Growth, Mortality and Stock Assessment of Indian Mackerel, Rastrelliger kanagurta (Cuvier, 1816) in the Coastal Waters of Pakistan, Northern Arabian Sea

Resumo

Population dynamics parameters of Rastrelliger kanagurta (Cuvier, 1816) were analyzed from January to December 2008 in coastal waters of Pakistan. FiSAT software was used to assess growth population dynamics parameters. The growth parameters K = 0.84 year^–1 and L∞ = 24.57 cm were estimated with the aid of von Bertalanffy growth function. The natural mortality rate (M), the fishing mortality rate (F), and the total mortality rate (Z) were calculated as 1.682, 2.208, and 3.890 year^–1, respectively. The annual instantaneous fishing mortality rate in our study was considerably greater than both the target (F_opt = 0.841 year⁻¹) and limit (F_limit = 1.121 year⁻¹) biological reference points, suggesting that this species is being over-exploited in the waters of Pakistan. An exploitation rate (E) was estimated to be 0.567 year^–1and longevity (t_max) was calculated as 3/K equal to 3.57 years. The fishery of R. kanagurta by the gillnet catches in our study are of ages 2 to 3 years which indicated a reasonable mesh size for the catch.