- Associated Press - Saturday, October 25, 2014

SAVANNAH, Ga. (AP) - This wasn’t your typical cruise.

For starters, the daylong journey around Chatham County waterways on the 92-foot R/V Savannah on Thursday was focused on a tiny parasite on shrimp that turns their gills an unsightly and unmarketable black.

And instead of scientists researching the problem by themselves and reporting their results in a scientific journal years from now, they invited along shrimpers, fisheries managers and outreach workers, even a pathologist from Mercer University Medical School who has been studying the parasite in her lab.

“Everybody here has some expertise and brings their perspective to it,” professor Marc Frischer of the UGA Skidaway Institute of Oceanography told the assembled stakeholders as the R/V Savannah made its way out to shrimping grounds off Wassaw Island. “The real opportunity here is to share our stories and our information as we’re doing a little bit of work.”

Over the next eight hours the crew dragged for shrimp in six locations, separating the catch into “clean” shrimp and “black gill” shrimp. Kept alive in separate holding tanks, the shrimp were destined for experiments about the transmission of black gill from shrimp to shrimp.

Other shrimp were whisked away to an onboard lab to ready them for analysis by out-of-state experts in shrimp and in ciliates, this category of parasites. Instruments deployed off the side of the ship collected water and mud samples for Skidaway researchers to comb through for evidence of where the parasite hides in the winter.

Throughout the cruise, shrimpers chatted with researchers. Fisheries managers compared notes. Researchers from three states experienced how their peers collected and handled samples. It was that synergy Frischer was trying to create.

“It brought together a really large spectrum of stakeholders from shrimpers to managers to scientist and the press,” he said. “I think that’s going to pay dividends.”

Shrimpers are more than ready for those dividends in the form of answers about black gill, a condition they first noticed in the 1990s. It usually shows up in mid August, peaks in the fall and wanes in the winter.

“It’s been around for years and years, but it just done got worse,” said Herbert “Truck” McIver, who sold his shrimp boat in December and now crews on another commercial boat and for the University of Georgia Marine Extension Service research vessel the Bulldog. “We didn’t hardly work at all in September.”

Last year was so bad shrimpers applied for federal disaster relief. They haven’t received an answer yet.

Skidaway scientists believe the ciliates don’t kill the shrimp outright but they do take their toll, speeding up their moulting process, which not only wastes their energy, but also makes them more vulnerable to predators. Plus, when the shrimp moults, the parasite takes advantage of the situation by feeding off the discarded tissue and progressing to its free swimming stage. It can then swim to a new host.

Black gill shrimp are not a danger to people even if the shrimp is consumed. Nor does black gill affect the taste of the shrimp. Usually consumers are unaware of the condition because shrimpers often remove shrimp heads, which contain the gills. With this in mind, the Georgia Sea Grant program has dropped the term “disease” when discussing black gill, for fear that it will needlessly turn off consumers.

Ciliates in general - you might remember your high school biology teacher using a ciliate called Paramecium to show the functions of a cell - are not associated with human disease, said Dr. Anna Walker, a professor at Mercer University Medical School.

“They tasted us and decided we didn’t taste good,” she said, noting there’s only one species of ciliates associated with human disease. “They moved on to other hosts.

“People need to be reassured that (black gill) does not get transmitted to humans,” she said. “You can eat shrimp with impunity, even if you ate it raw.”

For all that scientists do know about black gill, there’s much they don’t. They’re still trying to pinpoint exactly which ciliate causes black gill. Shrimp collected on the cruise will be sent to researchers in Alabama and Arizona to help answer that question. They’ll also examine the shrimp for other parasites or diseases.

“He’s going to look at the entire health status of the shrimp, including other diseases,” Frischer said. “He’ll give us an overview of the health of black gill shrimp.”

One of the most puzzling questions around black gill is why this ciliate organism, which is thought to “have been around forever,” only now seems problematic.

“What’s changed?” Frischer asked the research cruise participants. “Or is it really the ciliate causing the problem?”

Amy Fowler, assistant marine scientist at the South Carolina Department of Natural Resources, said it’s clear that shrimp with black gill are burdened. She’s put shrimp on a tiny, shrimp-sized treadmill and run them to exhaustion. Healthy shrimp can run for seven hours, but those with black gill last only half as long. It seems analogous to the effects of smoking in humans, she said.

Savannah State University graduate student Ashleigh Price is studying another puzzle: Where do the parasites go in the winter? Shrimpers have long noticed the peak of black gill in the late summer and fall, with a near absence of affected animals in the winter. Price and Skidaway researcher Tina Walters are analyzing mud and water samples drawn from the cruise for signs of the ciliates.

“We have a DNA marker specific for the ciliate,” Walters said. “We screen the sediment for its presence or absence.”

Skidaway researcher Karrie Bulski will be experimenting with the live shrimp caught on the cruise to learn how the parasite moves from shrimp to shrimp.

Research on black gill is moving forward with $140,000 in funding from Georgia Sea Grant, though the sea day for stakeholders was donated by Skidaway Institute of Oceanography. Along with UGA Skidaway Institute researchers, collaborators include Mercer University, UGA Marine Extension Service, the Georgia and South Carolina Departments of Natural Resources, the Florida Fish and Wildlife Conservation Commission, the Southern Shrimp Alliance and the Georgia Shrimp Association.

For shrimpers like Dennis Murphy, who’s now based in Sunbury but who shrimped for years out of South Carolina, the answers can’t come too soon.

“I thought my golden years would be golden,” Murphy said. “Instead they’re black gill.”

___

Information from: Savannah Morning News, http://www.savannahnow.com

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