Pronounced Genetic Structure and Site Fidelity among Native Muskellunge Populations in Lake Huron and Georgian Bay

Abstract

Conservation and management issues related to genetic diversity and stock structure of native populations of Muskellunge Esox masquinongy have largely been unexplored. In Lake Huron's North Channel and Georgian Bay, Muskellunge populations have been impacted by historical commercial fisheries, recreational fisheries, loss of spawning habitat, historical water quality issues, and ecosystem changes. To determine the spatial genetic structure of native Muskellunge in Lake Huron and Georgian Bay, spawning adults were sampled from 10 sites in the North Channel and eastern Georgian Bay. Genotyping with 20 microsatellite DNA loci showed substantial spatial genetic structure, with significant pairwise divergences among spawning sites. Individual‐ and population‐based analyses revealed hierarchical population structuring, with strong patterns of spawning site fidelity and isolation by distance; very low levels of dispersal and gene flow over historical and contemporary timescales were indicated. Estimation of effective population sizes highlighted the limited genetic resources that are present in these localized populations. The present results show that Muskellunge in Lake Huron and Georgian Bay consist of multiple small populations with limited ranges and high site fidelity and should be managed accordingly. Received February 28, 2016; accepted July 1, 2016 Published online October 11, 2016

Historical and Contemporary Gene Flow and the Genetic Structure of Muskellunge in the Ohio River Drainage

“…We observed levels of variation similar to other studies (Wilson et al. ) and significant population differentiation.…”

“…This is slightly lower but similar to the number of alleles observed in Lake Huron Muskellunge ( = 9.6 alleles per locus; Wilson et al. ). After adjusting for multiple comparisons (adjusted P = 0.001), 4 of 55 comparisons identified significant departures from Hardy–Weinberg equilibrium ( EmaD5 and EmaD6 in locality 4, Buckhannon River, and locality 6, Middle Island Creek).…”

“…The MIGRATE estimates of gene flow would reflect conditions well before any anthropogenic habitat alterations consistent with predictions of site fidelity or philopatry (Wilson et al. ).…”

“…Wilson et al. () observed highly significant differences among populations along the shore of Lake Huron, even sites separated by as little as 20 km. They suggested either site fidelity or philopatry as explanations.…”

Yellow perch genetic structure and habitat use among connected habitats in eastern Lake Michigan

“…In conclusion, understanding population structure of species residing in connected habitats and in sympatry at certain times of the year and/or life cycle has proved critical for maintaining sustainable fisheries (Hilborn et al, 2003;Brenden et al, 2015;Wilson et al, 2016). Here, we showed that yellow perch from Lake Michigan and DRMs represent distinct stocks and that Lake Michigan yellow perch can reside in DRMs during autumn, where they may be subjected to greater harvest than in Lake Michigan.…”