This note highlights the author's attempts to determine the vertical height for catching seers (Scomberomorus sp.) and other commercially important fish off Kakinada coast

Dawson, P.

Rao, J.S.

Sreekrishna, Y.

Aquatic Commons

	Fish. Technol. (1981) 18, 143-144 	 143 
NOTES 
	
On the V(--rt:c -1I 	 [ -_,tribution of Seers a d ar-.1 
Cornmerciall_ 	 it Fishes in fah St rfaeE 	 S 
Amongst the various factors considered 
while designing a suitable gill net the swim-
ming height of the fishes to be caught 
assumes paramount importance. Studies 
on this aspect have been made by Parrish 
(1963) Berst & Mcombie (1963), and Sulo-
chanan & Rao (1964) for perches and pom-
frets. This communication highlights the 
authors' attempts to determine the vertical 
height for catching seers and other commer-
cially important fishes off Kakinada coast. 
For a detailed description of the net 
attention is drawn to the paper on mesh 
selectivity studies for spotted seer (Sree-
krishna et al. 1972). The fishing height 
of the net was kept constant at 6 m. To 
determine the swimming height of the fishes, 
the nets were divided horizontally into six 
sections by passing coloured twines at every 
1 m interval. Twenty shots of nets were 
operated on all fishing days. 
The number of Scomberomorus commerson, 
S. guttatus, Parastomatous niger, Euthy-
nnus affinis, Hilsa toli and Sharks  
recorded from each 1 m division of the net 
together with statistical significance are 
presented in Table 1. Sut of 247 S. guttatus 
and 87 S. commerson caught, majority were 
found to be in 0-3 m depth of the net with 
maximum at 1-3 m. The chi-square (X 2) 
test indicated (Table 1) that the number of 
fishes caught in the different sections of the 
net were significantly different. It was 
1 % level for S. commerson and H. toli and 
0.1 % in S. guttatus, P. niger and sharks. 
For S. guttatus and sharks 1-3 m, for S. 
commerson 1-2 m, for P. niger, H. toli and 
tuna, 0-3 m gave significantly higher catch 
over the other sections. erst & Mcombie 
(1968) observed abundance of perches and 
sucker fish towards the foot rope of the net 
while Sulochanan & Rao (1964) emphasised 
the superiority of the first quarter of the net 
of 467 cm depth in catching silver pomfrets. 
The results of the present studies confirm 
the view that of the 6 m depth of the net, 
0 to 3 m is most efficient, 3 to 5m also con-
tribute substantially to the total catch, while 
5 to 6 m is least effective for catching different 
species of fish investigated. 
Table 1. 	 Vertical distribution of fishes in experimental gill nets 
Distance from head rope (m) Observed Level of 
Species 0-1 1-2 2-3 3-4 4-5 5-6 Total chi-square 
value 
.F. signifi-
cance 
S. guttatus 42 73 74 33 18 7 247 93.83 6 0.1 
S. commerson 9 39 19 10 10 87 18.34 4 1% 
P niger 134 199 135 56 49 8 581 259.49 5 0.1 
H. toll 10 22 12 6 1 1 52 11.78 3 1% 
E. affinis 57 93 69 29 22 6 276 115.73 5 0.1 
Shark 52 100 108 52 45 11 368 108.38 5 0.1 
Vol. 	 18, 	 1981 
144 	 PERCY DAWSON, J. SITARAMA RAO AND Y. SREEKRISHNA 
The authors are thankful to the late Shri 
	 Parrish, B. B. (1963) Int. Commn. North- 
G. K. Kuriyan and Shri K. A. Sadanandan for 
	 Atlantic Fish. Spl. Pub. 5, 165 
reading the manuscript and offering suggestions. 
References 
e st, A. H. & Mcombie, A. M. (1963) 
J. Fish. Res. Bd Can. 20, 755 
Sulochanan, P. & Rao, K. K. (1964) 
Indian J. Fish. 9B, 9 
Sreekrishna, Y., Rao, J. S., Percy Dawson, 
Mathai, T. J. & Sulochanan, P. (1972) 
Fish. Technol. 9, 133 
Kakinada Research Centre of 
Central Institute of Fisheries 
Technology, Kakinada 
PERCY DAWSON 
J. SITARAMA RAO 
Y. SREEKRISHNA 
FISHERY TECHNOLOGY 


On the vertical distribution of seers and other commercially important fishes in the surface drift nets

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On the vertical distribution of seers and other commercially important fishes in the surface drift nets

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