POST AND COURIER (Charleston, S Carolina) 14 June 03 A tough time for terrapins - Scientists say trapped diamondbacks are dying in crab pots (Lynne Langley)
After a week of plowing through pluff mud and pulling seines through Kiawah River creeks, scientist Whit Gibbons hasn't found many diamondback terrapins.
The few he's netted are old friends, brackish water turtles whose shells he already has marked in his 20-year-long terrapin study.
Photo: Whit Gibbons holds two diamondback terrapins caught on Kiawah Island. (Alan Hawes)
Gibbons, a University of Georgia ecology professor and internationally known author, lands 35 of the handsome reptiles in the time he used to get 150. Two or three heads pop above the surface where he used to see 15 to 20.
"Where are the young ones?" he asked Friday. "It's a bunch of old folks."
The youngest this year is 9 years old. Many are in their 20s and 30s, and one terrapin that he marked back in 1987 may be pushing 40.
"This could be alarming," said Gibbons, senior scientist at the Savannah River Ecology Lab. It means young are not coming back to Kiawah to reproduce. "Concern has reached a peak this year," said state biologist Meg Hoyle.
"The future looks grim," she said, adding that diamondback terrapins will vanish in parts of their range if the decline continues the way it is going -- not only here, but also from Cape Cod to Texas.
"Terrapins are the flagship of the salt marsh," Gibbons said. "If they are not doing well, what about the rest of the marsh? Our findings might be a warning shot across the bow."
Gibbons pointed to possible problems including development, runoff, poor quality water, less food, loss of nesting sites, crab pots and drowning.
He's certain about only one: Trapped crabs lure hungry terrapins, which can't last more than six hours without a breath of air.
"Recreational traps are what we have seen," Gibbons said of the four creeks he surveys.
The number of terrapins in one creek began dropping 10 years ago, when a dock was built and crab pots installed across the narrow Kiawah River from the creek. Gibbons couldn't find even one terrapin in that creek this week, he said, adding that the terrapins he marks consistently stay in the same creek all their adult lives.
Hoyle, a S.C. Department of Natural Resources biologist, studied Kiawah terrapins in 1999 for her master's thesis by placing crab traps, baited with chicken, in a creek. In three months, she had caught 10 percent of the adult terrapins in the creek. She checked the traps often and released all the captives alive.
A Kiawah resident found 23 dead terrapins in a commercial crab pot in the spring of 2002, Hoyle said.
"That wasn't the first time," she said, describing it as a catastrophic event.
In spring mating season, a female will go for a trapped crab, get caught and attract a pot full of eager males.
"There are anecdotal accounts of a decline statewide and range-wide," Hoyle said. At Kiawah, Gibbons has 20 years of precise numbers, she said. "We're fortunate this research has been going on."
Scientists have studied terrapins in Chesapeake Bay and found a similar drop in numbers and comparable accidental catches in crab traps, she said.
Gibbons has seen recreational crabbing in the area he studies. Folks may not check their pots for a week at a time, and seasonal residents may leave pots in the water year-round, he said. "It's terrible when you see a recreational crab pot buried in the mud. It keeps on trapping animals."
Last month, for the first time, Gibbons also spotted some commercial crab traps.
Hoyle points to increased competition, court cases, commercial crabbers' cutting one another's lines and ghost pots that keep on fishing and killing after lines are severed so crabbers can't locate their pots.
Elisabeth King sees the results, too. The Kiawah Island Nature Program manager finds ghost traps that wash up on shore. "It's so sad to see one of Whit's marked terrapins in an abandoned trap."
No one is trying to catch terrapins, which feed on crabs and don't provide much meat to be eaten, the biologists said.
The beautifully marked animals, which weigh up to 2 pounds, were fished into commercial extinction at the turn of the century when terrapin was a restaurant delicacy.
Now the creatures are accidental, or incidental, catch.
Gibbons and some of his students are spending this weekend marking terrapins. With a workshop file, he makes a small, permanent notch in some of the 24 plates around the edge of a shell that may measure 5 to 10 inches long. "Each one has his own Social Security number," said Gibbons, who has recorded more than 1,600 diamondbacks in the Kiawah River.
By weekend's end, the terrapins will have been moved out of a Kiawah apartment and will be swimming free once again.
Then Gibbons and his team will spend three more days pulling seines through creeks and setting trammel nets, temporarily trapping terrapins to see what percentage are repeats from this week and how many are new. That will help him estimate the population -- and the decline.
If it's as steep as he expects, he said, he will write DNR saying, "You need to do something."
DNR herpetologist Steve Bennett pointed to Gibbons' research and reports from other states, some of which have required terrapin excluder devices on crab traps or taken other action.
"My instinct is terrapins may be in need of conservation attention in the future," he said.
Help A Terrapin: Anyone finding a diamondback terrapin trapped in a crab pot is asked to call the S.C. Department of Natural Resources at 953-9300 and leave information for biologist Meg Hoyle.
A tough time for terrapins