Invasive Species The Chinese Mitten Crab By: Lina Le 1H1
Country of Origin The Chinese mitten crab can be found between China and Korea, it is native to the Yellow sea. This crab is one of the ten most unwanted species in the world.
How it got there?
These crabs were probably brought into Canada through ballast water or through the live food fish industry.
It first appeared in Canada in the Detroit river in 1965.
Now this species of crab has spread into the Great Lakes and the St. Lawrence River.
What Ecosystem it is affecting This crab is affecting the fresh water and brackish biological communities and ecosystems. The mitten crab, when burrowing can cause bank erosion and disrupt fisheries. The mitten crab feeds on salmon and sturgeon eggs. If these crabs eat the eggs of other fish species, the fish species will be in trouble.
What is being done to help it?
The group MD DNR are trying to take these encounters seriously.
They are taking samples at Chesapeake Bay watershed.
Also, they are monitoring the mitten crabs if they are present.
They are net working with fisherman and power companies that monitor the mitten crabs that are captured on the cooling water intake screens.
How you can help Learn to identify the Chinese mitten crab. If you find one DO NOT THROW back into the water. You either freeze it or preserve it with alcohol, if you can’t do that then destroy it. Also, if you find one report it to the proper authorities.
Identifying the mitten crab This crab of course has hairy tipped claws. It is a greenish brown colour. The crab has a notch. This crab has no swimming legs, but 8 sharp tipped walking legs. It has 4 spines on either side.
When the mitten crab appeared in Canada
It first appeared in the Great Lakes in 1965.
This crab sometimes shows up in Lake Ontario and Erie.
Then the mitten crab appeared in the St. Lawrence River in 2004.
It was the first time that there was a fresh water crab species that existed in North America before it appeared.
Map of distribution, where Chinese mitten crabs are.
Habitat of the mitten crab The mitten crab’s habitat is in black brackish water or fresh in estuaries, lakes, rivers, and wetlands. They are found down to the depth of ten meters. They can even survive in disturbed and polluted environments. They reproduce in saltwater, that is when the males and females migrate downstream. The young crabs stay in fresh water to 2-5 years.