Age, growth and mortality parameters of Indian oilsardine Sardinella longiceps Valenciennes, 1847 from Mumbai waters, off Maharashtra, India

Age, growth and mortality parameters of Sardinella longiceps Valenciennes, 1847 were studied based on the length-frequency data of 785 individuals collected on weekly basis from New Ferry Wharf Sassoon Docks and Versova landing centres in Mumbai from September 2013 to May 2014. The data were analysed through EI,EFAN employing the FiSAT program. Asymptotic length (L-infinity), growth coefficient (K) and age at zem-length (t(o)) were estimated at 233 mm, 1.51 y(-1) and -0.000022, respectively. The von Bertalanffy growth formula indicated that the fish reaches 182, 221 and 230 mm at the end of 1, 2 and 3 years of life, respectively. Total (Z), natural (M) and fishing (F) mortalities were estimated at 4.82, 2.46 and 2.36 y(-1), respectively. The estimated M/K ratio falls within the range for the accurate estimation of natural mortality coefficient, indicating that the M and K estimates are reasonable and reliable. With exploitation rate of 0.48 and the fishing mortality being only slightly lower than the natural mortality, it can be concluded that the stock is exploited to near optimum levels in the region.