffy growth function (VBGF) parameters for growth on length 
were found to beL== 49.8 em, K = 0.96/year, to= -.141 year. The length 
at recruitment Or) is 80 mm. (tr = .167 year) while the length at first 
capture (lc) for the commercial trawl fishery is 100 mm (tc = 0.25 year). 
The annual fishing mortality coefficient (F) for 1983-85 was 0.43, the 
natural mortality coefficient (M) was 1.33 and the exploitation ratio 
(E) was 0.25. The yield per recruit (YIR) attained the maximum of 54.99 
gat F = 1.091 forE = 0.45 for the present tc at 0.25 year. The annual 
total stock (P) and standing stock (P) in the exploitation portion at the 
inshore grounds to a depth of about 50 m were estimated to be 12,811 
tons and 6,034 tons respectively. The average annual yield of 2,635 
tons at the present F = 0.439 (E = 0.247) was less than the maximum 
sustainable yield (MSY) for 3,331 tons attainable from the inshore 
grounds at E = 0.45. 
INTRODUCTION 
The lizardfish, Saurida tumbil 
(Bloch) locally called the chorbon1bil 
in Maharashtra and Gujarat, is a 
fast growing demersal fish. Earlier 
studies on this species dealt with its 
systematic and comparative 
osteology (Rao, 1977), feeding habits 
(Rao, 1982), spawning biology (Rao, 
1983a) and lenth weight relationship 
(Rao, 1983b). As there is no study 
on the population dynamics of this 
fish from Indian seas, investigations 
were undertaken based on the length 
frequency distribution of samples of 
specimens landed by the commercial 
trawlers at the landing centres of 
New Ferry Wharf, Sassoon Dock and 
Versova in Bombay and also the data 
from exploratory fishing by M.F~V. 
Saraswati in the northwest 
continental shelf during 1983-85. 
MATERIAL AND METHODS 
Length frequency data included 
42 GULATI, DEVARAJ AND GEORGE 
4,423 fish sampled during 1983-85 
from (1) the catches of the 120 feet 
fishing vessel M.F.V. Saraswati 
during its trawling operations using 
40 mm cod end mesh (stretched) 
trawls in the northwest continental 
shelf of India (Maharashtra, Gujarat 
and Karnataka from lat 22°00' to 
16°30' Nand long. 69°00' to 73°.30'E) 
at a ground ranging from 30 to 200 
m depth and also the commercial 
landings at New Ferry Wharf, 
Sassoon Dock and Versova, in 
Bombay by the small inshore 
trawlers operating 20 mm cod end 
mesh trawl at a ground of upto 50m 
depth. 
Age was determined following 
Devaraj (1982) by tracing the 
progression of modes in the scatter 
diagram for the plots of length modes 
against length groups for successive 
months. 
The natural mortality coefficient 
(M) was estimated following 
empirical equation of Pauly (1980), 
while the total mortality coefficient 
(Z) was estimated from age 
composition data according to 
Jackson (1939). Yield per recruit (Y/ 
R) as functions of fishing mortality 
coefficient(F) and age at first capture 
(tc) was fitted as per Beverton and 
Holt (1966) while the length cohort 
analysis was performed according to 
Jones (1976, 1984). For the inshore 
fishery in 0-50 m deep grounds, the 
annual yield data (Y) was used for 
the estimation of total stock, p (P= Y/ 
U) where U =F/Z(1-t-z)standing stock 
P (=YIF) recruits Rc at tc (Rc=YIY/R), 
the mean n':lmber YN CRc x YN/R) 
(Beverton and Holt, 1957) for the 
inshore section of the stock. The 
maximum sustainable yield (MSY) 
' ' 
was determined by calibrating the 
current catch onto the Y/R curve. 
RESULTS AND DISCUSSION 
The length frequency plot (Fig. 
1) reveals the release of four br.oods 
each year : the first in March, the 
second in June, the third in 
September and the fourth in 
November-December: The fish 
attains a length of 276 mm in the 
first year, 430 mm in the second year 
and 480 mm: in the third year of life. 
The maximum length was 490 rrim 
while the maximum weight was 
1,100 g. 
Length growth parameters have 
been estimated to be leo = 498 mm K 
= 0.95/y, t 0 = -0.14/y. 
Length at recruitment (lr) was 
taken as the length of the smallest 
fish represented in the catch and has 
been 80 mm. Length at first capture 
(lc) was taken as the lowest limit of 
fully represented length class in the 
catch and has been found to be 100 
mm corresponding to 2 and 3 months 
of age respectively. 
