Abstract
Following an unusually temperate fall and early winter, the Atlantic coast of North Carolina experienced a sudden and drastic decrease of inshore water temperatures in early January 2016. This resulted in a massive cold stunning event affecting over 1700 sea turtles in a period of three weeks, predominantly juvenile green sea turtles (Chelonia mydas) in the 2.0–3.5 kg body weight class. The estuarine sounds of the Outer Banks are prolific foraging grounds for juvenile sea turtles, and their relatively shallow water and few inlets leading to open ocean result in prime conditions for cold stunning events.
Despite having the second-longest Atlantic coastline in the United States, North Carolina possesses modest resources to respond to marine animal stranding events, and only two dedicated sea turtle rehabilitation facilities, the Sea Turtle Assistance and Rehabilitation (STAR) Center at the NC Aquarium on Roanoke Island, and the Karen Beasley Sea Turtle Rescue and Rehabilitation Center (KBSTRRC), although the other two North Carolina Aquarium facilities frequently serve as overflow short-term holding facilities during sea turtle cold stun events.
In contrast to mass cold stunning events in more northern Atlantic states, sea turtles affected in the Southeastern United States, particularly in the early stages of an event, are consistently in good body condition with minimal physiological derangements and few indications of systemic illness. This allows for rapid triage and release of individuals meeting criteria for a high likelihood of survival upon release: adequate body condition, appropriate attitude, absence of appreciable visual deficits or physical injuries, and normal swimming and diving behavior.
Overall mortality was low in the first week of the event, but increased substantially as the month progressed. The majority of animals fell into two distinct categories: those that died either during transport to a triage facility or within the first 12–24 hours, despite basic supportive care, and those that promptly regained appropriate attitude and activity during rewarming, or that responded rapidly to a standard course of antibiotics for wounds or respiratory abnormalities and were candidates for release within a few weeks. A minority required more intensive fluid therapy, medications, and prolonged care.
By the end of January, over 800 affected turtles had been released into warmer waters off the coast of Florida or offshore of North Carolina adjacent to the Gulf Stream current. Some turtles were released directly upon rewarming, when transport was available; most spent a few days to weeks in triage and rehabilitation facilities. Slightly over 150 turtles remained in the care of facilities throughout North Carolina and neighboring states, including several aquaria that historically have not participated in sea turtle rehabilitation.
Acknowledgements
The authors gratefully acknowledge the extremely dedicated efforts of the staff and volunteers of the Karen Beasley Sea Turtle Rescue and Rehabilitation Center and the North Carolina Aquariums. National Park Service staff at Cape Lookout and Cape Hatteras, and volunteers from the Network for Endangered Sea Turtles (NEST), were responsible for recovery and transport of most of the affected animals. The US Coast Guard - Fort Macon, SC Department of Natural Resources, and GA Department of Natural Resources were instrumental in the successful release of so many. We thank the NC Museum of Natural Sciences, Greensboro Science Center, SEALIFE Charlotte-Concord, Ripley's Aquarium in Myrtle Beach, and the Virginia Aquarium Stranding Response for their rehabilitation efforts, as well as staff from the NOAA-NMFS Beaufort Laboratory, Dr. Kim Thompson, and Heather Broadhurst for extensive assistance with triage, tagging, and medical care.
* Presenting author