Some reproductive biology parameters of mosquitofish Gambusia holbrooki Girard, 1859 (Poeciliidae) in some waterbodies of southeastern Caspian basin, Iran
Eastern mosquitofish, Gambusia holbrooki, is an invasive exotic fish for Iranian inland water. This study conducted to evaluate some reproductive traits of this species in six waterbodies from southeastern Caspian basin. A total of 8500 individuals were sampled from the AlmaGol Wetland, Alakooli Dam Lake, Gomishan Lagoon, Voshmgir Dam Lake, Golestan Dam Lake, and estuary of Gorgan River during February to September 2014. The maximum age in all areas was 1+ for males and 2+ for females. The highest mean GSI value was 2.6 for males in April-May and 29.6 for females in May. Egg diameter ranged from 0.5 to 2.5 mm with a mean value of 1.43 mm. Absolute fecundity varied between 2 to 212 eggs. Both ova diameter and absolute fecundity were positively correlated with females' size, while relative fecundity had no significant correlation with females' size (length and weight). The results showed a significant variations in reproductive characteristics among the populations inhabiting different habitats. This finding is important with respect to life history of the species and ecological view as well
