The Alaska Department of Fish and Game (ADF&G) is notifying the public of the verified expansion of invasive European green crab (Carcinus maenas) distribution in Alaska waters. Carapaces of these invasive crabs were collected on the shores of Bostwick Inlet, Gravina Island in southern Southeast, Alaska.
On June 13, 2024, while engaging in shoreline carapace surveys under an ADF&G aquatic resources permit, the Metlakatla Indian Community (MIC) Department of Fish and Wildlife and Alaska Sea Grant collected 11 invasive European green crab (EGC) molted carapaces.
EGC were discovered in Tamgas Harbor, Annette Islands Reserve in July 2022. Subsequently, MIC has engaged in intensive trapping to reduce the population, removing more than 3,000 EGC, including gravid females.
EGC are considered one of the top 100 worst invasive species globally by the International Union for Conservation and Nature. As highly competitive, voracious predators, these crabs have destroyed commercial shellfish populations on the Atlantic Coast of North America, displaced native crabs, and reduced eelgrass and saltmarsh habitat in areas where they have become prevalent outside their native range. Unless controlled, they can significantly reduce biodiversity and abundance of inter- and subtidal species and cause damage to nearshore ecosystems.
ADF&G will continue to work with the organizations permitted to conduct monitoring and will also be conducting monitoring surveys while developing a plan to limit the impacts of EGC in Alaska waters.
Unfortunately, Pacific Northwest states (as well as Atlantic Coast states) have been trying to find ways to eradicate EGC for decades with no success. The best practice at this point has been to attempt to reduce EGC impacts by intensive trapping called “functional eradication”.
ADF&G, US Fish and Wildlife Service, National Oceanic Atmospheric Administration, MIC, Kachemak Bay National Estuarine Research Reserve and Pacific States Marine Fisheries Commission prepared and implemented an Early Detection and Response Plan for EGC in 2023 to provide guidelines to identify distribution and population characteristics of EGC.
You can help by reporting observations of crabs suspected to be invasive EGC. Visit the ADF&G website for information about how to identify these invasive crabs. If you find a crab or crab shell you suspect to be a EGC, collect it and take it to your nearest ADF&G office or take photos of the crab or carapace next to a key, coin or credit card for a size reference.
Banned invasive species, including EGC, may be collected, possessed or transported only for the purpose of reporting. Shoreline carapace surveys, may be conducted under the ADF&G blanket EGC carapace permit.
To report your observations, call the Invasive Species Hotline: 1-877-INVASIV or use our reporter. To submit photos and for more information about invasive species, contact: Tammy Davis, ADF&G Invasive Species Program coordinator: [email protected] or (907)465-6183.
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