Find content specifically related to mammals of the Puget Sound and Salish Sea ecosystems. For checklists and descriptive accounts of individual species, visit our species library.
Interannual differences in postrelease movements of rehabilitated harbor seal pups (Phoca vitulina richardii) in the Salish Sea
A study published in Marine Mammal Science in June 2020 followed the movements and behavior of rehabilitated harbor seal pups after being released into the Salish Sea. The results suggest that although their movements differ from wild pups that have been weaned, the rehabilitated pups do successfully make the transition.
Tiny bone samples show that seals alter their diets as conditions change. The findings could help scientists understand whether seals are contributing to local salmon declines.
Last month's federal authorization to kill more than 700 sea lions to protect salmon runs along the Columbia River is prompting discussions of similar actions for harbor seals in Puget Sound. But experts say the situations are very different with many unanswered questions.
North American river otters (Lontra canadensis) inhabit inland freshwater environments; however, from Alaska to California they also occur in coastal marine waters where they forage on a variety of marine fish and invertebrates. Little is known about mortality factors in marine-foraging river otters. Among 30 otter carcasses collected in San Juan County, Washington, analysis indicates that car collisions and gunshots were the most common causes of mortality.
The Salish Sea’s endangered southern resident orcas travel freely across the U.S.-Canada border, unconstrained by political boundaries. But while they don’t require passports, they can still face differing policies and conditions as they go back and forth between nations. We look at some of the ways that the United States and Canada compare in their efforts to protect the whales.
A paper published in the journal Oceans in 2020 describes cases of prey-related asphyxiation in harbor porpoises along the U.S. West Coast. The findings suggest that a majority of cases involve non-native American shad and that asphyxiation tends to occur more with reproductively active females than other age and sex classes.
A 2020 paper published in Frontiers in Marine Science describes details of the fungal disease Mucormycosis which has caused the death of harbor porpoises, harbor seals and one orca in Puget Sound in recent years. The authors discuss the implications for local marine mammals, specifically the endangered southern resident killer whale population.
A 2020 article in the journal Frontiers in Marine Science looks at harbor seal stranding and necropsy findings in the San Juan Islands to assess age-related stranding trends and causes of mortality. The harbor seal (Phoca vitulina richardii) population in the Salish Sea has been at equilibrium since the mid-1990s. This stable population of marine mammals resides relatively close to shore near a large human population and offers a novel opportunity to evaluate whether disease acts in a density-dependent manner to limit population growth.
Social scientists at Oregon State University have been analyzing a trove of more than 17,000 public comments sent to the Washington state governor's southern resident orca recovery task force. The researchers have added the comments to a keyword database to look at public emotions and perceptions around the issue of orca declines.
Researchers studying the killer whales that frequent Puget Sound are growing increasingly concerned that a dangerous virus or other disease-causing organism could spread through the population and hasten extinction of these critically endangered southern resident orcas.
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.
A new report from the Puget Sound Ecosystem Monitoring Program says climate change altered the base of Puget Sound's food web in 2018, diminishing microscopic phytoplankton necessary for marine life. Scientists also observed lower abundances of fish, seabirds, and marine mammals.
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).
In July, the recent trends of warm, dry conditions lessened; however, river flows remain low. Extensive macroalgae drifted through South and Central Sound and washed up on beaches. Macroalgae growth is fueled by excessive nutrients and sunshine. When it washes onto the beach, it is called beach wrack, and it can be a health risk to beachgoers because of bacteria it can harbor. From our aerial photography, we saw that Southern Hood Canal looks tropical because of a bloom of coccolithophores coloring the water turquoise. Schools of fish congregate in South Sound and southern Hood Canal. Jellyfish are abundant in Quartermaster Harbor.
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.
Warm and dry conditions this spring are predicted to persist into summer, resulting in saltier and warmer than normal Puget Sound water conditions. Early upwelling and a premature melt of the snowpack means nutrient-rich ocean water likely already entered Puget Sound. This sets the stage for a lot of biological activity. From the air, it is obvious that the productive season is in full swing. We saw large algae blooms in Central Sound along with abundant Noctiluca. Huge numbers of anchovies were documented in Case Inlet and other finger inlets in South Sound, attracting hundreds of marine mammals.
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?
