Summer Habitat Use by Lake Sturgeon in Manistee Lake, Michigan

Abstract

AbstractThe Lake Sturgeon Acipenser fulvescens is targeted for rehabilitation across its range, but little is known about habitat use by Lake Sturgeon during periods other than the spawning period. Insight into habitat use during nonspawning periods for these long‐lived fish is crucial to our understanding of this species and its recovery. Our goal was to characterize summer habitat use by Lake Sturgeon in Manistee Lake, Michigan, a drowned river mouth complex. Fish were tagged and relocated in the lake by using telemetry in 2003–2005. The lake was divided into 18 sampling sections, and abiotic and biotic variables with potential influences on habitat use were quantified in each section during May–July in 2003 and 2004. Lake Sturgeon were found in the lake during May–July and primarily occupied habitats near the wetland complex and shipping channel in the northern portion of the lake. Water depth, temperature, dissolved oxygen level, Secchi depth, and densities of chironomid larvae, dreissenid mussels, burrowing mayflies Hexagenia spp., and amphipods differed among sampling sections. Similarities between Lake Sturgeon relocation sites and the sampling sections were analyzed with Penrose distance statistics. Abiotic and biotic variables in the southern and central portions of the lake were most similar to those at sampling sections where Lake Sturgeon were relocated. The difference between southern and central sampling sections and the sections where fish were relocated suggests that habitat use was influenced by additional factors that were not monitored. Future efforts to conserve Lake Sturgeon populations should include habitat management during nonspawning periods.