In this study, 705 mosquitofish Gambusia affinis (Baird & Girard, 1853) were caught in Akgöl Lake near the town of Fethiye in Muğla province between November 1998 and October 1999, and the biological characteristics of their growth, reproduction and feeding were studied in detail. In the mosquitofish population, the 0 aged group comprised 97.58% and the 1+ aged group 2.42%; the proportion of females was 81.40%, and that of males was 18.60%. Total length (TL) varied from 1.3 to 5.5 cm; total weight was between 0.02 and 2.31 g. The average numbers of developing eggs were 21.90 (0+) and 52.81 (1); and the average egg productivity per gram was between 27.71 (0+) and 31.71 (1). The average condition number was 1.16 ± 0.16. The maximum condition number was 1.38, in November 1998. In the population, 34.68% of nutrition consisted of Diptera species (22.44% of this was mosquito larvae), 13.26% Nereidae family members and 11.22% Amphipoda members. Consequently, the fact that mosquito larvae are of great importance in the nourishment regime of G. affinis indicates the significance of G. affinis in the struggle against mosquitoes.

In this study, 705 mosquitofish Gambusia affinis (Baird & Girard, 1853) were caught in Akgöl Lake near the town of Fethiye in Muğla province between November 1998 and October 1999, and the biological characteristics of their growth, reproduction and feeding were studied in detail. In the mosquitofish population, the 0 aged group comprised 97.58% and the 1+ aged group 2.42%; the proportion of females was 81.40%, and that of males was 18.60%. Total length (TL) varied from 1.3 to 5.5 cm; total weight was between 0.02 and 2.31 g. The average numbers of developing eggs were 21.90 (0+) and 52.81 (1); and the average egg productivity per gram was between 27.71 (0+) and 31.71 (1). The average condition number was 1.16 ± 0.16. The maximum condition number was 1.38, in November 1998. In the population, 34.68% of nutrition consisted of Diptera species (22.44% of this was mosquito larvae), 13.26% Nereidae family members and 11.22% Amphipoda members. Consequently, the fact that mosquito larvae are of great importance in the nourishment regime of G. affinis indicates the significance of G. affinis in the struggle against mosquitoes.