Half of Oregon’s fish species may be at risk of extinction

PORTLAND – The first status report on wild fish in a decade suggests that nearly half the native species in the state are at risk of extinction.

Oregon Department of Fish and Wildlife biologists studied 69 distinct fish populations, including all varieties of the state’s salmon and steelhead species, and most of the trout population. They also assessed selected sturgeon, lamprey, dace and chub species listed under the Endangered Species Act.

Eleven of the 33 salmon and steelhead populations are at risk of irreversible decline, and seven are potentially at risk, according to a draft of the report.

Eight historic populations have gone extinct in the past century, most of them concentrated in upper reaches of the Snake and Klamath rivers cut off from migrating fish by the construction of power-generating dams.

Spring chinook salmon illustrate the pattern. The species went extinct in the upper Snake and Klamath after dams were built. Four of the remaining six spring chinook units are at risk because of the loss of habitat, the loss of many historic sub-populations, the escape of large numbers of domesticated hatchery fish into spawning grounds and other problems.

Among trout species, such as redband and bull trout, 17 of 27 unique populations are at risk, five are potentially at risk, and four are not at risk.

The Alvord cutthroat trout, a species native to springs and creeks of southeast Oregon and northern Nevada, is the only trout group considered extinct. The species disappeared within a few decades of the intentional release of non-native rainbow trout into the Alvord cutthroat’s only remaining habitat in the 1920s.

Biologists concluded that almost half the state’s unique wild fish stocks are at risk of slipping further toward extinction within five to 10 years.

The study is considered significant because the risk level it defines will set priorities for protecting fish and restoring streams.