Jasmine Maurer is a biologist and the outreach coordinator with the Research Reserve's Harmful Species Program where they monitor phytoplankton communities, as well as early detection for marine invasive species and then provide outreach and education on those topics. Maurer provided a general overview and history of Invasive Green Crabs in Alaska marine waters. “This summer, we're seeing a lot of new reports of invasive green crab in southeast Alaska. They have not yet reached south central Alaska, but they are being found all along the road system now in Ketchikan and in Kasan and the places where they have been trapping…they are finding much higher numbers than they have so far to date. So, they were first done 2022 and just then they had caught about 4000 at the end of the season last year, and so far in 2025 it cost almost 9000 green crabs on Annette island. So, we know that green crab survival, larval transport survival is much increased with warmer water temperatures, and with El Nino event of last year, we're definitely seeing that correlation continue. So Green Crab are spreading in southeast Alaska. They have become more abundant with the recent environmental conditions, July 19 is the anniversary of finding the first live Green Crab in Alaska,” Maurer said.
A NOAA Fisheries press release from 2022 provided a few more details on the species and the impacts of what their presence might mean for local marine environments. “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 2022 was the first confirmed presence in Alaska. They are a threat to native species and habitats. They are highly competitive predators that can decimate shellfish populations, outcompete native crabs, and reduce eelgrass and salt marsh habitats. They are a serious threat for Alaska’s tidal habitats,” according to the release.
Invasive green crabs have distinct physical features that distinguish them from other crabs. Their shell is a green-brown color with three rounded bumps between the eyes and five marginal teeth on each side of the eye.
For more information on the species join the research reserve on Saturday July 19th at Bishop’s Beach from 10 to 11 a.m.
