Study of Natural and Fishing Mortality and Exploitation Rate of Common Kilka Clupeonella cultriventris in Southeast Part of the Caspian Sea (Babolsar)

The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella cultriventris in the southern Caspian Sea. Survival rate and natural mortality were calculated using catch curve and Pauly methods, respectively. Natural and fishing mortality have been estimated up to 0.671yr-1 and 0.849 yr-1, respectively. According to catch curve method, the annual survival rate of common kilka has been estimated up to 0.218 yr-1. With owning this survival rate, the instantaneous coefficient of total mortality of common kilka has been estimated up to 1.52 yr-1. The exploitation rate of common kilka has been estimated up to 0.55. It was revealed that common kilka has been dominant in the catch because of habitat expansion and the change in life depth. It was concluded that common kilka stock is under over-fishing now