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California sea lions in Puget Sound and vicinity
California sea lions have become common in Puget Sound in non-summer months. The overall trend for the population has been a dramatic increase in numbers since the species was protected in 1972. They are opportunistic feeders that often target herring and juvenile salmon and steelhead species in Puget Sound.
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RECENT ARTICLES

Steller sea lions in Puget Sound and vicinity
Steller sea lions use Puget Sound as a feeding area from autumn through spring when they are not breeding in British Columbia and Alaska during summer. While the Western Stock of the species is considered Endangered under the US Endangered Species Act (ESA), the Eastern Stock, which occurs in Puget Sound, is increasing in numbers and not listed under the ESA.

Humpback whales find their voice
The Salish Sea may be a giant ‘practice room’ for humpback whales as they get ready to sing in their winter breeding grounds in Hawaii and Mexico. A network of hydrophones is recording it all.

2022 Salish Sea toxics monitoring synthesis: A selection of research
A 2023 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 tale of two islands
Were the islands half full of auklets or were they half empty? One scientist offers an insider's view of a newly published study of two Pacific seabird colonies. He says having good data for the paper was key, but finding the right title didn't hurt.

Dispatch from the last colony
Tufted puffins have become an increasingly rare sight in the Pacific Northwest. Biologist and writer Eric Wagner recently visited Puget Sound's Smith Island, home to one of the region's last surviving colonies of these colorful seabirds.

Salish Sea Model tracks pollution, currents and climate change
This article is the latest in a series about computer models and their uses within the Puget Sound ecosystem. Today, we look at the Salish Sea Model, one of several models in the region helping to predict water circulation, water quality and food-web relationships.

'A Field Guide to Fishes of the Salish Sea' (book review)
A new field guide brings together detailed accounts and illustrations of 260 species of fish known to occur in the Salish Sea. This review from EoPS editorial board member Joe Gaydos was originally published on the SeaDoc Society website.

Eyes Over Puget Sound: Surface Conditions Report - June 2023
In June we observed a widespread Noctiluca bloom in Central Puget Sound, evident by bright orange streaks in the water. Noctiluca blooms in Puget Sound have lasted much longer and occurred on a much larger scale than in previous years.

Synthesis of selected NEP Watershed Lead Organization grants administered by the Department of Ecology part 2
A 2023 report from the University of Washington Puget Sound Institute synthesizes past Watershed Lead Organization Program grants to support the EPA-funded Land Development and Cover and Floodplains and Estuaries Implementation Strategies. The report offers lessons learned from the habitat restoration and land acquisition-focused grants.

Six things that people should know about ecosystem modeling and virtual experiments
It’s hard to overstate the importance of mathematical models to science. Models show how planets move and how diseases spread. They track the paths of hurricanes and the future of climate change. Models allow scientists to look at systems or scenarios that they could never view otherwise. Increasingly, mathematical models are also helping scientists understand Puget Sound. In this series of articles, we look at some of the ways that models are being used in ecosystem recovery efforts. We start with the basics. What are mathematical models and which types are most common?

Before supercomputers, a structural model helped scientists predict currents in Puget Sound
One of the first working models of Puget Sound was a scaled-down concrete reproduction, with actual water running through channels, around islands and into bays, inlets, and harbors. Motors, pumps and timing gears are part of an elaborate mechanism that replicates tides and river flows in the still-functioning model.

Researchers use a qualitative network model to test ways to boost production at shellfish farms
The skeletal beginnings of nearly all models is a conceptual understanding of the basic workings of the system being studied: Who are the important actors, and what are their roles within the system?

Health of killer whales examined through Bayesian network modeling and informed predictions
Many types of computer models are helping researchers study the health of Puget Sound. Bayesian network models are used to examine the probabilities that certain actions will take place within the ecosystem.

Quantitative models, including Ecopath, take food web studies to a higher level of analysis
The Ecopath model, designed to describe the flow of energy through a food web, as evolved since it was first developed in the early 1980s in Hawaii. This article is part of a series focused on different models and their uses within the Puget Sound ecosystem.

Prey and predators create varying life-or-death conditions for salmon, as shown with Atlantis model
The three-dimensional Atlantis model can represent physical, chemical and biological processes and can incorporate direct human involvement, such as fisheries management, habitat improvements and economic outcomes. It has been used to study the food web to determine whether salmon in Puget Sound are more threatened by predators or by the lack of a stable food supply and to evaluate specific recovery actions to help the endangered Southern Resident killer whales.

Puget Sound's Grand Uncertainties Matrix
Researchers are compiling a strategic list of scientific uncertainties related to Puget Sound recovery. The list will be used to prioritize future funding and research to address critical knowledge gaps about the ecosystem.

