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In addition to comprehensive information about the European green crab in Washington state, please see the following:

• European Green Crab Background Information - StoryMap including monitoring and how to report sightings
• Interactive European Green Crab Hub which supports coordination of ongoing emergency measures, data collection, and science.

Quagga and zebra mussels have spread rapidly across the country since they were first discovered in the late 1980s and, according to U.S. Army Corps of Engineers officials, have spread to every major river basin in the U.S. except the Columbia River Basin in the northwest. The mussels typically are spread by recreational watercraft such as boats, canoes, and Jet Skis that have been in infested waters. Once established in a water body, the mussel species are extremely difficult to eradicate because they have no natural predators in the U.S. and rapidly reproduce.

GAO was asked to examine efforts the Corps has undertaken to prevent the spread of aquatic invasive species into the Columbia River Basin by recreational watercrafts. This report [PDF, 3.24 MB] provides information on the Corps' Watercraft Inspection and Decontamination Program and its role in helping to prevent the introduction or spread of quagga and zebra mussels—the aquatic invasive species of greatest concern to the Corps—as well as program challenges and opportunities for improvement.

In 2021 a team of scientists from the University of Iowa, US, deployed innovative eDNA detection techniques to identify water courses where the New Zealand mud snail may be hiding unseen, which should allow them to identify the scale of the problem and deploy early interventions to keep populations in check before they do visible, irreversible damage.

The Bureau of Reclamation has launched a new prize competition seeking innovative solutions for the 100-percent eradication of invasive quagga and zebra mussels from large reservoirs, lakes and rivers in a cost-effective and environmentally sound manner. Invasive mussel infestations pose significant logistical and economic challenges for local communities, recreationists, and water managers by potentially disrupting water deliveries, increasing facility maintenance cost, and impacting the local ecology.

Colorado Parks and Wildlife (CPW) announces additional zebra mussel veligers found in the Colorado River and Government Highline Canal after increased testing. With these additional detections, both the Highline Government Canal and the Colorado River meet the criteria for being considered “positive” for zebra mussels.
See also: Colorado Parks and Wildlife announces discovery of zebra mussels in the Colorado River and the Government Highline Canal (July 16, 2024), nearly two years after the invasive species was first detected in the state. 

Officials at the U.S. Department of the Interior (DOI) announced in June 2017 that DOI would coordinate with the Western Governors' Association, states, tribes, federal agencies, and other partners in a project to help strengthen existing efforts to address invasive mussels. The actions described in the 2017 report, Safeguarding the West from Invasive Species, Actions to Strengthen Federal, State, and Tribal Coordination to Address Invasive Mussels [PDF, 1.3 MB], vary from policy and program reviews to on-the-ground efforts to prevent, contain, and control invasive mussels. One recommendation in Safeguarding the West was the development of a reference manual to facilitate rapid response activities in the event of mussel introductions in the Columbia River Basin. The U.S. Fish and Wildlife Service recently finalized and released this manual, Dreissenid Mussel Rapid Response in the Columbia River Basin: Recommended Practices to Facilitate Endangered Species Act Section 7 Compliance (Oct 2019) [PDF, 4.3 MB].

Quagga mussels were found in the Snake River in September 2023. Immediately afterwards, Idaho Fish and Game assisted the Department of Agriculture in their evaluation of potential treatments to eliminate the mussels, and Idaho Fish and Game quantified the fish populations found in the six-mile stretch of river where the mussels were found, and where the treatment would occur. Biologists quickly learned that the treatment caused high mortality in certain species, while others survived quite well.

On Dec 4, 2021, the Minister of Environment and Climate Change and Minister responsible for Parks Canada, the Honourable Steven Guilbeault, announced federal investments of $14.7 million over the next five years for conservation projects to prevent and manage aquatic invasive species in Banff, Jasper, Kootenay, Waterton Lakes and Yoho national parks.

