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Join Date: Sep 2005
Location: Kill Devil Hills N.C.
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Re: Something we don't need in NC
Sorry I will try again
sBay's rockfish infected with disease
No evidence of health risk from eating stripers
March 12, 2006
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Nearly 75 percent of the Bay’s rockfish are infected with a wasting disease that can cause “fish handler’s disease” in anglers.
ANNAPOLIS (AP) — Rockfish, whose fortunes in the Chesapeake Bay took a dramatic turn for the better in the 1990s, are in trouble again.
Nearly 75 percent of the rockfish in the Bay are infected with a wasting disease that can kill the popular game fish and cause a severe skin infection in humans.
The epidemic of mycobacteriosis took researchers by surprise. As the number of rockfish, also known as striped bass, surged as a result of fishing limits, scientists say they remained in a body of water too polluted to support the level of life it once did.
“We used to think that if you got hold of fishing, all your problems would be solved,” said James Uphoff, a biologist at the Maryland Department of Natural Resources. “But now all these ecological problems crop up, and we don’t understand them.”
In the mid-1980s, rockfish numbers were so decimated by overfishing that Atlantic coastal states imposed a moratorium. The population rebounded, and the fishing ban was lifted in 1995. Wildlife officials called the restoration a rare triumph for the Bay, which has seen overfishing and disease threaten blue crabs, oysters and other species.
But less than two years after victory was declared, the first diseased rockfish landed on Bay shores.
Because the bacteria kill slowly, effects on the stock are only now emerging. And scientists remain baffled about the implications of the disease, including its effects on humans.
Researchers know that the Chesapeake, where most rockfish spawn, also breeds the bacterium and is the epicenter of the disease. But they don’t know how or why it appeared, whether it spread to other species or if the infection it causes is always fatal.
A new study suggests that since the illness was discovered among Bay rockfish, non-fishing mortality among them has tripled in the upper Bay. But anglers are not complaining about the volume of their catch, and scientists cannot explain why.
“Scientists attempt to unravel things (and) are supposed to follow the information wherever it leads us,” said Victor Crecco of the Connecticut Department of Environmental Protection, author of the mortality study. “We’re going to have to do more work to explain these contradictions.”
Watermen say the only sick fish they see are in small, overcrowded rivers and streams. The netting season that ended Feb. 28 “was a super-good season as far as catching, and a good season as far as the price,” said Larry Simns, president of the Maryland Watermen’s Association. With no evidence of health risk from eating the fish, watermen say, prices have remained stable.
In humans who touch the fish, the microbe can cause a skin infection known as fish handler’s disease, which is not life-threatening, but can lead to arthritis-like joint problems if untreated.
An infected rockfish can appear outwardly healthy. But inside, the bacteria settle first in its spleen, and the infection spreads to other organs. The rockfish loses weight, and it often develops sores. At some point — researchers do not know exactly when — it dies.
In the Bay, “by age 1, 11 percent are infected. By age 2, it’s 19 percent,” said DNR researcher Mark Matsche. But he cannot go beyond that — by the third year, some fish have left the Bay for open water.
“We can’t even say they die for sure,” Matsche said. “The severely infected fish I catch ... a lot of them die. Some moderately infected ones have some sign of healing going on. But I’m not able to see that same fish a year down the line.”
Wolfgang Vogelbein, a fish pathologist at the Virginia Institute of Marine Science, was the first to diagnose mycobacteriosis in the Bay’s rockfish and determined that three-quarters of them carry it.
Last fall, Vogelbein and other researchers affixed plastic tags to the bodies of 2,000 rockfish in the Rappahannock River, some with visible signs of the disease and some apparently healthy, with notes offering a reward for their return. They have received 120 from anglers. Using mathematical models, they hope to show whether the disease actually kills Bay fish and estimate how long that takes.
“It’s a difficult process trying to figure out the role of disease in a population of wild animals in a huge system like the Bay,” Vogelbein said. “In this case, we still don’t have the tools to efficiently answer the more compelling questions. That’s just the nature of the beast.”
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