Hundreds of cliff swallows live on Conneaut Lake in northwestern Pennsylvania. The birds snatch mosquito dinners off the surface of the lake and return to nests nuzzled under the roof of the Pennsylvania Fish and Boat Commission's Linesville fish hatchery.

Inside the building, large pumps send 2,000 gallons of lake water per minute through dozens of tubs filled with young fish.

Thousands of baby paddlefish from West Virginia are delivered to Linesville every year. Right now, they're the size of fish-food, but in a few months they'll be large enough to fend for themselves and released into the Ohio and Allegheny Rivers, where they could grow as large as seven feet, and weigh well over fifty pounds.

The Fish and Boat Commission has been stocking paddlefish since 1991. Rick Lorson is area fisheries manager in Somerset County, and author of the reintroduction plan. He says paddlefish, which are native to most of the Mississippi River Basin, haven't lived on their own in Pennsylvania for over 80 years.

"The closest place that paddlefish were to the state line at that time, around 1990, was 300 miles downstream," says Lorson. "Now paddlefish do move a long distance, but our speculation was that it would be a long time before they'd ever make their way to Pennsylvania."

Lorson says that polluted water and construction of dams at the turn of the century led to the disappearance of Pennsylvania paddlefish. Following water quality improvements in the '70s and '80s, the state determined that the Ohio and Allegheny Rivers could support the fish again.

To date, nearly a 100,000 paddlefish have been released in Pennsylvania. The goal is to start a self-sustaining population, which Lorson says would serve several functions.

"The pie in the sky idea is that we may have a recreational fishery some day down the road," he says. "But really the basis for returning them and having a restoration is related to having a healthy ecosystem."

Even if recreational fishing opportunities do arise, it's unlikely that the lower forty miles of the Ohio and Allegheny rivers would support enough paddlefish for widespread sporting. And despite the added value of paddlefish eggs for caviar production, Lorson says restoration is only partially about the economic value of paddlefish.

"You hear the term canary in a coal mine," explains Lorson, "They're really an indicator of what that water quality is. And if we start having trouble with them, or we see dead paddlefish somewhere along the line, they may be an indicator to us that something is going awry out there."

There is one big problem in the plan-so far, few paddlefish have been spotted at all. Dead or alive.

After ten years stocking the fish, a team of researchers from California University of Pennsylvania just last fall began the first major evaluation of the project. Drs. William Kimmel and David Argent have been searching the rivers for any sign of the elusive fish.

"We go out onto the rivers and set gill nets out, which are kind of like hanging a curtain in the water that's got netting on it," explains Argent. "And the theory is that the fish, if they're there, will get caught, and then we can assess them."

Argent says gill netting has proven effective in capturing paddlefish in other states. But Kimmel says, in the dozen or so trips researchers have made in Pennsylvania, paddlefish are the one endangered species that hasn't wound up in their nets.

"Things like mooneye, skip jack herring, several different species of red horse [have been found]," lists Kimmel. "So it seems like the fabric of the ecosystem is coming together, and we'd like to see this one last component make its way in."

Kimmel says these successes show that the water quality in the river systems has improved. And while it's possible introduced the paddlefish are dying, he says it's just as likely that they're swimming out of Pennsylvania.

Since most of the funding for the reintroduction comes from out-of-state, the program will likely continue no matter where the fish wind up.

But at this point, Argent says finding a paddlefish in Pennsylvania is becoming a matter of pride.

"The last known capture we have for this fish is 1919 in the Kiskiminetas River," says Argent. "And here we are 80 years later, still trying to find these guys!"

Later this year, researchers will begin radio-tagging fish to track their movement. Argent says knowing exactly where the fish are going could be the next step in bringing this long-nosed giant back to Pennsylvania waters.