Monday, November 16, 2009

Whirling Disease may Keep Hatchery Fish out of the Upper Deschutes

With fish passage facilities in place at Pelton-Round Butte Dam, managers are hoping that fish will soon be able to establish populations in the Upper Deschutes and its many tributaries. A new study however raises the possibility that if hatchery fish are passed into the upper river they may bring with them whirling disease. Whirling Disease is a parasite which effects the skeletal structure of young fish, causing deformities and extremely high mortality. Whirling disease has established a foothold in some of the hatcheries on the Lower Deschutes. Researchers fear that if hatchery fish are allowed into the upper basin they could bring the disease, and suggest that only naturally produced fish be allowed to pass into the upper Deschutes. More info in the Oregonian.

There are a host of other reasons to only allow wild fish into the upper river. Wild fish are typicaly more productive when spawning in the wild and allowing hatchery fish into the upper river may slow the establishment of naturally produced runs in the upper river. Additionally the Deschutes River gets an unusually high number of out of basin hatchery strays which lack the locally adaptive traits of the Lower Deschutes wild salmon and steelhead.

1 comment:

the nutman said...

this is what destroyed the wild trout populations on the eastcoast ,hatcherys were part of the watershed there and they had to be shut down ,I know of two hatcheries in New jersey which had to closed due to this .if it gets in the watershed the fish all of them are doomed ,and it will be hatchery city put the fish in yearly so we can spend money like the retarted society we have become