The revving of the engine serves as a wakeup call for those aboard the R/V Georgia Bulldog. It's 5:30 a.m. and the deck is soon abuzz with commotion as the crew prepares to depart for a research cruise aimed at sampling sea turtles off the coast of Brunswick, Ga.
For the 18th year, the South Carolina Department of Natural Resources (SC DNR) has enlisted the help of the University of Georgia Marine Extension and Georgia Sea Grant’s R/V Georgia Bulldog crew to provide logistical support and assist with the collection of biological data for their In-Water Sea Turtle Research program. The program, funded by the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, is designed to monitor abundance, distribution and health of sea turtles along the southeast coast.
“Sea turtles are long-lived, slow-growing, and late-maturing species that only go on land to nest unless they strand,” said Mike Arendt, assistant marine scientist at SC DNR and lead researcher on the project. “If you don't monitor them in the water like we do, and for a long period of time since they take decades to reach maturity, you're missing the most important information.”
Arendt has worked on the project since it began in 2000 and took over the survey in 2007. Because of where the survey is conducted, most of the data collected have been for loggerhead sea turtles, but in recent years, greater emphasis has been placed on understanding the distribution of the next most common species, the smaller, endangered Kemp’s ridley sea turtles.
“Between 2000 and 2015, over 2,300 loggerheads were captured compared to around 260 Kemp's ridleys,” said Arendt. “We were starting to wonder if we were sampling in the right places for them.”
The shallow coastal waters off Brunswick have been some of the best documented locations for Kemp's ridleys, and Lindsey Parker, captain of the R/V Georgia Bulldog, knows exactly where to find them.
“After so many years of random sampling all up and down the coast, I’ve found a few hot spots for ridleys,” said Parker. “We tend to see more around inlets and because of my familiarity with the Brunswick area, we can sample those areas more fully than in other areas that I’m less familiar with.”
The Bulldog, a 72-foot shrimp trawler that was converted to a multipurpose research vessel in the 1980s, is an ideal vessel for this type of sampling because it can easily navigate shallow waters and estuaries.
Sampling involves pulling two 60-foot trawl nets behind the boat for 30-minutes. Each time the nets are pulled up after a drag, excitement on board starts to build, especially if there’s a sea turtle in tow.
On this cruise, a Kemp’s ridley is caught on the first trawl. Once it’s safely on board, researchers work quickly to process it to reduce as much stress on the animal as possible. The team, made up of research biologists, technicians and graduate students, move around the boat with ease, grabbing gloves, measuring tools and vials while calling out information that’s recorded on a data sheet.
They first scan the turtle to make sure it hasn’t been tagged before assigning it a unique ID. They then collect blood samples, measure the carapace, administer the pit tag and place the animal in a harness so it can be weighed. The last step is the release, which involves gently lowering the turtle over the side of the R/V Georgia Bulldog using the harness.
“Kemp’s ridleys, by and large, are really easy to process,” said Arendt. “They’re healthy looking, they’re clean. Plus, they’re small, so it’s really easy to work them up.”
He adds, with a hint of pride, that their record processing time is 14 minutes.
By the end of the day, the team processed eight sea turtles, seven Kemp’s ridleys and one loggerhead.
“We’re about three-quarters of the way through our sampling period and we have 34 Kemp’s ridleys so far,” said Arendt. “Two thirds of our Kemp's for 2017 were caught this week, which amounted to almost half of the 2016 total.”
This long-term project has generated a wealth of data that’s been shared with over 25 collaborators, studying everything from sea turtle DNA to testosterone to blood chemistry. The cruises also train graduate students in veterinary or marine science programs in practical field experience that will help prepare them for their careers. Arendt explains that bringing in more partners and providing workforce development opportunities is important for getting the most bang out of the taxpayer dollar.
“We have the skill sets, funding, and federal and state permits to safely capture and handle the sea turtles, so that enables the collaborators easy access to animals that they wouldn't otherwise be able to study,” Arendt said. “In return, we get important information on sea turtle health and foraging behavior that the collaborators have the funding and skills sets for, so it’s win-win.”
Additionally, Arendt has the R/V Georgia Bulldog and her crew, who have decades of trawling experience and strong connections to the research community and the commercial fishing industry.
“The Bulldog crew is a great interface between science and industry to help disseminate our results and generate support for our endeavors,” said Arendt.
Writer: Emily Woodward, ewoodward@uga.edu, 912-598-2348, ext. 107
Credits:
Marine Extension and Georgia Sea Grant