Endocrine Changes Associated with Spawning Behavior in Male Kokanee Salmon (Oncorhynchus nerka) and the Effects of Anosmia

This study examines the relationship between social status, behavioral activity, and hormone levels through the spawning cycle in male kokanee salmon (Oncorhynchus nerka). Shortly after arrival at the spawning grounds, male kokanee undergo dramatic changes in morphological and physiological condition: there is an increase in body depth, a bright silvery appearance is replaced by an intense red coloration, and spermiation commences. Males become …