Dedicated to the Conservation of Southeastern Fishes
A Carp Of A Different Color Is Still A Worry
July 12, 2004
Another species of carp from Asia is loose in the Mississippi River.
Star Tribune (Minnesota)
The netting of a black carp last month north of St. Louis -- the third such catch in the river system in 1½ years -- has raised concern that the voracious feeder now is established in the wild.
Natural resource officials in several states say that the black carp, which can grow to three feet and more than 70 pounds, could devastate endangered snail and mussel populations.
"We're at the forefront of another invasion, it would appear," said Rob Maher, commercial fisheries biologist for the Illinois Department of Natural Resources.
The intruder joins three other Asian carp species already in the river, including the silver carp, which have jumped into boats and injured people.
Black carp are not jumpers, but they do like to eat.
That's why there were 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, 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. Illinois commercial fisherman Randy Watters, using a 6-foot diameter hoop net, scooped up a 30-inch, 11-pound fish that he couldn't identify. It looked like a sucker, but it had scales like a buffalo fish and a pointed head.
"I'd never seen anything like it," said Watters, who has been fishing out of Hamburg, Ill., for the past 25 years.
Watters brought the fish to Maher, who identified it as a black carp.
Worries about carp
Maher said it's worrisome that the fish probably moved upriver and passed through at least two lock 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," said Maher.
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 say that even sterile black carp are a problem, because they can live for more than 15 years and eat huge quantities of snails, mussels and other shellfish.
Ron Benjamin, fisheries supervisor for the Mississippi River 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."
Benjamin said the black carp captured so far are not likely to be solitary fish, and there are probably others in portions of the river system. "There's more of them out there," he said.
Wisconsin and Minnesota officials have considered installing a barrier that emits sounds and bubbles to block other Asian carp on the upper Mississippi. A carp barrier already operates on a canal near Chicago to block carp from entering the Great Lakes.
Fisheries officials from 27 states asked the U.S. Fish and Wildlife Service four years ago to restrict the interstate trade in black carp and prohibit further importation by putting the fish on its "injurious species list."
The service has been studying the issue, but has not acted despite calls to do so by more than two dozen members of Congress.
Bill Reeves, fisheries chief for Tennessee Wildlife Resources Agency, said that although the black carp are showing up in the wild, their distribution so far is spotty. It's not too late to impose regulations that could reduce the risks from black carp, he said.
Arkansas aquaculture coordinator McNulty said it would be a mistake to restrict the black carp because it provides essential protection against parasites for the commercial catfish industry. "You can always find something that may cause a problem, but you've got to weigh that against putting people out of business and costing jobs," he said. "And right now, three or four black carp doesn't raise a red flag with me."
But Maher said aquaculture officials were making the same arguments in the early 1980s about silver and bighead Asian carp, which fish farmers use to control algae and other growth in ponds. Ten years after commercial fishermen began to catch those species in rivers, Maher said, they were reproducing by the millions in the wild, competing with native fish for food and space, and driving dozens of commercial fishermen in Illinois and elsewhere out of business. The silver carp, which tend to jump out of the water when disturbed by boat engines, have also struck and seriously injured boaters, anglers and personal watercraft owners in Illinois and Missouri.