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 2003. A total of 3230 biweekly samples were collected from commercially landed kilka at 3 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 95000 tons in 1999 to 15497 tons in 2003. The contribution of anchovy kilka to the total kilka fishery also showed a decline from 71% in 1999 to 52.5% in 2003, while common kilka (C. cultriventris) increased from 13.7% in 1999 to 48.9% in 2003. Fork length range of anchovy kilka showed an increase from 89.2±12mm in 1999 to 100.4±4.9mm in 2003. The age composition of anchovy ranged between 1+ to 7+ years and the dominant group was 5+ years old (age group of 4+ and 5+ comprised 84.6% of population). The K value and L∞ calculated 0.598/year and 110.13 mm respectively. Natural, fishing and total mortality coefficient was estimated 0.69, 0.31 and 1 per year respectively. The results showed a sex ratio of F: M= 68.2: 31.8.