An invasive green crab carapace sits next to a whole live crab. Photo by Linda Show/NOAA

Invasive European green crab in Southeast Alaska and the impact of climate change on the prevalence and impacts of species invasions are the focus of the 2023 Alaska Invasive Species Workshop. The workshop is planned for Sitka from Nov. 7-9 by the University of Alaska Fairbanks Cooperative Extension Service. 

The keynote address, on how climate change may influence the risk of invasion by non-native species and range shifting by native species, is to be delivered by Cascade Sorte, an associate professor at the University of California at Irvine. Sorte will also share ideas on tools for managing nonnative species. In 2014, Sorte served as a scientist in residency fellow at the Sitka Sound Science Center.  

Cooperative Extension is coordinating the workshop with the Alaska Invasive Species Partnership, an informal statewide group of agencies, organizations and individuals. The annual workshop helps coordinate invasive species management efforts and promotes awareness of new concerns, particularly any that could cause economic or environmental damage, said Gino Graziano an agent with the Cooperative Extensive Service. 

Speakers in addition to Sorte will highlight invasive species science, management and planning, while identifying emerging issues statewide. Topics include European green crab detection in Alaska, invasive plants and wildfire, early detection and rapid response efforts, biocontrol research, citizen science, community-driven stewardship, and more.  

In 2022 Alaska became known as the most northerly location along the U.S. Pacific coast to confirm the presence of the Carcinus maenas, the European green crab. These small but aggressive predators of nearshore shellfish have expanded their range since first defeated in San Francisco Bay in the late 1980s. They are now listed among the 100 worst invasive species in the world by the International Union for the Conservation of Nature. 

Agencies and partners, including the Metlakatla Indian Community and the National Oceanic and Atmospheric Administration, have been engaged in early detection of green crabs.  


The crabs were first discovered during a survey of Tangas Harbor, on the Annette Islands Reserve in Southeast Alaska. 

The tentative agenda and registration form for those planning to attend in person and virtually are available online at The cost is $160 for those planning to be at the workshop, and $100 for virtual participation.