Freshwater habitat in the Puget Sound region consists of rivers, marshes, streams, lakes and ponds that do not have any saltwater input. Many species depend on these freshwater resources, including salmon, salamanders, frogs, and beavers. The freshwater habitat is also intricately linked with land use and the terrestrial environment. Sediment runoff, logging, and flood control measures all influence the patterns of freshwater flow and habitat quality.
Sound Science: Synthesizing ecological and socioeconomic information about the Puget Sound ecosystem. Published 2007. Used by permission.
Freshwater habitat in the Puget Sound region consists of rivers, marshes, streams, lakes and ponds that do not have any saltwater input. Many species depend on these freshwater resources, including salmon, salamanders, frogs, and beavers.
The Benthic Index of Biotic Integrity (B-IBI) Implementation Strategy is designed to improve freshwater quality by analyzing the health and diversity of invertebrate populations in Puget Sound area streams.
A river spawning species of forage fish known as the longfin smelt is rare and getting rarer in the Salish Sea. Biologists are looking into the mysterious decline of the ‘hooligans’ of the Nooksack.
The search for why large numbers of spawning coho salmon have been dying in Puget Sound's urban streams goes as far back as the 1980s and culminated this year with the discovery of a previously unidentified chemical related to automobile tires. We offer a detailed timeline for the discovery.
Environmental engineers and chemists at the University of Washington Tacoma have identified a mysterious compound implicated in the deaths of large numbers of coho salmon in Puget Sound. The chemical is linked with a rubber additive commonly used in tires and is thought to kill more than half of the spawning coho that enter the region's urban streams every year.
Many creeks and waterbodies in Puget Sound may look pristine, but most face serious threats from stormwater pollution. A new study at Soos Creek shows how mud-dwelling bugs, traditional chemistry and digital "heatmaps" can be used to track stormwater impacts and identify the most polluted areas. Scientists and planners hope that this may one day lower the price tag on costly stormwater fixes.
The Nooksack River watershed spans part of the border between British Columbia and the State of Washington. In August 2018, the international, multi-agency Nooksack River Transboundary Technical Collaboration Group (TCG) was established to implement a three-year work plan to reduce fecal bacteria concentrations in the Nooksack River watershed. This 2019-2020 TCG annual report summarizes second year project activities and focuses on three of the watershed's transborder sub-basins.
Climate models project that if carbon emmisions continue as they are now, the vast majority of watersheds feeding Puget Sound will receive more rain and far less snow by 2080, causing increased flooding and other dramatic changes to the freshwater ecosystem. We look at the past and possible future of the region's snowpack and what this might mean for salmon and other species — including humans.
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.
Genetic composition and conservation status of coastal cutthroat trout in the San Juan Islands, Washington
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.
Spring and fall Chinook salmon were thought to be alike until researchers discovered a gene for early migration. Now, federal biologists and legal experts are struggling to decide if spring Chinook should be granted their own legal protection under the Endangered Species Act.
Eight aquatic reserves, managed by the Washington Department of Natural Resources, have been established to protect important ecosystems on state aquatic lands.
In most reserves, area residents work with state, local and tribal officials and nonprofit groups to develop and carry out management plans, including scientific research.
The aquatic reserves in the order they were established include:
- Maury Island 2004
- Cypress Island 2007
- Fidalgo Bay 2008
- Cherry Point 2010
- Protection Island 2010
- Smith and Minor Islands 2010
- Nisqually Reach 2011
- Lake Kapowsin 2016
The Puget Sound River History Project at the University of Washington features historical topographic data for Puget Sound's river systems.
A 2018 report from the University of Washington Puget Sound Institute analyzes trends in summer stream flows and finds they are declining, but not necessarily because of abstractions by humans.
During June, near normal air temperatures and continued low precipitation have resulted in highly variable freshwater inputs to Puget Sound. A large Noctiluca bloom extends across the South Central Basin of Puget Sound. Coccolithophores are blooming in Hood Canal. Macroalgae is drifting as mats on the water in Port Madison, South Central Basin, and South Sound. They are also piling up on beaches in South and Central Puget Sound and Whidbey Basin. Juvenile fish are migrating out of the estuaries and meeting a complex thermal habitat. New infrared images tell the story. Meet our ocean acidification expert, Stephen Gonski.
