Growth, mortality and stock status of three commercially important catfishes from the River Ganga, India

Abstract

A study was undertaken to determine population parameters and stock status of three commercially important catfishes viz. Eutropiicthys vacha (Hamilton, 1822), Clupisoma garua (Hamilton, 1822) and Ailia coila (Hamilton, 1822) from middle and lower stretch of the River Ganga. Monthly length and weight data of three species from Patna, Buxar and Bhagalpur was collected for determining population parameters and stock status using standard procedures. The von Bertalanffy growth parameters (VBGF) parameters including the total mortaliy (Z), natural mortality (M) and fishing mortality (F) rates for all three catfishes were analysed and compared with past studies. The calculated E value of the three catfishes was above the level of optimum exploitation (0.5) but was below 0.7 indicating that caution need to be excercised in order to avoid overexploitaton of the fish stocks. Management measures such as reduction of fishing pressure either by limiting number of boats or fishing hours, imposing mesh size regulation to avoid growth overfishing, minimum legal size, declaring closed season or closed area throughout the breeding season of the catfish can be suggested for revival of the fish stocks. Further, studies on the reproductive biology, identification of spawning season and spawning grounds is suggested which will play apivotal role in the management of stocks of these fishes in the River Ganga. Keywords: Exploitation rate, FiSAT II, Length frequency, Population dynamics (Hamilton, 1822)