Population parameters of the catfishes, Arius caelatus (Valenciennes, 1830) and Arius tenuispinis (Day, 1877) from Mumbai waters

The population parameters like growth, mortality, exploitation rate and length at first capture of Arius caelatus and A. tenuispinis from Mumbai waters were investigated to derive information required for their management. Asymptotic length (L infinity) and growth coefficient (K) were calculated as 520 mm and 0.70 year super(-1) for A. caelatus and 550 mm and 0.73 year super(-1) for A. tenuispinis, respectively. Instantaneous rate of total, natural and fishing mortalities were estimated to be 2.37, 1.18 and 1.19 for A. caelatus and 2.42, 1.19 and 1.23 for A. tenuispinis, respectively. Size at first capture was estimated as 274 mm for A. caelatus and 268 mm for A. tenuispinis. Exploitation ratio (E) was found to be at optimum level for both A. caelatus (0.5) and A. tenuispinis (0.51), indicating the stocks are exploited at optimum level and can be fished sustainably in years to come.