Getting bigger faster can help save juvenile Chinook salmon from a gauntlet of hungry predators ranging from birds and marine mammals to larger fish. We continue our series on the Salish Sea Marine Survival Project with a look at what helps salmon grow and prepare for life in the open ocean.
Under the federal Clean Water Act, states are required to assess the quality of their surface waters and compile a list of polluted water bodies. The law mandates cleanup plans to address pollution and other water-quality problems. This article describes how this process works in Washington state for dissolved oxygen.
The Salish Sea Model is used to predict spatial and temporal patterns in the Salish Sea related to factors such as phytoplankton, nutrients and Dissolved Oxygen. It is a collaborative effort between the Pacific Northwest National Lab, the Washington State Department of Ecology and U.S. Environmental Protection Agency.
Toxic chemicals have been showing up in Puget Sound fish for more than a century, but consistent testing over the past 30 years has helped to reveal some unusual patterns of pollution.
In recent decades, hundreds of millions of dollars have been spent to restore habitat for Puget Sound salmon. In this article, we look at how scientists are gauging their progress. Are environmental conditions improving or getting worse? The answer may depend on where you look and who you ask.
A biennial report produced by the Governor's Salmon Recovery Office provides stories and data about salmon, habitat, and salmon recovery in Washington, including Puget Sound.
The state of Washington estimates that the Puget Sound area will grow by more than 1.5 million residents within the next two decades. That is expected to have profound effects on the environment as more and more people move to undeveloped areas. The race is on to protect this critical rural habitat, but planners say what happens in the cities may be just as important.
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.
The Puget Sound Ecosystem Monitoring Program (PSEMP) is an independent program established by state and federal statute to monitor environmental conditions in Puget Sound.
A new approach to flood control is taking hold across Puget Sound. Rivers, scientists say, can be contained by setting them free. Conservationists hope this is good news for salmon recovery.
As threatened Chinook populations in Puget Sound continue to lose ground, the state is looking to new strategies to reverse the trend. In the Skagit watershed, the scientists — and the fish — are among those leading the way.
Many groups have been formed around the goal of saving salmon, but few people talk about a concerted effort to save microscopic creatures. Whether or not a pro-bug movement catches on, future strategies to save salmon are likely to incorporate ideas for restoring streambound creatures known as benthic invertebrates.
The Puget Sound Ecosystem Monitoring Program released its fifth annual Marine Waters Overview this week. The report provides an assessment of marine conditions for the year 2015 and includes updates on water quality as well as status reports for select plankton, seabirds, fish and marine mammals.
New, smaller acoustic tags will allow scientists to track steelhead migrations in Puget Sound in ways that were once impossible. Will they provide answers to the mysterious decline of these now-threatened fish?
The Salish Sea Marine Survival Project has mobilized dozens of organizations in the U.S. and Canada to find an answer to one of the region's greatest mysteries. What is killing so many young salmon before they can return home to spawn? A series of talks at the 2016 Salish Sea Ecosystem Conference brought together some of the latest research.
Protecting Puget Sound watersheds from agricultural pollution using a progressive manure application risk management (ARM) system
Throughout the Puget Sound region, impacted and poorly managed agriculture has been repeatedly advanced as a leading contributor to surface and ground water pollution, particularly during the winter months. A study conducted from 2010 - 2015 aimed to develop an Application Risk Management (ARM) System to minimize pollution from manure in Whatcom County.
A 2015 report from Snohomish County, King County and the Tulalip Tribes outlines protection strategies for salmon and salmon habitat within the Snohomish Basin.
The growing number of species of concern in the Salish Sea suggests ecosystem decay is outpacing recovery
The number of species of concern in the Salish Sea is growing at an average annual rate of 2.6%, according to a report published in the proceedings of the 2016 Salish Sea Ecosystem Conference in Vancouver, B.C.
The number of species of concern in the Salish Sea is growing at an average annual rate of 2.6%, according to a report published in the proceedings of the 2016 Salish Sea Ecosystem Conference in Vancouver, B.C.
