Catch composition and fishing trend of kilka in Iranian part of the Caspian Sea

Population structure of three kilka fishes (Clupeonella spp.), particularly anchovy kilka (C. engrauliformis), in Iranian waters of the Caspian Sea was surveyed in ۲۰۰۳. A total of ۳۲۳۰ biweekly samples were collected from commercially landed kilka at ۳ stations in Mazandaran and Guilan provinces. Catch and effort statistics were obtained from the relevant organization. Results showed a great decline in the commercial kilka catch from ۹۵۰۰۰ tons in ۱۹۹۹ to ۱۵۴۹۷ tons in ۲۰۰۳. The contribution of anchovy kilka to the total kilka fishery also showed a decline from ۷۱% in ۱۹۹۹ to ۵۲.۵% in ۲۰۰۳, while common kilka (C. cultriventris) increased from ۱۳.۷% in ۱۹۹۹ to ۴۸.۹% in ۲۰۰۳. Fork length range of anchovy kilka showed an increase from ۸۹.۲±۱۲mm in ۱۹۹۹ to ۱۰۰.۴±۴.۹mm in ۲۰۰۳. The age composition of anchovy ranged between ۱+ to ۷+ years and the dominant group was ۵+ years old (age group of ۴+ and ۵+ comprised ۸۴.۶% of population). The K value and L∞ calculated ۰.۵۹۸/year and ۱۱۰.۱۳ mm respectively. Natural, fishing and total mortality coefficient was estimated ۰.۶۹, ۰.۳۱ and ۱ per year respectively. The results showed a sex ratio of F: M= ۶۸.۲: ۳۱.۸.