Impacts of low oxygen on Puget Sound aquatic life (infographic)
Chronic stress from lack of oxygen can make aquatic organisms more vulnerable to disease, pollution, or predation. Low oxygen can also result in reduced habitat for some species. Aquatic species may escape, acclimate, adapt, or die with exposure.

Circulation in Puget Sound (infographic)
Estuaries around the world including Puget Sound perform an amazing feat of continuous water mixing called estuarine exchange flow.

Low dissolved oxygen in Puget Sound (infographic)
Like the air we breathe, oxygen that is dissolved in the water is critical for aquatic life. When dissolved oxygen is low, fish and other aquatic organisms may not be able to survive.

Sources of nitrogen in Puget Sound (infographic)
Nitrogen is a chemical element that is essential for the growth of all life on earth. But too much nitrogen can lead to low dissolved oxygen and other problems such as toxic algal blooms that can harm or kill aquatic organisms.

Hypoxia (fact sheet)
The following fact sheet provides an overview of low oxygen conditions in Puget Sound. It addresses some of the related causes and concerns that have been identified by scientists in the region. The overview was prepared in conjunction with a series of workshops on hypoxia and nutrient pollution presented by the University of Washington Puget Sound Institute.

Phytoplankton and primary productivity (fact sheet)
In many parts of Puget Sound, hypoxic waters are thought to be at least in part due to overgrowth of microscopic algae, which is triggered by excess nitrogen. That means it’s important to understand the dynamics of primary productivity – the rate at which those microscopic algae, known as phytoplankton, produce organic matter through photosynthesis and in this way provide the base of the food web. Researchers are investigating different types of phytoplankton and rates of primary productivity throughout the Salish Sea, and seeking to understand how primary productivity is likely to change as climate change alters patterns of coastal upwelling and freshwater flow into the Sound.

The role of sediment in nitrogen cycling and hypoxia (fact sheet)
How do marine sediments affect oxygen and nutrient levels in the water?

Legal milestones for Indigenous sovereignty and salmon co-management in the Puget Sound region
Treaty rights are critical to the sovereignity of Puget Sound area Tribes and are deeply connected to natural resource management. Five landmark treaties in our region were signed during a three-year period from 1854 to 1856 and continue to drive policy to this day.

When are waters considered hypoxic?
The search goes on for a set of definitions and thresholds to represent low-oxygen concentrations that threaten various aquatic creatures. Over the years, ecologists have relocated, reshaped and revised the word “hypoxia” to describe these conditions. In part four of our series "Oxygen for life" we look at how scientists determine whether oxygen levels are low enough to be considered harmful to sea life.

Oxygen for life: How low dissolved oxygen affects species in Puget Sound
Scientists are reporting a decline in oxygen-rich waters throughout the world. Causes for the decline vary from place to place but may involve climate change and increasing discharges of tainted water. In Puget Sound, low oxygen levels can occur naturally or due to eutrophication from human-caused pollution. In this five-part series, we describe the critical nature of oxygen to Puget Sound sea life. Scientists are finding that changes in oxygen levels can lead to physiological adjustments, shifts in predator-prey relationships and other repercussions throughout the food web.

How crabs respond to low oxygen in Hood Canal
As observed in Hood Canal, low-oxygen conditions can upend the lives of Dungeness crabs trying to stay alive. Levels of dissolved oxygen can alter predator-prey relationships for a multitude of species, affecting populations throughout the food web. Part two of our series "Oxygen for life" examines a crab case study.

Warmer waters will mean less oxygen for species
In time, lower dissolved oxygen worsened by climate change could increase the abundance of rare species in Puget Sound while putting populations of more common species into a tailspin. Part three of our series "Oxygen for life" looks at how warmer waters will gradually make it harder for many sea creatures to breathe.

Inbreeding hinders population recovery among endangered Southern Resident killer whales
While a scarcity of Chinook salmon and other environmental factors may be pushing the Southern Resident killer whales toward extinction, a new genetics study has revealed that inbreeding has been exerting a powerful, overriding influence upon the small, genetically isolated population.

Resilience to a severe marine heat wave at two Pacific seabird colonies (author summary)
A 2023 paper in the journal Marine Ecology Progress Series examines seabird reproductive and dietary response to a severe marine heat wave affecting the California Current ecosystem from 2014 to 2016. The study involved rhinoceros auklet colonies on Destruction Island (California Current) and Protection Island (Salish Sea). The paper's first author Eric Wagner describes some of the findings from the study in this informal summary.