Genetic diversity and divergence of yellow perch spawning populations across the Huron–Erie Corridor, from Lake Huron through western Lake Erie

Abstract

The yellow perch Perca flavescens supports one of the largest Great Lakes fisheries, whose populations have varied due to environmental changes, including exploitation and habitat degradation. The Huron–Erie Corridor (HEC) connects the upper and lower Great Lakes, running from Lake Huron through the St. Clair River, Lake St. Clair, and Detroit River to western Lake Erie; it serves as an essential fish migration corridor, and contains key spawning and nursery grounds. Its shipping importance led to its extensive channelization and dredging, destroying and degrading habitats. Since 2004, the HEC Initiative has restored some fish spawning and nursery grounds. Our objective is to assess the genetic diversity, connectivity, and divergence of yellow perch spawning populations along the HEC to provide a baseline for assessing future patterns, including responses to improved habitat. Genetic variation of seven spawning populations (N=248), four in the HEC, one in Lake Huron, and two in western Lake Erie, are analyzed at 15 nuclear microsatellite loci. Results showed appreciable genetic diversity of the seven spawning populations (mean observed heterozygosity=0.637±0.020, range 0.568–0.699), which significantly differed in genetic composition (θST=0.011–0.099, p<0.0001–0.0007), suggesting a history of genetic isolation; relationships did not follow a pattern of genetic isolation by geographic distance. Notably, some nearby spawning populations were very genetically distinctive, with high genetic diversity and high proportions of private alleles, as characterized by the Belle Isle restoration site in the Detroit River. Our study provides a genetic benchmark to assess ongoing and future habitat restoration efforts across the HEC and beyond.