Tammy Davis is the invasive species program coordinator at the Alaska Department of Fish & Game. In the Alaska Invasive Species Partnership workshop in Sitka on Thursday, she taught an audience of about a dozen how to recognize the presence of invasive green crabs that, as it turns out they aren’t always green.
“They may be brown, and they could be reddish or orange and yellowish.” Davis continues. “They’re four inches wide -an adult measures 4 inches wide across the rear of the carapace.”
European green crabs were first arrived on their first lands on the Pacific coastal waters in 1989 however it was not until 2022 when they appeared in Alaska. Davis recalls the moment she discovered the green crabs were discovered in Metlakatla in the summer of last year.
“And I’m sure we were all near tears, as we ought to have known they were on the way,” Davis said. “But we didn’t anticipate that they’d show up this quickly I suppose.”
Genelle Winter works as Climate & Energy Grant Coordinator for the Metlakatla Indian Community. Although Metlakatla may be the sole location in Alaska in which green crabs can be positively discovered, Winter said it’s likely that they’ve already expanded.
“The amounts we’re seeing them inWe’re pretty sure there are more places to find them however we haven’t yet found these yet.” Winter said. “And in the moment, as of at the moment, we’re a little less than 3000 crabs that have been spotted since the discovery in 2022.”
She added that an aggressive trapping strategy in Metlakatla together with the early detection of these pests, makes it easier to limit the spread of these parasites.
“The first thing discovered was the shell.” Winter said. “And this triggered the reaction to begin intensifying our trapping, and later changing the way and locations to ensure that we actually put traps where the crab were. Now, those guys, they’ve got been able to dial in something powerful.”
They are known to destroy eelgrass habitats, which are vital habitats for young salmon as well as other animals. They also eat a lot of clams as well as other smaller crabs. They reproduce rapidly, and can live in a range of conditions.
Davis added that communities such as Sitka ought to be watching for signs of trouble.
“It is so scary and negative to think that it’s likely, but on the basis of the ocean’s currents it’s most likely,” Davis said. “We don’t have any reliable information on the oceanographic conditions of the currents that run through the Alexander Archipelago, so some of our Southeast communities could be better protected in the event that the currents are more prevalent to the ocean. However, this puts Sitka more at risk.”
Davis stated that Alaskans could help by learning to recognize green crabs and look out for them when walking along the beach. Although collecting certain invading species requires the approval of a permit, Alaska beachcombers can collect potential green crabs to use for reasons of reporting. However, they must keep the crab in containers and report the catch immediately. Report any invasive species on the Alaska Department of Fish & Game website or by contacting the hotline for invasive species at 1-877-INVASIV.
