Electronic Bugs Reeling In Fish Thieves : Environment: Maryland biologists’ bass-tracking project provides key evidence in huge poaching case. Four men are facing federal charges.

All biologists meant to do by injecting electronic bugs into the bellies of thousands of Potomac River bass a few years ago was track fish.

Instead, they reeled in a surprise catch--what law enforcement authorities are calling Maryland’s largest fish-poaching case.

By emitting radio signals that identified the fish as Potomac River natives, the bugs became key evidence in a 22-month investigation that began with an alert Canadian customs inspector and wound through Ohio and Michigan to Charles County, Md.

A federal indictment alleges that for three years, four commercial watermen netted tens of thousands of largemouth bass, a protected species that underpins a booming sport-fishing industry at Washington’s doorstep.

The fish were sold live under false documents, primarily to Asian restaurant owners for use in tanks from which customers choose their dinners, authorities allege.

Two of the alleged poachers deny the charges, and the other two declined to comment.

The case has drawn vivid reactions from the bass-fishing industry, which has blossomed into a multimillion-dollar business in recent years as cleanup measures have turned the formerly dirty, moribund Potomac River into one of the best bass fisheries in the country.

“They’re stealing the results of our hard work. It’s theft,” said Ken Penrod, a full-time fishing guide for 14 years. He noted with satisfaction: “It was the little snoopy bug that got them.”

That snoopy bug is formally known as a PIT tag, for Passive Integrated Transponder. Each is about a third of an inch long and about the same diameter as the tubes that hold ink inside a disposable pen. Once placed in a fish, the bugs cannot be seen.

Each tag emits a signal when activated by a pistol-gripped scanning device attached to a small, battery-powered box. Workers can scan a fish quickly and, if a PIT tag is within, know when and where it was tagged and released or when it was last scanned.

In 1990 biologists wanted to investigate what happened to fish that were caught, weighed and released at bass tournaments. This was no petty concern, with more than 100 major tournaments held each year in the Potomac. Events can draw hundreds of participants who stay as long as a week.

State workers using large syringes injected tags into the gut cavities of 3,361 largemouth bass. Subsequent scans, routinely conducted at tournaments, helped allay fears that the contests concentrated fish around release areas or cleared bass out of heavily fished pockets of the river.

Yet another scan was conducted under circumstances that biologists found surprising: under a search warrant, in the company of state Natural Resources Police at commercial fish ponds being used by Dennis P. Woodruff--one of the four men named in the 10-count federal indictment.

Authorities say they found bass from the river in Woodruff’s ponds.

“We could take the wand and determine when and where they were released,” said Mel Beaven, a state regional fisheries biologist, “and they certainly weren’t released in his ponds.”

Woodruff, 47, of Bryans Road, Md., is accused of buying fish hauled from the river by the three other men, then shipping the bass onward under cover of his aquaculture permit, which allows him to raise and sell fish. He denied the charges through his attorney.

Also accused are Alfred B. Grinder, 42, and Walter I. Maddox, 61, both of Marbury, Md.; and Robert T. Brown Sr., 44, of Avenue, Md. Maddox and Brown declined to comment; Grinder’s attorney said his client denies the charges.

The four are charged under a federal law that prohibits selling protected wildlife across state lines and carries penalties of up to five years in prison. Authorities say that between 1990 and 1993, the foursome shipped more than 40,000 pounds of wild bass worth more than $150,000.

Authorities say the men used several types of nets to capture the game fish. In the bass industry a strong conservationist ethic has taken hold, and anglers return fish to the river far more often than they take them home.

The first nibble in the case came in April, 1993, when Maryland authorities received a letter from Michigan wildlife officials questioning a shipment of 3,000 pounds of live largemouth bass from their jurisdiction to Toronto. A copy of Woodruff’s aquaculture permit accompanied the shipment, court documents said.