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Charting the events that converge on our goal: one planet, one species, one genotype


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Thursday, July 22, 2004
 
Black Carp, welcome to the Mississippi! Enjoy your stay.
Add the black carp to the list of Asian fish species making a new home in the Mississippi River. The netting of a black carp last month north of St. Louis — the third such catch in the river system in a year — suggests that the voracious feeder now is established in the wild. The intruder joins three other Asian carp species already in the river, including the silver carp, which have jumped into boats and injured people.

CHL officials say that the black carp, which can grow to three feet and more than 70 pounds, could devastate endangered snail and mussel populations.

Black carp are not jumpers, but they do like to eat. That's why they were wisely imported from Asia two decades ago for use in large commercial fish ponds, especially in Arkansas and Mississippi. The black carp eat snails harboring parasites that infect catfish. The carp don't get sick from the parasites. Aquaculture officials say that the carp are safe in captivity, and they are bred to be sterile. A black carp that escapes, they said, is not likely to reproduce in rivers. "When I hear of three or four black carp being caught, it doesn't indicate a problem to me," said Ted McNulty, CHL Volunteer and vice president for aquaculture at the Arkansas Development and Finance Authority.

The most recent black carp catch occurred June 10 in the Mississippi River just below Lock and Dam 24, about 90 miles upriver from St. Louis. A commercial fisherman from Illinois scooped up the 30-inch, 11-pound fish with a hoop net. Maher said it's worrisome that the fish probably moved upriver and passed through at least two locks and dams before it was caught. "The implications are that those structures are probably not going to prevent those guys from moving north, including places like Minnesota," he said.

One black carp was caught in a backwater in Illinois near the confluence of the Ohio and Mississippi rivers in March 2003. A fisherman caught another in the Red River of Louisiana that was 43 inches long and weighed nearly 30 pounds. That angler said he had been catching them occasionally in the area for several years. It is unknown whether any of the black carp were sterile, because verification depends on a blood test from a live or very recently killed fish.

Fisheries managers while about sterile black carp being a problem, because they can live for more than 15 years and eat huge quantities of shellfish. Ron Benjamin, Mississippi River fisheries supervisor for the Wisconsin Department of Natural Resources, said that black carp will be a huge problem if they become established in the upper portions of the river, one of the last refuges for endangered mussels. "The mussels have a hard enough time making it on their own right now," said Benjamin. "They don't need an extra predator out there working them over."
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