HR: 11:15h
AN: NB32E-04    [Abstracts]
TI: Interactions Between Trout and Sculpin: Consequences of Trout Introductions for a Native Fish
AU: * Henry Zimmerman, J K
EM: henry041@umn.edu
AF: Minnesota Cooperative Fish and Wildlife Research Unit and Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, 1980 Folwell Ave., St. Paul, MN 55108 United States
AU: Vondracek, B
EM: bvondrac@umn.edu
AF: Minnesota Cooperative Fish and Wildlife Research Unit, 1980 Folwell Ave., St. Paul, MN 55108 United States
AB: We examined interactions between a native (brook) and a nonnative (brown) trout with native slimy sculpin, to test whether introductions of a nonnative salmonid has an effect on growth and diet of sculpin where a native trout was present. Enclosures (1m²) were stocked with fish (five treatments: juvenile brown trout with sculpin, juvenile brook trout with sculpin, and single species controls) at three densities. Replicates of each treatment were placed in Valley Creek, MN, and fish growth rates were measured over six 38-day experiments, conducted over three years. We examined growth of each species in combined-species treatments versus growth of each species alone. We did not find evidence of competition between brook trout and sculpin, regardless of density or fish size. However, we observed competition between brown trout and sculpin, which depended on initial mass of each species. Sculpin gained greater mass when alone than with brown trout when sculpin size was large (>17g). Likewise, brown trout gained greater mass alone than with sculpin when brown trout size was large (>26g). We suggest that differences in morphology and foraging modes between the two native species allow them to coexist without competition, whereas nonnative brown trout compete with sculpin.
DE: 9810 New fields (not classifiable under other headings)
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly