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Ecological Impact of Introduced Trout on Native Aquatic Communities in Mountain Lakes
Completed
Many once fishless lakes the western US now contain fish as a result of introductions made to enhance recreational opportunities. Fish introductions have been implicated in the disappearance of amphibian communities and in the alteration of zooplankton communities. Furthermore, the presence and abundance of amphibian larvae and zooplankton in mountain lakes are directly related to nutrient concentrations in the aquatic environment. Our field studies suggest that introduced trout may have the greatest impact on native biota in shallow lakes (10 m maximum depth) in instances when reproducing trout reach high densities. Shallow fishless lakes with higher concentrations of total Kjeldahl-nitrogen (TKN) are productive habitats for larval salamanders. When reproducing trout reach high densities in these lakes, both larval salamanders and large diaptomid copepods are absent or persist at low abundances. Trout appear to have the least impact on native biota in deep lakes (>10 m maximum depth) with non-reproducing trout. Because larval densities are low in fishless lakes with low TKN, it is difficult to detect statistically significant differences in larval densities between fishless lakes and lakes with fish. The current study is designed to quantify the impacts that populations of non-reproducing fish populations may have upon native zooplankton and amphibian communities in naturally fishless lakes of the northern Cascade mountain range. Fish effects will be quantified by comparing lakes with stocked fish to fishless lakes along a nutrient gradient. Lakes with non-reproducing trout will be a crucial component of the high lakes management plan in North Cascades National Park Service Complex because this type of lake is common within the park.
2002, Ecological impact of introduced trout on native aquatic communities in mountain lakes- Phase III Final Report: U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, p. 102. [FullText] Catalog No: 1119 Liss, W.J., Larson, G.L., Tyler, T., Ganio, L., Hoffman, Jr., R., Deimling, E., Lomnicky, G.A., McIntire, D., Truitt, R., 1999, Ecological effects of stocked trout in naturally fishless high-elevation lakes, North Cascades National Park Service Complex, WA, USA- Phase II: U.S. National Park Service, Pacific Northwest Region Technical Report NPS/CCSOOSU/NRTR-98/01, p. 133. [FullText] Catalog No: 1118 Larson, G.L., Lomnicky, G.A., Liss, W.J., Deimling, E., 1999, Integrating physical and chemical characteristics of lakes into the glacially influenced landscape of the Northern Cascade Mountains, Washington State, USA: Environmental Management, v. 24, no. 2, p. 219-228. [Abs] [FullText] Catalog No: 624 Larson, G.L., Lomnicky, G.A., Hoffman, Jr., R., Liss, W.J., Deimling, E., 1999, Integrating physical and chemical characteristics of lakes into the glacially influenced landscape of the Northern Cascade Mountains, Washington State, USA: Environmental Management, v. 24, no. 2, p. 219-228. [FullText] Catalog No: 1672 Larson, G.L., McIntire, C.D., Truitt, R.E., Liss, W.J., Hoffman, Jr., R., Deimling, E., Lomnicky, G.A., 1998, Phytoplankton assemblages in high-elevation lakes in the northern Cascade Mountains, Washington State, USA: Archiv fur Hydrobiologie, v. 142, no. 1, p. 71-93. [FullText] Catalog No: 115 Tyler, T., Liss, W.J., Ganio, L., Larson, G.L., Hoffman, Jr., R., Deimling, E., Lomnicky, G.A., 1998, Interactions between introduced trout and larval salamanders ( Ambystoma macrodactylum) in high-elevation lakes: Conservation Biology, v. 12, no. 1, p. 94-105. [FullText] Catalog No: 311 Liss, W.J., Larson, G.L., Deimling, E., Ganio, L., Hoffman, Jr., R., Lomnicky, G.A., 1998, Factors influencing the distribution and abundance of diaptomid copepods in high elevation lakes in the Pacific Northwest, USA: Hydrobiologia, v. 379, no. 1-3, p. 63-75. [Abs] [FullText] Catalog No: 568 Tyler, T., Liss, W.J., Hoffman, Jr., R., Ganio, L., 1998, Experimental analysis of trout effects on survival, growth, and habitat use of two species of western Ambystomatid salamanders: Journal of Herpetology, v. 32, no. 3, p. 345-349. [FullText] Catalog No: 1265 Deimling, E., Liss, W.J., Larson, G.L., Hoffman, Jr., R., Lomnicky, G.A., 1997, Rotifer abundance and distribution in the northern Cascade Mountains, Washington, USA: Archiv fur Hydrobiologie, v. 138, no. 3, p. 345-363. [FullText] Catalog No: 1671 Hoffman, Jr., R., Liss, W.J., Larson, G.L., Deimling, E., Lomnicky, G.A., 1996, Distribution of nearshore macroinvertebrates in lakes of the Northern Cascade Mountains, Washington, USA: Archiv fur Hydrobiologie, v. 136, no. 3, p. 363-389. [FullText] Catalog No: 338 Liss, W.J., Larson, G.L., Deimling, E., Ganio, L., Gresswell, R.E., Hoffman, Jr., R., Kiss, M., Lomnicky, G.A., McIntire, D., Truitt, R., Tyler, T., 1995, Ecological Effects of Stocked Trout in Naturally Fishless High Mountain Lakes, North Cascades National Park Service Complex, WA, USA: U.S. National Park Service, Pacific Northwest Region Technical Report NPS/PNROSU/NRTR-95-03, p. 254. [FullText] Catalog No: 1117
North Cascades Water Chemistry
North Cascades Water Temperature
North Cascades Lake Physical Characteristics
North Cascades Macroinvertebrate Community
North Cascades Fish Population Estimates
North Cascades Salamander Density
North Cascades Phytoplankton Community
North Cascades Zooplankton Community
Fitzpatrick, Martin - Deputy Center Director
Phone: 541-750-1032
Email: Martin_Fitzpatrick@usgs.gov
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