Survey on the population structure of anchovy kilka Clupeonella engrauliformis emphasizing on length, weight and age in southern parts of the Caspian Sea

The aim of this article is surveying on biological parameters of anchovy kilka (Clupeonella engrauliformis Svetovidov, 1941) including length, weight and age in southern waters of the Caspian Sea in order to attain the population structure of this species for optimal management of its stock. In this study which has done during 2010, the samples were fortnightly provided from fishing landing site (Babolsar harbor). In the laboratory, length and weight has been measured and classified and age determination has done using sagitta otoliths. Results were compared with the previous years. In the present study, mean length and weight were 116.78±16.5 mm and 12.59±4.2 g, respectively, which has increased in comparison with the previous years. About 45 percent of length abundance belonged to 120-130 mm length classes and about 69 percent of weight abundance belonged to 8.1-12.9 g weight classes. Length-weight relationship was and the growth pattern was negative allometric (p<0.05). Age composition of anchovy kilka was constituted of 7 age groups, including 1-7 years. Age average was 4.34±0.81 year and age 4 was the largest age group, composing 26.55% of the catch population. According to the results we concluded that anchovy kilka population structure has been older and their length and weight increased during last decade. These changes can be due to infirmity in stock rebuilding which is affected by the invader ctenophore and over-fishing.

Clupeonella engrauliformis – Caspian Sea – length – weight - age