Fish as Food: What River Otter Presence and Abundance Can Tell Us about Aquatic Communities in Michigan

The North American river otter (Lontra canadensis) is a semi-aquatic mammal that is considered a top predator in many aquatic systems in Michigan and throughout the United States. Due to high energetic demands, otters have the capacity to alter the fish community composition and thus fisheries management activities, however wildlife and fisheries management is often segregated within natural resource agencies. We designed and evaluated a spatially explicit approach to identify large scale landscape features significant to river otter distribution in Michigan with specific attention given to the relationship between the interspersion and juxtaposition of aquatic habitats and associated fisheries dynamics.  We found that the connectivity between water bodies with high fish productivity was significantly related to the presence and relative abundance of otters in the watersheds studied. Our findings further emphasize that the ecological requirements of river otters necessitate an understanding of the linkages between aquatic and terrestrial systems for effective management of otters and the fish populations they impact through predatory demand. As such, fish and wildlife agencies need to develop spatially explicit cooperative land and water management programs that integrate key piscine predators on associated aquatic communities in order to achieve sustainable fisheries conservation objectives.