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App may help ID shrimp affliction
Black gill causing decline in population
W blackgill
Scientists on the Georgia coast are documenting an affliction in shrimp known as black gill as part of an ongoing research project. - photo by Special

SAVANNAH — Scientists on the Georgia coast are documenting an affliction in shrimp known as black gill as part of an ongoing research project.

The University of Georgia's Skidaway Institute of Oceanography has been involved with the research for several years, and now scientists hope a new smart phone app yields more insight.

The app is aimed at getting shrimpers to report what they see while on the job, The Savannah Morning News reported .

The affliction is known as black gill because of a telltale dark coloration on shrimps' gills. The disease is caused by a microscopic parasite.

Scientists have determined that the parasite is a ciliate, a single-cell organism, but have yet to identify the specific type. Scientists say shrimp suffering from black gill are safe for humans to eat, the Savannah newspaper reported.

Black gill could be one of many factors contributing to a decline in commercial shrimp fishing, but there are other factors as well, said Marc Frischer, a professor at the Skidaway Institute.

Other contributors to decline in the industry include a decrease in the number of trawling licenses, competition from foreign seafood imports, increased operating costs and expensive upkeep of aging vessels, according to the Institute.

Black gill has been spotted along the Georgia coast for about two decades now, and Frischer said it's in the "epicenter" of where shrimp have tested positive for the cilia. But that's subject to change.

"We've gotten samples all the way through the Gulf of Mexico to the Chesapeake Bay that also tested positive for this cilia," he said. ". I suspect as we start looking further, if we get samples, which we'll continue to try to do, we'll find it probably globally."

Typically, black gill starts showing up in July or August and disappears when the water cools down. Last year, which Frischer said was "unusual," shrimp with black gill started showing up in May.

Frischer says the parasites are likely feeding on the shrimps' gills. Experiments have shown that shrimp with black gill tend to have less endurance than shrimp without it, which has scientists wondering whether afflicted shrimp are more likely to get caught by predators in the wild.

"It could explain why we don't have a body count," he said.

Gale says he hopes scientists continue to focus on shallow water, especially near marsh grass. If the black gill-causing cilia don't like cold weather, Gale says, shallow water that gets more sunlight would be a good place to hide. Plus, shrimp go into the marsh grass areas to feed at night, he said.

Gale said he's pleased to see improved coordination between scientists and shrimpers over the last few years. He just hopes they get some more answers soon because, as he put it, "something freaky is going on."

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