The Chinook salmon is an important keystone species of the U.S. Pacific Northwest. It is a vital food source for a diversity of wildlife, including orca whales, bears, seals, and large birds of prey. Chinook salmon is also prized by people who harvest salmon both commercially and for sport. Chinook are the largest Pacific salmon species. On average, these fish are 3 feet long and approximately 30 pounds, but some individuals can grow to over 5 feet long and 110 pounds! Chinook salmon live about three to seven years. Juvenile salmon stay in freshwater habitat for the first year or so, before moving to the estuaries and then the open ocean. Estuaries provide a lot of food and nutrients to the developing salmon. The fish will spend approximately two to four years feeding in the ocean before returning to the spawning grounds to breed and die.
The Chinook Salmon is on the U.S. Endangered Species List. The Sacramento River winter-run population in California is classified as endangered wherever it is found. Other naturally spawned populations in California, Idaho, Oregon, and Washington are classified as threatened. Why the Chinook and other Pacific Northwest salmon have declined is no mystery. The causes are known as “the four H’s”: harvest, habitat, hatcheries, and hydroelectric power. Harvest refers to the overfishing of these species by commercial fishing interests. Habitat refers to the degradation of habitat, usually by pollutants or sediment in the water that make it uninhabitable by the salmon or their eggs. Captive-bred hatchery fish, released in the waterways used by native fish, compete and interbreed with the natives, weakening their stocks. Hydroelectric dams have had perhaps the largest impact, blocking migration routes and changing the quality, quantity, rate of flow, and temperature of the water in rivers, lakes, and tributary streams that once supported tens of millions of salmon. Protection of Chinook salmon is crucial to maintain healthy Pacific Northwest ecosystems and to provide a delicious food source for years to come.