Invasion
Invasion Description
1st Record: Portland/OR/Oswego Lake, Willamette River (1924, Chapman 1942; Lampman 1946; Hughes and Gammon 1987; Farr and Ward 1993)
Geographic Extent
Portland/OR/Oswego Lake, Willamette River (1924, Chapman 1942; Lampman 1946; Hughes and Gammon 1987; Farr and Ward 1993); OR-WA/Willamette & Columbia Rivers (Chapman 1942; Lampman 1946; Hughes and Gammon 1987; Farr and Ward 1993); Cowlitz County/WA/lower Columbia (2005, USGS Nonindigenous Aquatic Species Program 2018); Crimms Island (downriver from Longview WA/OR/Columbia River (2004, Haskell and Tiffin 2011); Reaches B-H, lower to uppermost estuary/OR-WA/Columbia River (2010-2016, Sol et al. 2021)
Vectors
| Level | Vector |
|---|---|
| Probable | Fisheries Intentional |
Regional Impacts
| Economic Impact | Fisheries | |
| Smallmouth Bass are a highly valued sportfish in Pacific Northwest fishes and lakes, with an estimated 140,000 bass anglers in Washington, Oregon, and Idaho, spending ~$66 million (2006 estimates). Smallmouth Bass have proliferated in the Columbia River system reservoirs. The population has been favored by rising temperatures. Smallmouth Bass overlap with migrating juvenile Chinook Salmon (Oncorhynchus tshawytscha) and Steelhead (O. mykiss) in part of the year, and at times salmon form a significant part of the basses' diet. Young Smallmouth Bass also compete with juvenile salmon for zooplankton, insects, and crayfish. Salmon and Steelhead fisheries are of equal or greater economic value to the bass fishery, so the challenge for fisheries management is to find strategies that preserve native fish populations and support sport fisheries Chinook Salmon populations are protected by the Endangered Species Act (Carey et al. 2011). | ||
| Ecological Impact | Predation | |
Smallmouth Bass have become an important predator in Columbia River system reservoirs. The population has been favored by rising temperatures. Smallmouth Bass overlap with migrating juvenile Chinook Salmon (Oncorhynchus tshawytscha) and Steelhead (O. mykiss) in part of the year, and at times salmon and steelhead form a significant part of the basses' diet (Harvey and Kareiva 2005; Sanderson et al. 2009; Carey et al. 2011). The Smallmouth Bass's impact on salmonids is large because its large gape permits it to start predation at a smaller size, 150-200 mm and earlier age than the native Northern Pikeminnow (Ptychocheilus oregonensis), increasing the predation risk (Fritts and Pearson 2006). Smallmouth Bass in the Columbia River basin consume and estimated 18,000 to 2,000,000 juvenile salmonids per year at various locations (Sanderson 2009). | ||
| Ecological Impact | Competition | |
| Young Smallmouth Bass also compete with juvenile salmon for zooplankton, insects, and crayfish. Adult Smallmouth Bass compete with native predators, mostly Northern Pikeminnow (Ptychocheilus oregonensis) (Harvey and Kareiva 2005; Carey et al. 2005). | ||