مقايسه هم آوري ماهي شاه كولي (Alburnus chalcoides, Guldenstaedt 1772) مهاجر به تالاب انزلي. رودخانه هاي سفيدرود، چمخاله و شيرود

A Comprative of fecundity in Shemaya (Alburnus chalcoides, Guidenstaedt 1772) immigrant to the Anzali Wetland, Sefidrood, Chamkhaleh and Shirood Rivers

Shemaya {Alburnus chalcoides) is one of the economically valuable fishes in the Caspian Sea. This fish enters rivers and wetlands entering the Caspian Sea for spawning. The study of fecundity is one of the important indicators of reproduction biology in fishes. The present study was conducted in the spring of 2008 on 33 shemaya specimens caught from each of the regions; the Anzali Wetland, Sefldrood, Chamkhaleh and Shirood Rivers in order to investigate the fecundity in this immigrant species. According to the results obtained the highest average fork length (15.83±1.2cm), weight (42.71±7.98g), gonad weight (5.54±1.81g) and absolute fecundity (4447.84±1132.51 eggs) belonged to shemaya specimens caught from the Anzali Wetland, while the lowest average fork length (13.41±0.81cm), weight (24.51±4.55g), gonad weight (3.54±0.88) and absolute fecundity (2613.97±548.79eggs) were recorded in Sefidroodʹs Shemaya. The maximum and minimum average relative fecundity were recorded in Shiroodʹs Shemaya (113.15±21.06eggs) and Chamkhalehʹs Shemaya (101.06±22.51eggs), respectively. Maximum (898.48±255.72) and minimum (763.94±70.62) average number of ovules in each gram of body weight belonged to Shemaya specimens belonging to Chamkhaleh River and Sefidrood River, respectively. The highest average diameter ovules (1.175±0.04mm) and the average mean gonadsomatic index (14.72%) belonged to Sefidroodʹs Shemaya, while the lowest average diameter ovules (1.106±0.117mm) and average mean gonadsomatic index (12.15%) were recorded in Chamkhalehʹs Shemaya. On the basis of Kruskal-Wallis and Mann Whitney tests, significant differences were detected in the biometry parameters and fecundity of Shemaya specimens from different regions.