Green crab's invasion worries, angers locals
BY LEEANN NEAL Headlight-Herald staff (Tillamook)
The European green crab isn't content to move in, it wants to raid the refrigerator as well
Last year, scientists' projections that the tenacious shellfish would become a fixture on the Oregon Coast within a year had those in the Tillamook County oyster industry worried
They said if the green crab were to invade en masse, its omnivorous tendencies would likely mean a reduction in clams and oysters as well as the displacement of competitor shellfish species, such as the Dungeness crab and the hairy Oregon crab
Recent sightings of the green crab along the Southern Oregon Coast have prompted the Oregon Department of Fish and Wildlife (ODFW) to order inspections of any live oyster shipments imported at Tillamook Bay, as well as Yaquina and Winchester bays
Having proliferated throughout much of the rest of the world, the green crab has maintained a northward sideways march along the West Coast of the United States for nearly a decade, and was spotted in Coos Bay last spring. One year later, more representatives of the invader species which can pierce the shells of most other shellfish with what scientists regard as frightening ease were seen at Charleston
"The jury's still out on whether if and when it colonizes, it will be a serious threat," said Neil Richmond, ODFW shellfish biologist, stationed at Charleston. "Frankly, we've only found nine green crabs so far, so we're far from being fully invaded."
However, the green craba stalwart and indiscriminately predatory crustacean "could change links in the food web," said Richmond. "Its (appearance) has caused quite a stir in the academic community."
Although researchers are not certain how much the green crab might affect the ecosystem or the seafood industry, no one doubts it will move up the coast and that there will be an impact. The consensus "is not if, but when and to what degree," said Richmond
Unlike Oregon's native cancer crabs (Dungeness and red rock) the green crab prefers shallow waters of estuaries and bays to wave-swept coastlines. "They don't live on the ocean to any great degree." said Richmond. For this reason, the green crab poses no' threat to razor clam populations, he added
However, this "fairly aggressive predator" could be the bane of the oyster industry. "The oyster growers are extremely worried," said Sylvia Yamada, zoology instructor at Oregon State University. They are especially concerned "when it comes to transporting oysters from bay to bay, " she said
Bays and estuaries, which contain a mix of saltwater and freshwater are ideal habitats for the green crab, which is able to tolerate a relatively low level of salinity, said Yamada
If green crab populations expand in Oregon, they are likely to inhabit the Coquille Estuary, Yaquina Bay, Tillamook Bay, the lower Nehalem River, and possibly the Necanicum River, said Richmond
Although scientists are not certain how the green crab has been transported from one bay to another, they have their suspicions. "They could have been introduced through ballast water," said Richmond. Green crabs may also have hitched a ride in the seaweed in which Atlantic lobsters are packed, he added
Now that the green crab is here, however, oyster growers are wondering what is to keep the invader species from traveling to points north. The green crab could be transported in the shellstock that contains oyster cultures, or baby oysters, said Richmond
"We're worried about oysters being shipped from Coos Bay to Tillamook Bay," said Rob Mercer owner of the Cape Meares Gourmet Oyster Co., in Wheeler
ODFW has arranged for a contractor to conduct preliminary inspections of Coos Bay shipments, in the hope of preventing the spread, said Richmond. An ODFW official in Newport is maintaining contact with receivers of the shipments to ensure that oyster shuckers are complying with temporary green crab control efforts, he added
These efforts include keeping shipments 100 feet away from the shoreline and using screens when shucking oysters to avoid inadvertently washing green crabs into bays. "This is part of the interim green crab management plan," said Richmond
Cape Meares Gourmet Oyster Co. oyster beds are located in Tillamook Bay, said Mercer. "We're nervous about it." Although he said there is little he can do personally to prevent further spread of the green crab, he is attempting to stay as informed as possible. "Some of my buddies have been in touch with the Oregon Department of Fish and Wildlife," he said
Although Yamada refers to the green crab as an "efficient crab" in terms of its feeding habits she said its eventual arrival on the North Oregon Coast "poses serious concern, not chaos ... It may not be as bad as the worst-case scenario. (Oyster growers) may just have to live with it."
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