For close to 100 years, Seattle's Ballard Locks has been one of the region's busiest waterways, drawing major boat traffic along with millions of tourists. But as it prepares to celebrate its centennial, the aged structure is also drawing the concern of engineers. They worry that an earthquake could cause the locks to fail, draining massive amounts of water from Lake Washington and Lake Union. In some scenarios, the two lakes could drop by as much as 20 feet, stranding boats, disabling bridges and causing big problems for salmon restoration.
Chinook, coho and sockeye salmon, along with steelhead trout, live in the Lake Washington watershed and navigate a treacherous route through the Ballard Locks on their way to Puget Sound.
This overview discusses the processes that control ocean and climate characteristics. Topics include atmospheric forcing, precipitation patterns, oscillation trends, coastal upwelling, and climate change.
Lake Washington was heavily contaminated by untreated sewage until extensive pollution controls by the city of Seattle.
Land cover conversion through human development was listed as a leading cause of ecosystem decline in the 2014 Puget Sound Pressures Assessment, a document supported by the Environmental Protection Agency and prepared by more than 60 of the region's scientists.
Runoff from rain and melting snow is one of the leading causes of pollution in Puget Sound. Here are selected facts related to stormwater, its prevalence, how it affects the Puget Sound ecosystem, and its environmental and economic impacts.
Chinook, coho and steelhead populations in Puget Sound have declined dramatically over the past 30 years. In some cases, counts of fish returning to the rivers are just a tenth what they were in the 1980s. While many possible causes of this decline are under consideration, some researchers are focusing on the combined effects of predators and disease. This article continues our coverage of the ecological impacts of disease in Puget Sound.
A 2015 report from the Whatcom Conservation District and Whatcom County describes a pilot watershed characterization study focusing on the Terrell Creek and Birch Bay areas. The report and related appendices are available for download.
A 2015 report from the University of Washington provides the most comprehensive assessment to date of the expected impacts of climate change on the Puget Sound region.
An EPA-funded study by the Thurston Regional Planning Council identified recommended strategies and actions to protect and improve water quality and aquatic resources in the Woodard Creek Basin.
An EPA-funded study by the Thurston Regional Planning Council identified recommended strategies and actions to protect and improve water quality and aquatic resources in the McLane Creek Basin.
An EPA-funded study by the Thurston Regional Planning Council identified recommended strategies and actions to protect and improve water quality and aquatic resources in the Black Lake Basin.
The Lower Duwamish Waterway in Puget Sound was designated a Superfund cleanup site in 2001. Its legacy of contamination predates World War II and the waterway continues to pollute Puget Sound through stormwater runoff.
The 2015 Puget Sound Fact Book brings together statistics and other information about the health and makeup of the Puget Sound ecosystem. Areas of focus include climate change, geography, water quality, habitats, human dimensions and regional species. The fact book was prepared for the Encyclopedia of Puget Sound with funding from the Environmental Protection Agency and the Puget Sound Partnership.
Puget Sound is the second largest estuary in the United States. Today, we understand that estuaries—where freshwater and saltwater merge—are among the most productive places for life to exist.
This report documents how Washingtonians have responded to the challenges of protecting and restoring salmon and steelhead to healthy status. It also serves as a tool to summarize achievements, track salmon recovery progress through common indicators, and identify data gaps that need to be filled.
The final report on a knotweed removal and native plant project from grant PO-00J08401 to King County DNR for the grant entitled: Protection and enhancement of the riparian buffers in WRIA 7 through restoration and stewardship.
Habitat restoration was undertaken in 2009-2010 on lower Hansen Creek, Washington. The project converted 140 acres of isolated floodplain into 53 acres of alluvial fan and 87 acres of flow-through wetlands.
This report, Priority science for restoring and protecting Puget Sound: a Biennial Science Work Plan for 2011-2013, identifies priority science and monitoring questions needed to coordinate and implement effective recovery and protection strategies for Puget Sound.
Salmon recovery demands both dedication among people with different interests, and sustained resources. This biennial report tells the story of the progress made to date and the challenges ahead.
