Survival rates between the first feeding and 200
days is presented in Figs 1 and 2.Very high mortalities
were observed in diploid and heat-shocked triploid
hybrid groups between the first feeding and the 20th
day. Triploid rainbow trout groups had also demonstrated
high mortality during this period. Survival
rates of control hybrids were higher than for triploids
in days 20,40 and 60 but differences were not signifi-
cant. During this period, from the first feeding to the
60th day, heat-shocked hybrid mortality was higher
than for control hybrids. In later periods, between the
140th and the 200th day, viability of heat-shocked
hybrids was higher than for non-shock-induced control
hybrids.