Fish Assemblage Shifts and Population Dynamics of Smallmouth Bass in the Beaver Archipelago, Northern Lake Michigan: A Comparison between Historical and Recent Time Periods amidst Ecosystem Changes

Abstract

The ecological and economic importance of Great Lakes nearshore areas and the paucity of information on nearshore Lake Michigan fish assemblages prompted us to document changes that occurred from a historical time period (1969–1972, 1975, 1977, and 1984) to a recent period (2005–2008) in a nearshore northern Lake Michigan (Beaver Archipelago) fish assemblage, with an emphasis on smallmouth bass Micropterus dolomieu. From historical to recent periods, the Beaver Archipelago fish assemblage shifted from predominantly brown bullheads Ameiurus nebulosus to predominantly smallmouth bass. Relative abundance of brown bullheads and white suckers Catostomus commersonii declined from historical to recent time periods, as did overall species richness. The relative abundance, recruitment variability, and mortality rates of smallmouth bass have not significantly changed since the historical time period, whereas both condition (ages 5–7) and growth (ages 2–7) of this species have significantly increased. Our results suggest that the smallmouth bass population in the Beaver Archipelago area has not been negatively affected by recent ecological changes (i.e., declining primary productivity, increasing benthic invertebrate densities, increasing numbers of double-crested cormorants Phalacrocorax auritus, and increasing introductions of nonnative species). The smallmouth bass is currently the dominant nearshore species and remains a critical component of the nearshore fish assemblage in northern Lake Michigan.

Received March 7, 2011; accepted October 11, 2011

ACKNOWLEDGMENTS

We thank N. Arend, A. Clem, A. Kaemingk, and all other volunteers at the Central Michigan University Biological Station for field assistance. Jim Gillingham provided technical and logistical support. Funding was provided by Central Michigan University, the Michigan Department of Natural Resources (Game and Fish Protection Fund), and the Saginaw Bay Walleye Club. David Jude and two anonymous reviewers provided helpful comments on earlier versions of this manuscript.