Sound Science: Synthesizing Ecological and Socio-economic Information about the Puget Sound Ecosystem summarizes what we know about the greater Puget Sound ecosystem and what we think could happen in the future given present trajectories and trends.
This is the first annual report of the Puget Sound Ambient Monitoring Program (PSAMP); it briefly describes PSAMP, explains the significance of each type of measurement, and provides initial interpretation of the results.
This is the second annual Puget Sound Update. Findings from the first two years of the Puget Sound Ambient Monitoring Program (PSAMP) form the basis of this report. This report briefly describes PSAMP, explains the significance of each type of monitoring, and discusses the results. It provides some background on the workings of the Puget Sound ecosystem and the history of contamination problems in the Sound.
In 1996 the Washington State Legislature decided that, in order to effectively target protection efforts in the future, it was time to evaluate how well current efforts to protect Puget Sound are working.
This is the Puget Sound Water Quality Action Team’s second report on key indicators of Puget Sound’s health. This report has been prepared in response to the Washington State Legislature’s request to evaluate efforts to protect Puget Sound. This second report includes updated information on the 12 indicators originally presented in 1998 as well as information on five new indicators.
This is the Puget Sound Water Quality Action Team's third report on key indicators of Puget Sound's Health. We prepared the report in response to the Washington State Legislature's request to evaluate efforts to protect Puget Sound. The report includes updated information on the 17 indicators presented in 2000 as well as information on two new indicators.
The 2011 Salish Sea Ecosystem Conference was held October 25 to 27 at the Sheraton Wall Centre in Vancouver, British Columbia. This event brought together a diverse group of government officials, community leaders, First Nations and tribal members, environmental managers, scientists and academics to learn from each other about the state and threats to the shared ecosystem. Over 950 delegates attended.
Scientists say low marine survival rates threaten Puget Sound coho salmon populations. A 2015 article in the journal Marine and Coastal Fisheries reports that wild cohos in the Salish Sea had higher smolt survival rates over a 30 year period than hatchery coho salmon. Smolt survival in the Strait of Georgia during that time declined faster than it did in Puget Sound.
A December 2014 report from the University of Washington examines when and where climate change impacts will occur in the Puget Sound watershed.
When and where will we see the impacts of climate change in Puget Sound? A web-based tool factors in dozens of site-specific variables for watersheds throughout the Pacific Northwest. The resource was developed by the University of Washington Climate Impacts Group with support from the EPA, the US Army Corps of Engineers and the Center for Data Science, University of Washington-Tacoma.
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.
This paper summarizes a 2014 report ranking the greatest human-caused threats to the Puget Sound ecosystem.
The Puget Sound Ecosystem Monitoring Program (PSEMP), along with partners from the US EPA Columbia River Program and USGS Oregon Water Science Center, have developed a framework for prioritizing monitoring of Contaminants of Emerging Concern (CECs) in the Pacific Northwest.
A 2014 report by the North Cascadia Adaptation Partnership identifies climate change issues relevant to resource management in the North Cascades, and recommends solutions that will facilitate the transition of the diverse ecosystems of this region into a warmer climate.
How does one of the West's busiest airports deal with extreme stormwater, and what does that mean for water quality standards in the rest of the state?
Development of a stormwater retrofit plan for Water Resources Inventory Area (WRIA) 9: Comprehensive needs and cost assessment and extrapolation to Puget Sound
A 2014 King County report projects the capital and maintenance costs of the stormwater treatment facilities that would be needed, within WRIA 9 and the Puget Sound region, to fully comply with the Clean Water Act.
A 2014 report prepared by the Stillaguamish Tribe analyzes potential causes of changes in peak and low flows in the Stillaguamish River basin.
A December 2014 paper in the journal Aquatic Ecosystem Health & Management describes a project to identify transboundary ecosystem indicators for the Salish Sea.
Scientists are rethinking floodplain management in Puget Sound. Can we have our farms and salmon too?
A 2014 paper decribes how monitoring the energy density of key Pacific salmon species could affect the recovery of northern and southern killer whales through fisheries management.
