Blue crabs are showing up in Maine waters. What could that mean for green crabs?

PORTLAND PRESS HERALD • July 17, 2026

Green crabs have been an invasive scourge in the Gulf of Maine since arriving from Europe a century ago, hitching rides in the ballasts of ships. They rip up eelgrass habitats and devour soft-shell clams, harming vital fisheries and ecosystems. But in the past few years, fishermen have started to notice another unwelcome crustacean in Maine waters — the invasive blue crab. Native to the mid-Atlantic and moving north as the Gulf of Maine rapidly warms, scientists wonder if the blue crabs could help bring their invasive counterparts to heel, but also worry about the damage the blues might cause.