Cooperative Fish and Wildlife Research Units Program: Idaho
Education, Research and Technical Assistance for Managing Our Natural Resources

Sockeye salmon and kokanee Oncorhynchus nerka commonly spawn in both lotic and lentic environments; however, the habitat requirements of shore-spawners are virtually unknown relative to those of stream-spawners. A laboratory experiment and an in situ incubation study were conducted to better understand the influence of habitat characteristics on the shoreline incubation success of kokanee. The laboratory experiment assessed kokanee intragravel survival, fry emergence, and fry condition in response to eight substrate treatments, and was the first attempt to simulate shore-spawning conditions for an Oncorhynchus species. The in situ study, conducted at three major shoreline spawning sites in Lake Pend Oreille, ID, evaluated the effect of depth, substrate composition, dissolved oxygen, shoreline slope, and groundwater on intragravel survival. Substrate size composition was a poor predictor of survival in both the laboratory experiment and in situ study. In the laboratory, fry condition and counts of emerged fry were lowest for the substrate treatment with the highest proportion of fine sediment. Results of the in situ study suggest that groundwater flow plays an important role in enhancing intragravel survival in habitats generally considered unsuitable for spawning.