Designing a Turtle-Proof Crab Trap

Designing a Turtle-Proof Crab Trap

(Photo: E. Weeks/SCDNR)

(Photo: E. Weeks/SCDNR)

My first trip to meet crabbers Robert Sollott and Cheri Ward was delayed by frost.

Since last fall, the two have been working with an SCDNR biologist to improve the sustainability of their crap traps, and Sollott invited me out to see their work in action.

But Sollott and Ward aren’t just crabbers – they’re McClellanville-based blueberry farmers and beekeepers, too. So when an unexpected couple nights of sub-freezing temperatures threatened to ruin their blueberry crop in late March, crabbing took a back seat to saving Blue Pearl Farms’ bushes.

“We had to take some very drastic measures,” Sollott said. They spent a sleepless night standing watch over several fires burning across the farm, the smoke from which was intended to protect the blueberry buds from mid-20º F temperatures.

Strawberry, blueberry, and peach crops across the state suffered devastating damage from the record low temperatures. But Sollott and Ward were able to save their blueberry crop for the season – and return their attention to crabbing.

Crabber Robert Sollot finishes installing four bycatch reduction devices (BRDs) on one of his 120 crab traps. (Photo: E. Weeks/SCDNR)

Crabber Robert Sollot finishes installing four bycatch reduction devices (BRDs) on one of his 120 crab traps. (Photo: E. Weeks/SCDNR)

Sollott grew up crabbing in the Chesapeake, and he and Ward started commercially crabbing the waters of the Cape Romain National Wildlife Refuge shortly after starting their blueberry operation.

Keeper-sized blue crabs (larger than 5 inches from point to point on the shell) there are plentiful, Sollott says, and like crabbers everywhere, with every trap they also pull in a lot of bycatch – undersized flounder and black drum, spider and hermit crabs, whelks, and especially diamondback terrapins.

It was this colorful marsh turtle that brought the blueberry-farming crabbers together with an SCDNR research project last year.

Diamondback terrapins, once popular table fare, are no longer commercially harvested, but their numbers remain in gradual decline across South Carolina due to threats including habitat loss, sea level rise, car collisions, and entrapment in crab pots. Drawn to the pungent smell of fish heads and chicken necks, the turtles frequently enter crab pots. But like all reptiles, diamondback terrapins breathe air – and they can drown when they’re unable to leave the traps.

Diamondback terrapins are only found in the salt marshes of the East and Gulf Coasts, and their skin and shells come in a range of striking colors and patterns. (Photo: E. Weeks/SCDNR)

Diamondback terrapins are only found in the salt marshes of the East and Gulf Coasts, and their skin and shells come in a range of striking colors and patterns. (Photo: E. Weeks/SCDNR)

SCDNR biologist Mike Arendt and his team have spent several years working on a solution to this problem. Bycatch reduction devices (BRDs) are pieces of plastic that fit over the entrances of crab traps, restricting the size and shape of the hole. Several BRD designs have made it to market over the years, but adoption has been slow, as BRDs can sometimes reduce blue crab catch rates in addition to reducing bycatch.

After three years and thousands of crabs worth of testing, Arendt and his team designed a BRD that would keep terrapins out while still allowing large crabs to enter traps.

Robert Sollott was one of 29 commercial crabbers who agreed to pilot the devices in ten of his crab traps last fall, when the biggest crabs are typically landed. The crabbers’ responses to the BRDs have been mixed so far, with many feeling that the devices still restricted some of the largest-sized crabs from entering their traps. But in early 2017, Sollott called Arendt with the most surprising response yet. He was so pleased with the BRDs’ ability to capture blue crabs as large as 7.5 inches that he wanted to outfit all 120 of his traps with them.

Sollott says he’s seen no difference in the amount of crabs caught in the pots outfitted with BRDs versus those without. What he and Ward have seen is a dramatic drop in bycatch.

The new SCDNR design (in red) is smaller than other commercially available BRDs, but the key difference is its larger diagonal opening. (Photo: E. Weeks/SCDNR)

The new SCDNR design (in red) is smaller than other commercially available BRDs, but the key difference is its larger diagonal opening. (Photo: E. Weeks/SCDNR)

One picture Sollott took shows a crab trap they pulled that’s loaded down with black drum too small to keep – that trap did not have BRDs. There are some areas of Cape Romain that are so thick with terrapins they might catch dozens in a day, Sollott says. He and Ward sometimes adjust their plans aboard the Crab Bus, their crabbing boat, to avoid those areas.

SCDNR staff and volunteers trekked up to Blue Pearl Farms in early April to help Sollott and Ward outfit the remainder of their crab traps with BRDs, a time-consuming process that can take 20 minutes per trap. Sollott will continue to work with SCDNR to provide feedback on the BRDs, and Arendt hopes that, in conjunction with feedback from crabbers with less BRD success, will help him continue to refine the design.

“It’s important to us to give back to the resource,” Sollott said. With a livelihood depending on bees, blueberries and the Crab Bus, Sollott and Ward know just how connected South Carolina’s natural resources are to the quality of life we enjoy along the coast.

The bycatch reduction devices fitted over the mouths of these crab traps will help prevent diamondback terrapins -- but not crabs -- from entering. (Photo: E. Weeks/SCDNR)

The bycatch reduction devices fitted over the mouths of these crab traps will help prevent diamondback terrapins -- but not crabs -- from entering. (Photo: E. Weeks/SCDNR)

Get Involved!

Are you a recreational or commercial crabber interested in testing the BRDs? Contact Mike Arendt at arendtm@dnr.sc.gov or 843-953-9097 for more information.

SCDNR biologists also want to hear about your diamondback terrapin sightings. Report them online here.

The crew installed 288 BRDs on 72 crab traps over the course of one day.  From L-R, volunteer Dale Aren, crabbers Cheri Ward and Robert Sollott, volunteer Chandler Boyd, and SCDNR staff Chris Evans and Mike Arendt. Pups Oslo and Stinger provided emotional support and entertainment. (Photo: E. Weeks/SCDNR)

The crew installed 288 BRDs on 72 crab traps over the course of one day.  From L-R, volunteer Dale Aren, crabbers Cheri Ward and Robert Sollott, volunteer Chandler Boyd, and SCDNR staff Chris Evans and Mike Arendt. Pups Oslo and Stinger provided emotional support and entertainment. (Photo: E. Weeks/SCDNR)

Putting reducers on crab traps is rough on the hands, but working with beekeepers has its perks -- Sollott and Ward have perfected a beeswax-based salve to soothe cracked and callused skin. (Photo: E. Weeks/SCDNR)

Putting reducers on crab traps is rough on the hands, but working with beekeepers has its perks -- Sollott and Ward have perfected a beeswax-based salve to soothe cracked and callused skin. (Photo: E. Weeks/SCDNR)

Stocking South Carolina's Favorite Saltwater Fish

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