Abstract
The Kootenai River is a large river in the Pacific Northwest. The Kootenai River basin contains several native fishes that are in decline due to the effects of water development. Conservation actions (e.g., habitat restoration, nutrient addition, conservation aquaculture) have been taken to restore native fishes in the Kootenai River basin. However, the challenges associated with describing the life history structure of migratory fishes in large aquatic systems has prevented managers from describing the response of some fish to mitigation. The objective of my research was to describe the life history structure and movement dynamics of White Sturgeon Acipenser transmontanus and Redband Trout Oncorhynchus mykiss gairdnerii in the Kootenai River basin using microchemistry analysis. I was unable to describe the life history structure of White Sturgeon but provide insight into considerations for planning the use of microchemistry in ecological monitoring. The unique morphology of fin rays influences the resolution of information obtained using microchemistry analysis. The results of White Sturgeon microchemistry can be used to plan the monitoring program in the Kootenai River basin, and also provide insight for the preliminary research process when considering microchemistry as a management tool. In contrast, microchemistry was able to describe the life history characteristics of Redband Trout in the Kootenai River. Redband Trout were assigned natal habitats in both the mainstem and tributaries throughout the Kootenai River basin. Nearly 20% of Redband Trout sampled in this research were a product of mainstem spawning in the Kootenai River. The remaining fish migrated to the Kootenai river from 31 tributaries throughout the Kootenai River basin. Most migratory Redband Trout had migratory mothers and originated in Montana tributaries. Redband Trout outmigrated from natal streams at a variety of ages (0-3 years) and lengths (12-430 mm). Several streams with apparent barriers to fish movement contributed Redband Trout in this study. My results provide information that can be used to prioritize restoration efforts to recover Redband Trout in the Kootenai River basin.