Description:Chinese mitten crabs are a light brown color, hairy claws with white tips (normally equal in size), a smooth round carapace or body shape, a notch between the eyes, four lateral carapace spines, and a maximum carapace width of approximately 3 inches (80 mm). The legs of the adult crab are generally more than twice as long as the carapace width.
Distribution:Native to the coastal rivers and estuaries of the Yellow Sea in Korea and China. It has been introduced to Germany, many northern European rivers and estuaries, and the St. Lawrence River in Canada.
In the United States, the Chinese mitten crab has been reported from Lake Erie and Lake Superior and Chesapeake Bay, Maryland. It is established in San Francisco, California, and has recently been found on the Atlantic Coast.
Other invasive invertebrates include bivalve mollusks (mussels, clams, etc), crustaceans (crabs and crayfish), tunicates (sea squirts), cnidarians (jellyfish), gastropods (slugs and snails), and annelids (earthworms). For more information on these animals please see the links below.
Species Spotlight
Greg Jensen, Washington Sea Grant
European green crab Carcinus maenas
Description:The European green crab's color varies from dark mottled green to light green with yellow markings, and an underside of dull orange or red. It is the only crab species on the West Coast that has two different-sized claws: a "strong" claw that acts like a nutcracker and a "fast" claw that serves as a tweezers.
Habitat:It is highly adaptable and can survive a wide range of temperatures and salinities. Lives in shallow water, under rocks, and in disturbed areas which makes it difficult for its natural predators to capture them. Under special circumstances, it can survive up to two months out of water.
Distribution:Native along the coast of the North and Baltic Seas. It has invaded the coasts of South Africa, Australia, Japan, and North America, including California, Maine, New Jersey, Oregon and Washington.
Golden apple snail (Pomacea sp.) Photo: Rita T. dela Cruz.
Scientific Information Database on Golden Apple Snail (Pomacea spp.) [ISBN 971-92558-7-0. Produced by Department of Agriculture-Cordillera Administrative Region, Cordillera Highland Agricultural Resource Management Project, Philippine Rice Research Institute Agricultural Librarians Association of Philippines.]
Species Spotlight
Rusty crayfish Orconectes rusticus
Description:Rusty crayfish have a brown body, and greenish-rusty colored claws with dark black bands near the tip. It has more robust claws and is larger than other native species of crayfish. Prominent rusty patches on either side of the carapace may or may not always be present.
Habitat:Rusty crayfish will inhabit lakes, rivers, ponds, and streams with adequate rock, log, and debris cover. They prefer bottoms of clay, silt and gravel.
Distribution:Rusty crayfish are native to the Ohio River Basin, particularly throughout the states of Ohio, Kentucky, Tennessee, Indiana, and Illinois. But, now rusty crayfish are also found in Connecticut, Iowa, Maine, Michigan, Massachusetts, Missouri, Minnesota, New Hampshire, New Mexico, New York, New Jersey, Pennsylvania, Vermont, Wisconsin, and many areas in Ontario, Canada as a result of bait releases.
