RICHMOND HILL, Ga. -- You can call him Dr. Frankenfish if you like.
But senior fisheries biologist Bob Rees is no mad scientist, although he has spent the past 29 years tampering with Mother Nature.
"We do this once a year," Rees said from a concrete room where biologists gather each spring to follow a proven recipe for building a better bass.
Rees and his colleagues manage Georgia's hybrid bass program, in which the popular sportfish are "made" by mixing eggs from white bass with sperm extracted from male striped bass.
If it sounds simple, it is.
"You just take a bowl of female eggs, and put the male sperm right in on top," said hatchery technician Jason Howard. "Then you just stir it up. It's kind of like making a cake or something."
The Richmond Hill hatchery provides all the hybrids for Georgia's 16 receiving lakes, which include Thurmond Lake near Augusta.
Each spring, 600 to 780 female white bass are captured in the Chattahoochee River near Franklin, Ga., and in the Coosa River near Rome. The male stripers number about 75, and are taken from Lake Lanier.
"Once they're caught, everything's hauled right down here," said Tom Meronek, another fisheries biologist. "This is where we do it."
The challenge is knowing when to squeeze the eggs from the females, and when to remove the sperm from the males, he said.
The annual, two-week ritual repeats itself each year, from mid-March to early April, when the hatchery's indoor tanks are packed with bass.
"This is one of the busiest times of the year," he said. "We all pitch in. When we're done breeding our fish, we all have other jobs."
Georgia began stocking hybrid bass in 1975, when 89,368 fish were released, according to the Georgia Department of Natural Resources. Since then, the numbers stocked have grown to more than 4 million annually.
"They grow quick," Meronek said. "A striper will put on eight to 10 inches in a year, and a hybrid will do a little less than that. In two to three years, they're all catchable size."
Hybrids offer an additional sportfish that adopts the qualities of both of its parent species.
"What the hybrid offers is an extra gamefish -- something more to catch," Meronek said. "They are aggressive fighters, and they absolutely cannot reproduce, which makes them especially valuable."
The non-reproducing aspect of hybrids is important from a fisheries management perspective.
"You can stock them to keep forage fish (shad and herring) in check, and not worry about having something in a lake that will overpopulate and take over," he said. "If they become a problem, you just quit stocking them."
Rees figures he and his colleagues have hatched upwards of 750 million hybrids during his 29-year tenure at the hatchery.
The remarkable program, he added, is one of many in a long line of successful fisheries programs worldwide. "As far back as 1849, striped bass were shipped by rail to the West Coast," he said.
Jerry Germann, a fisheries biologist in Thomson, Ga., helps decide each year how many hybrids should be added to Thurmond Lake near Augusta.
"This year, the minimum is four and the max is seven for hybrids," he said. Computed into the reservoir's 70,000-plus acres, the total would range from 286,140 to 500,745 this year.
Chances are, if you've ever boated a hybrid in Thurmond Lake, it likely came from Rees' annual science project, although the state of South Carolina stocks some hybrids in Thurmond Lake as well.
Anglers like Ben Peacock of Augusta troll for hybrids and stripers often.
"I fish every week," Peacock said. "I mainly fish for stripers, but we catch a lot of hybrids, too. If you catch one, it spoils you for everything else. Unless you get a striper."
Reach Robert Pavey at (706) 868-1222, Ext. 119.