2. 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.
3. 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.
4. 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.
5. • 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.
6. 1. Learn to identify the Chinese mitten crab.
2. If you find one DO NOT THROW back into the
water.
3. You either freeze it or preserve it with alcohol, if you
can’t do that then destroy it.
4. Also, if you find one report it to the proper
authorities.
7. Identifying the mitten
crab
1. This crab of
course has
hairy tipped
claws.
2. It is a greenish
brown colour.
3. The crab has a
notch.
4. This crab has
no swimming
legs, but 8
sharp tipped
walking legs.
5. It has 4 spines
on either side.
8. • 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.
9. 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.