Monitoring and adaptive management of the Nisqually Delta after tidal marsh restoration: Restoring ecosystem function for salmon
This 2009 report by the Nisqually Tribe establishes key measures of restoration development, habitat processes, and Chinook salmon response for the largest delta restoration project in the Pacific Northwest.
New research presented at the 2014 Salish Sea Ecosystem Conference shows that some of the greatest dangers to Puget Sound marine life come from our common, everyday activities. These pervasive sources of pollution are so woven into our lives that they are almost invisible to us, but it’s becoming impossible to ignore their effects.
The growth and survival of young salmon in streams, river deltas and floodplains are seen as crucial pieces of the salmon recovery puzzle. In part two of this two-part series, researchers at the Salish Sea Ecosystem Conference in Seattle say the complexities of the salmon life cycle require new coordination among scientists.
Why did all the grebes leave? Where did they go? And what does their disappearance say about the health of the Salish Sea? Seasonal declines among some regional bird species could hold important clues to the overall health of the ecosystem.
The July 2014 issue of the journal Coastal Management focuses on the role of social sciences in Puget Sound ecosystem recovery. Articles range from political ecology to the development of human wellbeing indicators and directly address current Puget Sound restoration efforts. Guest editors include Encyclopedia of Puget Sound topic editor Kelly Biedenweg and Puget Sound Science Panel co-chair Katharine Wellman. The journal is co-edited by Patrick Christie of our editorial board. Extended abstracts of the articles will be available on these pages in coming weeks.
A list of over 1800 benthic infaunal invertebrates is now available on the Encyclopedia of Puget Sound. The list was prepared as part of the Washington State Department of Ecology’s Marine Sediment Monitoring Program (MSMP). This program, initiated in 1989, is one component of the Puget Sound Ecosystem Monitoring Program, a collaborative effort dedicated to monitoring environmental conditions in Puget Sound.
Spatial and Temporal Variation in River Otter (Lontra canadensis) Diet and Predation on Rockfish (Genus Sebastes) in the San Juan Islands, Washington
A 2014 paper in the journal Aquatic Mammals examines coastal river otter predation on rockfish at three islands in the Salish Sea.
Approximately every two years, the SeaDoc Society prepares a list of species of concern within the Salish Sea ecosystem. The following paper found 119 species at risk and was presented as part of the proceedings of the 2014 Salish Sea Ecosystem Conference, April 30 – May 2, 2014, Seattle, Washington.
Several studies have been performed to determine the occurrence of selected Contaminants of Emerging Concern (CECs) in the environment.
Thousands of different compounds are produced and used as part of our daily lives. Examples include pharmaceuticals (NSAIDs, birth control pills, etc), personal care products (sun screen agents, scents, preservatives, etc), food additives (artificial sweeteners) and compounds used in industrial and commercial applications (flame retardants, antibiotics, etc). Advances in analytical methods have allowed the detection of many of these compounds in the environment.
A 2014 report describes a study of socio-cultural values associated with blueback salmon in the Quinault Indian Nation. The blueback salmon (Oncorhynchus nerka) is a unique strain of sockeye that returns primarily to the Quinault river system.
A December 2013 report identifies marine and terrestrial bird species for use as indicators within the Puget Sound Partnership's "Vital Signs" for ecosystem health.
Making science useful in complex political and legal arenas: A case for frontloading science in anticipation of environmental changes to support natural resource laws and policies
A December 2013 report by the University of Washington Climate Impacts Group projects wide reaching change for the Puget Sound ecosystem and the Pacific Northwest. Lead author: Encyclopedia of Puget Sound climate change topic editor Amy Snover.
An October 2013 report released by the Puget Sound Ecosystem Monitoring Program inventories and assesses monitoring activities of Puget Sound's ESA-listed salmon and steelhead stocks and habitats.
The Encyclopedia of Puget Sound spoke with Seattle Times reporter Lynda Mapes about the exhibit Elwha: A River Reborn, which opened at the University of Washington Burke Museum on November 23rd. The exhibit is based on the book of the same title by Mapes and photographer Steve Ringman, and tells the story of the largest dam removal in U.S. history.