New technology is helping to remove deadly “ghost nets” that have been lost in the depths of Puget Sound. It is part of an effort that saves millions of animals every year, but managers say better reporting of these lost nets by fishermen is still needed.
Understanding the social networks and family bonds of Puget Sound's southern resident orcas may be critical to keeping the endangered whales from extinction. A healthy population is about more than numbers, scientists say. It's about connections.
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.
This three-part series explores opportunities and challenges of using medical interventions to save Puget Sound's southern resident orcas from extinction. Part 1 looks at how scientists might treat endangered southern resident orcas that face starvation and risks of disease; Part 2 considers how veterinarians have intervened with other animals in the wild, and how this might apply to orcas in Puget Sound; and Part 3 explores a federally approved vaccination program designed to ward of a deadly virus among endangered Hawaiian monk seals.
A 2019 report from the non-profit group Earth Economics look at revenues and other economic activity resulting from whale watching in San Juan County, Washington.
For critically endangered animal populations, experts worry that a highly infectious disease could be the final nail in the coffin, forcing the species into extinction. That’s one reason why federal authorities approved the development and deployment of a new vaccine to ward off the deadly morbillivirus among Hawaiian monk seals. The vaccination program raises the possibility of using vaccines to prevent disease among Puget Sound's southern resident killer whales, but no specific steps have been taken so far.
As the plight of Puget Sound’s southern resident orcas becomes increasingly desperate, with the population dropping from 98 to 75 in just 22 years, scientists are weighing the options of medical intervention. In part two of our two-part series The Orca Docs we look at how veterinarians have intervened with other animals in the wild, and how this might apply to the situation here in Puget Sound. [Part one, "When should medical experts intervene to save a killer whale?" is also available.]
The death of a young female orca in September has sparked a discussion of how and whether scientists should step in with medical care for distressed animals in the wild. Medical intervention has become routine for some endangered mammals, but scientists say Puget Sound’s resident orcas present a series of unique challenges and ethical questions. In part one of our two-part series The Orca Docs we look at how scientists are preparing to treat endangered southern resident orcas that face starvation and risks of disease.
The Puget Sound Ecosystem Monitoring Program has released its seventh annual Marine Waters Overview. The report provides an assessment of marine conditions for the year 2017 and includes updates on water quality as well as status reports for select plankton, seabirds and fish.
With a population growth of about 10 percent per year in inland waters, harbor porpoises are having an undetermined but growing effect on food dynamics in Puget Sound.
Sightings of southern resident killer whales in the Salish Sea 1976−2014: the importance of a long-term opportunistic dataset
A 2018 paper in the journal Endangered Species Research analyzes southern resident killer whale sightings in the Salish Sea between 1976 and 2014.
Between 1962 and 1973, at least 263 killer whales were caught or killed in the waters of British Columbia and Washington (Bigg and Wolman 1975). Twelve of these died during capture and fifty were kept for display in aquariums. The remainder of the captured animals escaped or were released. Twenty-seven of the whales kept as captive were taken from the population now designated as endangered southern-resident killer whales (Balcomb 2018). All but one of those, nicknamed Lolita, have since died. Lolita remains in captivity at the Miami Seaquarium.
Balcomb, Ken. (2018). Center for Whale Research. Personal correspondence.
The reasons for the surprise visits are unknown, but changes in environmental conditions here or elsewhere are one possibility.
As wildlife managers work to recover Puget Sound’s diminished Chinook population, a proposed white paper is expected to review the impacts of some of the salmon's chief predators. The study would include a section on potential management of seals and sea lions, prompting open discussion of a long taboo subject: Could officials seek to revise the Marine Mammal Protection Act — or even conduct lethal or non-lethal removal of seals and sea lions in some cases? Such actions are hypothetical, but we look at some of the ongoing discussions around the issue as prompted by a new resolution from the Puget Sound Leadership Council.
A December 2017 article in the journal PLOS One reports that incidents and violations among whale watching vessels have increased in the Central Salish Sea since 1998.
Sea lions living along the coast of Washington are at risk from harmful algal blooms throughout the year, according to a 2017 study published in the Marine Ecology Progress Series.
Group characteristics, site fidelity, and photo-identification of harbor porpoises, Phocoena phocoena, in Burrows Pass, Fidalgo Island, Washington
A 2017 paper in the journal Marine Mammal Science examines harbor porpoise group structure and site fidelity in the Salish Sea.
