Competition/predators
In its natural habitat parasites keep the green crab in check; so do fish, birds and larger crustaceans. In Europe the crab is fished commercially and is not a problem. Although in other parts of the world it does not have these predators and its ability to reproduce in great numbers only helps it more.
Reproductive STRATEGIES
The European Shore Crab can attribute its success to the fact that it can reproduce quickly and in large quantities. The crab is able to mate after three to four years and have up to 180,000 eggs. The Crab can also live in many areas because of it's ability to survive in temperatures from below zero to more than 30 degrees Celsius.