Effect of safe concentrations of some pesticides on ovarian recrudescence in the freshwater murrel, Channa punctatus (Bl.): a quantitative study.

The effects of safe concentrations of carbofuran 3% G (5 ppm) and fenitrothion 30% E.C. (1.5 ppm) on ovarian recrudescence of Channa punctatus during the maturing, prespawning, and spawning phases (mid-April through mid-August) of the annual reproduction cycle were studied. The results reveal that, compared to carbofuran treatment, fenitrothion was more effective not only in lowering ovarian weights, but also in retarding the growth of previtellogenic (stage I) oocytes into vitellogenic (stage II) and yolky (stage III) oocytes. In addition, more previtellogenic and vitellogenic oocytes underwent atresia in fenitrothion-treated fish and only atretic oocytes were observed in the ovaries of these fish after 120 days of exposure. The fenitrothion treatment also caused a significant decline in the diameter of stage III oocytes, and in the number of nucleoli in stage I oocytes.