Ảnh hưởng của độ cứng đến một số chỉ tiêu sinh sản của cá chép (<i>Cyprinus carpio</i> Linnaeus, 1758)

Abstract

This study was carried out to determine the effect of water hardness on the fertilized rate, hatched rate, survival rate and deformed rate of common carp larvae. In the experiment, fertilized eggs of common carp were incubated in different water hardness of 70, 100, 130, 160, and 190 mg CaCO₃.L^-1 at a stocking density of 400 eggs.L^-1. The experimental results showed that the fertilized rate was high (88,7-90,0%) and not significantly different between the treatments (p>0.05). The hatching rate ranged from 85,3 to 88,3%, and the greatest value was in 70 mg CaCO₃.L^-1. At the stage of complete yolk digestion, the survival rate of larvae was highest in 70 mg CaCO₃.L^-1, in comparison with the other treatments. Larval deformity rates varied from 1.3 to 10.3%, the lowest value was in the 70 mg CaCO₃.L^-1. It can be inferred from the study’s these result that common carp eggs should be incubated in water with a hardness of 70 mg CaCO₃.L^-1.

Keywords: common carp, Cyprinus carpio, water hardness, hatchability rate.