Sea turtles are a reminder of the resilience of early species, and the places life began from. The aquatic reptiles have been around for at least 110 million years, and today seven species remain, a few of which are highly endangered. Sea turtles are often associated with beach vacationing and casual snorkeling, and it’s strange to think of them as a species which also lived with dinosaurs.
Interestingly, Bermuda was probably one of the first, or indeed the first, to pass legislation towards the conservation of animals. When Bermuda was colonized in 1609, early settlers noted the abundance of fish, hogs, birds, and also turtles. For their long sea voyages, turtles also provided a source of fresh food. Once a turtle is caught, it is easy to stand it on its shell on the deck of a boat and keep at alive as available food for long periods of time. As a result, legislation was passed in 1620 which stated that turtles of a certain size could not be caught and eaten.
A few days ago I had the chance to attend a wonderful talk by Bermuda’s Jennifer Gray – head of the Bermuda Turtle Project. The project conducts research about turtles in our close-by waters, and promotes the conservation of the animals. The lecture was very interesting and I will outline a few of Ms. Gray’s main points below.
Firstly, only five of the seven worldwide species of turtle occur in Bermuda; the green, hawksbill, leatherback, loggerhead, and kemp’s ridley. The most common turtle seen is the Green turtle, the only species of turtle whose adult form feeds almost exclusively on seagrass. They are so named for the colour of the fat underneath their skin which is commonly sought after to make turtle soup. As a result, the green turtle is endangered.
The hawksbill turtle I named for its hawk-like beak used to scrape sponges off of rocks. The shell scutes of the species are intricately patterned and have been sold as a prized commodity. As a result, these animals are critically endangered.
The leatherback turtle is the largest living reptile, growing to a weight of 2,000 pounds. They are adapted to pelagic life in deep water, and as a result have leathery, oily skin, rather which covers the bone of their shell. This turtle is able to tolerate the coldest living temperatures of any turtle, and has been seen as far as Iceland.
The Kemp’s ridley is a critically endangered turtle which hatches on the east coast of the U.S., and whose juvenile forms sometimes find themselves in Bermuda waters.
Loggerhead turtles are characterized by a large head with powerful jaws. In their juvenile form, they spend their first months in the sargasso sea, sustained by floating mats of sargassum weed. In powerful winter storms, these turtles can sometimes be found washed up on Bermuda’s beaches.
To understand why only certain turtles at certain life stages frequent Bermuda, we must first understand the life cycle of the turtle.
Bermuda is situated in a hotspot of ocean activity; the Sargasso Sea. As you can see, the “open ocean surface feeding zone” is referred to as “the lost years” because scientists did not know where hatchling turtles went during this period. We not know that young turtles use the Sargasso sea in the early years of their life, floating on the mats of sargassum weed which provides shelter and food.
In Bermuda, a few very young species of Loggerhead turtles have been found on island after hurricanes. It is thought that these turtles, which are found with gooseneck barnacles on their shells, a type of barnacle unique to pelagic oceanic zones, are blown in from the Sargasso sea. They are so young, in fact, that some still have their egg tooth.
Bermuda is home to intermediate and adult stage turtles, but we are not a suitable place for turtle breeding. What the Bermuda Turtle Project’s research has found is that the sex of a turtle is not determined by the X and Y chromosome, but rather the temperature of the sand where they are laid. Warmer temperatures tend to produce females, while colder regions produce males. As Bermuda is the northernmost coral reef habitat, our cool temperatures would, in theory, produce almost exclusively male turtles.
Through the Bermuda Turtle Project’s research initiatives, it is hoped that conservation of turtles the world over will increase. The Bermuda Turtle Project tags turtles in order to track where they go, how long they live, and collect other important pieces of data. Since the turtle is a species that travels great distances, one nation deciding to conserve these animals is not suficient for their survival as a whole.
To learn more about the Bermuda Turtle Project, visit their webpage here.