A 2017 paper in the journal Aquatic Mammals reports that harbor seals in the Salish Sea are less concerned about predators when they become habituated to humans.
Increased consumption of Chinook salmon by seals and sea lions in the Salish Sea “could be masking the success of coastwide salmon recovery efforts,” according to a new study published in the journal Scientific Reports. Endangered resident orcas are said to be declining in part due to a lack of available Chinook, the orcas' preferred prey.
The marine habitat of Puget Sound can be divided up into nearshore, benthic (associated with the sea floor), and pelagic (open water) habitats. This article focuses on the pelagic habitat within the Puget Sound. This article was prepared as part of the 2015 Puget Sound Fact Book produced by the University of Washington Puget Sound Institute.
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 2017 article in the online journal Authorea reports that a comparatively small portion of ships produce much of the ocean's underwater noise.
Vessel traffic is increasing in the Puget Sound region. A 2017 article in the journal Aquatic Mammals looks at the potential impacts that increasing vessel disturbance may have on resident harbor seal populations and how future management decisions may need to look at variable buffer zones related to level of human activity.
A new study shows that increased populations of seals and sea lions are eating far more of Puget Sound’s threatened chinook than previously known, potentially hampering recovery efforts for both salmon and endangered killer whales.
After an almost complete collapse in the 1970s, harbor porpoise populations in Puget Sound have rebounded. Scientists are celebrating the recovery of the species sometimes known as the "puffing pig."
New techniques for studying orcas have been credited with breakthroughs in reproductive and developmental research. Drones and hormone-sniffing dogs are helping scientists connect declines in food supply with low birth rates and poor health. Update: The research described in this 2016 article has now been published in the 6/29/17 issue of the journal PLOS ONE.
Researchers are proposing a shift in thinking about how some of the region’s most damaging pollutants enter Puget Sound species like herring, salmon and orcas.
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.
Scientists are realizing that underwater noise in the Salish Sea affects a broad range of species, even plankton. Read a Q & A with the organizers of the session 'From plankton to whales: underwater noise and its impacts on marine life.'
The mysterious practice of killing porpoises may have a useful function, but it has yet to be fully explained, according to orca researcher Deborah Giles.
A 2016 technical report from the Washington Department of Fish and Wildlife and the Cascadia Research Collective details the decline of the harbor porpoise in Puget Sound in the 1970s and reports that species numbers have increased over the past twenty years likely due to outside immigration.
Impacts of anthropogenic noise on marine life: Publication patterns, new discoveries, and future directions in research and management
A 2015 review in Ocean & Coastal Management looks at trends in research related to anthropogenic noise and its affect on a wide variety of marine organisms, from whales and fish to invertebrates. The review includes case studies from the Salish Sea.
This article describes the first known case of conjoined twins in a harbor seal. The case was documented in the Salish Sea region where harbor seals are often used as indicators of contaminant levels. However, researchers say their findings do not support that this anomaly was due to any common contaminants and hypothesize that the twinning was caused by disordered embryo migration and fusion.
From orcas to starfish to humans, disease affects every living creature in the ecosystem. Scientists are increasingly alarmed by its potential to devastate already compromised populations of species in Puget Sound.
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.
In the 1940s, harbor porpoise were among the most frequently sighted cetaceans in Puget Sound, but by the early 1970s they had all but disappeared from local waters. Their numbers have since increased, but they remain a Species of Concern in the state of Washington. This in-depth profile looks at harbor porpoise in the Salish Sea, and was prepared by the SeaDoc Society for inclusion in the Encyclopedia of Puget Sound.
A report from NOAA and the Puget Sound Ecosystem Monitoring Program provides an overview of 2014 marine water quality and conditions in Puget Sound from comprehensive monitoring and observing programs.
Review of the marine environment and biota of Strait of Georgia, Puget Sound and Juan de Fuca Strait
Proceedings of the BC/Washington Symposium on the Marine Environment, January 13 and 14, 1994
Increased harbor porpoise mortality in the Pacific Northwest, USA: understanding when higher levels may be normal
A 2015 paper in the journal Diseases of Aquatic Organisms examines potential causes of increased harbor porpoise strandings in Washington and Oregon.
The Puget Sound Update is a technical report that integrates results of PSAMP and other scientific activities in Puget Sound focused on marine life and nearshore habitat, marine and freshwater quality, and toxic contamination.