Annual total mortality coefficient 
(Z) was estimated to be 1. 77 for the 
stock exploited by the trawlers 
during 1983-85 while natural 
mortality coefficient (M) was found 
to be 1.34 indicating very low fishing 
mortality (F = 0.44). 
ASSESSMENT OF SAURIDA TUMBIL IN SHELF WATERS 43 
The optimum age of exploitation 
( ty) and potential yield per recruit 
(Y') were estimated to be .1.93 years 
and 84.74 g respectively (Fig.2). The 
yield per recruit attains maximum 
value (Y/R = 54,99 g)·E = 0.45 (F = 
1.091) for the present tc = 0.25 year 
(Fig. 3). 
The standing stock (P) and 
annual total stock (P) in the exploited 
inshore along the northwest coast 
(Maharashtra and Gujarat) during 
1983-85 for E = 0.247 have been 
estimated to be 6,034 tons and 
12,881 tons respectively. 
The absolute number of recruits 
(R) at entry to the exploited phase 
(PN) in the inshore grounds was 
estimated to be 61 x 106 . The yield 
in number (YN) from the inshore 
grounds for the present F = 0.4393 
and tc = 0.25 year has been found to 
be 13.5 x 106 while the maximum 
yield in number 57.65 x 106 could be 
obtained at the exploitation ratio (E) 
of 0.95 (Table 1). 
The mean number. of fish in the 
exploited phase (PN) for the present 
F = 0.44, E = 0.25 and tc = 0.25 year 
has been found to be 30.45 x 106, 
while the maximum mean number 
of fish (PN) in the exploited phase to 
be 38.6 x 106 · at the minimum E = 
0.05 (F = 0.0702 (Table 1). 
The maximum sustainable yield 
(MSY) of 3_.337 tons is attainable at 
E = 0.45 (F = 1.091) (Fig. 3). 
Jones' length cohort analysis for 
the period 1983-85 reveals that 
maximum fishing mortality, and 
hence, maximum exploitation ratio 
(E = F/Z) occur at the 28.0 to 30.0 
em length group at the age of 0.68 
year when the fish just begin to 
attain maturity (Table 2). Hence, the 
catches are predominently of 
immature or just maturing fish. 
The maximum catch of 367 tons 
from the inshore was obtained at the 
age 0.68 year which contributed 
11.18% to the total biomass of the 
population. The mean annual 
number of fish caught along the 
northwest coast (Maharashtra, 
Gujarat and Karnataka) during 
1983-85 was 23.26 x 106 which 
contributed only 4.9% to the total 
number of fishes in the size range of 
60 to 500 mm available in the inshore 
sea. The average annual catch 
obtained during this period was 
2,660 tons which was only 11.75% of 
total biomass (stock) of 22,643 tons 
available in the inshore sea. Thus, 
the standing stock (P = Y/F = 6,034 
tons) represents 26.65% of the total 
biomass (Table 2). 
The yield curve and yield mesh 
curve have been drawn to get a clear 
picture of the status of fishery at the 
existing level of mesh size and effort. 
The MSY/R of 54.99 could have been 
obtained at the level of E = 0.45 and 
F = 1.091 for the present tc = 0.25 
year, whereas the present yield per 
recruit was estimated to be 4$.5 g 
only at the pr~sent exploitation level 
(E) of 0.247. This fish was found to 
be underexploited. Hence, it is 
suggested that in order to get 
520 
480j _____.... _______-o 
440 
400 
~ 360 
~ 320~ / /// ~//-/ ~ 
z 280 .. .. .. 
01 
c 
2 2G.O 
.. .. 
.g 200 • 
0 
:::E 
1601 
" 
120 ~ / / / / / / / / / / / 
80-l / / / I I I / / I I / 
40-l / I I I I I I / I I I 
0 
M M J s N J M M J s N J M M J s N J .M M J s N J M M J s 
. 1982 1983 1984 1985 1986 
Fig. 1 : Growth of individual broods on the basis of the modes in the length frequency distribution for 
successive months 
" 
1+>-j.j:>. 
§ 
t"' 
~ 
1-< 
tl 
tt:l 
~ 
~ 
t 
~ 
z 
tl 
0 
tt:l 
0 
~ 
0 
tt:l 
ASSESSMENT OF SAURIDA TUMBIL IN SHELF WATERS 45 
lc/[oc lc(mm) 
0·96 -4?8 
0·92·458 lOg 
0{18 ·438 
0·84-l.lS 
0·80 -396 
0·76·378 
0·72-358 
0·68-338 
0·64-31\?. 
