Invasive crab species reaches Ketchikan. Here’s how UA community can help

June 20, 2025

UAS has shared an important press release. The invasive European green crab (Carcinus maenas) has been confirmed on the Ketchikan road system for the first time.

Two crab shells were found June 6 at Refuge Cove State Park by UAS-Ketchikan faculty during a shoreline carapace survey. The survey was part of a community education class led by professors Charmaine Lewis and Barbara Morgan. The effort was funded by the Alaska Climate Adaptation Science Center and conducted with a permit from the Alaska Department of Fish and Game (ADF&G).

The European green crab is considered one of the most damaging marine invaders in the world. It preys on juvenile salmon and shellfish, destroys eelgrass beds, and competes with native crab species. This poses a serious risk to Alaska’s coastal ecosystems and fishing industries.

This concern is not new to the Alaska. In 2023, the UA System Office highlighted efforts by UAA students and the Kachemak Bay National Estuarine Research Reserve (KBNERR) to raise awareness.

Their outreach project was featured in a Did You Know article:
UAA students help educate Alaskans on green crab threat

How UA community can help:

  • Familiarize yourself with green crab identification resources from ADF&G or KBNERR.
  • Share information with your networks, especially in coastal communities.
  • Report sightings by calling the Alaska Invasive Species Hotline at 1-877-INVASIV. Photos should include an item for scale such as a key or coin.

For more information and resources, visit the ADF&G Invasive Species page.

You can check out this Crab Identification Guide from KBNERR.

Visit the European Green Crab page on Alaska Department of Fish & Game website.

A diagram of a European Green Crab, hand drawn with text that points out the five spines and three bumps on shellFrom the Green Crab Identification Guide, published by KBNERR. Diagram by Tim Sullivan.