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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.

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.

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. 

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.

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. 

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 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. 

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.

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.

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?

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.

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?

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.

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.

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.

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.

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.

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

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. 

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. 

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. 

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.

How do marine sediments affect oxygen and nutrient levels in the water?

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.  

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.