Ecology, Environment and Conservation Paper

POPULATION DYNAMICS OF BIG EYE HILSA, ILISHA MEGALOPTERA FROM ESTUARINE REGION OF DIAMOND HARBOUR, WEST BENGAL

Saptarishi Mondal, Samarendra Behera, Sanjeev Kumar, T.S. Nagesh, N.A. Talwar, Rinku Gogoi1 Anish Das and Sudipta Sarkar

Abstract

This study describes the growth, mortality and exploitation level of Big Eye Hilsa, Ilisha megaloptera from estuarine region of Diamond Harbour, West Bengal. A total of 354 specimens were studied, which were captured mostly by stationary bag-net, (locally called Beenjal, Behundijal) Gill net, Trawl net. These are nonselective multispecies small mesh sized nets operated from June 2014 to March 2015. Data analysis was performed using Length Frequency Distribution Analysis (LFDA),Version 5.0, a PC-based computer package developed under (FMSP) for estimating growth parameters of the non-seasonal version of the Von- Bertalanffy growth curve. From the ELEFAN method the asymptotic length (L”), curvature parameters (K), age at zero length (to) and Growth performance index (֒) were found to be 74.942 cm, 0.284 per year, - 0.4 year and 3.2028. The growth parameters obtained from the ELEFAN method were total mortality co-efficient (Z), Natural mortality co-efficient (M), Fishing mortality co-efficient (F) and Exploitation level (E) were calculated as to be 1.105 per year, 0.435 per year, 0.67 per year and 0.60, respectively. All the mortality parameters mainly help to estimate the exploitation level of Ilisha megaloptera. In the present study the value of exploitation level (E) mainly indicated over exploitation of the Ilisha megaloptera in the Diamond Harbour estuarine region.