Evidence of Morphological and Functional Variation among Bluegill Lepomis macrochirus Populations across Grand Lake St Mary\u27s Watershed Area

A myriad of factors have been shown to influence the morphology offreshwaterfish. However, studies that parse out where variation is comingfrom (e.g. body size, sex, and habitat) as well as what potential thesechanges have to influence function (e.g. swimming performance) areunderstudied. Therefore, the objectives of this study were to describemorphological variation of BluegillLepomis macrochirusacross the GrandLake St Mary’s watershed area (northwest OH, USA) and test forcovariation of morphology with size, sex, and habitat as well as to assessswimming performance to discern whether any differences in habitat (andmorphology) correspond with functional aspects related to criticalswimming velocity. Geometric morphometric methods were used toassess shape variation among individuals and general linear models wereused to test for covariation of morphology with size, sex, and habitat.Analyses indicated that body size was the strongest driver ofmorphological variation followed by sex, habitat, and interactions–indicating the presence of allometry, sexual dimorphism, and the potentialfor habitat induced plasticity. In general, more robust morphologiestended to correspond with larger individuals, males, and/or individualsfrom lentic habitats. Swimming performance trials supported functionaldifferences as individuals from lotic habitats demonstrated significantlyhigherUcritswimming performance values (»+20%) than lenticindividuals. Broader applications of thesefindings can link to evolutionaryecology, management, and conservation