Pa. plan to allow carp would harm bay, Md. fears Officials lobby against effort to legalize fish

March 08, 1993|By Mark Guidera | Mark Guidera,Staff Writer

Maryland Department of Natural Resources officials are convinced that a voracious, plant-eating fish that hails from the Orient and grows up to 35 pounds could wreak havoc on the Chesapeake Bay's shaky but rebounding ecosystem.

The department has launched a campaign to deter Pennsylvania from legalizing use of the fish, known as the grass carp, to control vegetation in ponds and other impounded water bodies.

"There is no question in our minds grass carp would destroy critical habitats in the Chesapeake Bay, even if just a few able to reproduce were to escape from Pennsylvania into the bay," said Robert Lunsford, director of Maryland's Freshwater Fisheries Division

"The fish has no known predators in the Chesapeake and eats an enormous amount of food -- its own body weight every day. We really feel this a gamble that just isn't worth taking."

Experts on each side of the debate agree that if the fish -- also known as the White Amur -- is permitted for use in Pennsylvania, an accidental escape of fecund grass carp into the bay is a strong probability.

The most likely scenario for an accidental release is flooding of ponds near flowing water that feeds into the bay or a tributary, such as the Susquehanna River, experts say.

Maryland officials are concerned that if bay habitats were damaged by escaped grass carp it would result in a decline of some game fish. That would be a blow to the state's important sport-fishing industry, Mr. Lunsford said.

He and other state fishery experts have been lobbying Pennsylvania's 10-member Boat and Fish Commission to reject a proposal to allow use of the fish there.

The commission is scheduled to decide the issue in April, said David Wolf, a commission spokesman.

The commission rejected a similar proposal in November on a tie vote, then re-introduced the proposal at the same meeting, Mr. Wolf said. At the time, several commissioners wanted additional information on the fish, a native of the Amur River along the China-Russia border.

Last month, Dr. Torrey C. Brown, secretary of Maryland's DNR, weighed in with a stern, three-page letter to the commission objecting to the grass carp proposal.

In the Feb. 11 letter, Dr. Brown says a review of a study on the grass carp found "compelling evidence that grass carp present a clear and present danger to the Chesapeake Bay ecosystem."

He listed 13 reasons legalization of the fish in Pennsylvania should be blocked.

The concerns included the worry that grass carp would ruin vital aquatic vegetation needed for spawning and feeding by

established fish populations. Dr. Brown also raised questions about the testing method used to determine whether grass carp purchased for use are sterile.

Dr. Brown is particularly concerned that a community of fecund grass carp would destroy the bay's underwater grasses and other plants, already under heavy assault from pollution. The plants provide food and shelter for most fish, as well as ambush hideaways for predatory fish.

"A self-sustaining population of grass carp would undoubtedly eradicate most, if not all of, the submersed aquatic vegetation in the Lower Susquehanna River, Susquehanna Flats, the tidal-freshwater portions of the Potomac River, and other tidal freshwater tributaries of the bay," Mr. Brown says in his letter.

Maryland bans use or placement in state waters of any fish species not naturally occurring in the state. Howard County has looked into the possibility of seeking a state exemption so as many as 12 grass carp could be used in Centennial Lake to help control a spunky aquatic weed known as hydrilla. The plant has overtaken the lake.

The golf course and farming industries in Pennsylvania have been seeking legalization of the grass carp.

The proposal would require a permit for their use. The fish would be banned from wetlands and in waters where endangered or threatened fish live.

J. Wayne Yorks, president of Pennsylvania's Fish and Boat Commission, favors the proposal because it would offer a nonpolluting alternative to chemicals for the control of vegetation.

"It's a fact that all of these golf courses and farmers are using chemicals. They drain into the ponds and you know where they eventually end up -- our streams and the Chesapeake Bay," he said.

"We know some of the people are already bringing the grass carp in illegally and using them. I feel it would be better if we had some controls on it rather then just turning a blind eye and allowing people to do what they naturally want to do."

Pennsylvania's proposal only would permit use of sterile grass carp.

Mr. Lunsford and Dr. Brown argue that the blood test used to determine whether grass carp can reproduce is flawed, and therefore vendors cannot guarantee that all carp sold would be sterile.

While Pennsylvania fish experts agree that the testing method isn't fail-safe, they believe Maryland officials are overstating the perceived danger to Chesapeake Bay.

Del Graff, chief of Pennsylvania's Bureau of Fisheries, is considered that state's expert on grass carp. His staff reviewed several studies on the carp and spoke with biologists in southern states that permit its use, he said.

Mr. Graff concluded from the information that the Chesapeake Bay "would not be significantly threatened" by any grass carp population that might become established in the 200-mile long estuary.

"It's unlikely escaped fish would ever be able to establish the extensive populations needed to destroy the bay's aquatic life. We really see this fish as an acceptable risk," he said.

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