Population structure of Alosa Linck, 1970 in the southern Coast of Caspian Sea (Guilan province)

Genus Alosa Linck, 1970 is widely distributed in the Caspian Sea but in Southern region of Caspian Sea identified species has not been reconsidered during past ten years. To study the population density of Alosa species of Iranian waters of Caspian Sea, samples were collected over a period of one year (Jun 2012 to March 2013) from Chaboksar, Chaf and Kiashahr coastal water by beach seines and gill net.After collection all samples were brought to laboratory in ice boxes.for identification of different species had been done according to morphological characteristic. A total of 430 specimens were examined to identify four species namely Alosa braschnikowi, Alosa caspia, Alosa kessleri and Alosa saposchnikowi. A.braschnikowi was the most frequent species and Alosa saposchnikowi had the lowest prevalence. A.braschnikowi and A.caspia had the highest and lowest mean fork length and weight, respectively. Sex survey showed that females were dominant in all species. The obtained samples were of 2 to 7 years of age.