A productive fishing ground for rock perch (Epinephelus fasciatus) was located off Ratnagiri between 17 degree 00' to 17 degree 10' N latitude and 72 degree 20' to 72 degree 30' E longitude, around a depth of 96m during November, 1983. An average catch of 2 ton/hr. was recorded. Length frequency studies of E. fasciatus indicate the probability of a nursery ground consisting of three brood stocks. Hydrographic studies of the ground revealed that the bottom water was oxygen deficient below a strong thermocline extending from 15-75 m depth with the recorded bottom temperature amounting to 20.5 degree C

Ansari, S.K.R.

Kamat, S.

Ravindranathan, V.

Aquatic Commons

Journal of the Indian Fisheries Association. 
10 & 11, 1980-81, 49-53 
RECORD CATCH OF ROCK PERCH, EPINEPHELUS FASCIATUS BY BOTTOM 
TRAWLING OFF RATNAGIRI 
V. RA'VINDRANATHAN, S. K. R. ANSARI & S. KAMAT 
Central Institute of Fisheries Education Versova, Bombay-400 061. 
ABSTRACT 
A productive fishing ground for rock perch (Epinephelus fasciatus) was located off 
Ratnagiri between 17° 00' to 17° 10' N latitude and no 20' to 72° 30 E longitude, around 
a depth of 96 m during November, 1983. An averagE! catch of 2 ton/hr. was recorded. 
length frequency <;tudies of E. fasciatus indicate the probatility of a nursery ground 
consisting of three brood stock. Hydrographic ·studies of the ground revealed that the 
bottom water was oxygen deficient below a strong thermocline extending from 15-75 m 
depth with the recorded bottom temperature amounting to 20. 5o C. 
INTRODUCTION 
Immediate attention is need~d to exploit the deeper zone of Indian ocean where 
the marine fish potential is far more than the present yield (Dwivedi, 1981). In the 
above context M. V. Saraswati (CIFE, Bombay) is being ex'"ensively used for the 
tra;ning cum research cruises of the Institute within the EEZ limit. The vessel 
36.57 m long is e{JUipped with modern navigational and fish finding equipments. Dur-
ing her cruise>which covered the EEZ between Mam:alore and Dwarka, the vessel ws.s 
used for bottom and pelagic trawling, longlining and hydrographic studies. The 
surveys had been valuable in fishery resource assessment and in studying th;, re]atio-
nship between fishery and hydrographic conditions of the region. 
MATERIAL AND METHODS 
The XVIth cruise of M. V. Saraswati covered the area between 16° 30' -
19° 10' N latitude and 71 o 50' - 73° 00' E longitude within a depth range of 25 to 
100 m for bottom trawling during 9th to 17th November, 1983 (Ravindranathan 
et al., 1983). Position fixing was done with the Satellite navigator. Echosounders 
EQ 30 and EQ 50 and Sonar were used for fish finding. Fishing was done using a 
bottom trawl 40 m lonfS of 50 mm mesh size. The catch reported presently was 
made in the area 17-72/IC (Fig. 1). 
SQ RA VINDRANATHAN, ANSARI & KAMAT 
0 
\7 
0 
72 
g. 1 : Map showing the l9cation of rock perch fishing ground off Ratnagiri. 
Hydrographic par:ameters were studied at the fishing ground from varying depths 
(0, 15, 30, 50, 75 & 95 m). Surface sample was collected with a bucket and the 
temperature was recorded by an ordinary thermometer. Subsurface samples were col-
lected by N ansen Reversing bottle fitted with protected reversing thermometer. pH was 
measured by the Digital pH meter 5 50 (Germany). Dissolved oxygen and salinity 
were analysed after Strickland & Parson (1968) and nutrients according to Carlberg 
( 1972). 
296 fishes (E. fasciatus) were measured for total length on millimeter 
scale and the weight was taken on a spring balance. Length frequency composition 
was tabulated in class interval of 1 Omm and actual frequency and % frequency 
were calculated. Running average was calculated by the formula a+ 2~ + c where 
a = frequency of previous class interval'; b = frequency of class interval under 
consideration ; c = frequency of class interval next to cLass interval under 
consideration inorder to remove chance fluctuations while collect ing the data. 
RESULTS AND DISCUSSION 
Epinephelus fasciatus locally known on Kalava belonging to Family Serranidae, 
generally inhabiting the waters of coral and rocky areas has the following identifica-
tion characteristics according to F AO (1979). 
1. Orange-red colour on head and fins with an oblong and somewhat robust body. 
2. A red band from tip of snout along dorsal part of head through eye to the front 
of dorsal.fin; 6 red bands on the body margin of spinous dorsal fin black. 
3 . Preopercuh1m with a convex finely serrated upper edge, its angle sl~ghtly pro-
duced and bearing enlarged spinules. 
4. Dorsal fin with, 11 spines and 16 soft rays, caudal fin rounded. 
RECORD CATCH OF E. FASCIATUS OFF RATNAGIRI 51 
A total of 6. 9 tons of E. fasciatus was caught in three hauls expending 3 
hours, 30 min. of fishing effort at a catch per unit effort ( cpue) of about 2 tons/ 
hour (T:abl'e). A record catch of 4. 5 tons was caught in a single haul' of 1 hour, 30 
min. duration of trawling . Ave<·age weight of the fish was recorded to be 
777.03 g. 
Table-1 : Fishing particulars and the catch date of rock perch 
Area Fishing Fishing Total Catch/hour 
depth effort catch 
(m) (hr.-min) (tons) (tons) 
17-72/ lC 93-96 1- 00 0.4 0.4 
" 
,, 1- 00 2.0 2.Q 
" 
,, 1- 30 4.5 3.0 
As the E. fasciatus is a inhabitant Of rocky and coral grounds, it was being gener-