0·60-298 
0·56"278 
g 
0·52"258 
0·48-238 
Q.t.t.-218 
0·40-198 
0·36-mt 
Q.J::Z-158 
0·28-138 
0-24-118 
. 0·20 ·98 
0-16-18 
0·12 • 58 
0·05 0·15 0·25 0·35 O·L.S 0·55 o.ss 0·75 0·85 0-95 
I I I I 
' 
I I I 1 
' ().07 0·2L. 0-45 0·72 0·69 1·33 1-63 2·00 N5 L.·OO 
Exploitation ratio ( E ) 
Fig. 2 : Yield isopleth diagram depicting Y I R as a function of length at 
first capture ac) and exploitation ratio (E) 
46 
55 
50 
Cl 45 
.E 
a::: 
40 
........ 35 ~ 
> 
-4J 30 
·-::J 
L.. 
t) 25 (» 
a::: 
L.. 20 
Ql 
a. 
"0 15 
..... 
Ql 
> 10 
s 
0 
GULATI, DEVARAJ AND GEORGE 
3,337 (MSY) 
3,000 
J----+-1 --------....J-2,635 
I Pres~n: 
I yield 
I 
I 
I 
I 
I 
I 
I 
2,000 
I 1,000 
0·1 0·2 0·3 0·4 0·5 0·6 0· 7 0·8 0·9 1~0 
1 I I 1 I I I I . I 
0·15 0·33 0·57 0·89 1·33 2·0 3·1 5·3 12·0 O(J 
E1eploitation ratio (E) 
Fig. 3 : Estimation of MSY and annual yield for various levels of 
exploitation from current yield and exploitation for northwest coast 
optimum yield from the stock, either 
effort (E) has to be increased from 
0.247 to 0.45 or the level of c (index 
of size at first capture) be increased 
upto the level of 0.60. 
Suggestion to increase mesh size 
as to increase c may not be advisable 
as the trawl fishery is mainly aimed 
at fishing ·of other commercial fishes. 
Further, as this fish forms only a 
bycatch the suggestion to increase 
fishing effort to exploit such a stock 
may be acceptable to fishermen. 
Table 1 : Estimate of' yield in number (PN) and mean number of exploited fish S.tumbil for the period 
1983-85. 
Exploitation Fishing PN=RCxPN/R YN=RCxYN/R Standing stock Total Y!U 
ratio mortality million million Y/F (tons) (tons) 
0.05 0.07 38.60 2.78 9710.68 18072.60 > m 
0.10 0.15 36.59 5.42 8691.05 16669.66 m tzj 
0.15 0.24 34.47 8.10 7675.44 15190.25 m m 
0.20 0.33 32.47 19.82 6734.30 13842.26 ~ tzj 
0.25 0.45 30.45 13.57 5914.58 12692.20 z 8 
0.30 0.57 28.44 16.23 5104.59 11432.80 0 ~ 
0.35 0.72 26.39 19.87 4335.51 10212.40 ~ 
0.40 0.89 24.38 21.67 3669.40 1145.80 ~ 
0.45 1.09 22.35 24.38 3053.38 8121.47 b 
0.50 1.34 20.29 27.14 2479.62 7126.00 ~ 
"-3 
0.55 1.63 18.29 29.82 1980.44 6189.40 ~ 0.60 2.01 16.25 32.51 1526.62 5294.00 tti 
0.65 2.48 14.19 35.27 1145.94 4479.38 ~ H 
0.70 3.12 12.19 37.94 838.29 3771.03 z 
m 
0.75 4.01 10.16 41.12 548.41 2939.50 p:: tzj 
0.80 5.34 8.13 43.38 369.18 2465.11 t'" ~ 
0.85 7.56 6.09 46.04 236.05 2099.30 ~ 0.90 12.01 4.06 48.74 115.28 1538.19 8 
tzj 
0.95 25.34 2.08 57.56 41.90 1117.89 ::0 m 
P N/ R = Mean population number per recruit 
P N = The number of fish in the exploited phase 
Y N/ R = Yield in number per recruit 
Y N = Yield in number ,j::. ~ 
.... 
Table 2 .: Length Cohort analysis of S. tumbil for. inshore (0 to 50 m. depth) section of populations for the 00 
period of 1983-85. 
