Study of reproductive characteristics of white bream, Blicca bjoerkna (Linnaeus, 1758) in Anzali Wetland

The study carried out in reproduction status project of commercial fishes of Anzali wetland from April 2016 until March 2017 and samples were caught using electroshocker in different points of studied area. The studied adult males (n=173) weight varied between 1.08 and 33.22 with an average of 7.12±4.06g and adult females (n=271) between 0.71 and 59.9 with an average of 12.66±9.16g. Total length were measured between 45.5 and 136 with an average of 80.02±14.03mm in adult males and between 41.3 and 166 with an average of 92.81±22.06mm in adult females, too. Age composition was from 2 to 11 and 1 to 15 years old for adult males(n=57) and females (n=130), respectively. Adult males and females formed 38.96% and 61.04% of adults. Monthly average of gonado-somatic index was determined 1% in August and 13.7% in April with an annual average of 6.54±7.08%for adult females. Spawning period of the fish species was determined on basis of gonado-somatic index and composition of gonad maturity stages of adult females from April to July. Absolute fecundity of studied fish (n=16) was calculated 3805-11483 with an average of 6898.1±1997.89 eggs and average of egg diameters was 0.9±0.1 mm. Although this fish has no economic value but this species is caught in Anzali wetland for consumption. Due to its Reproduction season, its overfishing should be avoided.