Puget Sound Main Basin

Map of regional water masses and subareas of Puget SoundThe main basin of Puget Sound runs from the Tacoma Narrows to the waters between Point Wilson, on the Olympic Peninsula, and Whidbey Island.  There are sills at the northern and southern ends, and depths in the central part range from 100 to 140 meters. The five sub-basins within this part of the Sound all reach depths below 150 meters, with the deepest being 290 meters west of Port Madison. The basin includes Elliott Bay and Commencement Bay, which receive fresh water from the Duwamish-Green river system and the Puyallup River, respectively.

The Skagit River provides around 30 percent of the freshwater flow into the main basin, which is stratified in summer but mixes well in winter due to cool temperatures and increased wind. Decadal climate regimes influence the circulation patterns in the basin. During cool periods, the strongest currents flow from the Strait of Juan de Fuca at a medium depth, but when warmer, drier weather dominates, currents tend to be strongest at the bottom of the basin. Dominant vegetation is green algae and eelgrass, but overall vegetation is sparse. Only 8 percent of the shoreline has continuous eelgrass beds, with a patchy distribution over an additional 40 percent.



A baseline assessment report cover page

A baseline assessment of priority invasive species in the Puget Sound Basin

The baseline assessment summarizes the status and trends of 15 priority invasive species, as identified by the Washington Invasive Species Council, within the Puget Sound Basin.

Book cover for The Salish Sea: Jewel of the Pacific Northwest

New book focuses on the natural history of the Salish Sea

The Salish Sea: Jewel of the Pacific Northwest brings together more than 230 extraordinary images of the Salish Sea. But don't call it a coffee table book. Its lush photos are backed by a serious scientific perspective on this complex and fragile ecosystem.

Seattle's central waterfront at sunset. Photo: Michael Matti (CC BY-NC 2.0) https://www.flickr.com/photos/michaelmattiphotography/9090323308/

Brighter future for salmon at downtown seawall

The decaying seawall along Seattle’s waterfront is providing scientists with an opportunity to improve long-lost habitat for migrating salmon. It could also show the way for habitat enhancements to crumbling infrastructure worldwide. One University of Washington researcher describes the project.

Canary rockfish. Photo by Tippy Jackson, courtesy of NOAA.

Proposed designation of critical habitat for the distinct population segments of Yelloweye Rockfish, Canary Rockfish, and Bocaccio

The National Marine Fisheries Service has released a Draft Biological Report proposing designation of critical habitat for yelloweye rockfish, canary rockfish, and bocaccio in the Salish Sea. Download the full report and supporting data.

Screenshot of 2013 Health of the Salish Sea Ecosystem Report

Report: 2013 Health of the Salish Sea Ecosystem Report

The 2013 Health of the Salish Sea Ecosystem Report was prepared jointly by the U.S. Environmental Protection Agency and Environment Canada. View the complete report, or read the Executive Summary below.


Western Grebe; image by mikebaird, courtesy of Encyclopedia of Life

Paper: Citizen science reveals an extensive shift in the winter distribution of migratory Western Grebes

A June 19, 2013 paper in the journal PLoS ONE hypothesizes that regional declines in Western Grebe populations may be related to decreasing numbers of forage fish. Using citizen science data from 36 years of bird counts, researchers were able to look at population trends up and down the entire West Coast, finding that abundance of grebes decreased in the Salish Sea but increased in southern California. North American population declined by 52% overall.