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

Clinocottus analis eggs extracted from the ovary develop normally, showing that internal fertilization occurs in the ovary. Females are capable of storing sperm at least two months. Cleavage does not occur until after the eggs are extruded. The eggs will develop at temperatures ranging from a minimum between 6 and 11° C and a maximum between 20 and 24° C. 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.