Effect of temperature and salinity on egg hatch of the rainbow trout <special>Salmo gairdneri</special>

Responses of eggs of the rainbow trout Salmo gairdneri to a series of temperature and salinity combinations were measured for percentages of total-and viable-hatch and time to 50% hatch. Hatch occurred at the combinations of temperature range of 8.0 to 16.0℃ and chlorinity range of 0 to 6.0‰. Response surface analysis suggests that the maximum percentages of total-and viable-hatch (i.e.,optimum) may be found at 10.0℃ combined with 0‰. Time required to 50% hatch varied 18.5 and 44.6 days after fertilization,and was inversely and exponentially related to the temperature. The effect of chlorinity on the time was statistically insignificant within the hatchable range of eggs