The European green crab, a small but vicious predator, has been making its presence known on the West Coast of North America and wreaking havoc on native ecosystems. Native to the coastlines of Europe and northern Africa, the green crab has spread to coastlines around the world, from Australia to South Africa, and now to the western United States. With alarming impact, these predators have been nicknamed “cockroaches of the sea”. Having reached Alaska, they may pose a new threat to salmon populations.
“I worry about the salmonids,” says Tammy Davis, Invasive Species Program coordinator at the Alaska Dept. of Fish & Game (ADF&G). “I don’t have any evidence that they are competing for food at certain life stages, but the green crabs tear up the eelgrass that provides vital habitat for juvenile salmon and their prey, and in an already stressed ecosystem, having another stressor can affect the whole food web.”
“In Southeast Alaska, we have an estimated 19,000 miles of coastline and much of it is suitable habitat for green crabs.” She adds that many of the islands and passages of the Southeast archipelago have estuaries with eelgrass meadows protected from heavy surf, providing food and protection for green crabs.