The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis in the southern Caspian Sea. Survival rate and natural mortality were cal...The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis 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 0.633 yr^-1 and 0.437 yr^-1, respectively. According to catch curve method, the annual survival rate of anchovy kilka has been estimated up to 0.343 yr^-1. With owning this survival rate, the instantaneous coefficient of total mortality of anchovy kilka has been estimated up to 1.07 yr^-1. The exploitation rate of anchovy kilka has been estimated up to 0.408. The catch amounts of anchovy kilka decreased gradually mainly due to overfishing, predators and ecological disturbances occurred in the Caspian Sea. The results suggest that the population of anchovy kilka were overexploited in the past years and were vulnerable to their natural predators.展开更多
文摘The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis 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 0.633 yr^-1 and 0.437 yr^-1, respectively. According to catch curve method, the annual survival rate of anchovy kilka has been estimated up to 0.343 yr^-1. With owning this survival rate, the instantaneous coefficient of total mortality of anchovy kilka has been estimated up to 1.07 yr^-1. The exploitation rate of anchovy kilka has been estimated up to 0.408. The catch amounts of anchovy kilka decreased gradually mainly due to overfishing, predators and ecological disturbances occurred in the Caspian Sea. The results suggest that the population of anchovy kilka were overexploited in the past years and were vulnerable to their natural predators.
