Portland, Ore. – Sometimes being under water is a good thing, especially for Columbia River salmon nests, called redds. This fall, federal agencies have increased Columbia River flows below Bonneville Lock and Dam to ensure the redds of spawning chum salmon stay covered with water. The agencies have conducted these chum operations every fall since 2000. Beginning in November, the U.S. Army Corps of Engineers holds the Columbia River below Bonneville Dam to between 11.5 and 13 feet above sea level to ensure chum can spawn at the mouth of Hamilton Creek in the Columbia River Gorge. For chum operations to occur, water is released from reservoirs as far away as Hungry Horse and Libby dams in Montana, more than 850 river-miles upriver from Bonneville Dam. The water is then captured and released as needed to keep the redds under water. “Chum are listed under the federal Endangered Species Act and they’re an important part of the ecosystem,” says Scott Armentrout, BPA vice president of Environment Fish and Wildlife. “This operation is just one of the things we do with our federal partners to support this critical species.” The annual run of Columbia River chum salmon historically numbered more than 1 million. However, habitat loss, harvest and other factors caused their numbers to plummet during the last century to a low of just a few thousand fish returning to the river each year. An important ecological species and food for mammals such as whales, the federal government listed Columbia River chum as threatened under the Endangered Species Act in 1999. Called “dog” salmon because of their canine-like teeth, chum are the last salmon of the year to return to the Columbia to spawn, and their young are the first to leave for the ocean in the spring. Chum salmon generally spawn in the lower part of the Columbia River below Bonneville Dam in areas where warm ground water pushes up through gravel. The warm water then quickly incubates their eggs. The Bonneville Power Administration has funded two hatchery programs and constructed new spawning habitat for chum in several areas of the lower Columbia River. These efforts appear to be showing signs of success: More than 45,000 chum returned to the Columbia in 2016 and scientists say 2019 shows signs of a good return as well.
