Tuesday, May 27, 2008 - 11:15 AM
156

Prey availability as a predictor of mottled sculpin foraging behavior in a small Michigan stream

Matthew J. Breen, Northeastern Region, Utah Division of Wildlife Resources, 152 East 100 North, Vernal, UT 84078, Carl R. Ruetz III, Annis Water Resources Institute, Grand Valley State University, Lake Michigan Center, 740 West Shoreline Drive, Muskegon, MI 49441, and Steven L. Kohler, Department of Biological Sciences and Environmental Studies Program, Western Michigan University, 1903 W. Michigan Ave., Kalamazoo, MI 49008.

We evaluated community composition of benthic macroinvertebrates and mottled sculpin (Cottus bairdii) stomach contents collected from erosional and depositional areas of a small coldwater stream.  Nonmetric multidimensional scaling demonstrated that macroinvertebrate species composition of core samples (depositional) were structured differently than Hess (erosional) and wood samples (erosional or depositional) in spring, summer, and winter.  Species composition of leaf packs (erosional) collected in winter also differed from cores, but mirrored Hess and wood communities.  When analyzed by sample type, macroinvertebrate communities and dominant prey differed between seasons except for spring and summer cores.  Macroinvertebrate densities (mean±1SE) were higher in erosional habitat patches occupied by a sculpin (903.87±160.35) than random patches without sculpins (523.23±115.61).  Although patch densities differed significantly in winter (P=0.015) and not summer (P=0.309), patch communities were similar regardless of season.  Finally, mottled sculpins consumed similar prey despite habitat type, suggesting they switch between habitats when foraging based on available and preferred prey.  Woody debris was sampled in both habitats, yet macroinvertebrate communities closely resemble that of erosional substrate.  Therefore, our preliminary results suggest that preferred prey in erosional habitats are also available in depositional areas and may provide a mechanism for mottled sculpin movement between habitats to forage.


Web Page: sculpin, macroinvertebrates, forage

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