Fertilization, Initiation of Cleavage, and Developmental Temperature Tolerance of the Cottid Fish, Clinocottus analis

Eggs from coldwater stations are more cold adapted than are the warm adapted eggs from warmwater stations. Eggs exposed to diurnal temperature changes have survivals approximating that occurring at the more optimal temperature. Thermal lethalities are associated with failures at gastrulation, initiation of circulation, hatching, and perhaps melanophore formation. Hatching appears to be stimulated by agitation. Developmental rates are nearly equal above 20? C but double with an increase of 7 or 8? C at lower temperatures.