Historical Trends in New York State Cold-Stunned Sea Turtle Stranding-to-Release: 1998–2019

Abstract

Long Island Sound and the Great Peconic Bay (New York) contain southern barrier lagoons and eastern bays and are known habitats for foraging juvenile populations of sea turtles during summer months. Every year, sea turtles strand throughout these areas due to climate-related cold snaps that typically occur in the late fall and lead to cold-stunning, a physiological temperature shock similar to hypothermia that renders turtles unable to swim and prone to wash up onto beaches. Cold-stunning events in this area tend to last longer than a few weeks and typically affect juvenile Kemp's ridley (Lepidochelys kempii), juvenile green (Chelonia mydas) and subadult loggerhead (Caretta caretta) sea turtles. The New York Marine Rescue Center, formally known as the Riverhead Foundation for Marine Research and Preservation, is the sole rehabilitation facility for cold-stunned sea turtles in New York and responds to the second-largest number of cold stuns in the Greater Atlantic Region, which encompasses marine ecosystems from Maine to North Carolina. Since 1998, a total of 510 sea turtles have been recovered from New York state waters or beaches between the months of October and February. Of these 510 cases, 5 individuals restranded under similar conditions following rehabilitation and release, resulting in 505 distinct sea turtles stranding due to cold-stunning. These 505 cold-stunned sea turtles were composed of 3 different species: 281 L. kempii (56.0%), 174 C. mydas (31.3%), 48 C. caretta (9.5%), and 2 hybrids (0.4%). Over the course of 22 yrs, stranding frequency varied from 3 to 85 turtles per season, with an average of 23. However, a large increase in stranding numbers began in 2007; average stranding numbers from 1998 to 2006 were 7 per season, increasing to 34 per season from 2007 to 2019. Multiple factors are likely contributing to the increase in stranding/rescue frequency such as the gradual warming of northern waters (which may entice turtles farther north and prevent their timely southern migration), development of a free public outreach program targeted at educating patrons about local sea turtle populations, and implementation of an effective beach patrolling system. More efficient management of patrolling efforts has contributed to the quick response time and resulting increase in live turtle rescues. In addition, modification and enhancement of in-house treatment protocols have contributed to the upward trend of successfully rehabilitated cold-stunned turtles. Understanding historical cold-stun trends will allow local and national organizations to identify needs and allocate funding for conservation initiatives of endangered Atlantic sea turtle populations.