The mountain national parks are particularly vulnerable to aquatic invasive species due to the high amount of water recreationists who visit each year. Aquatic invasive species alter aquatic ecosystems, cause irreversible damage, impact vulnerable species at risk, and spread downstream beyond park boundaries through the interconnected river systems. Of particular concern for the mountain national parks are invasive mussels, which deplete available nutrients and in turn affects the entire food web by altering water chemistry and quality, as well as the parasite that causes whirling disease, which leads to skeletal deformities for native species. This investment will help address major threats to aquatic ecosystems by funding programs to prevent and educate against the spread of aquatic invasive species.

The green crab is an invasive marine species spreading throughout the coastal waters of the United States. Efforts between NOAA Fisheries and Metlakatla Indian Community have been leading the way on monitoring to detect this species’ presence in Alaskan waters. The green crab has been found in U.S. waters since the 1800s, but this is the first confirmed presence in Alaska. They are a serious threat for Alaska’s tidal habitats.

If you see an invasive green crab on Annette Islands Reserve, call (907) 886-FISH to make a report. If you encounter a potential green crab elsewhere in Alaska, take photographs from multiple angles and send them to Tammy Davis. Then submit a report to the Alaska Invasive Species Reporter, or call the Invasive Species Hotline: (877) INVASIV.

Invasive zebra and quagga mussels are an immediate threat to Western states. With no controls, they spread rapidly, foul boats and equipment, clog water intake, and increase costs to hydropower operations and municipal water utilities. Even dead mussels can be a nuisance, littering beaches with shells. Management of these invaders is expensive; in the Great Lakes, managing mussels costs about $500 million annually. Until 2007, the mussels were limited to waterways and lakes east of the Mississippi, but now they have spread westward. In 2016, quagga mussels were found in Lake Powell.

Unfortunately, there are no foolproof existing technologies or treatments to eradicate established mussel populations in large, open water systems in an environmentally sound manner. Early warning, however, helps us prepare before the mussels or other invasive species arrive.

European green crabs are one of the most widespread invasive marine species on the planet, originally reaching Washington in 1996. When green crab populations grow too large, they compete with other shellfish, disturb the sediment, and destroy the eelgrass that is an important habitat for Dungeness crab and salmon. The U.S. Geological Survey (USGS) is working to increase the effectiveness of Washington’s green crab early detection and rapid response program. Research conducted at the USGS' Western Fisheries Research Center aims to improve native shellfish habitat and limit the spread of European green crabs in coastal waters.

The green crab, Carcinus maenas, is a widely distributed invasive species that eventually alters its new environment. It's assumed that such species have high genetic diversity, or a variety of characteristics allowing them to adapt and thrive. But the green crab has low genetic diversity, while still spreading rapidly in a new part of the world. A U.S. National Science Foundation-funded study led by Carolyn Tepolot of the Woods Hole Oceanographic Institution is investigating the adaptive mechanisms of the green crab along the west coast of North America, where it has shown extensive dispersal in the last decade despite minimal genetic diversity. The results are published in Molecular Ecology. The project is a collaboration among scientists at WHOI, Portland State University, the Smithsonian Environmental Research Center and the University of California, Davis.

Montana’s economy could see more than $230 million in annual mitigation costs and lost revenue if invasive mussels become established in the state, according to a report released by the Montana Invasive Species Council (MISC). Commissioned by MISC and completed by the University of Montana Flathead Biological Station, the economic impact study provides “a snapshot of projected direct costs to affected stakeholders dependent on water resources,” said Bryce Christiaens, MISC chair. “It does not reflect the total economic impact to the state, which would be considerably higher.” View a one-page fact sheet [PDF, 484 KB] or the full report [PDF, 4.0 MB].

Divers monitoring Lake Tahoe have discovered invasive New Zealand mudsnails in areas off the South Shore, the Tahoe Regional Planning Agency (TRPA) and Tahoe Resource Conservation District (Tahoe RCD) announced today. This is the first time the species has been detected in the Tahoe Basin.

Following rapid response protocols under the federally approved Lake Tahoe Aquatic Invasive Species Management Plan, TRPA convened an incident team comprised of staff from TRPA and Tahoe RCD and partner experts. The team is rapidly deploying scientists, beginning with lake-wide dive surveys to determine the extent of the infestation and sharing all available information with state and federal wildlife managers through the Lake Tahoe Aquatic Invasive Species Coordinating Committee. Get up-to-date information on the response and potential protocols for management of the infestation on the TRPA New Zealand mudsnail page.

