Life Cycle of Salmincola californiensis (Dana 1852) (Copepoda: Lernaeopodidae)

Abstract

A description is given of the life cycle of Salmincola californiensis (Copepoda: Lernaeopodidae), studied by continuous observation of developing parasites and by intermittent examination of infected sockeye salmon (Oncorhynchus nerka). The cycle consists of six stages: copepodid (free-swimming), four chalimus stages (attached by second maxillae to frontal filament), and adult (attached by bulla). The copepodid settles on the fish and uncoils its frontal filament. Each successive chalimus stage reattaches the filament during moulting, but chalimus IV breaks off, searches for the site of final attachment, and excavates an implantation cavity for the bulla. The male cycle is similar but its chalimus IV is of shorter duration and soon moults into the male adult, actively searching for the female. Morphology of all stages is described in detail. Some comments are made on life cycles in Caligoida.