In 1949, Hubbs and Lagler described morphological variation among pearl dace (Margariscus margarita) of inland lakes on Isle Royale, Michigan. For Harvey Lake, Hubbs and Lagler, proposed that pearl dace were sufficiently morphologically distinct to warrant subspecific status. They argued that divergence of the Harvey Lake pearl dace was due to allopatric differentiation in isolation from lower elevation lakes. Harvey Lake has been isolated by elevation from lower elevation lakes for approximately 10 to 15 thousand years. No genetic studies have been done on Isle Royale pearl dace to evaluate this hypothesis to date. Here we report the analysis of Margariscus margarita populations using a limited battery of microsatellite loci to assess the extent of and genetic divergence among the Harvey Lake and other Isle Royale lowland lake populations. Microsatellite loci were analyzed using PCR primers developed for the non-congener, longnose dace (Rhinichthys cataractae). Statistical analyses of allele frequency data indicate genetic differentiation among all Isle Royale pearl dace populations inclusive of both Harvey Lake and lowland populations concurring with Hubbs and Lagler’s hypothesis that the Harvey Lake population is genetically divergent. Results also indicate that the lowland Isle Royale populations are apparently equally divergent from one another.


ACKNOWLEDGEMENTS We would like to extend our special thanks to The US Geological Survey for monetary and logistic support. Larry Kallemeyn and Staff, Voyageurs’ National Park, MN for field and sample collection support. We further thank the US National Parks Service, Isle Royale Wilderness Reserve for field support and lodgings. Thanks also to Dr. Bob Gannon and the Valdosta State University Biology Department for lab and monetary support of J.Ryce Martin's thesis. This work was further supported by the VSU Faculty Research Grant Program.