Want Another Carp?

Wildlife, Fisheries and Parks sent down a crew that made an unsuccessful attempt to eliminate the naturalized tilapia with rotenone, removing six truckloads of the aliens along with just one bucket of native fish. When the department revoked Robohm’s tilapia permit temporarily (today he’s probably the biggest producer in the state) he claimed he was being abused and took his case to the legislature, which promptly transferred regulatory authority for fish farms to the Dept. of Agriculture. So when Mississippi catfish farmers started playing with black carp there wasn’t a thing Wildlife, Fisheries and Parks could do except give advice to the Dept. of Agriculture, an outfit that doesn’t care much or understand much about aquatic ecosystems.

Pack any species together in tight quarters and parasites are going to flourish. Three years ago a trematode that moves from pelicans to ram’s horn snails to fish started killing a few commercially raised channel cats. Black carp, which can grow to six feet and more than 150 pounds, eat snails and mussels; so they can break the cycle by cleaning out the ram’s horn snails in a fish pond. Chemical alternatives such as copper sulfate and lime are available, but they’re more expensive and perhaps less effective. Native molluscavores such as redear sunfish, blue catfish and freshwater drum might also work, but they’ve not been evaluated.

After black carp wipe out the snails and mussels (except for zebra mussels, which they can’t pick off the structure), they eat crustaceans (such as crawfish) and God knows what else. The threat to native fish, many of which depend on mollusks and crustaceans, is significant; the threat to freshwater mussels—the most endangered group of animals in North America—is enormous. Waterfowl such as canvasback ducks feed heavily on the fingernail clams of the Mississippi system. If black carp get established there, these already stressed ducks will take a hit from which they may not recover.

An injurious listing for the black carp isn’t going to mean a whole lot because the species is already in the country being propagated in research and production facilities in Arkansas, Florida, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, Texas and maybe elsewhere. Although black carp haven’t yet turned up in the wild, they may already have escaped into the Mississippi system from a catfish farm in Missouri. But at least injurious-species status would proscribe future importation from Asia and impede (although not stop) interstate transport.

Farmers of channel catfish contribute about $500 million a year to the US economy, or about half the volume of the entire aquaculture industry. What catfish farmers want, catfish farmers get; and what they want is black carp. The Mississippi Dept. of Wildlife, Fisheries and Parks pled with the state Dept. of Agriculture to at least make the catfish industry use sterile (“triploid”) black carp. That’s not much protection, because in order to make triploids you have to have fertile “diploids,” and virtually every hatchery in existence has had fish escape from it. Also, fish may be mistakenly certified as triploid when they’re actually diploid. But diploids, explained the Dept. of Agriculture, are cheaper and more readily available, and the industry just had to have them. So, as I write, Mississippi catfish farmers are flinging black carp around the state and even importing them from Arkansas.

“If we could remove Arkansas from the Mississippi drainage, we’d be a long way to improving conditions for some of our native fish,” declares MICRA member and past chairman Marion Conover, chief of fisheries for the Iowa Dept. of Natural Resources. It was Arkansas and its fish farmers that gave us the other three Asian carps—grass (now extant in 45 states), silvers and bigheads. The grass carp were going to eat aquatic weeds. The silvers and bigheads were going to clean up pollution by eating phytoplankton and zooplankton, respectively. The industry assured all hands that it wouldn’t let them escape, and if by some act of God or osprey they did escape, it assured all hands that reproduction in North America would be impossible.

Today in parts of the Mississippi River commercial fishermen can’t lift their nets because they’re so full of bighead carp. In October 1999 a Fish and Wildlife Service biologist investigating a fish kill on a Mississippi backwater in southern Illinois counted 157 silver carp, 18 bighead carp, nine grass carp, 30 common carp, and one individual each of five native species. On a recent visit to find what swims in the waters of Mark Twain’s mighty Mississippi a Japanese film crew encountered acres of carp rolling and leaping, occasionally landing in their boats. One cameraman got hit on the head.

“We prohibit black carp in Iowa,” says Conover. “But we can’t keep them from swimming up the Mississippi River. We prohibited bigheads, too, and we have millions of pounds of them. Ted McNulty and the whole industry have it exactly backward. They say that unless you prove black carp are harmful they should be allowed to use them. They stuffed that down our throat in St. Louis at a MICRA meeting we hosted with the catfish farmers. They’re in tight with [Sen.] Trent Lott [R-MS] and other politicians, and they’re just going to walk right over the natural resource agencies.”

Such walking was recently accomplished by another prolific and passionate letter writer, one Pete Kahrs, of Osage Catfisheries, Inc., Osage Beach, Missouri. By persuading the state Dept. of Conservation’s policy-setting commission (comprised of lay people) to “reign in,” as he puts it, the professional fish managers, he got the department to raise black carp for him. This despite the fact that his fish farm was the one from which black carp may have escaped into the Mississippi system (via the Osage and Missouri rivers) after flood waters swept over the ponds in 1994. “Three fish were unaccounted for,” Kahrs told me. “But maybe they died.” Anyway, he says, black carp are now being widely and inadvertently distributed throughout the Midwest with baitfish from Arkansas. The fact that black carp haven’t been seen in the wild doesn’t prove anything because they look so much like grass carp that they may have gone unnoticed. At least the state will be providing him with triploids, and it vows to wean him (and the other fish farmers who will get the fish) within five years so that the state can be “black-carp free.”

Kahrs, McNulty, and Freeze have attacked Rasmussen for using “inflammatory” language and publishing “misinformation” in River Crossings. Wrote Kahrs in one of his letters, this to Anita Gorman of the Missouri Dept. of Conservation Commission: “MICRA posts lobbying positions on government web pages using state and federal electronic mail, to accuse people, i.e., private taxpayers trying to make a living in the aquaculture industry, as ‘selfish’ and ‘whose only interest is the financial gain of the few’ as it relates to the use of black carp.”