· Connecting the Land to the Sea
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
· Looking Ahead

Global 200 Snapshot

The migration of anadromous fish in the Pacific Northwest Rivers and Streams ecoregion is important not only as a spectacular natural phenomenon but also for the transfer of nutrients from marine to freshwater environments.  

Connecting the Land to the Sea

In the Pacific Northwest Rivers and Streams ecoregion, anadromous fish (those that migrate from freshwater to the ocean and back to freshwater) are like living bridges between the ocean and the land. The fish hatch in streams and rivers, then migrate to the Pacific Ocean to take advantage of its rich nutrients and to grow strong. They then migrate back to spawn, often to the stream where they were hatched. And when bears and eagles feed on the spawning salmon, the circle is completed: Nutrients have moved from the ocean to freshwater and from freshwater to the land.

Special Features

Five high mountain ranges are the source of most freshwater in the Pacific Northwest. Mighty rivers and winding streams flow from the Cascades, Coastal Ranges, Klamath Mountains, Sierra Nevada, and Siskiyou Mountains. The largest rivers, such as the Columbia, Klamath, and Sacramento/San Joaquin, run for hundreds of miles through gorges and valleys before pouring into the Pacific Ocean. Smaller rivers, such as the Chetco, Elk, and Rogue, take shorter routes to the coast.

Salmon are not the biggest fish in the world, but they may be among the most robust. In spring, young salmon swim for hundreds of miles downstream through rushing rapids, over waterfalls, through industrial and agricultural pollution, and (if lucky) past the spinning turbines of dams. After growing up at sea, many of these salmon find their way back to the exact place where they were hatched. And once they deposit eggs in rocky nests and fertilize them, the adults die.

Wild Side

Migratory salmon species include pink, chum, sockeye, Chinook, and coho. Anyone who has witnessed it will testify to the amazing site of a river turned red by the congregation of hundreds of migrating sockeye salmon. But the migrating within this ecoregion is not limited to salmon. Pacific lamprey, river lamprey, white sturgeon, green sturgeon, Dolly Varden trout, cutthroat trout, steelhead trout, inconnu, longfin smelt, eulachon, prickly sculpin, three-spine stickleback, and others also migrate between freshwater and the ocean.

Cause for Concern

Anadromous fish have suffered great losses in the face of huge changes to their habitats over the last 100 years. For example, coho salmon in California are at less than 5 percent of their historic numbers. The threats to the watersheds of the Pacific Northwest Rivers and Streams are numerous. Trees are cut down for timber and to clear land for urban areas or agriculture. This leads to the erosion of soil and high rates of runoff from the land, resulting in the pollution of streams and rivers with silt and toxic chemicals. With fewer trees shading the streams, temperatures rise beyond a level that salmon and trout can tolerate. Dams have also been built, which often make it difficult for fish to move upstream or downstream. Introduced alien fish species compete for food and habitat with native species. In some areas, overfishing is also a problem.

Looking Ahead

Conservationists are working toward the creation of a Siskiyou Wild Rivers National Monument in Oregon. If such a monument were created, it would encompass more than one million acres, including the highest concentration of wild and scenic rivers in the nation, the best remaining salmon and steelhead habitat in the Pacific Northwest, and globally significant plant diversity.