The Northern pikeminnow, Columbia River dace or colloquially Squawfish (Ptychocheilus oregonensis) is a large member of the minnow family, Leuciscidae.[2] This predatory freshwater fish is native to northwestern North America, ranging from the Nass River basin to the Columbia River basin.[2] A good deal of concern has been expressed regarding the impact northern pikeminnow populations may have on salmon in Columbia and Snake River impoundments.[3]
Naming
Until 1999, when the American Fisheries Society officially changed the common name to pikeminnow, the four species of Ptychocheilus were known as squawfish. The renaming effort was undertaken due to the word squaw being an ethnic slur for Native American women.[4][5]
Behavior and habitat
Northern pikeminnows can live at least 11 years, reaching up to 35 in (89 cm) in total length and 15 lb (6.8 kg) in weight.[2] Female northern pikeminnow reach sexual maturity at about six years, males in three to five. A mature female can lay 30,000 eggs annually. Pikeminnow are adept predators, and in the Columbia and Snake Rivers, salmonsmolts comprise a large part of their diets. Their populations have flourished with the development of the Columbia River hydropower system.[6] The reservoirs have provided excellent habitat for pikeminnow and given them an advantage over depressed salmon and steelhead populations. Data has been collected to suggest they can eat up to 650,000 salmon fry annually.[7]
The northern pikeminnow has been shown to consume terrestrial insects, benthic invertebrates, other fish, aquatic insects, and plant matter.[8]
Relationship with people
Northern pikeminnow caught as part of the Bonneville Power Administration's Sport Reward Program.
While historically northern pikeminnow have not been of interest commercially nor to sport anglers, Washington and Oregon state fisheries agencies and the Bonneville Power Administration have placed a bounty[9] on them to reduce predation on scarce salmon stocks. A commercial fishery has developed based on that bounty. The current International Game Fish Association all tackle world record for northern pikeminnow is 7 lb 14 oz (3.6 kg) from the Snake River near Almota, Washington.[10]
^Mesa, M. 1994. Effects of multiple acute stressors on the predator avoidance ability and physiology of juvenile chinook salmon. Transactions of the American Fisheries Society 123:786–793.
^Petersen, J. 1994. Importance of spatial pattern in estimating predation on juvenile salmonids in the Columbia River. Transactions of the American Fisheries Society 123:924–930.
^Haggerty, M. 2009. Lake Ozette Sockeye Limiting Factors Analysis. p 2–33.
