Nearshore habitat

An estuary is a place where saltwater from the ocean mixes with freshwater from rivers and streams. Technically, this defines all of Puget Sound, but scientists have identified several types of "sub-estuaries" within the water body. These include pocket estuaries (or embayments), tidally-influenced rivers and wetlands and other areas near the shoreline connected with freshwater sources. This summary provides descriptions of these estuaries from the Washington State Department of Natural Resources, the Puget Sound Nearshore Partnership and others.  

The search for why large numbers of spawning coho salmon have been dying in Puget Sound's urban streams goes as far back as the 1980s and culminated this year with the discovery of a previously unidentified chemical related to automobile tires. We offer a detailed timeline for the discovery. 

Environmental engineers and chemists at the University of Washington Tacoma have identified a mysterious compound implicated in the deaths of large numbers of coho salmon in Puget Sound. The chemical is linked with a rubber additive commonly used in tires and is thought to kill more than half of the spawning coho that enter the region's urban streams every year. 

Last month's federal authorization to kill more than 700 sea lions to protect salmon runs along the Columbia River is prompting discussions of similar actions for harbor seals in Puget Sound. But experts say the situations are very different with many unanswered questions. 

North American river otters (Lontra canadensis) inhabit inland freshwater environments; however, from Alaska to California they also occur in coastal marine waters where they forage on a variety of marine fish and invertebrates. Little is known about mortality factors in marine-foraging river otters. Among 30 otter carcasses collected in San Juan County, Washington, analysis indicates that car collisions and gunshots were the most common causes of mortality.

The Elwha River has become famous as the site of the largest dam removal project in U.S. history. Several years ago, scientists began knocking down another barrier about a mile away from the river's delta. They removed a large seawall along the Salish Sea shoreline and discovered that sediment from the dam removal had huge benefits for their project.