On Monday, February 3, 2014 at 6:30pm, the Orleans Conservation Trust (OCT) hosted the second of five presentations associated with our 2014 Winter & Spring Lecture Series at the Orleans Yacht Club.
Despite the steady snow beating against the Orleans Yacht Club windows, 20 hardy souls braved the miserable driving conditions to hear Dennis Murley, Science Coordinator at MA Audubon Wellfleet Bay Wildlife Sanctuary discuss the higher than usual sea turtle strandings over the last two years.
Murley began his presentation by first explaining which sea turtles are found off the shores of the Cape: the Green sea turtle, Kemp’s ridley, Loggerhead, and Leatherback. Murley noted that the Leatherbacks are the largest sea turtles in the world and the species most commonly seen in southern New England waters. They can reach lengths of 8 feet and can weigh up to 1500 pounds. Unlike the other local sea turtles, Leatherbacks do not become cold stunned in the fall/ winter because they have the unique ability to generate their own heat, allowing them to swim in much colder waters than other sea turtles throughout the entire year.
Murley went on to talk about the life history of a sea turtle as well as the recent strandings between 2012 and 2014. Using a number of graphs and aerial maps of the Cape, Murley identified how many strandings took place, where, and of what species. The largest number of strandings in recorded history occurred in 2012 when more than 400 turtles were found along the shores of Cape Cod Bay, between Sandwich and Provincetown. This was nearly double the total strandings in any other year dating back to 1999.
“So why do turtle strandings occur and why are they becoming increasingly common” an attendee asked? Murley explained that the term “cold stunning” refers to the hypothermic reaction that occurs when sea turtles are exposed to prolonged cold water temperatures. Other than the Leatherback turtle, sea turtles are affected by the cold stunning because they are cold-blooded reptiles that depend on external sources of heat to determine their body temperature. Therefore, in cold water they do not have the ability to warm themselves, and must instead migrate to warmer waters during winter months to survive.
While it is largely unknown why some sea turtle do not migrate south prior to the drop in water temperatures, it is thought by some that the turtles foraging north of Provincetown could simply be caught off guard or in a storm that pushes them into the Bay, preventing them from getting out of the Bay once the temperature drops rapidly after October.
As for the sudden rise in sea turtle strandings, Murley thought it might simply be the fact that we are doing a better job of protecting the turtles when they are laying their eggs, leading to a higher overall population of sea turtles, and we have more volunteers looking for cold stunned turtles washing ashore each year.
If you missed this presentation please join us on March 3, 2014 at 6:30pm at the Orleans Yacht Club for the next lecture entitled, “Sustainable Coastal Erosion Control: Is it Possible?” given by Jim O’Connell, a private Coastal Geologist and Coastal Land Use Specialist.