Artificial spawning of carp Cyprinus carpio L.: differences between the effects on reproduction in females of Israeli strain Dor-70 and its cross-breed treated with carp pituitary and Ovopel

The effects on carp reproduction were investigated in females of the Dor-70 strain and a cross-breed of this line with a Hungarian one of carp pituita ry and Ovopel as ovulation stimulators. It was clear that, in the case of t he Ovopel treatment, a higher percentage of females spawned, although the w eight of eggs obtained was less than that yielded by hypophysed fish, the d ifferences being highly significant (P less than or equal to 0.01) with res pect to the weight in grams and to percentage of female body weight. No sta tistically significant differences were determined in the quality of eggs, measured by both the fertilization percentage and the percentage of living embryos, obtained after the two stimulators were used, Neither the provenan ce of females nor the interaction of female provenance and the stimulator h as any effect on the traits investigated. The correlation between the perce ntage of fertilization and the percentage of live embryos was 0.54 for stra in Dor-70 and 0.95 for the cross-breed. The multiple regression equations w ere calculated for strain Dor-70 and for cross-breed 5 separately, where th e percentage of living embryos constituted a dependent variable and the mas s of a female, mass of eggs in grams and the percentage of fertilization we re independent variables. We appraised the regressions as significant for D or-70 (P less than or equal to 0.04) and highly significant for the cross-b reed (P less than or equal to 0.0001).