بيولوژي توليد مثل سياه كولي (Vimba vimba L. 1758) در منطقه كياشهر استان گيلان

Study on biology of reproduction in Vimba vimba (L. 1758) in Kiashahr region

This study was carried out in the south-west Caspian Sea (in coastal of Kiashahr waters) form September 2007 to May 2008 on Vimba vimba spicies of Cyprinidae. The samplings were monthly and samples were collected by several fishing gears beach seine. 415 specimens of Vimba vimba persa were catch. The measured parameters were: TL, FL, SL, body weight, aging (using scales), sex, gonad weight and egg diameter. All studied fishes were classified in 3 age groups (l4, 2+, 3+) years. We could recognize sexuality in 412 specimens. Males provided 42 percent and females provided 58 percent of the catch. The sex-ratio was, F: M=l:l/38. The range of agg diameter was measured 22 to 130 M and the average of agg diameter has been 77±21/25 M. The minimum and maximum of absolute fecundity were estimated 6435, 13589 eggs in March and April, respectively. Itʹs mean was 10526 eggs. The minimum and maximum of relative fecundity were 92 and 152 eggs in March and December, respectively. The mean of relative fecundity in all samples was 128 eggs. The minimum and maximum of Gonadosomatic index (GSI) of males were 0.57±0.22% and 3.18±1.14% in November and May; and for females were 1.7±2.6% and 14.53±3.25% in October and June, respectively. The mean of Gonadosomatic index (±SD) in males and females were 2.16±1.53 and 6.35±4.19%, respectively.