Washington state will soon have another tool to support long-term management for one of the highest priority invasive species, European green crab, thanks to additional state funding dedicated to genetic research.

Last fall, Washington Sea Grant (WSG) received $185,000 in state appropriations to work with Washington Department of Fish and Wildlife (WDFW) and Woods Hole Oceanographic Institution (WHOI) to sequence the European green crab genome. That work is currently underway.

The European green crab, an invasive species that has had severe impacts on the East Coast shellfish industry and can harm important eelgrass and estuary habitats, is listed as a priority species for the Washington Invasive Species Council and is a top management priority for WDFW, the state’s jurisdictional lead for aquatic invasive species.

WSG, housed within the University of Washington College of the Environment, has hosted WSG Crab Team, an extensive green crab monitoring program, since 2015.

In early 2022, Gov. Jay Inslee issued an emergency proclamation in response to growing populations of European green crab in Washington waters, including in Grays Harbor and the Willapa Bay. As of 2024, European green crab infestations have been found along much of Washington’s Pacific coast as well as in smaller, localized detections in the Salish Sea.

Existing genetics research indicates that all the European green crab along the Pacific coast of the U.S. and Canada originated from a single introduction event to San Francisco Bay from the northeastern United States. However, a deeper investigation of the European green crab genetic makeup is still needed to understand how the species could continue to spread and to form the basis for potential management strategies.

Mapping the genome of the European green crab will provide crucial information such as how genes play a role in enabling green crabs to adapt to a variety of environments including changing water temperatures along the Pacific coast. Knowing which genes influence key traits in green crabs could give valuable insight on the long-term management of this invasive species.

“The green crab is one of the most successful invasive species globally, and a large part of that success is its adaptability to a wide range of variable marine habitats,” says Emily Grason, marine ecologist and lead of the WSG Crab Team program. “In Washington, we are likely to be managing European green crab for a long time, so we will need every tool we can access to protect local shorelines. Mapping the genome is a very forward-looking effort to find and develop new management tools.”

Genome sequencing is a particularly difficult endeavor for a species like European green crab. “Crustaceans like crab, shrimp and lobsters have very complex genomes, and it is only with recent advances in sequencing technology that this research has become possible for them” says Carolyn Tepolt, associate biologist with the Woods Hole Oceanographic Institution. “A high-quality genome is a critical scientific tool that will enable a much wider range of research into green crab biology and management.” Tepolt is an expert in green crab genomics, and in collaboration with WDFW and WSG, her work seeks to better understand the expansion of green crab populations in Washington waters and on the West Coast more broadly.

“This research not only has positive implications for European green crab management in Washington, but for the rest of the West Coast and anywhere in the world where European green crab may be impacting local ecosystems and industry,” said state Rep. Joel McEntire, R-19th District, sponsor of the funding to support the project.

This project’s findings will be summarized in a publication led by the Woods Hole Oceanographic Institution, and the genome itself will be made publicly available on National Center for Biotechnology Information’s (NCBI) GenBank, the standard for long-term public archiving of genomic data. WSG will work with WDFW and Washington Recreation and Conservation Office’s Invasive Species Council to more broadly communicate the results.

Here’s how the public can continue to help with European green crab efforts:

If you find a suspected European green crab or its shell in Washington, take photos and report it as soon as possible to WDFW using the form at wdfw.wa.gov/greencrab or the WA Invasives mobile app.

At this time, WDFW is not asking the public to kill suspected green crabs. This is intended to protect native crabs from cases of mistaken identity. As a prohibited species, it is illegal to possess a live European green crab in Washington.

Volunteer to monitor for European green crab with the Washington Sea Grant Crab Team program.