Condition-dependent reproductive tactics by large and small anadromous male sockeye salmon Oncorhynchus nerka
Reproductive tactics, aggression and courtship by large and small (jack) male sockeye salmon Oncorhynchus nerka with ripe females in temporary enclosures depended on the size and behaviour of the competitor, not the size of the focal male. When paired with other jacks or with large but less aggressive males, jacks fought for access to ripe females rather than sneaking, but used sneaking tactics when paired with large, aggressive males. Dominant males of both size groups courted actively and females spawned readily with all combinations of males.
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