Matching Management to Biological Scale: Connectivity among Lacustrine Brook Trout Populations

Abstract

Determining appropriate spatial scales for managing fisheries is a key element of sustainable management. For inland fisheries, management or harvest regulations are often implemented as general regional guidelines or on a lake-by-lake basis. Wild lacustrine brook trout Salvelinus fontinalis from four waterbodies in the Galipo River watershed of Algonquin Provincial Park, Ontario, were used as a model system to determine the extent of population structure among lakes and to identify appropriate scale(s) for managing inland brook trout fisheries. Individual multilocus genotypes were measured using 10 microsatellite loci and were used to characterize movement and gene flow among lakes. Both population- and individual-based analyses showed very little genetic structure among all pairs of waterbodies, suggesting high levels of movement and gene flow between all pairs of lakes. Varying levels of limited genetic structure between pairs of lakes indicate that gene flow may not be uniform within the study system. These results suggest that contrary to previous studies, local watersheds may be the most appropriate management scale for lacustrine brook trout populations in watersheds where physical characteristics provide the potential for migration and gene flow.