Risk of stock extinction in two species of kilkas (Clupeonella engrauliformis and C. grimmi) from the Caspian Sea

Abstract

The present study aimed to update and describe the current stock status and to provide quantitative methods for assessing vulnerability extinction of two main pelagic species i.e. Clupeonella engrauliformis and C. grimmi in Iranian waters of the Caspian Sea during 1995-2017. The biomass of C. engrauliformis and C. grimmi were collapsed from more than 180,000 and 47,000 mt in 1996 to 520 and 448 mt in 2017, respectively. The proportional rate of population mature biomass of C. engrauliformis and C. grimmi were declined from about 105,000 and 32,000 mt in 1998 to less than 490 and 440 mt in 2017, respectively. The generation length of both species was estimated five years. Base on IUCN criterion A, the proportional rates of population mature biomass of both kilka species show an exponential reduction and are Critically Endangered. The stocks of two kilka species are being shared among all bordering countries of the Caspian Sea. Therefore, it is suggested a coordinated regional effort between surrounding countries of the Caspian Sea to perform a proper management of kilka fishes’ resources.