Intersex bass a problem in Potomac

ANNAPOLIS. — During a Black Bass Roundtable — a yearly meeting comprising local anglers, fishing guides, bass federation members and a host of Maryland Department of Natural Resources biologists — the top item easily was a subject on every freshwater angler’s mind these days: the intersex of smallmouth bass in the Potomac River watershed.

A large number of smallmouth bass in the upper Potomac appear to have both male and female characteristics. The fisheries scientists say it’s caused by endocrine disrupting compounds. Something somehow enters the bass bodies that mimic hormones, resulting in male bass suddenly having immature eggs in its testes.

John Mullican, the DNR biologist in charge of western Maryland portions of the Potomac, noted a broad variety of substances might be the culprits. No one knows just why, although federal agencies and state fisheries scientists are hard at work to identify the cause of this strange occurrence.

Mullican said the presence of eggs in a male fish’s body (the intersexing) could be caused by discharges of various chemicals, pesticides, herbicides, perhaps such odd items as birth control pills (synthetic hormones), various other pharmaceuticals or even antimicrobial soaps. “We just don’t know yet,” he said.

The presence of chemical compounds in the Potomac River is not a revelation. They’ve been found up and down the river, as well as in every other river in this state — as well as in Virginia and West Virginia — for years. However, in matters of locating the responsible substance that causes intersexing of smallmouth bass, the biologists are confronting big odds.

Sadly, the Maryland biologists who hope to determine the cause of what they call “decreased gonad function” in smallmouth bass also found in the upper Potomac’s Conococheague Creek and the Monocacy feeder river continue to need funding. Such funding has not yet been provided.

What is the government waiting for? Female fish that grow antlers?

Despite all this disquieting news, Mullican said the overall smallmouth bass reproduction has been good since 2005. It hasn’t been great but was sufficient to supply new year classes of the “brown” fish. Oddly, the largemouth bass in the freshwater portions of the Potomac River do not appear to be as susceptible as their smallmouthed cousins to the current intersex problem.

In other Roundtable discussions that should be of particular interest to area bass anglers, DNR Freshwater Fisheries director Bob Lunsford, along with biologist Mary Groves and DNR tournament watchdog Ray Boras, distributed a data sheet detailing angler participation at Smallwood State Park in Charles County.

The available data didn’t provide everyday, private weekend angler participation, but it showed the number of tidal Potomac River bass tournaments that were conducted out of Smallwood. In 2004, there were 102 of them involving 4,869 fishermen. In 2005 “only” 92 tournaments came out of Smallwood’s Mattawoman Creek, but 5,223 anglers competed. Last year, 100 bass tournaments were headquartered at Smallwood with 5,730 participants.

Now add heaven-only-knows-how-many tournaments that are launched opposite Smallwood in Leesylvania State Park and Pohick Bay — both in Virginia — not to mention Maryland’s Marshall Hall and smaller events out of the Piscataway Creek’s Fort Washington Marina.

If you start believing the Potomac River’s bass are being “hammered” by all those tournament anglers and untold non-tournament fishermen, you’re right.

Lunsford and his department’s biologists, however, say all is well with the Potomac River’s largemouth bass.

I don’t believe that even for a moment, but that’s what the state fisheries people say.

• Look for Gene Mueller’s Outdoors column Sunday, Wednesday and Thursday, only in The Washington Times. E-mail: gmueller@washingtontimes.com.

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