Spatio-temporal distribution patterns and relationships with environmental variables in a Michigan coastal lake

We examined patterns in fish community composition and the relation to environmental variation in a coastal system of Lake Michigan. Direct hydrological connections to Muskegon River and Lake Michigan contribute to a unique ecosystem in Muskegon Lake, containing both lacustrine and riverine type wetlands, thus making it of particular interest in assessing fish community structure across a temporal and spatial scale. Using overnight fyke nets, we sampled the fish community at 4 littoral sites in Muskegon Lake in the spring, summer and fall of 2003-2009. We also measured a suite of physico-chemical variables at each sampling location and event. Among the most abundant species captured were yellow perch Perca flavescens, round goby Neogobius melanostomus, and bluntnose minnow Pimephales notatus. Ordination analyses showed that fish assemblages most strongly differed by season and location sampled but were also influenced by temperature, conductivity, pH and macrophyte coverage. While lepomis sp. were positively correlated with macrophyte coverage, round gobies were negatively correlated with temperature and conductivity. Our results suggest that patterns in species distribution and abundance respond to short term seasonal variation rather than long term changes in the environment.