In the beginning, Bruce Saul never dreamed his monthly fishing trips could help unlock the mysteries of prehistoric man.
"It's a sideline -- mostly just for fun," the Augusta State University biology professor said of his frequent trips to coastal Georgia's St. Catherines Island.
What began as an effort to write a book on the area's fish evolved into an ongoing program to help archeologists identify fish species favored by Indian tribes of long ago.
"My project is categorizing fishes along the coast and St. Catherines Island, and they examine the ones we catch and compare them to bones found in middens," he said.
The middens, or shell mounds, were prehistoric man's equivalent of today's landfill -- and contain discarded evidence of island life dating back almost 4,000 years.
"We've been collecting fishes for them off and on since 1996," he said. "Now we're in year 14, and we try to do it three days a month."
Much of the fish collecting is accomplished with seines operated by students and volunteers. So far, the groups have caught and identified more than 100 species.
The archeologists' findings indicate early man pursued many of today's favorite sportfish and baitfish -- and were quite accomplished at catching them.
"The top thing they are finding is trout, and right there with trout is mullet," he said. "Then there are some of the things that are almost as common: croaker, various types of drum -- and catfish."
One of the surprises was the presence of garfish remains in almost every site, despite the island's distance from the fish's freshwater habitat.
"I would have never guessed gar," Saul said. "Ninety percent of the middens they have checked have them, and we're still trying to figure that out."
The toothy fish typically live in freshwater or brackish areas closer to the mainland. "We wondered if the island, that long ago, was bigger, and may have had fresh or brackish water somewhere."
Saul's project is funded by the St. Catherines Island Foundation and administered through the American Museum of Natural History -- whose curator, David Hearst Thomas, has studied the island, located about 50 miles south of Savannah, for decades.