While doing a search on Chinese Mitten Crab status for this year, I found:
http://www.nj.com/news/index.ssf/2009/08/chinese_mitten_crab_set_to_pum.htmlChinese Mitten Crab set to Pummel N.J. EcologyPosted by tdinges August 08, 2009 23:58PM
The patches of dense hair, located near the white-tipped pincers, earned the Chinese mitten crab its deceptively benign name.
But there is nothing soft or comforting about these invasive Asian critters, and lately that have taken a sudden shine to New Jersey waters.
While long treasured as a culinary delight in their native East Asia, the crabs have become a scourge to most everyone else. In Europe, they have eroded estuaries by burrowing into earthen dams and river banks. In California, the only state where they have gained a major foothold so far, mitten tribes have exploded into a major ecological nightmare, venturing inland to clog water systems in Central Valley, and disrupting fishing operations in San Francisco Bay, where they steal bait and get entangled in fishing gear. Predatory as well as vegetarian, they crowd out other species by eating their food supply and sometimes by eating them.
As near as anyone can figure, they have been on the march in North America since 1965, when a lone crab was discovered in Ontario. But they are being seen in plenty of places now.
On the Atlantic Coast, the 2006 discovery of just one male crab near Maryland's coastal waters sent fishermen into alarm. Scientists are monitoring the situation. Only about 50 of the crabs have surfaced from Maryland to the Hudson River in New York in the past three years, but for reasons yet unexplained, sightings have increased this year -- and most of them have been in New Jersey.
"So far, 40 crabs have been caught, reported and confirmed in New Jersey alone, making that state ground zero right now for mitten crabs," said Gregory Ruiz, a senior scientist at the Marine Invasions Research Lab of the Smithsonian Environmental Research Center in Maryland.
"It's difficult to say whether there are more in New Jersey or that it's just a situation where a lot of people are at the right place at the right time in that state to find them," he explained. "We are just now at the stage of trying to understand whether they have established anywhere along the Atlantic, and the geographic footprint of their distribution.
"We aren't sure if they have established anywhere or what the potential impact is," Ruiz said.
The crabs appear to have periods of population booms and busts, much like the gypsy moth outbreaks, so researchers like Ruiz and Linda Barry of the New Jersey Marine Fisheries Administration say it just may be a matter of time before the Asian crabs enter a prolific, destructive phase. The concerns are multiple.
The crabs are capable of out-competing important native species, such as blue crabs, for food. Because the Asian invaders feed on both plants and animals, they may prey on native wildlife, as they have in Britain, where dwindling crayfish populations are under siege. Additionally, as evidenced throughout Europe, the crabs destroy freshwater river beds and estuaries by burrowing into the banks, causing erosion and destroying habitat on which many aquatic and land-based creatures depend for survival.
The state Division of Fish and Wildlife, which has been monitoring the crab since the first New Jersey invader was found in Toms River in 2008, issued several alerts last week asking fishermen and anyone else using coastal waters to look for them.
"This is really the first year we've seen so many cropping up here," said Barry.
The bulk of New Jersey sightings have been in the Raritan Bay. Others have been found in Barnegat Bay, the Shrewsbury River, Little Egg Inlet, the New Jersey side of Delaware Bay and the Hudson River outside Jersey City. Confirming a sighting, said Barry, requires capturing and freezing the specimen or photographing it, and scientists want anyone who finds an invader to take it out of the water.
"The most distinguishing aspect of the mitten crab is the claws. They are the only crab to have that amount of hair or fur covering their claw," Barry explained. "If they see a crab that looks like a mitten crab, take a picture, take notes and give us as much information as possible. If they can keep it, then freeze it. Just please don't release it back into the wild."
Their hairy claws are not the only feature that sets the mitten crabs apart.
They are biologically unique because they reproduce in brackish or saltwater in winter, leaving their young to migrate upstream into freshwater streams in spring. The Atlantic Coast waters are home to several species of native crabs, but none venture from the sea into freshwater, where juvenile mitten crabs will live for up to five years before returning to the sea for reproduction.
Female mitten crabs can produce 250,000 to 1 million eggs in one reproductive cycle, and the crabs easily adjust to varying water temperatures, salinities and pollution concentrations, which is why international conservation groups have listed them among the top worst invasive species in the world.
Scientists suspect their global distribution occurred through the ballasts of ocean-going vessels, and their threat prompted the United States Fish and Wildlife Service to criminalize all importation and commerce of mitten crabs in 1989. But they are still sold on black markets, according to a Congressional Research Service report released last year.
Categories: Animals, Environment, Jersey Shore, Science
