Influence of Habitat Characteristics on Shore-Spawning Kokanee

Abstract

Sockeye Salmon Oncorhynchus nerka and kokanee (lacustrine Sockeye Salmon) commonly spawn in both lentic and lotic 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. The in situ study, conducted at three major shoreline spawning sites in Lake Pend Oreille, Idaho, evaluated the effect of depth, substrate composition, dissolved oxygen, shoreline slope, and groundwater on intragravel survival. Substrate size composition was generally a poor predictor of survival in both the laboratory experiment and in situ study; although, fry condition and counts of emerged fry in the laboratory were lowest for the substrate treatment that had 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.

Received January 7, 2014; accepted May 28, 2014

ACKNOWLEDGMENTS

The authors thank William Ament, William Harryman, Kelly Carter-Lynn, and Nicholas Wahl for assistance with the in situ study, and Jarrod Yates, Amy Long, Christine Moffitt, and many others for assistance with the laboratory experiment. The authors also thank Michelle Wiest for statistical support. Helpful comments on a previous version of the manuscript were provided by David Beauchamp, Daniel Schill, Michelle Wiest, Frank Wilhelm, and three anonymous reviewers. Funding for this project was provided by Idaho Department of Fish and Game and the Bonneville Power Administration. The Idaho Cooperative Fish and Wildlife Research Unit is jointly sponsored by the University of Idaho, U.S. Geological Survey, Idaho Department of Fish and Game, and Wildlife Management Institute. This project was conducted under the University of Idaho Institutional Animal Care and Use Committee Protocol 2012-7. The use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.