Biology and stock assessment of Tachysurus jella (Day) from Mumbai waters

Abstract

Biological parameters such as length-composition, food and feeding, length-weight relations and growth of Tachysurus jella was studied using the data collected during 1987-2003. The occurrence of empty stomach was high (70%). Stomach content analysis revealed that the fish is a carnivore feeding mainly on bottom dwelling crustaceans (Preponderance Index, PI : 97.3) such as Squilla spp. (PI: 39) and crabs (PI: 35). The length-weight relationship was Log W = -5.7938 + 3.4426 Log L (r = 0.96). Estimated values of L∞ and K were 518 mm and 0.65yr-1 respectively. It was estimated that T. jella reaches 278 mm at the end of one year and 377 mm in two years. The longevity was estimated to be 4 to 4 ½ years. Stock assessment of T. jella during 1987-1999 indicated that the stock was overexploited (E = 0.73). Higher fishing effort and sharp reduction in yield during 2000 - 2004 confirmed that the species was under heavy fishing pressure and regulatory measures have to be imposed to sustain and improve the fishery of this species.