Crab nabbed; circumstances fishy

MIT researchers have confirmed the first sighting of a Dungeness crab in the Atlantic Ocean. The male, whose species is common on North America's West Coast, was caught off Thatcher Island, Massachusetts, on July 19 by Lou Williams, captain of the fishing vessel Orin C.

The origin of the crab is not known. One possibility is that it may have been purchased from a live seafood market and released. The size of the crab (18 cm) and its gender suggest it most likely arrived as an adult exotic species. Also known as invasive species or bioinvaders, exotic species are of concern because they can establish themselves in a new ecosystem, where they can proliferate and push out native species.

The crab was caught while Williams was gillnetting for groundfish at 45 fathoms. Suspecting the crab to be a Dungeness, he took it to Brandy Wilbur, aquaculture specialist for MIT Sea Grant, and Eric Sabo, educator at the Gloucester Maritime Heritage Center, for verification.

After distributing photographs of the crab to several scientists, the researchers received confirmation of the species, Cancer magister, from several experts: Julie Barber, Massachusetts Division of Marine Fisheries; Thomas C. Shirley, Texas A&M University at Corpus Christi; David Tapley, Salem State College; and Richard Strathmann and Eugene Kozloff, the University of Washington's Friday Harbor Laboratories.

Judy Pederson, MIT Sea Grant's manager for coastal resources and an expert on marine invasives, says that the finding of a female crab would have raised greater concerns about the possibility of a marine bioinvasion. In the West Coast fishery for Dungeness crab, only males may be caught and sold. Pederson adds that the chance of two species of crabs cross mating is highly unlikely. However, she points out that the male crab could carry hitchhikers, such as native Pacific barnacles, or diseases that could harm native crustaceans, such as Jonah and rock crabs.

While the crab's method of entry is unknown, Pederson notes that the capture underscores the importance of not releasing any seafood into natural waters. In addition, MIT Sea Grant's Wilbur notes that this finding should put seafood distributors and fishermen on watch.

MIT Sea Grant will be producing and distributing "most wanted" posters to help those who might come across a Dungeness crab identify it and alert authorities.

Source: MIT

Related stories:

New study offers solution to global fisheries collapse
A study published in the September 19 issue of Science shows that an innovative yet contentious fisheries management strategy called "catch shares" can reverse fisheries collapse. Where traditional "open access" fisheries have converted to catch shares, both fishermen and the oceans have benefited.
Study sets high economic value on threatened Mexican mangroves
The ecological value of coastal mangrove forests in Mexico has been apparent to marine scientists for years. Now, for the first time, researchers have used a wide-ranging compilation of fisheries landings, the official record of fish catches, to place an economic price tag on that value.
Queen's marine biologist investigates aliens beneath the waves
Queen's University Belfast is appealing for help from the public in looking at ways to detect and stop the spread of marine aliens.
Divers find new species in Aleutians
There are unknown creatures lurking under the windswept islands of the Aleutians, according to a team of scientific divers from the University of Alaska Fairbanks.
Humboldt squid on the move
Over the last five years, large, predatory Humboldt squid moved north from equatorial waters and invaded the sea off Central California, where they may be decimating populations of Pacific hake, an important commercial fish. Ironically, these squid may have benefited from the decline of large tuna and billfish in the Equatorial Pacific, which previously preyed upon and competed with the Humboldt squid for food.
Scientists discover new marine species in eastern Pacific
Smithsonian scientists have discovered a biodiversity bounty in the Eastern Pacific—approximately 50 percent of the organisms found in some groups are new to science. The research team spent 11 days in the Eastern Pacific, a unique, understudied region off the coast of Panama.
Climate changes, Cod collapse have altered North Atlantic ecosystems
Ecosystems along the continental shelf waters of the Northwest Atlantic Ocean, from the Labrador Sea south of Greenland all the way to North Carolina, are experiencing large, rapid changes, reports a Cornell oceanographer in the Feb. 23 issue of Science.
MIT warns of dumping seafood
In its latest outreach campaign, MIT Sea Grant has developed an educational pamphlet to encourage people not to release or dump live and fresh seafood and seafood waste into the wild.

News discussion:

Space & Earth science news