Big effort to track largemouth bass Scientists tag fish to balance nature


April 19, 1992

HAVRE DE GRACE -- Almost 20 years ago, a state fisheries biologist requested federal money to study and improve

largemouth bass fishing. It took three years to get a management program in the Chesapeake estuary under way.

Since 1977, Leon Fewlass and a handful of biologists and technicians have been part of a booming recreational fishery built almost from scratch.

"You should have seen some of the equipment we had in the beginning," Fewlass said Wednesday, as he and members of his staff were radio-tagging five largemouth bass that would be released and tracked at the head of the Chesapeake Bay.

"It wasn't any of this kind of fancy stuff that we have now. It was just a generator and a 14-foot boat with a nine-horse outboard -- and it took a lot of careful handling to get out around here."

These days, funded through federal taxes on outdoors gear and a portion of state fishing-license revenues, Fewlass and his crew have access to airboats, sophisticated electroshocking craft in several sizes, and computers in which to analyze the data they collect.

The radio-tagging effort on the upper bay offers a glimpse of how technology is helping the management program learn more about the habits of tidewater bass.

Early Wednesday, Fewlass and biologist Alan Heft electrofished the Northeast River, some 10 miles across the Susquehanna Flats from the municipal marina here, and brought back four bass. They then caught a fifth bass a few hundred yards from the marina.

While Fewlass and Heft were completing their catch, biologist Carol Richardson was preparing to implant surgically miniature radio transmitters in each of the fish, which later would be released near the marina ramp.

"What we are trying to see is just where they are going to go," said Richardson, who is directing the radio-tagging program. "We want to know if they will go back to where they were caught, and if they can go back where they were caught."

Knowing where the fish will go is important in several ways, Fewlass said -- from providing good recreation to maintaining a natural balance of species to cutting management costs.

Similar studies have been done in the Potomac River, where tournament fishing has been going strong since the late 1980s, after 20 years of cleanup of the river.

But in the upper bay and its tributaries, where the runs between good bass rivers can be long and tortuous at more than 50 mph, tournaments have not hit so grand a scale, even though the BASS Masters Classic was held there last summer.

"I think that the fish that are here are just in the initial stages of coming back from the work that we have done on the watersheds and stocking and the new harvest regulations in the spawning season," Fewlass said. "But when this thing really gets going, there are going to be a lot more tournaments here and that is what we want to be ready for."

The radio-tagging survey is expected to determine whether fish caught in waters distant from tournament weigh-in sites will return to their home waters after they are released.

The Potomac studies showed that 50 percent of the bass returned to their home waters within 30 days and traveled distances of up to 20 miles.

"But is it going to happen in other tidal waters, and can we count on it so that we don't have to go in and spread the fish back out?" Fewlass said. "We have a large boat that can handle the job, but we don't have a lot of people to do the work. So it could be a very big expense."

A survey last fall showed that only one tagged fish crossed north of the mouth of the Susquehanna, and it settled in waters a quarter-mile from where it was initially caught in the Northeast River. The rest of the fish moved north or south along the western shoreline.

A group of six tagged fish that was released on April 1 has headed north or south rather than cross the flats or the Susquehanna proper, Richardson said.

If the upper bay, in areas such as Dundee Creek and Havre de Grace, does build a tournament circuit comparable to the Potomac's, then there could be another problem as well.

"If the fish are all released in one area," Fewlass said, "then there is the possibility that they could use up the forage in that area and compete with each other and things like that. They might lose weight and become thin and eat up the forage fish in that area that other [species] need."

The result would be a natural imbalance that could be detrimental to nursery areas for young rockfish, bluefish, white and yellow perch, and catfish.

"There is not a whole lot that is known about tidal bass," Fewlass said. "We are one of the first groups that have worked on them, and they are working on them in the Hudson River in New York."

Among the questions: What do bass do when the tide goes out? Conventional thinking says that at low tide bass leave the shallows of the flats and coves and concentrate in deeper holes.

Baltimore Sun Articles
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.