Conserving the Nature of America

News Release

Study Suggests Upper Klamath Lake is Able to Support Juvenile Salmon

July 15, 2008


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External Affairs
Telephone: 703-358-2220

Young Chinook Salmon should be able to grow and develop in the waters of Upper Klamath Lake and the Williamson River, according to a new study. That could be the first step in a journey back to ancestral waters for fall-run Chinook salmon.

Researchers found that water-quality conditions in those bodies of water appear adequate for the physiological development of the salmon. The study was conducted by the U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service (FWS), and Oregon State University. The study examined Iron Gate Hatchery fall-run Chinook salmon, which are a potential candidate for reintroduction.

Chinook salmon historically occupied Upper Klamath Lake and the tributaries that flow into it. However, anadromous fish like Chinook salmon that live part of their lives in the ocean and part in fresh water have not had access to these waters since 1918. That was the year the first Klamath River hydroelectric dam was completed.

"Biologists were concerned about the effects of decades of habitat loss and declining water quality on the fish," said USGS scientist Alec Maule. "We wanted to determine how Chinook salmon would respond physiologically to being reintroduced to their ancestral waters after being absent for almost 90 years."

The biologists studied how current water-quality conditions impacted young Chinook smolts that were kept in netpens in Upper Klamath Lake and in the Williamson River. Smolts are young fish that develop a readiness to migrate to the sea. The researchers found water quality to be conducive to salmon development and survival during the study. They also found no vulnerability to disease that would preclude or impair these young fish from properly developing in the areas where the tests occurred.

"This study is an important first step and will help state, federal and Tribal fish managers in their efforts to eventually restore anadromous fish to Upper Klamath Lake and tributaries," said FWS field supervisor Phil Detrich. "The findings suggest that conditions in Upper Klamath Lake and the Williamson River are sufficient to support the physiological development of this native fish."

The study, which was conducted in October 2005 and May 2006, is available on the Web at:

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