High levels of mercury and other toxic chemicals are showing up in seemingly remote and pristine parts of the Puget Sound watershed, the result of atmospheric deposition. Scientists talk about a “dome” of pollution hanging over urban areas, leading to a never-ending cycle of persistent compounds working their way through the air, onto the land and into the water.

Harbor porpoises declined dramatically in the Salish Sea in the 1970s but their populations have since rebounded, increasing by more than 10% per year in recent decades. A 2020 report for the Encyclopedia of Puget Sound examines harbor porpoise status and trends, natural history and recent policy considerations for the species.

Scientists are still trying to understand what caused the deaths of thousands of rhinoceros auklets in the Salish Sea in 2016. Some studies point to disease as a central factor in that incident and potentially other large seabird die-offs along the coast. That is prompting a deeper look at what makes these birds sick, and how local populations are faring. We followed a group of researchers as they gave a health checkup to a breeding colony of rhinoceros auklets on Protection Island.

The watersheds of Washington’s San Juan Islands were thought to be too small to support wild salmonid populations, and many streams flow only seasonally. But a 2019 article in the journal Conservation Genetics reports that at least five watersheds in the region support populations of coastal cutthroat trout (Oncorhynchus clarki clarki). Genetic analysis of the cutthroat trout in three of the watersheds suggest two support native populations. The findings are important for understanding the conservation status of these previously unknown populations. 

They rival tropical forests in their richness and diversity, but Puget Sound's kelp beds have declined steeply in recent decades. Scientists are just starting to understand the extent of these losses. What they are finding is bringing kelp to the forefront of Puget Sound's environmental concerns.

A 2019 article in the Journal of Wildlife Diseases looked at trace element concentrations of heavy metals in the livers of harbor seals that died and stranded in the San Juan Islands. The study indicated exposure to trace elements (naturally occurring, human-introduced, or both) in the Salish Sea; however, the study reports that trace element toxicity is not a major threat to harbor seal health.

Officially known as West Coast transients but increasingly referred to as Bigg’s killer whales, these marine mammal-eating orcas (Orcinus orca) are spending increasing time in the Salish Sea to consume their marine mammal prey including harbor seals, Steller sea lions, and harbor and Dall’s porpoise. They range from Southeast Alaska to California, but over the last 15 years more members of the population are spending increasing time in the inland waters of Washington State and British Columbia (Houghton et al. 2015, Shields et al. 2018). They have no predators (except perhaps occasionally other Bigg’s killer whales - see Towers et al. 2018), but are at risk from anthropogenic effects, including toxics and noise pollution (Ford et al. 2007).

Volunteer researchers are tracking the plastic and other debris washing up on Puget Sound's beaches. They hope the data can be used to protect sea creatures from the growing amounts of trash littering the world's oceans. [A version of this article first appeared in the COASST blog.]

The first comprehensive guide to the fishes of the Salish Sea is the culmination of more than 40 years of research by University of Washington authors Ted Pietsch and Jay Orr. The new, three-volume set includes descriptions and illustrations for every fish species known to have been documented within the Salish Sea, all gathered from an exhaustive search of libraries, aquariums, fish collections and even one restaurant.

A 2014 paper in the journal PLoS ONE examines differences between foraging behavior of harbor seals based on haulout site locations, seasons, sexes and times of day. The authors hypothesize that these factors may help explain the variability in diet among harbor seals observed at different haul-out site groups in the Salish Sea. 

A new video series follows local scientists into the water, capturing the adventure behind the research. "Salish Sea Wild" is entering its second season and we interviewed the series host and producers. Among our burning questions: What's it like to have a Steller sea lion chew on your head? 

Washington and British Columbia residents are largely unfamiliar with the Salish Sea. A recent study conducted by the SeaDoc Society and Oregon State University reveals a need to improve geographic literacy and familiarity with the Salish Sea among those communities who share and live alongside this integrated transboundary ecosystem. This summary was provided by two of the collaborators on the survey, David Trimbach of Oregon State University and Joe Gaydos, Science Director at the SeaDoc Society.

A 2019 report from the Puget Sound Ecosystem Monitoring Program presents an overview of selected recent monitoring and research activities focused on toxic contaminants in the Salish Sea. 

Kids around the region are learning about the Salish Sea thanks to a new book that is being offered — in many cases free of cost — to Washington schools and libraries. Explore the Salish Sea by Joe Gaydos and Audrey Benedict inspires the next generation to appreciate and perhaps someday protect the environment close at hand. 

A 2017 report from the Puget Sound Ecosystem Monitoring Program presents an overview of selected recent monitoring and research activities focused on toxic contaminants in the Salish Sea. 

A scientific assessment of current status and future trends in resource abundance and environmental quality in the Strait of Juan de Fuca, Strait of Georgia, and Puget Sound 

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.

The Salish Sea extends across the U.S.-Canada border, and includes the combined waters of the Strait of Georgia, the Strait of Juan de Fuca, Puget Sound Basin and the San Juan Islands (see map).

The name Salish Sea was proposed by Bert Webber in 1989 to reflect the entire cross-border ecosystem. Both Washington State and British Columbia voted to officially recognize the name in late 2009. The name honors the Coast Salish people, who were the first to live in the region.