Sunday, June 13, 2010

Chesapeake Bay Blue Crabs

There's nothing more "Chesapeake" than the Bay's signature crustacean, the blue crab. Callinectes ("beautiful swimmer") sapidus ("savory"), a member of the swimming crab family, is an aggressive, bottom-dwelling predator and one of the most recognizable species in the Bay.

The Chesapeake Bay, located in Virginia and Maryland, is famous for its blue crabs and they are one of the most important economic items harvested from it.

As both predator and prey, blue crabs are a keystone species in the Chesapeake Bay food web. Blue crabs also make up the most productive commercial and recreational fisheries in the Bay.
*Blue crabs are prey for fish-even other blue crabs! Soft-shelled crabs that have recently molted are especiall vulnerable to predators.
*Predatory fish like striped bass as well as drums, eels, catfish, cownose rays and some sharks, rely on juvenile blue crabs as part of their diet.
*Blue crab larvae are part of the planktonic community and are fed on by filters feeders such as oysters, menhaden bay anchovies and juveniles of other fish speicies.
*Bottom-dwelling blue crabs are among the chief consumers of the benthos. They feed on thin-shelled bivalves, other crustaceans, fish, marine worms, plants, detrius and nearly anything else they can find.
*Blue crabs enhance salt marsh communities by feeding on marsh periwinkles.

Catch restrictions were imposed in 2008 prompted by increasingly urgent warnings from scientists that the bay's crab population was dangerously close to collapse. They estimated that the number had declined by more than 70 percent in the previous 15 years. In the wake of the crisis, the U.S. government in 2008 declared the famed Bay crab fishery a national disaster. Restrictions were aimed at reducing the catch of female crabs by a third, and ensuring that fewer than half of all the bay's crabs would be caught each year. The federal government sought to soften the blow by doling out $15 million each to Virginia and Maryland to help cushion the blow. The states used the funds to hire watermen to rehabilitate oyster reefs and retrieve abandoned crabbing gear, and to buy back licenses in an effort to prevent future overfishing.

In April, 2010, based on the annual winter dredge survey of crabs as they slumber on the bottom of the bay, Maryland and Virginia scientists estimated there to be 658 million crabs, the highest since 1997.

This announcement is the second year of good news from the annual winter survey of crab abundance conducted by Maryland and Virginia scientists. However, it is unlikely to ease catch restrictions. Officials want to avoid a boom and bust in the crabbing industry that occurred in the 1990s.

The governors of the two Bay states jointly announced the happy results, saying that strict, controversial regulations enacted in 2008 are paying off-but that more work remains. State officials said the rapid and remarkable turnaround vindicates their politically difficult decisions two years ago to impose stiff rules that significantly cut harvests of female crabs and shut down Virginia's winter crabbing season for the first time in more than 100 years.

By leaving female crabs alone, Virginia allowed more mothers to spawn, which led ato a baby boom last year- almost a doubling of the number of juveniles born into the population.

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