Shrimpers, others join UGA Skidaway Institute Black Gill research cruise

UGA Skidaway Institute of Oceanography scientists are studying a condition in shrimp found along the Southeast Coast known as Black Gill. As part of this effort, a group that included UGA Skidaway Institute scientists and representatives from Georgia Sea Grant, UGA Marine Extension, Georgia DNR, the shrimping industry and researchers from North and South Carolina joined a one-day research cruise on board the R/V Savannah on October 9. The focus of the cruise was to collect shrimp for the Black Gill research project, and also to give the various groups the opportunity to exchange ideas. This account of the project comes from UGA Skidaway Institute scientist and cruise-organizer Marc Frischer.

We had 20 people on board (not including the ship’s crew), representing three states (Ga. S.C. and N.C.) and interests from the industry, management, research, and education/outreach communities. Although sometimes the conversations were outside of my comfort zone, I found the discussions and interactions that I had interesting, significant and useful. I found particularly interesting the perspectives from some of the professional shrimpers who were onboard made it clear to me that a research priority should be investigating the relationship between shrimp mortality in the field and the incidence of Black Gill. Discussions with the management community also provided me new insights into the difficulties we are facing with management and regulation. Conversations with those charged with communicating with the broader public remind me to choose words carefully to avoid misunderstanding.

A shrimp with the Black Gill condition clearly evident.

A shrimp with the Black Gill condition clearly evident.

In terms of the science, the day was largely successful despite the very low shrimp catches. Our priority was to collect enough live shrimp to conduct experiments to investigate black gill transmission and to explore the effect of ciliate infection on molting frequency. Although there were not many shrimp caught, we caught enough to conduct our planned experiments, and we were able to bring live shrimp into our facilities with almost no mortality. Utilizing the relatively large R/V Savannah and being able to dock within feet of our labs made this possible.

Skidaway Institute professor Marc Frischer examining a shrimp.

Skidaway Institute professor Marc Frischer examining a shrimp.

Thanks goes to the director of the Skidaway Institute of Oceanography (Jim Sanders) for making the vessel available to us. Cost for the ship is not covered by funding provided by Georgia Sea Grant and was provided as matching funds by the Institute.

Experiments got underway immediately upon our return and will continue for the next several weeks. If anyone is interested and wants to visit the lab for an update you are welcome to do so.

DNR's Pat Geer and Sea Grant's Jill Gambill sort through the marine life caught in a trawl.

DNR’s Pat Geer and Sea Grant’s Jill Gambill sort through the marine life caught in a trawl.

In addition to collecting live specimens, we were able to collect and preserve samples for a large variety of other analyses that will contribute to our identification of the Black Gill agent and to understanding its impact on shrimp. Several of the samples we collected are now on their way to various labs around the world where researchers with expertise beyond ours will study them.

Also, for the first time, we, collected water and sediments to be examined using our novel molecular-based diagnostic tools that are just now coming online. These studies will form the basis of a student project and thus generate both new information and new talent.

The team from the October Black Gill cruise.

The team from the October Black Gill cruise.

Unfortunately, because we were not able to catch more shrimp, we were not able to quantify the prevalence of Black Gill along the transect we sampled (offshore Wassaw Island, Wassaw Sound, and the Wilmington and Skidaway Rivers). However, this is a task valiantly undertaken by the GA DNR who had just visited the area in September and will be at it again. However, in addition to observing that catches were low everywhere, we were able to estimate a prevalence in the neighborhood of 50 percent. Except for offshore where we only caught one shrimp and it had black gill (so 100 percent). Two insights from this experience — first, our observations agree very well with DNR’s estimates and it is clear that we are probably not sampling sufficiently. Second — engaging the fishing community in this effort, if we can do so in a scientifically sound manner, will be truly helpful.

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