A number of folks out for a stroll on Long Beach in Noyac on Saturday encountered a very unusual and disturbing sight at the water’s edge: a huge sea turtle, alive and intact, with no obvious external injuries, was stranded and seemingly helpless on the shore.Other than the mature females coming ashore to dig nests and lay eggs, sea turtles do not leave the water. And nesting does not occur this far north.
I received several photos of the animal via emails from Jim Monaco and Press Sports Editor Cailin Riley that evening. Sea turtles as a group are very distinguishable from other turtles by their long, flipper-like front feet. But they can be very difficult to identify to species, with one exception: the leatherback (Dermochelys coriacea).
This unusual sea turtle lacks the typical hard plastron, or upper shell, of most turtles. In its place it has a thick, flexible, leather-like outer skin of oil-saturated connective tissue embedded with a mosaic of tiny bones. This outer skin has seven prominent ridges running fore and aft on its topsides.
One of my references explains that the flexible outer skin is an adaptation for making deep dives, allowing the skin to compress under pressures that would crack the typical hard, inflexible turtle shell. I was surprised to learn that leatherbacks can dive as deep as whales—down to 4,300 feet!
Its oversized front flippers also are key in making those deep dives. Although whenever I’ve encountered leatherbacks in the water, they were barely moving; in one instance, I thought I was looking at a black garbage bag floating at the surface. But the big flippers enable this turtle to reach swim speeds of up to 22 mph. This ensures that it can make the underwater round trip before running out of oxygen.
Local photographer Kathryn Szoka, who was at the scene of the Long Beach stranding, described the large turtle’s movements as being limited to periodically raising its head. She added that within a short amount of time a surprisingly large crowd of onlookers had assembled, and it was not long before representatives of the State Department of Environmental Conservation, Southampton Town Trustees, Turtle Rescue of the Hamptons, and the Riverhead Foundation for Marine Research and Preservation arrived.
The cause of the incident, according to the Riverhead Foundation biologist, as relayed to me from Kathryn, was that the turtle had become “cold-stunned.” Sea turtles, being cold-blooded, or ectotherms, cannot regulate their internal body temperature by generating heat as mammals and birds do. Their body temperature mirrors that of the water in which they swim and, according to the National Oceanic and Atmospheric Administration monitoring station data, most of the Peconic Bay waters, including Noyac Bay, are currently in the low 50-degree range.
Once its body temperature drops below 55 degrees, most sea turtles cross a threshold for maintaining normal systemic function. Digestion fails as key enzymes are not produced, and feeding ceases. The heart rate drops to as low as two or three beats per minute. Respiration may not be detectable. And, of course, swimming ability is seriously impaired.
Cold-stunned turtles will float, but they are at the mercy of currents generated by wind and tide and cannot make their way offshore and south to warmer water. And this is the start of cold-stunning season on Long Island. Riverhead Foundation organizes and trains volunteers to patrol beaches where endangered cold-stunned sea turtles might wash ashore.
A notable exception to this rule among sea turtles is the leatherback, which can generate internal heat by metabolizing stored reserves of brown fat and maintain an internal body temperature that is as much as 32 degrees warmer than the ambient sea water. This, and several other characteristics of this fascinating creature—its large mass (reaching up to 6 feet in length and 1,300 pounds in weight) and countercurrent heat exchangers in its vascular system that restrict heat loss via oversized flippers—enables the leatherback to range into cold waters as far north as Newfoundland and the Bering Sea, and south to the Cape of Good Hope and New Zealand.
The leatherback has the largest distribution and home range of any reptile on earth, and is the most pelagic of all sea turtles. It is found in the Atlantic, Pacific and Indian oceans, where it will migrate among tropical, temperate and boreal waters to optimize foraging opportunities, and where sea temperatures may register as low as 45 degrees. One tagged individual logged a 3,600-mile trip across the Atlantic!
Another of its unusual characteristics is its diet. This huge creature can sustain itself on some of the lowest nutritional foods in the ocean: jellyfish, salp and other tunicates.
I was quite surprised to learn of this sighting for several reasons. First, I’ve encountered this amazing creature in the ocean but never in the shallow waters of the Peconic bays. And although our bay water temps are in the low 50-degree range, that should not be a problem for a large leatherback.
Something else must have caused the stranding, but I have not been able to talk to Riverhead Foundation staff before press time. I did learn that the magnificent turtle, unfortunately, died at their facility.