The effects of varied densities on the growth and emigration of adult cutthroat trout and brook trout in fenced stream enclosures
Western North American Naturalist
By: D.J. Buys, R.H. Hilderbrand, and J. L. Kershner
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Abstract
We evaluated the effects of various density treatments on adult fish growth and emigration rates between Bonneville cutthroat trout Oncorhynchus clarki utah and brook trout Salvelinus fontinalis in stream enclosures in Beaver Creek, Idaho, We used 3 density treatments (low, ambient, and high fish densities) to evaluate density-related effects and to ensure a response. Intraspecific ambient-density tests using cutthroat trout only were also performed. Results indicated an absence of cage effects in the stream enclosures and no differences in fish growth between ambient-density stream-enclosure fish and free-range fish. Brook trout outgrew and moved less than cutthroat trout in the stream enclosures, especially as density increased, In all 3 density treatments, brook trout gained more weight than cutthroat trout, with brook trout gaining weight in each density treatment and cutthroat trout losing weight at the highest density. At high densities, cutthroat trout attempted to emigrate more frequently than brook trout in sympatry and allopatry. We observed a negative correlation between growth and emigration for interspecific cutthroat trout, indicating a possible competitive response due to the presence of brook trout. We observed similar responses for weight and emigration in trials of allopatric cutthroat trout, indicating strong intraspecific effects as density increased. While cutthroat trout showed a response to experimental manipulation with brook trout at different densities, there has been long-term coexistence between these species in Beaver Creek, This system presents a unique opportunity to study the mechanisms that lead cutthroat trout to coexist with rather than be replaced by nonnative brook trout.
Suggested Citation
Buys, D., Hilderbrand, R., Kershner, J.L., 2009, The effects of varied densities on the growth and emigration of adult cutthroat trout and brook trout in fenced stream enclosures: Western North American Naturalist, v. 69, no. 3, p. 371-381, https://doi.org/10.3398/064.069.0311.
ISSN: 1944-8341 (online)
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | The effects of varied densities on the growth and emigration of adult cutthroat trout and brook trout in fenced stream enclosures |
| Series title | Western North American Naturalist |
| DOI | 10.3398/064.069.0311 |
| Volume | 69 |
| Issue | 3 |
| Year Published | 2009 |
| Language | English |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Western North American Naturalist |
| First page | 371 |
| Last page | 381 |