ally caught by h;mdliningor longline fishing as the bottom trawling operations in these 
grounds hamper the gear and also involve· risk. Hence. locating a high productive 
rock perch ground suitable for bottom trawling oper:ations along Maharashtra coast is 
a new finding. However, during the year 1965, R. V. Vanma had conducted explo.:. 
ratory survey of rock perch on the southwest coast of India. Many of the fishing 
grounds were located by acoustic survey and fish was caught by , handlining (SHas, 
1969). Fewer information is available today on the location of rock perchgrounds 
in the west and north west coast of India and very few reports are availalfle 
on the catches of rock perch by bottom trawling operations except from a large por-
tion of Wadge Bank off Kerala coast. 
The length frequency anal~Jsis (Fig. 2) indicates the exploited stock in the 
range of 180 mm to 450 mm. Dominant length group ranged between 351 mm to 361 
mm constituting 8.78% of the total catch. Running average resulted in 3 distinct 
modes in the class intervals of 291 mm - 300 mm (7. 43% of the total numbers), 
341 mm- 350 mm (7.77%) and 381 mm- 390 mm (6.08%). That, only the 
adul't individual were caught shows the are!Cl was probably a nursery ground for E. 
fasciatus. Spawning of the fish is likley to be taking place in some other ground awa)l 
from the exploited ground. 3 distinct modes reveal that the exploited stock of 
E. fa!Sciatus consists of 3 different broods released at very short interval of 2 to 
3 months. The exact age of the fishes of different modes cannot be found out 
becaus'.'l of discontinuity in the observed data. 
52 RAVINDRANATHAN, ANSARI & KAMAT 
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1so 110 19o 110 IJo zso 2.10 zso JIO J:lo :1so -;10 J9o ~~o t.Jo ~so 470 
-----------TOTAL LENGTH IN mm--------
Fig. 2 : Histogram for length frequency of E. fasciatus. (Figures above the histogram 
indicate running average). 
Resul1s of the hydrographic parameters recorded at varying depth of the fishing 
g1;ound is shown in Fig. 3. Water temperature ranged between 27. 6°C (10 m) to 
I 
20. soc (bottom) where surface temperature was 27. 2°C, Dissolved oxygen leye]s 
were recorded in the decreasing order , 4. 66 ml/1 at surface and 0 . 6~ m.I/1 at the 
bottom. Salinity ranged between 33. 13 to 32.53% o from surface to bottom 
and pH measured was in the range of 8. 57 to 8 . 03. 
Minimum phosphate values ( 0 . 62 .ug -at/1) was recorded at 15m depth and 
maximum ( 1. 70 ,.ug-at/ 1) at 7 5 m. Phosphate leve~ at the surface was found to be 
0:81 .ug -at/ 1 and bottom 0 . 72 ug-at/ 1. Nitrite concentration was minimum at 15 m 
( 0 . 03 ug-at/ 1) and maximum at bottom ( 2. 0 ..ug-at/ 1 ) . Surface nitrite level. was 
observed to be 0.03 .ug-at/1. 
E 
:r: 
1-
0... 
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l-L..-1--J.--l-~-..__..__~ I I l I 
0·0 1·0 1·0 
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Fig. 3 : Vertical distribution of physico-chemical characteristics at the fishing ground. 
RECORD CATCH OF E. FASCIATGS OFF RATNAGIRI 53 
Hydrobiological conditions at the bottom have great impact on the fish 
populations. Bottom cha1~acteristics studied at the ground explains that the 
temperature (20. 5°C), salinity (32. 53%o) and pH (8. 03) observed in the 
normal ranges are favourable for E. fasciatus. Low dissolved oxygen levels recorded 
at and near the bottom (Fig. 3) indicate the tolerance of the fish to low oxygen 
levels. High concentrations of nutrients (Fig. 3) at 75 m and the bottom, reveals the 
positive environmental conditions for the rock perch' E. fasciatus. 
ACKNOWLEDGEMENT 
The authors are grateful to Dr. S. N. Dwivedi, Director, CIFE, Bombay for 
his valuable guidance under whom the project work is being carried out. We wish to 
express our sincere thanks to all the cruise participants and to the Skipper and staff 
of M. V. Saraswati for their wholehearted cooperation and to Dr. M. D. Zingade and 
Dr. (Mrs.) Vijayalakshmi Nair for their suggestions in improving the manuscript. 
REFERENCES 
Carlberg, S. R. 1972. New Baltic manual with methods for sampling and analysis of physical che-
mical and biological parameters. Series A. No. 29. Co-op. Research Report. Int. Coun-
cil for the exploration' of the sea, Denmark. 145 pp. 
Dwivedi S. N. 1981, An approach for assessment and management of marine living resources of 
EEZ and fishery estates. In Seminar on Management of the living resources of Indian 
Exclusive Economic Zone. 16 Dec. 1984 C. FE, Bombay. 
FAO, 1979. FAO species identification sheets for fishery purposes. Vol. IV. 
Ravindranathan, V.; S. K. R. Ansari & S. Kamat 1983. Report on the XVIth cruise of M. 
V. Saraswati, CIFE, Publication, Bombay 8 pp. 
s:las, E. G. 1969. Exploratory fishing for 'Kalava '. In Exploratory fishing by R. V. VARUNA. 
CMFRI Bull. 12. 52-66 pp. 
Strickland, J. D. F. and T. R. Parsons, 1968. A practical hand book of sea water analysis. 
Bulletin 167. Res. Board of Canada, Ottawa. Canada, 310 pp. 


Record catch of rock perch, Epinephelus fasciatus by bottom trawling off Ratnagiri

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Record catch of rock perch, Epinephelus fasciatus by bottom trawling off Ratnagiri

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