Distribution, abundance and genetic diversity of the longear sunfish (Lepomis megalotis) in Minnesota, with determination of important populations

The northern longear sunfish (Lepomis megalotis peltastes) is recognized by the Minnesota Department of Natural Resources (MN DNR) as a Species in Greatest Conservation Need (SGCN) due to its extremely spotty distribution in Minnesota (known only from 26 lakes) and its threatened status in Wisconsin. This study, funded primarily by the Minnesota State Wildlife Grant (SWG) program and by a smaller amount from the Chippewa National Forest (CNF), serves as an initial effort to begin to understand the distribution, habitat requirements, relative abundance, and genetic variation of the longear sunfish in Minnesota. A total of 119 lakes and one river were visited during June–August 2006, and June, August, and October 2007. Seventeen of the 26 historical lakes were sampled. Longear sunfishes were found in 23 bodies of water (22 lakes or major bays and one river). Twelve of these waters represent new distributional records for Minnesota, and 11 serve as confirmation of historic records. Longear sunfishes were quite restricted in their habitat use, which included high-quality waters with shorelines that have relatively undisturbed stretches of emergent aquatic plants, extensive shallows (< 3' depths), and a firm substrate that was usually rich with organic detritus and submerged plants. Individuals live in these shoreline shallows at least during the warmer months of the year (May-October). During the summer spawning season the colonies of saucer-shaped nests can be found within or nearby the emergent plant beds, and often right next to the shoreline. The species is rarely found in deeper waters, even if these waters support large populations of other sunfish species. Lakes that did not produce longears did not possess the combination of habitat traits that longear sunfishes seem to require. Although we characterized some populations as being abundant in terms of the numbers of individuals within a lake"