Can Habitat Alteration And Spring Fishing Explain Black Bass Nest Distribution And Success?
Tyler Wagner, Department of Fisheries and Wildlife, 13 Natural Resources Building, Michigan State University, East Lansing, MI 48824; (517) 353-2267; FAX (517) 432-1699; wagnerty@msu.edu
Aaron K. Jubar, Department of Fisheries and Wildlife, 13 Natural Resources Building, Michigan State University, East Lansing, MI 48824
Mary T. Bremigan, Department of Fisheries and Wildlife, 13 Natural Resources Building, Michigan State University, East Lansing, MI 48824
The reproductive behavior of black bass (largemouth Micropterus salmoides and smallmouth, M. dolomieu) makes these species vulnerable to negative effects of habitat alteration and fishing during the spring nesting period. Because of the propensity of bass to nest in shallow littoral areas, human development of lake shoreline (through removal of plant and woody material cover, and alteration of substrate in the littoral area) may reduce the quality and abundance of nesting habitat. In addition, the visibility of bass nests and the aggressive guarding behavior of nesting males increases their vulnerability to fishing, which may increase predation on bass eggs and larvae. Despite the potential negative effects of these anthropogenic factors, whether they can meaningfully reduce bass recruitment remains uncertain in part because of the compensatory nature of bass populations. One critical component to resolving this debate is determination of the extent to which habitat alteration and/or fishing limit the number of nests that successfully produce swim-up fry. In spring 2004, we monitored nest distribution and success, and quantified angler effort, in five southeastern Michigan lakes spanning a wide range of shoreline dwelling density (8 To 22 dwellings/km) to determine the extent to which nest success varies within and among lakes due to local (e.g., substrate, cover, and status of nearby shoreline development) and lakewide (e.g., dwellings/km and fishing effort) factors. Nest density ranged from 4 -10 nests/km and was not correlated with dwelling density. Local nest habitat characteristics and lakewide angler effort during the nesting period were not important determinants of the probability of a nest producing swim-up fry (P > 0.05). At the whole-lake scale, however, nest success was negatively related to dwelling density, declining from 0.76 in the lowest dwelling density lake to 0.44 in the highest dwelling density lake (P = 0.002). Knowledge of the magnitude of anthropogenic effects and the spatial scale at which they operate is integral for sound scientific management of bass populations.