By Jill Gambill, Georgia Sea Grant
Reporting from the Gulf by Ed Lallo, Gulf Seafood News Editor
In Georgia, as in the Gulf of Mexico, shrimp is king. A cornerstone of coastal Georgia’s culture and economy, shrimping has generated a dockside value of over 8.6 million dollars annually for the state over the past decade. But Georgia shrimp have come under attack by a parasite that could impact the economy of local coastal communities.
The fishery has long struggled against challenges such as rising costs of fuel, competition with imports and a lack of young people entering the industry. However, something else seemed to be at play in 2013, when fall commercial landings of white shrimp fell by 74 percent compared to the five-year average.
Georgia shrimp fisherman suspected this decline was due in part to outbreaks of black gill, a condition caused by a ciliate, or type of parasite.
Although present in Georgia wild shrimp since the early 1990s, studies by the Georgia Department of Natural Resources indicated that approximately 43 percent of sampled shrimp were affected by black gill in October 2013, over 10 percent higher than the long-term average for this month.
A record amount of rainfall occurred in 2013, marking the wettest summer and third wettest year ever recorded in Georgia. Questions remain about how the rain, run-off and associated river flow influenced black gill infection rates and the recruitment of juvenile white shrimp in Georgia’s estuaries.
Shrimp with black gill appear to be struggling. In response, Georgia Sea Grant and University of Georgia Marine Extension have amassed a regional team of scientists, fishermen, resource managers and fisheries experts to explore how the parasite is spreading, what is causing its upsurge and how this is impacting shrimp.
Georgia Sea Grant is funding research by UGA’s Skidaway Institute of Oceanography to investigate the cause, transmission and environmental triggers of black gill. Scientists are inventing parasite genetic testing to better identify the parasite and compare it with ciliates affecting shrimp in North Carolina, South Carolina and Florida.
UGA Marine Extension will host workshops to educate shrimpers about the parasite and teach safe practices to reduce its spread. In 2014, the research team is also partnering with commercial shrimpers to study black gill in real-time during the shrimping season.
Gulf white shrimp are considered some of the best tasting in the world. According to Julie Anderson, Ph.D., a fisheries specialist with Louisiana Sea Grant and a professor at LSU AgCenter, there are currently no known cases of black gill found in any Gulf shrimp.
“Currently we do not have any problem with black gill disease in the Gulf,” said the professor currently doing research on black gill found in Gulf blue crab. “If shrimpers see anything unusual in their catch they bring it to us, so far we have not seen any black gill in shrimp.”
The Georgia study cites possibilities of heavy rain influencing the spread. “With the heavy rains parts of the Gulf coast have been experiencing, combined with the warm temperatures, there is a possibility for black gill to surface in Gulf shrimp,” said Mississippi State University marine resource specialist David Burrage. “The disease seems to effect primary white shrimp and is not harmful to humans.”
Burrage says that biologists in the Gulf are aware of the possibilities of an outbreak and “are keeping a watchful eye on the situation.”