Sea Turtle Strandings: A Growing Concern Across US Coastlines
A surge in sea turtle strandings along US coastlines has placed increased strain on turtle hospitals and aquariums, highlighting the complex challenges facing these marine reptiles. While the winter stranding season is drawing to a close, the increased numbers raise significant questions about the underlying causes and the long-term implications for sea turtle populations.
Florida’s east coast has been particularly affected. Data from the Florida Fish and Wildlife Conservation Commission (FWC) reveals a concerning trend in Brevard County, where strandings through mid-March were approximately triple the five- and ten-year averages. While state data indicates a less pronounced increase overall, the situation underscores a significant deviation from historical patterns. This localized spike, however, contrasts with trends in northeast Florida, where such occurrences are deemed more typical for this time of year, according to the FWC.
The problem is not confined to Florida. Massachusetts witnessed a tripling of turtle strandings between 2019 and 2023 compared to the period from 2009 to 2013. Even Canadas Atlantic Coast is experiencing a similar rise in stranded turtles, painting a broader picture of escalating challenges.
Scientists are actively investigating the reasons behind this increase, but a definitive explanation remains elusive. Current hypotheses point to a combination of factors, including growing turtle populations, the effects of climate change, variations in water temperatures, and human-induced threats like vessel strikes and entanglement in marine debris. Each of these contributes in its own way to the overall problem.
Unusually cold temperatures along the East Coast in January exacerbated the situation. NOAA data ranked January as the 25th coolest in 95 years of records. According to Brian McNoldy, a senior research scientist at the University of Miami’s Rosenstiel School, strong cold fronts pushing off the coast caused water temperatures to plummet.
Sea turtles are cold-blooded animals, meaning they cannot regulate their body temperatures internally. When water temperatures drop below 50 degrees Fahrenheit, they become cold-stunned, resulting in lethargy and impaired mobility. This makes it difficult for them to swim, increasing the risk of being washed ashore by winds and tides, or even drowning. Prolonged exposure to cold water can severely compromise their circulation, organ function, and immune system.
Although the average temperature for the three-month climatological winter has shifted to the 91st warmest out of 95 years of data by late March, sea surface temperature maps still indicate a persistent ribbon of cooler-than-normal water along the coast. This prolonged thermal stress, even in localized areas, continues to pose a risk to sea turtles.
In Florida, the sea turtle stranding surge began in mid-February, with late-month numbers exceeding the 10-year average by 65%. Although the most recent cumulative count has dropped to approximately 43% of the 10-year average, the initial spike underscores the intensity of the event.
The majority of stranded turtles on the northeast Florida coast have been identified as juvenile green turtles. These turtles commonly inhabit the shallow coastal regions of northeast Florida, where they primarily feed on algae. Andrea M. Wasilew, with NOAA Fisheries Public Affairs, highlights the green turtle population in the southeast US as a conservation success story. Record-breaking green turtle nesting in Florida has led to a higher population of juvenile turtles in the nearshore waters of the southeastern US, increasing the likelihood of strandings during the late winter and early spring months.
Another hypothesis suggests that some turtles strand due to being in the wrong place at the wrong time, struggling to find sufficient food. According to Allen Foley, a biologist with the Florida Fish and Wildlife Commission, the winter water temperatures in these areas are close to the tolerance limit for green turtles. Foley noted that while this spike is unusual for Brevard County, it is more typical for northeast Florida, particularly the counties immediately north of Brevard. The FWC is collaborating with a veterinary pathologist at NOAA to investigate the causes of the strandings. Their initial findings indicate that the turtles generally lack significant injuries or signs of infectious disease and do not appear to be linked to harmful algal blooms.
In New England, the unique shape of Cape Cod Bay poses a risk to sea turtles. NOAA scientists explain that the bay can trap turtles for weeks or months as water temperatures decline. Because turtle body temperatures mirror the surrounding waters, they become increasingly vulnerable. As the water cools, the turtles cease feeding, their metabolic processes slow down, and their immune systems weaken.
To address this growing crisis, sea turtle stranding networks along the coasts play a vital role. They collect stranded turtles and transport them to certified sea turtle hospitals and aquariums for care.
At the New England Aquarium’s Sea Turtle Hospital in Quincy, Massachusetts, numerous turtles are receiving treatment for complex medical conditions. This season, the long-term care patients have been given names from Greek mythology, such as Aphrodite, Hercules, and Pegasus. The Clearwater Marine Aquarium recently released turtles rescued earlier in the winter from Cape Cod beaches, some of which were transferred from the New England Aquarium.
Recognizing the need for increased support, the U.S. Senate Commerce Science and Transportation committee recently passed a bill aimed at establishing funding for sea turtle rescue, recovery, and research in Massachusetts and throughout the United States. According to a news release from Senator Edward J. Markey (D-Massachusetts), a member of the committee, the bill would create a new grant program, providing $5 million annually for sea turtle rescue and recovery efforts, as well as a turtle research fund.
Senator Markey’s office highlighted the dramatic increase in sea turtle strandings on Cape Cod beaches, from fewer than 50 in 2000 to 866 in 2022. He also cited the 2021 cold snap in Texas, which resulted in over 12,100 cold-stunned turtles. Senator Markey emphasized the urgency of the situation, stating that "Sea turtles along our coasts are increasingly stranded and face extinction." He believes that the new grant program will provide a crucial lifeline to both rescuers and endangered sea turtles. The legislation is co-sponsored by Senators Chris Van Hollen (D-Maryland), Lindsey Graham (R-South Carolina), Cory Booker (D-N.J.), and Tom Tillis (R-North Carolina). A companion bill has been introduced in the House by Massachusetts Rep. Bill Keating. The bill represents a significant step towards ensuring the long-term survival of these important marine creatures. The increased funding could greatly improve the care they get and help understand the causes of these strandings better.