A 2000 report from the Washington Department of Fish and Wildlife provides information on haulout sites for harbor seals, Steller sea lions, California sea lions, and northern elephant seals located in Washington waters.
Foraging differences between male and female harbor seals present challenges for fisheries management
A 2015 article published in the Marine Ecology Progress Series identifies intraspecific differences in diet between harbor seals in the Salish Sea, suggesting implications for marine reserve management.
Living in the fast lane: rapid development of the locomotor muscle in immature harbor porpoises (Phocoena phocoena)
A study in the Journal of Comparative Physiology shows that muscle development necessary for diving can take several years to mature in harbor porpoises. Scientists argue that this may make immature harbor porpoises more vulnerable than adults to impacts from boat traffic or other disturbances.
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.
A 2015 paper presented to the International Whaling Commission compares the impacts of kayaks and powerboats on killer whale populations.
Population structure and intergeneric hybridization in harbour porpoises Phocoena phocoena in British Columbia, Canada
A 2014 paper in Endangered Species Research suggests that harbour porpoises inhabiting coastal waters of southern British Columbia constitute a single genetic population, which should be reflected in management decisions.
Northwest Coast First Peoples made clam garden terraces to expand ideal clam habitat at tidal heights that provided optimal conditions for clam growth and survival, therefore enhancing food production and increasing food security.
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.
A report from the Puget Sound Ecosystem Monitoring Program provides an overview of 2013 marine water quality and conditions in Puget Sound from comprehensive monitoring and observing programs.
Scientists say Puget Sound’s salmon are dying young and point to low growth rates in the marine environment as a possible cause. In part one of this two-part series, scientists consider threats facing young salmon in the open waters of Puget Sound.
Scientists say eelgrass, an unassuming flowering plant found just off shore in Puget Sound, is vital to the health of the ecosystem. They also say the plant is declining. New and increasingly urgent efforts to restore it brought a group of researchers to the 2014 Salish Sea Ecosystem Conference.
Age, region, and temporal patterns of trace elements measured in stranded harbor seals (Phoca vitulina richardii) from Washington inland waters
A 2014 article in the journal Northwestern Naturalist shows how Harbor Seal tissues can reflect regional and temporal trends in contaminants in Puget Sound.
Harbor seals (Phoca vitulina) are the most commonly seen marine mammals in the Salish Sea and can be found throughout the region year round. They have been intensively studied within the Salish Sea and this species profile provides an overview of what is known about them. It was produced for the Encyclopedia of Puget Sound by the SeaDoc Society.
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.
Harbor porpoise (Phocoena phocoena) are one of the most frequently sighted cetaceans in the Salish Sea. Anecdotal information, possibly supported with stranding encounter rate data, suggests that harbor porpoise may have increased in Puget Sound, or have shifted their distribution back to Puget Sound relative to earlier decades.
Harbor porpoises were once common in Puget Sound, but had all but disappeared from local waters by the 1970s. Regular and numerous anecdotal sightings in recent years show that populations of these cetaceans are now increasing and may be approaching their former status. The attached document from NOAA Fisheries describes harbor porpoise numbers and their geographic range in Puget Sound as of 2011.
The Salish Sea Hydrophone Network and Orca Network are two citizen science projects dedicated to furthering our understanding of abundance, distribution, behavior, and habitat use by the endangered population of Southern Resident Killer Whales, also called orcas. The Hydrophone Network lets the public listen for orcas through their computers and phones, while the Orca Network gathers and disseminates sightings of orcas as they move between Puget Sound, the Fraser River, and the Pacific Ocean.
In December 2013 NOAA released what it classifies as a "Highly Influential Scientific Assessment" of the effects of anthropogenic sound on marine mammals. The comment period on the draft assessment extends until March 13, 2014.
A 2013 article in the journal Animal Conservation compares the effects of increasing anthropogenic noise to habitat loss for endangered fin, humpback and killer whales in the Salish Sea.
Can Puget Sound claim a new species? Ribbon seals were not previously thought to venture into the Salish Sea, but a series of sightings in Puget Sound in 2012 expands their potential range. Scientists are keeping an eye out for future sightings.
This paper discusses the dietary habits of harbor seals (Phoca vitulina) in two estuaries in Puget Sound.
