Affects on the ecosystem
The European Green Crab main food is clams. The Crab enjoys soft shelled clams and other crabs, such as quahogs and Dungeness crabs. The European Green Crab can often be the ones to blame when there is a shortage of clams in the area. Fisheries are often the ones who are the most effected because the green crab eats all the harvest. In California Manila clam harvests have dropped by 40% because of the invader.
Ecological Impact
The European Green Crab is devastating for the ecosystem because it eats quahogs and Dungeness crabs. The Green crab is is capable of learning and can improve prey-handling skills while foraging. This makes more it of a threat because it is more versatile and can open shells much easier than other crabs. The European Green Crab also does not have much competition for food so it can become very abundant. Its ability to crush mussels and eat them damages the fisheries in states next to the coast.