Reproductive biology of Mossul bleak (Alburnus mossulensis) in Bibi-Sayyedan River of Tigris basin in Iran

Reproductive characteristics of Mossul bleak, Alburnus mossulensis, a native species of Cyprinidae family in Bibi-Sayyedan River of Semirom, Isfahan, were investigated by monthly sampling during December ۲۰۱۰ to December ۲۰۱۱. Five hundred and fourty three specimens (۲۵۶ females, ۱۵۹ males and ۳۱ immature) were caught by a sein net (۵ mm mesh size). The collected sampeles were anesthesized in ۱% clove oil solution and transported to the laboratory on ice and subjected to dissection and biometric measurments. Age of males and females ranged from ۰+ to ۵+ years. The sex ratio was ۱M: ۲.۲F (p < ۰.۰۵). The females outnumbered the males in all age classes. The largest female was ۱۶.۸cm in total length and ۴۹.۱۲g in weight and the largest male was ۱۴.۱cm in total length and ۲۸.۱۹g in weight. The age and total length at first maturity of females and males were estimated as ۱ year and ۵.۳cm total length, and ۲ years and ۴.۴cm, respectively. The minimum, maximum, and avarge absolute fecundity were ۲۰۶۴, ۱۰۳۱۶, and ۵۵۰۵ ± ۲۶۸۶SD, respectively and also, the relative fecundity was ۲۰۳ ± ۵۸ egg/g body weight. Macroscopic analysis of gonads and gonadostomatic index (GSI) values suggested that spawning ofA. mossulensis occurs from March to June with a peak in April. Thus, A. mosullensis is considered a group-synchronous type species with a capacity for multiple ovulations within a reproductive season (multiple spawner).

کلیدواژه ها:

Cyprinidae ، Fecundity ، Age ، gonad development ، Gonadosomatic index