USGS Washington Water Science Center
|Project Home | Publications and Products | Related Links | News Releases | Data | Project Summaries | Partnerships ||
In September 2002, fish in Hood Canal near Hoodsport were under stress from low concentrations of dissolved oxygen, prompting the Washington State Department of Fish and Wildlife to temporarily close parts of Hood Canal to some types of fishing during the month of October. In 2003, low dissolved oxygen conditions worsened, some fish kills were observed as early as June, and by October large fish kills were reported. It was estimated that about 30 percent of rockfish were killed in October. Low concentrations of dissolved oxygen in Hood Canal during late summer and early fall have been observed as far back as the 1950s. The U.S. Geological Survey (USGS) was asked by Congress to become actively involved in the study of the causes of low dissolved oxygen concentrations in Hood Canal. At a meeting between the USGS, local groups and governments, agencies, tribes, and the University of Washington, it was agreed that one of the major factors affecting dissolved oxygen in Hood Canal was the input of nutrients, especially nitrogen, into the canal. Thus, the USGS developed a study plan to assess the sources and quantifying the amounts of nitrogen compounds discharged by those sources to Hood Canal.