Update: Invasive Zebra Mussels Found in Pets Stores in 21 States (Mar 8, 2021; U.S. Geological Survey Press Release). Agencies, industry in coordinated response to help stores and consumers find and destroy troublesome shellfish.

The Pet Advocacy Network (formerly PIJAC - Pet Industry Joint Advisory Council) wishes to inform you of an important invasive species threat that was recently discovered in the U.S. Zebra mussels (Dreissena polymorpha), which are regarded as one of the most troublesome invasive species in North America, have been discovered within a variety of moss ball products designed for aquarium use, including products being sold and used in aquariums in stores in multiple states, including Oregon, Washington and Florida.

Specifically identified in a report from the U.S. Geological Survey Nonindigenous Aquatic Species Database, a release from the Oregon Department of Fish and Wildlife, and a press release from Montana Fish, Wildlife and Parks, PIJAC urges you to take immediate action to inspect your fish tanks and take action as necessary. For more information on how to dispose of recently-purchased moss balls, see Zebra Mussel Disposal from the U.S. Fish and Wildlife Service.

On August 5, the Washington Department of Fish and Wildlife (WDFW) received notification from a local wholesale aquarium company in Renton of possible invasive freshwater mussels on a shipment of Marimo moss balls (Aegagropila linnaei). Moss balls are a commonly used decorative algae in aquariums and water gardens. Lab testing confirmed the mussels were zebra mussels (Dreisena polymorpha), a prohibited aquatic invasive species in Washington that, if established in local waters, would be capable of causing significant infrastructure and environmental damage. Zebra mussels and a close relative, the quagga mussel, are not known to be established in Washington.

Idaho watercraft inspectors have identified zebra mussels on a commercially hauled sailboat destined for Lake Coeur d’Alene in the state’s northern panhandle, marking the first time the invasive species has been found live this year.

The North Carolina Wildlife Resources Commission (NCWRC) announced today that zebra mussels, a harmful invasive aquatic species, have been identified in an Iredell County waterbody. This is the first time this species has been identified in the wild in North Carolina. On Thursday, September 21, 2023, NCWRC, with assistance from scuba divers from the U.S. Fish and Wildlife Service, investigated and confirmed a report of zebra mussels in a quarry on private property. NCWRC believes the mussels are contained to the quarry and is working on options for treatment while continuing its investigation.

To report suspected zebra mussels, please contact the NCWRC's district fisheries biologist offices. Visit NCWRC's aquatic nuisance species webpage for guidance on disinfecting snorkel and SCUBA gear and for more information on zebra mussels.

In early December Washington Department of Fish and Wildlife (WDFW) Police received information that a Seattle market was selling live “green crabs”. The Seattle seller had bought the live green crabs from a seller in Massachusetts with the intention of selling them for crab stock and soup. The crabs were destroyed by WDFW Police officers.

The National European Green Crab (EGC) Management and Control Plan was developed by a multi-agency European Green Crab Working Group for implementation by the Aquatic Nuisance Species Task Force following final approval.

The purpose of the 2023 EGC plan is to provide guidance for efforts to prevent future introductions, to rapidly detect and respond to new invasions of EGC before they become established and create ecological and economic damage, and to manage current populations that pose an undue threat to resources of importance for ecosystems and local cultures. The 2023 EGC plan proposes to update the 2002 plan by providing a more focused set of approaches for future management, based on significant changes in the distribution of EGC, new technologies available for identifying sources and mechanisms of spread, better information regarding the tradeoffs for different management efforts, and new methods for data management and sharing. The 2023 EGC plan also describes current strategies for coordinating the activities of scientists, resource agencies, Tribal and First Nation organizations, and other entities.

Public Comment Period -- Written comments must be submitted on or before February 9, 2024. For more information, see the Federal Register notice Draft Revised National European Green Crab Management and Control Plan (Dec 26, 2023)