Coarse Woody Habitat, Lakeshore Residential Development, and Largemouth Bass Nesting Behavior

摘要

Lakeshore residential development (LRD) is associated with both low riparian tree density and reduced structural complexity of the littoral zone. Fallen trees from riparian zones (coarse woody habitat [CWH]) provide littoral structure for fish refuge, substrate for invertebrate production, and habitat for nesting fish. We performed a subsurface viewing and snorkel survey comparing the spawning behavior of largemouth bass Micropterus salmoides in six lakes that span the known regional gradients of CWH and LRD in Wisconsin's Northern Highlands Lake District. We tested for differences in the water depth at nest sites and the nest distance to littoral structures (including every dock encountered) among lakes with contrasting CWH or LRD density. Largemouth bass nested under or near CWH in lakes with high CWH density. In lakes with low CWH, many males nested near CWH; however, nests contained smaller pieces of wood and were established in deeper water within low-CWH lakes than within high-CWH lakes. No nests were closer to a dock than to CWH, which suggested that docks do not act as surrogates for CWH. Habitat alterations associated with LRD significantly affect largemouth bass nest site location, and an understanding of these impacts will be important for maintaining viable populations of this prized game fish as LRD pressures expand.