Every year, the Potomac Electric Power Co.'s Chalk Point generating station, the largest power plant in Maryland, produces enough electricity to light more than 19.5 million household lightbulbs. But behind the scenes in a clever melding of nature and industry, the 1,160-acre plant is pouring some of its resources into another line of manufacturing: wildlife.

Last year, 300,000 rockfish were raised at the plant and transplanted into the Patuxent River.

The large plant on the banks of the Patuxent at the southern end of Prince George's County hardly seems a suitable site for a major hatchery program for rockfish, also known as striped bass. Two large cooling towers spout plumes of steam that obscure the horizon. Power lines crisscross and stretch over the landscape for miles.

But the hatchery is just one of the plant's wildlife areas, which includes a 15-acre wetland that is home to egrets, herons, beavers and American bald eagles. It also is a popular resting area for migratory birds. Inland from the marsh, the compound turns to forest, where songbirds, deer, fox and raccoons live.

Chalk Point has the first program operated by a business to be certified by the National Institute for Urban Wildlife as a sanctuary for animals. About 80 percent of the acreage is dedicated to wildlife.

"The thought that you need to go to Yosemite to experience wildlife is false," said Stephen Guiland, manager for the water and land use department at Pepco.

The $600,000 hatchery at the Chalk Point station is the largest rockfish supplier in Maryland and has brought praise from the state, which has banned striped bass fishing to help replenish the declining numbers of the popular fish.

"They have a serious commitment to restoring the fish," said Pete Jensen, state director of fisheries. "It's not like they said, 'We'll put some fish in a pond and if it doesn't work out we'll give them back.' Their effort was quite a boost and appeared to be more than a {public relations} commitment."

Pepco officials said they decided to build the hatchery after the state imposed the rockfish moratorium. The company's decision followed similar moves by other power plants that, like Chalk Point, use river water to cool their generators and then must hold the warm water until it is cool enough to return to the river. That warm water, however, is suitable for a fish hatchery.

By raising fish, electric companies help deflect critics' concerns that the process of using river water to cool generators can be harmful to river fish and the environment. Among those environmental concerns are that young fish can be sucked in and killed when the power plants draw in the river water, said Paul Miller, administrator of research for the Maryland Power Plant Research Program, which is a study group sponsored by the state Department of Natural Resources.

He said such power plants use chemicals, often chlorine, to get rid of algae and other organisms that grow in the warm water. Some of that is flushed into rivers, but the state has "investigated this and have found {it} to be acceptable."

Bill Goldsborough, a staff scientist at the Chesapeake Bay Foundation, said, "There's no doubt that striped bass is very good {public relations} for any industry to be involved in . . . . They're putting their resources and their waste to use."

Jensen calls the facility at Chalk Point "high tech." Two full-time biologists oversee the project, in addition to eight staff members who work on a full- and part-time basis. The hatchery contains 11 rearing ponds for the young fish.

In April, the hatchery begins operation with thousands of rockfish larvae. Each young fish is less than a quarter of an inch long and is fed microscopic organisms called zooplankton.

After four to six weeks, the larvae are moved to large fiberglass tanks and fed vitamin-packed food pellets.

Before its release into the Patuxent, each fish is trucked to the state fishery in nearby Cedarville to be tagged with a tiny piece of wire that carries a code for tracking.

Pepco biologist Paul Willenborg said the process of caring for the fish is delicate.

"Raising striped bass is a high-risk adventure," he said. "You accept the fact that you're going to lose fish, like if there's a power failure and no oxygen, or disease. My wife calls these my mistresses because I spend so much time with them."

The hatchery costs about $160,000 a year to operate and the company receives no tax breaks for its efforts, said Nancy Moses, manager of media relations for Pepco.