KINGS BAY, GA – The Georgia Department of Natural Resources and the Georgia Aquarium in a project led by the Sea to Shore Alliance are helping scientists near Kings Bay submarine base tag manatees to better understand how these animals use coastal Georgia’s waters.
Eight manatees were caught recently and fitted with GPS transmitters and returned to Cumberland Island Sound. Two of the 13 manatees tracked the previous two summers are still transmitting data.
The goal of the project is to map the movements of the manatees near the submarine base, document migratory patterns, study habitat use in the region, and collect baseline data to help evaluate the manatee health conditions.
Researchers are dealing with challenges such as quick shedding of the tracking device by the animals along with obtaining better insights into the mammal’s reclassification from endangered to threatened under the Endangered Species Act this past year.
The GPS data show that manatees regularly venture into the submarine base, find freshwater sources to drink from, and few of them have traveled into the open Atlantic. Biologists are confirming that the Inter-coastal Waterway (ICW) passage of natural or dredged rivers along the mainland and barriers islands act as an important passage way for the manatees.
“The Intracoastal Waterway is like a manatee highway,” DNR wildlife biologist Clay George said. “But the ICW is also a primary passageway for boats moving up and down the coast, so this behavior may place manatees at added risk of boat strikes.”
Out of the 13 previously tagged manatees, only three have traveled the entire coastline of Georgia. “We’re hoping some of the new batch will migrate up the coast toward Savannah, or even South Carolina,” George said. So far, most of the manatees have spent the winter months in Brevard County in east-central Florida, although one migrated more than 500 miles and wintered in Fort Lauderdale.
According to Monica Ross of Sea to Shore Alliance, understand more about the manatee’s habitat and migration patterns will help conservation efforts.
“We know manatees need warm water to survive,” said Ross, a research scientist with the nonprofit focused on conserving coastal environments and species. “Unfortunately, several manatees are rescued or die from cold stress outside of Florida each year. Through this study, we are gaining a better insight into when manatees make their migration south.”
Manatees migrate from Florida to Georgia in spring, drawn by abundant marsh grass and other aquatic vegetation. They occur in tidal waters throughout coastal Georgia from at least April through October. Yet shorter winters and warming waters have widened that window. Manatees were reported at Kings Bay this February.
Since 2000, boat collisions have caused 27 percent of manatee mortalities documented in Georgia, highlighting the need to better understand manatee movements in the state.
Wildlife agencies between Georgia and Florida netted the eight manatees in Cumberland Sound May 31 – June 2. Using the DNR helicopter to spot the animals, a custom manatee capture boat from Clearwater Marine Aquarium was used to circle the animals with a net and then tagged. Biologists and veterinary staff from the Georgia Aquarium and the University of Florida, examined the six makes and two female manatees and fitted them with transmitters.
The biologists and staff at DNR monitor the manatees daily online.
“At least every two weeks, we’ll physically locate each animal, to see what they are doing, check the equipment and take the opportunity to photo ID other animals they might be with,” Ross said. “If at any point the tag activity is abnormal, we will get eyes on the animals immediately.”
“This year we are exceptionally excited to have two females to monitor, the first two captured for this study. Females use habitat differently than males, so it will be exciting to gather their movement data.”
Georgia Aquarium is directing the health assessment studies, which are patterned after the Aquarium’s long-standing bottle-nose dolphin Health and Environmental Risk Assessment research in Florida’s Indian River Lagoon.
“We are continuing to generate important health data from manatees in Georgia that help us better understand these unique animals,” said Dr. Gregory Bossart, senior vice president and chief veterinary officer at Georgia Aquarium. “This information tells us not only about manatee health but also provides important new clues about the health of the environment and potentially the impacts on overall human health.”
As of this week, seven of the manatees were still within 10 miles of their capture site, near Cumberland Island and Florida’s Amelia Island. One had ventured north to the Brunswick area. Of the two manatees still tagged from 2016, one was near Richmond Hill and the other was in the Charleston, S.C., area.
Project funding has been provided by the U.S. Navy, the U.S. Fish and Wildlife Service, Georgia Aquarium, Georgia Nongame Wildlife Conservation Fund, The Environmental Resources Network, or TERN (friends group of DNR’s Nongame Conservation Section) and Sea to Shore Alliance.