Abstract
Heat shocks were applied to wild rainbow trout eggs for 10 min, starting at 1 and 40 min after fertilization and at temperatures ranging from 24 to 30°C. Analysis of blood samples by flow cytometry revealed triploid induction ranging from 10 to 100% depending on the temperature and timing of the treatment. Survival from fertilization to 60 days and growth of the treated groups were lower than the control. The best temperature shock treatment with regard to percentage of triploids and percentage survival relative to controls was 26°C starting 1 min after fertilization. Histological analysis of the gonads revealed sterility in triploid female fish.