Males become jet black and fight over territory during winter, prior to arrival of ripening females. Males will successively spawn with different females, guarding up to three egg masses at a time. Males are capable of spawning at two years of age, and females at three, but most females do not lay eggs until they are four. If larger females are not abundant, then females tend to mature and spawn a very small egg mass at three years of age. In British Columbia, peak abundance of guarded egg masses is during February, although spawning can occur from December through April. Spawning occurs later in more northerly latitudes. Older females of 10-15 years of age can spawn a half million eggs, and they spawn earlier and deeper than the younger fish. Larvae spawned by the largest females tend to be slightly larger than larvae of small females, which could confer advantage under certain feeding conditions in the plankton. Thus, a population with a full demographic spread from young to old fish will have greater chances of survival of young under a variety of environmental conditions.
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