مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

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 cultriventrisi increased from 13.7% in 1999 to 48.9% in 2003. Fork length range of anchovy kilka showed an increase from 89.2±12 mm in 1999 to 100.4±4.9 mm 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 Leo 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.