Local and Lake‐Scale Habitat Effects on Abundance, Lengths, and Diets of Age‐0 Largemouth Bass and Bluegill in Indiana Temperate Lakes

Abstract

Littoral zones of lentic systems are important nursery habitats for age-0 fish as they provide foraging habitat and refuge from predation. While local habitat characteristics in a lake's littoral zone can affect abundances, mean lengths, and trophic interactions of age-0 fish, lake-scale characteristics may also influence these factors. Given that local and lake-scale characteristics are probably related, it may be difficult to interpret perceived associations between habitat characteristics and fish population metrics, as well as elucidate consequences of anthropogenic alterations of habitat. We used classification and regression tree (CART) analysis to evaluate relationships between local and lake-scale habitat characteristics, abundances, and mean lengths of age-0 Largemouth Bass Micropterus salmoides and Bluegills Lepomis macrochirus collected from glacial lakes in northern Indiana during 2009 and 2010. We also evaluated habitat influences on stomach contents of age-0 Largemouth Bass. Our results suggest there are complex, multiscale interactions among habitat characteristics and population and diet metrics of age-0 fish. Site-specific abundances of both fishes were most strongly associated with local-scale characteristics (e.g., high densities of Bluegills at sites with dense submerged vegetation), while mean lengths were associated with lake-scale characteristics (e.g., greater mean length of age-0 Bluegills and Largemouth Bass in small, shallow lakes). Diet composition of age-0 Largemouth Bass was strongly related to individual fish length, though local (e.g., percent coverage by vegetation) and lake-scale (e.g., lake depth) habitat characteristics also affected the type of prey consumed. We suggest that managers consider both local and lake-scale features when undertaking habitat improvement activities, selecting stocking locations, or otherwise jointly managing habitat and age-0 lentic fish populations.

Influence of Aquatic Macrophytes on Age‐0 Largemouth Bass Growth and Diets

“…If so, this would be consistent with the increased age‐0 Largemouth Bass size and abundance corresponding with macrophytes in previous field surveys (Miranda and Pugh ; Middaugh et al. ). However, correlations between locations of capture, diet, and growth in field studies (Miranda and Pugh ; Middaugh et al.…”

“…; Middaugh et al. ). However, the effects of macrophyte removal on growth, survival, and recruitment of many game fishes have not been thoroughly studied.…”

“…; Middaugh et al. ). Age‐0 Largemouth Bass typically switch to a mainly piscivorous diet and consume zooplankton and aquatic macroinvertebrates secondarily during the late summer and fall (Keast and Eadie ; Carpenter et al.…”

“…These actions may disrupt relationships between aquatic macrophytes and fish populations (Miranda and Pugh ; Middaugh et al. ), so management actions such as regulations restricting macrophyte removal may result in improved growth, decreased mortality, and increased recruitment of fish. However, these macrophyte and fisheries management actions require a better understanding of the effects of littoral habitat changes, such as macrophyte removal, on fishes.…”

“…However, correlations between locations of capture, diet, and growth in field studies (Miranda and Pugh ; Middaugh et al. ) depend on the assumption that fish did not move among different habitats. Age‐0 Largemouth Bass are known to disperse distances of up to 500 m from the nest (Hessenauer et al.…”