Eastern Oregon's desert environment is home to many diverse and ancient fish populations, many of which are suffering from loss of habitat and degraded water quality.  Species such as Lahontan cutthroat trout are uniquely adapted to life in the desert, and are found only in the Great Basin region of Nevada and Oregon.  Native fish species are important economically and culturally to the communities of Eastern Oregon, but face threats from habitat degradation, high water temperatures, and competition from introduced fish.

Central Oregon's John Day River is home to one of the largest populations of all-wild Summer steelhead in the United States.  Bull trout ply cold, clear waters throughout eastern Oregon.  Both species are listed as threatened under the Endangered Species Act.  ONDA works in the John Day Basin to help protect habitat for steelhead, chinook salmon and bull trout by organizing riparian restoration projects and promoting federal grazing permit retirement in areas of sensitive habitat.

In 1997, ONDA and several other fish conservation organizations filed a petition with U.S. Fish and Wildlife Service to list Great Basin redband trout as threatened or endangered.  In 2000, the Fish and Wildlife Service decided that the species did not currently need federal ESA protection, citing an increase in numbers over recent years.  However, redband trout still face problems of habitat degradation by livestock grazing, irrigation withdrawls, stream channelization, and timber harvest.