Length group Number caught Fishing Total Age in year Cw PW 
(mm) (in 000) (F) (Z) eN x wt PN x wt 
Ll-L2 (Ll, L2) (tons) (tons) 
60-100 73 0.02 1.36 0.02 0.06 53.37 
80-100 415 0.14 1.48 0.04 0.90 127.17 
100-120 1562 0.56 1.89 0.09 7.13 248.61 
120-140 2051 0.78 2.11 0.15 17.44 417.72 
140-160 2335 0.95 2.28 0.20 33.81 630.54 § 
t"' 
160-180 983 0.43 1.76 0.27 22.68 874.73 f:3 
180-200 1194 0.55 1.88 0.33 41.64 1181.82 ..... 
tJ 
200-220 1998 0.10 2.33 0.40 101.14 1507.83 trJ 
220-240 2167 1.21 2.54 0.47 153.80 1783.54 ~ 
240-260 1825 1.16 2.49 0.55 176.64 1991.31 ~ c... 
260-280 1730 1.26 2.60 0.63 222.98 2145.45 ~ z 
280-300 2182 1.93 3.26 0.68 366.90 2201.06 tJ 
300-320 1572 1.76 3.09 0.78 $38.77 2025.20 Q trJ 
320-340 1788 1.87 3.20 0.89 350.25 1804.30 0 ~ 
340-360 883 1.72 3.05 1.06 298.93 1499.12 Q trJ 
360-380 489 1.27 2.60 1.14 203.43 1190.48 
380-400 241 0.81 2.15 1.30 122.40 940.83 
400-420 120 0.50 1.84 1.48 73.72 744.02 
420-440 63 0.33 1.66 1.71 45.91 570.00 
440-460 42 0.28 1.61 2.00 36.25 401.41 
460-480 26 0.26 .1.59 2.56 26.63 228.81 
480-500 15 0.44 1.77 3.34 18.66 75.30 
Cw = Catch biomass Pw =Population biomass 
ASSESSMENT OF SAURIDA TUMBIL IN SHELF WATERS 49 
ACKNOWLEDGEMENTS 
The authors are deeply indebted to 
Dr. S.D. Tripathi, Director, Central 
Institute of Fisheries Education, 
Bombay, for facilities. We are thankful 
to Prof. K.K. Ghosh for critically going 
through the manuscript. 
REFERENCES 
Beverton, R.J.H. and Holt, S.J. 1957. 
On dynamics of exploited fish 
populations. Fishery Investigations 
(Ministry of Agriculture Fisheries 
and Foods, London) Series II, Volume 
XIX, 533 pp. 
Beverton, R.J.H. and Holt, S.J. 
1966. Manual of Methods for Fish 
Stock Assessment Pt.2, Table of 
Yield Functions. FAO Fish Tech. 
Rap. Rev. 1-67. 
Devaraj, M. 1982. Age and growth of 
three species of seer fish 
Scomberomorous commerson, 
S.guattus and S.linealatus. Indian 
J. Fish. 28 (182) 104-127. 
Jackson, C.H.N., 1929. The analysis 
of an animal population. J.Anim. 
Ecol. 8 : 238-246. 
Jones, R., 1984. Assessing the efects 
of changes in exploitation pattern 
using length composition data 
(with notes on VPA and cohort 
analysis) FAO Fish. Tech. Paper, 
No. 256. 
Rao, K.V.S. 1977. Systematics and 
comparative osteology of Indian 
lizard fishes (Saurida spp.) 
Indian J.Fish. 24 (1 & 2) : 143-
171. 
Rao, K.V.S. 1981. Food and feeding 
of lizard fishes (Saurida spp.) 
from north western part of Bay 
of Bengal. Indian J. Fish. 28 (1 
& 2) : 47-64. 
Rao, K.V.S., 1987. Studies on 
population of Saurida tumbil 
(Bloch) from Indian waters. 
Indian J. Fish. 29 (1 & 2) : 8-19. 
Rao, K.V.S. 1983 a. Maturation and 
spawning 
(Saurida 
of lizard 
spp.) from 
fishes 
north 
western part of Bay of Bangal. 
Indian J. Fish. 30 (1) : 27-45. 
Rao, K.V.S. 1983 b. Length-weight 
relationship in Saurida tumbil 
and S. undosquanis and relative 
condition in Saurida tumbil. 
Indian J. Fish. 30 (2): 296-305. 
Pauly, D., 198{) Ori the inter-
relationships between natural 
mortality, growth parameters. 
and mean environmental 
temperature in 175 fish stock. J. 
Cons. ClEM, 39 (2) : 175-192. 


Assessment of Saurida tumbil (Bloch) stock in the northwest continental shelf water of India

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Assessment of Saurida tumbil (Bloch) stock in the northwest continental shelf water of India

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