“LENGTH - WEIGHT RELATIONSHIP AND BIOLOGY OF Wallago attu (FRESH WATER SHARK) FROM BHADAR RESERVOIR’’ 2923
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Date
2019-08
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JAU, JUNAGADH
Abstract
The present study on Wallago attu was conducted Bhukhi village Dhoraji Taluka
of Rajkot district of Gujarat at Bhadar reservoir. Biological information on W. attu such
as length-weight relationship, food and feeding habits, sex ratio and fecundity were
collected from the Bhadar reservoir gear used by giilnet. The maximum size 109.5 cm
was founded during investigation of research. The length weight relationship for males
and females were not significant. The condition factor female was higher than male. The
overall sex ratio was 1:1.008 and the females dominated in the population during entire
investigation. All Maturity stages where founded during study period. The spawning
percentage was higher during in month of August because only one breeding season
attained by W. attu. The absolute fecundity of W. attu ranged from 16565 – 29883. The
annual average ova diameter was 1.38 mm (range 1.1 – 1.9 mm). The GSI of the species
was higher in month of August. The Gastrosometic index (GaSI) of the male and female
was higher in February and September because it directly relationship between GIS.
During breeding season the size of gonad was high so its preferred less food. The
percentage of empty stomachs was the highest (26.67%) in July, and the percentage of
full stomachs was highest (50%) in February and absent in month of breeding season. The
Chanda nama and M. rosenbrgii were the favorite food of W. attu are because it founded
to entire season. Morphometric parameters with total length show positive allometric
growth for W. attu. The water quality parameter like Temperature, pH, DO. Alkalinity
and Hardnees it directly or indirectly relation between them and survivability of W. attu
fish. Suggestion to reduce catch of small size fishes for future sustainability and re recruitment.