The carp conundrum: Science-based insights to control an invasive fish
| Authors: | Andrea Watts, J. Ryan Bellmore, Jason Dunham, James Pearson |
| Year: | 2025 |
| Type: | Science Findings |
| Station: | Pacific Northwest Research Station |
| Source: | Science Findings 275. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 6 p. |
Abstract
Nonnative carp were spotted nearly 75 years ago in eastern Oregon’s Malheur Lake and have subsequently fully colonized the lake and surrounding wetlands, compromising water quality and the growth of native aquatic vegetation eaten by resident and migratory waterfowl. Eradication efforts have proven challenging; only a few carp are needed for the population to rebound. Managers at Malheur Lake are not alone in dealing with this invasive fish; aquatic managers elsewhere in the country face similar issues.
Following a Carp Control Workshop in 2010, Jason Dunham, a researcher with the U.S. Geological Survey, assembled a team consisting of J. Ryan Bellmore, a researcher with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, and James Pearson, then a Ph.D. student at Oregon State University, to develop management options for controlling the carp.
Collectively they developed CarpMOD, a model that examines potential responses to alternative control measures (commercially harvesting adults, trapping juveniles, and electroshocking embryos) and passive carp removal via avian predation, to determine which measures might work best at depleting carp populations. Lower summer water levels resulting from less snowmelt may naturally cause the carp population to decline but not completely eradicate it. The modeling results indicate a combination of all methods are needed to reduce the carp population and maintain the health of the native ecosystem.