This paper discusses Brucella pinnipedalis infections in harbor seals (Phoca vitulina) in Washington state and transmission to humans and other wildlife. The disease poses a threat to endangered populations and may be exacerbated by organic pollutants.
Potential effects of the interaction between marine mammals and tidal turbines – an engineering and biomechanical analysis
A paper presented at the European Wave and Tidal Energy Conference in Aalborg, Denmark describes the potential effects of a tidal turbine strike on an endangered Southern Resident Killer Whale in Puget Sound (SRKW). A tidal turbine is proposed for deployment in Admiralty Inlet in Island County.
This page includes documents and links related to the status of Steller Sea Lion in Washington state and the Salish Sea region.
The Puget Sound Marine Waters 2012 Overview from the Puget Sound Ecosystem Monitoring Program synthesizes conditions measured in 2012 and has been expanded to include observations on seabirds that rely on marine waters. Read an excerpt below, or download the full report.
The U.S. Environmental Protection Agency Region 10 and the National Marine Fisheries Service Northwest Region have released a report describing results from a series of technical workgroups about the potential effects of polybrominated diphenyl ethers (PBDEs) on Puget Sound and Southern Resident killer whales.
Paper: Spatial and temporal analysis of killer whale (Orcinus orca) strandings in the North Pacific Ocean and the benefits of a coordinated stranding response protocol
A new paper by Puget Sound area scientists from the SeaDoc Society and their collaborators represents the most complete summary to date of killer whale (Orcinus orca) strandings in the North Pacific. The authors analyzed stranding records dating back to 1925, obtained from scientists worldwide, finding that very few whales are stranded (an average of ten a year over the last twenty years). However, most of those strandings result in death. Only 12% of stranded whales survive.
Audio recordings of the Mazama Pocket Gopher.
This 2004 report looks at the status of Washington's four killer whale populations.
A master's thesis prepared at Western Washington University discusses the impact of harbor seals on fish stocks in the San Juan Islands, where the seals are a year-round predator.
The Washington Department of Fish and Wildlife recently released a Bat Conservation Plan for the 15 species of bats found in Washington State. All but four of these species occur within the greater Puget Sound watershed1, including:
The Encyclopedia of Puget Sound species library now includes a list of species of concern in the Salish Sea watershed. The list was created by Joe Gaydos and Jacqlynn Zier of the SeaDoc Society, and was released as a paper presented as part of the Proceedings of the 2016 Salish Sea Ecosystem Conference in Vancouver, BC.
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.
Three distinct groups of killer whales (Orcinus orca) occupy the coastal waters of the northeastern Pacific. These groups—northern and southern residents, transients, and offshores—are distinguished by diet, behavior, morphology, and other characteristics. Among these, southern resident and transient killer whales commonly are found in Puget Sound. Northern residents and offshore killer whales rarely enter Puget Sound (Wiles 2004, Kriete 2007), and therefore are not described in detail here.
Harbor seal numbers were severely reduced in Puget Sound during the first half of the twentieth century by a state-financed population control program. This bounty program ceased in 1960, and in 1972, harbor seals became protected under the federal Marine Mammal Protection Act and by Washington State.
The Puget Sound Marine Waters 2011 report is now available. The report was produced by the Puget Sound Ecosystem Monitoring Program and assesses the condition and quality of the waters of Puget Sound.
The Encyclopedia of Puget Sound, in cooperation with the USGS, has developed a list of terrestrial vertebrates occurring within the Puget Sound basin.
They are sometimes called Autonomous Underwater Vehicles (AUVs), or submersible drones. They glide like airships through the deeper channels of Puget Sound, and have become an important tool for a wide array of open ocean applications, including detection of marine mammals, military reconnaissance and the monitoring of environmental disasters like the Deepwater Horizon oil spill. Puget Sound is the birthplace and key testing area of the Seaglider.
Puget Sound hosts more than 100 species of seabirds, 200 species of fish, 15 marine mammal species, hundreds of plant species, and thousands of invertebrate species. These species do not exist in isolation, but rather interact with each other in a variety of ways: they eat and are eaten by each other; they serve as vectors of disease or toxins; they are parasitic; and they compete with each other for food, habitat, and other resources.
Fishes, birds, and mammals (including humans) serve as top-level carnivores in the Puget Sound ecosystem. With the exception of humans, these organisms have a diet that consists almost entirely of fish or other vertebrates.
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.