Survie embryonnaire précoce de 9 espèces de poissons d'eau douce après un choc de pH appliqué pendant la fécondation ou au cours des premiers stades du développement embryonnaire

Abstract

Summary. Prehatching embryo survival of 9 freshwater fish eggs after a pH shock during fertilization or early stages of development.The tolerance of freshwater fish eggs to a pH shock was studied by plunging the eggs for 30 min into highly buffered acid or alkaline solutions and by measuring the survival rates at the eyed embryo stage. The study was made on eggs from 9 species : common carp, roach, crucian carp, rainbow trout, brown trout, houting, artic char, pike and perch subjected to acid or alkaline shocks either during fertilization or after activation of the egg.During the life cycle of fresh water fish, the fertilization stage represented a period of high sensitivity to acid shocks for all 9 species : a pH value of 5 was lethal under our experimental conditions. Cyprinids and rainbow trouts seemed to be the most sensitive to an acid pH. During egg activation, a large increase in the tolerance of the egg to the pH shock was observed.Introduction.