Ecology and life history of coaster brook trout and potential bottlenecks in their rehabilitation

Document Type

Conference Proceeding

Publication Date

8-1-2008

Abstract

Lake Superior once supported abundant lake-dwelling brook trout Salvelinus fontinalis called coasters; however, only scattered remnant populations remained by the early 20th century. Owing to their early decline, there is little information about their ecology and life history, yet such information is vital for the ecologically based rehabilitation and management of coasters. This study reviews the ecology of coaster brook trout from a life history perspective and presents quantitative data on the biology and status of the few populations that have been studied. Within the Lake Superior basin, some brook trout are stream residents while others are lacustrine or adfluvial. Although the variation in migratory behavior may be related to individual energetics, the role of evolution and the proximate factors triggering specific life histories remain uncertain. Comparisons of recent biological data from populations in the Lake Superior basin show that the northern populations have longer lengths at age and length frequency distributions skewed toward longer individuals. The degrees to which this difference is driven by variation in individual growth rates and size-selective mortality are unknown. All known populations around the Lake Superior basin appear to have a small number of individuals and are thus of conservation concern. We believe that biotic interactions such as competition with introduced salmonines (in particular coho salmon Oncorhynchus kisutch) have a strong negative influence on the individual and population performance of coasters. Coupled with high past and recent mortality from fisheries, these factors may create bottlenecks limiting the growth and rehabilitation of the remnant populations. Lake Superior coaster brook trout are persisting, albeit uncertainly, under conditions different from those in which they once thrived. Management focused on native ecosystem rehabilitation may foster the return of these fish as abundant members of Great Lakes food webs, and recent basinwide restrictions on length and catch limits are a positive step toward enhancing their rehabilitation and evolution. © Copyright by the American Fisheries Society 2008.

Publication Title

North American Journal of Fisheries Management

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