In the 1970s and 1980s, research from a division of NOAA's Montlake Lab suddenly and irreversibly changed the way scientists and the public viewed the health of Puget Sound. Their discoveries of industrial toxics in the region's sediment-dwelling fish led to the creation of two Superfund sites, and new approaches to ecosystem management across the Sound. The man at the forefront of this research was Dr. Donald Malins, featured here as part of the Puget Sound Voices series.
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.
This document was prepared by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency and the National Park Service. Download the entire report, or read the Introduction below. Portions of this document were originally published in June 2013 and were updated in February 2014.
Vern Morgas remembers the early days of scuba diving in Puget Sound.
A new Chinook monitoring framework is designed to build cooperation among managers and policymakers working across the Puget Sound watershed. The report, prepared by an independent team of scientists and released by NOAA, includes a regionally specific, common classification system for Chinook habitats and key ecological attributes.
Puget Sound Chinook Salmon recovery: a framework for the development of monitoring and adaptive management plans
The Puget Sound Recovery Implementation Technical Team has released a draft of a NOAA technical memorandum describing frameworks for adaptive management and monitoring of Chinook salmon in Puget Sound. Download the report.
This article was originally published by the Washington Department of Fish and Wildlife as part of its annual report Threatened and Endangered Wildlife in Washington.
The Sauk-Suiattle Indian Tribe conducts annual surveys of amphibian egg masses in the Reservation Slough wetland near the Sauk River.
A recent report by an independent science panel reviewed data on the effects of salmon fisheries on Southern Resident Killer Whale populations. The report was released on November 30, 2012 and was commissioned by NOAA Fisheries and Oceans Canada.
Fish in the family Salmonidae (salmon, trout, and charr) play potentially integral roles in the upland freshwater, nearshore and pelagic marine ecosystems and food webs of Puget Sound.
The State of Our Watersheds Report is produced by the treaty tribes of western Washington, and seeks to present a comprehensive view of 20 watersheds in the Puget Sound region and the major issues that are impacting habitat.
Puget Sound Stream Benthos is a data management project which monitors benthic invertebrates in streams and rivers in the Puget Sound region. The system is maintained and operated by King County and was the result of a joint effort between King, Pierce, and Snohomish Counties.
Wetlands are recognized as critical ecosystems for biodiversity because of their disproportional use by wildlife and exceptional habitats for plants. It is their unique combination of shallow aquatic habitats and adjacent terrestrial conditions extending over a wide range of geomorphic and elevational settings that accounts for their ecological complexity and resultant richness. Because of their landscape setting, each wetland tends to exhibit unique habitat types and characteristic arrays of species adapted to idiosyncratic conditions, products of each wetland’s ecological and evolutionary history.
The diversity of streams in the county is a reflection of the diversity of its geography. From the small rivulets that begin high in the Cascade Mountains, to the brooks that flow gently across the lowlands, to the five major rivers of the county, there are over 4,800 kilometers (3,000 miles) of perennial streamcourses in King County.
Riparian habitats are often characterized by particular trees and shrub species that line the banks of most rivers and streams in the lowlands and foothills of King County.
The natural biodiversity of the lakes of King County is strongly influenced by geography. The county runs from the Cascade mountain crest to the shores of Puget Sound, covering all three different Level III ecoregions (Puget Lowland, North Cascade, and Cascade). The geology, elevation, climate, and ecology in these three ecoregions are all different, and these differences in environmental factors determine the natural biodiversity of the lakes and also influence the risks, vulnerability, and impacts to that biodiversity.
The Northern Red-legged Frog is described here relative to its local behavior, habitat, threats and morphology.
Fecal bacteria are found in the feces of humans and other homeothermic animals. They are monitored in recreational waters because they are good indicators of harmful pathogens that are more difficult to measure.
"Habitat" describes the physical and biological conditions that support a species or species assemblage and refers to conditions that exist at many scales. An oyster shell provides habitat for some algae and invertebrates, whereas cubic miles of sunlit water in Puget Sound comprise the habitat for many planktonic species.
Non-native species are those that do not naturally occur in an ecosystem. A non-native species is considered invasive when it is capable of aggressively establishing itself and causing environmental damage to an ecosystem. Plants, animals, and pathogens all can be invasive.