Col Limpus and His Turtle Cowboys - To save endangered sea turtles, a band of Aussie researchers parlays reptile-dogging at sea to cutting- edge science - turtle researcher Col Limpus

International Wildlife, Sept-Oct, 2001 by John Parrish

I'm perched on the gunwale of a boat rocketing along at breakneck speed, getting ready to jump into the emerald waters of Australia's Moreton Bay. The boat slews in a tight half circle as marine scientist Col Limpus spots our quarry and steers hard right. About 25 yards away, a shadow glides over the sandy-bottomed shallows like an underwater flying saucer. "Get ready," he urges, bringing the boat alongside our target-a green sea turtle about the size of a Jeep tire. I dive into the water, landing on top of the startled reptile with an ungraceful belly flop. The turtle drags me under, knocking the breath out of me, then slaps my head with its scaly flippers.

My underwater bulldogging isn't just for kicks. As a curious journalist, I've come to Moreton Bay to be-for one day at least-a scientific cowboy performing in what Limpus, senior principal conservation officer with the Queensland Parks and Wildlife Service, calls the "turtle rodeo." This annual five-day event is a quirky, nontraditional way to study sea turtles-a far cry from conventional research based on observations of egg-laying females on nesting beaches, yet one that is beginning to produce a treasure trove of new insights into the lives of these mysterious marine creatures.

And just in time. For millennia, sea turtles thrived in these waters off the coast of Australia, but beginning in the 1980s their numbers began to decline. Among other problems, the reptiles have been falling victim to hunting, pollution, collisions with speedboats and entanglement in fishing and crab-pot lines. Today five of the six marine turtle species here are listed as endangered by both the Bonn Convention and IUCN-The World Conservation Union. Worst off of all of them is Australia's genetically distinct loggerhead turtle. Over the past two decades, the animal's numbers have dropped by 80 percent.

With a few broad strokes of its flippers, the turtle I've nabbed tows me along under the shallow water until I find my feet, only to be pulled off them again as the powerful creature yanks me forward. After I'm knocked down for the fourth time, my fingers finally find the shell rim around the turtle's neck, which I use to pull it back toward me, while at the same time yanking down on a flipper. In seconds, Limpus brings the speedboat alongside me. Volunteers Jessica Andre and Rod Kennett lean over the side, attach looped ropes to the turtle's front flippers and haul it aboard. Quickly, they get to work-logging the animal's exact location and recording its sex, markings, injuries and other data. Finally, the turtle is christened "K34518" as Kennett fixes a titanium tag high on its left front flipper.

The idea of the turtle rodeo came to Limpus just over a decade ago, when one of the reptiles surfaced just beside his small boat. He already knew that a true understanding of any wildlife population requires sampling a large number of individuals over a long period of time, and suddenly a speedboat seemed like a good way to chase down lots of animals. "I'd seen Tarzan wrestle crocodiles in the movies, so I figured I could tackle a turtle," Limpus recalls with a grin.

Though unconventional, his technique has garnered praise from colleagues who have stuck with traditional-and easier-methods that target nesting females on beaches. In contrast to such projects, Limpus studies turtles during the critical 99 percent of their lives that they do not spend on land, says herpetologist Peter Pritchard, director of the Chelonian Research Institute in Oviedo, Florida. "Unlike mature females, males and immature turtles are hardly ever seen on beaches, so Col's ability to catch and examine them is invaluable."

Kennett rides the gunwale now and soon adds another turtle to our catch. With five others captured earlier, we're riding low in the water as the weight of our load adds up. "If the boat sinks, save the data," Limpus jokes as we speed back to the mother ship. Other catch boats have been working all day as well, so the ship's deck is stacked with turtles-placed carefully side-by-side at an angle so they don't sit on top of one another. We haul our own catch aboard, and then we're off again.

By catching many of the same individual turtles year after year, Limpus has been able to confirm hunches he could only speculate about before. His data have demonstrated, for example, that boat strikes take a higher toll on loggerhead populations than researchers previously assumed. While the precise number of boating-accident mortalities remains unknown-"not all the bodies wash up," he says-it is believed to be a significant fraction of the roughly 200 loggerheads that are killed annually along the Queensland coast, along with 350 sea turtles of other species. Now Limpus has found that even nonfatal injuries suffered by boat-collision victims can disrupt the animals' breeding behavior for years to come.

Using a laparoscope-a flexible, cameralike instrument with a lens at one end and an eyepiece at the other-Limpus examines the ovaries of female loggerheads that have been injured by boats. He's found that many of the turtles do not breed for up to seven years after an accident, compared with the species' norm of breeding once every two years. (Loggerheads do not even reach sexual maturity until they are 30 years old.) With only 300 females left to lay eggs on Queensland's beaches-there were 3,000 just 20 years ago-this discovery was critical to conservationists, who used it to convince the government to designate five "go-slow" zones in parts of Moreton Bay where Limpus's data show that turtles congregate.