Artificial spawning of carp, Cyprinus carpio (L.)

The effect of reproduction was investigated on females of Hungarian strain W, French strain F, and their cross-breed 1X whose ovulation was stimulated with carp pituitary (0.3 mg kg(-1) and, after 12 h, 2.7 mg kg(-1) ) or Ovopel (one-fifth of a pellet per kg and, after 12 h, one pellet per kg). It was found that in the case of Ovopel treatment, the percentage of spawning females of strain F and the cross-breed 1X was higher than in the hypophysed fish compared. The applied ovulation stimulators did not significantly affect the weight of obtained eggs, whereas the significant (P less than or equal to 0.01) effect was recorded with respect to the quality of eggs after 12-, 24-, 36- and 48-h of incubation. After Ovopel stimulation, the quality of eggs was better. The origin of the females had no statistically significant effect on the weight of eggs although the yield of eggs from fish of strain W was much smaller than that from females of strain F and the 1X cross-breed. The interaction between the ovulation stimulator and the provenance of the females was significant (P less than or equal to 0.05) for the percentage of live embryos after 48-h of incubation of eggs. Eggs of the best quality (and highest weight) were obtained from fish of strain F and cross-breed 1X treated with Ovopel. In females of strain F that spawned within 6 and 10 h after the second Ovopel injection, the effect of the ovulation time on the weight of eggs was non-significant. It was significant with respect to the percentage of egg fertilization and of live embryos after 36-h of incubation (P less than or equal to 0.01 and P less than or equal to 0.05 respectively). The better quality of eggs (and their higher weight) was recorded when this time was shorter.