As the New York Times recently reported, sea turtle strandings along Cape Cod’s beaches are on the rise, which got us thinking: what is contributing to this phenomenon, and what can we do about it at Cape Clasp?

Winter on the Cape means three things: empty beaches, frigid ocean temperatures, and in recent years, the odd appearance of hypothermic sea turtles. Over the past two decades, thousands of half-frozen sea turtles have become stranded on beaches around the Cape with a condition known as cold-stunning, a phenomenon which networks of scientists and concerned citizens alike are scrambling to address.

Sea Turtle Adaptations

Perhaps one of the most unique behavioral adaptations sea turtles exhibit is the ability to swim hundreds, if not thousands, of miles every year in search of food, mates, and a nesting site. During these long migrations, sea turtles can use a variety of navigational clues such as the earth’s magnetic field, physical landmarks like underwater seamounts, and, importantly, gradients in water temperature to successfully reach their destination. In a most impressive feat of navigational prowess, female sea turtles have even been shown to swim hundreds of miles to repeatedly return to the same beach where they were born to lay a nest of their own. 

Yet despite having one of the most impressive innate senses of navigational ability in the ocean, sea turtles are increasingly becoming disoriented and stranded along Cape Cod’s beaches. As data from Mass Audubon indicates, sea turtle strandings along the Cape have increased from fewer than 10 turtles per fall season in the late 1970s to currently more than 1,200 turtles per fall season. This data, therefore, begs the question, why the sudden increase in the occurrence of stranding events? 

Simply stated, climate change is affecting the temperature of our oceans in a major way. 

The Effects of Climate Change

As climate change increases the average temperature of our planet, masses of unusually warm ocean water are becoming more common along the eastern seaboard of the United States, causing sea turtles to expand their range into areas where they have not typically been observed. Swimming from the adjacent Sargasso Sea, juvenile sea turtles are utilizing the rapidly warming Gulf of Maine as foraging grounds where they can feed on prey like jellyfish, crabs, and algae.

As the Gulf of Maine continues to warm at an alarming rate - 99% more quickly than the rest of the ocean, according to scientists from the Gulf of Maine Research Institute in Portland, Maine - this massive body of warm water is simply too enticing for sea turtles to ignore. And therein lies the problem: as ectothermic, or “cold-blooded,” reptiles, sea turtles are unable to regulate their body temperature and increasingly find themselves in a dangerous situation when exposed to decreasing water temperatures. 

As sea turtles are utilizing the Gulf of Maine and Cape Cod Bay to forage, scientists hypothesize that the turtles become disoriented by the Cape’s unique “hook” shape, lingering long after they would otherwise return south with the approach of winter. Trapped by a geographic anomaly, the sea turtles are then suddenly exposed to the frigid water temperatures typical of a New England winter. After just a few days of exposure to these harsh conditions, the turtles become sluggish and unable to swim south toward warmer waters. Eventually, the cold-stunned turtles may die without intervention. 

Saving the Sea Turtles! 

Fortunately for our sea turtle friends, our partner, Mass Audubon Wellfleet Bay Wildlife Sanctuary, is on the case (and has been for the past 41 years!). Thanks to a highly dedicated chain of scientists, aquarists, and volunteers, cold-stunned sea turtles now have a fighting chance at making a full recovery from a cold stun. This work entirely begins with our partner, Mass Audubon, and its team of dedicated volunteers walking the beaches in search of cold-stunned sea turtles, so further supporting their mission is a no-brainer here at Cape Clasp! 

It is very important to recover these stranded turtles as quickly as possible. Do not assume a turtle is dead—turtles that appear lifeless are often still alive. If you come across a stranded sea turtle on the beach, please follow these simple steps:

• Move the turtle above the high tide line. Never grab or hold the turtle by the head or flippers.
• Cover it with dry seaweed or wrack.
• Mark it with an obvious piece of debris—buoys, driftwood, or branches.
• Call the Wellfleet Bay Wildlife Sanctuary hotline at 508-349-2615 x6104.

Sea turtles are federally protected under the Endangered Species Act; as such, it is illegal to harass sea turtles or transport them without a permit

Shaun Swartz for Cape Clasp
Environmental Educator, Science Communications Professional