The endangered leatherback sea turtle is an annual visitor along the shore of Owls Head Provincial Park, spotted here most recently feeding on jellyfish last July.
The World’s Best-Travelled Reptile
The leatherback sea turtle (Mi’kmawi’simk: mikjikj) is by a considerable stretch the world’s most well-travelled reptile, and among the most worldly of all vertebrate animals, with a migration on record by one individual of nearly 21,000 kilometres. (The longest measured annual migration of any animal is the meandering 70,000 to 90,000-km return trip of the Arctic tern from its breeding grounds in the Arctic to the Antarctic and back.)
Unique Among Sea Turtle Species
Of Earth’s seven sea turtle species, the leatherback is the only one that makes do without a hard shell. This might seem at first blush to put it at a disadvantage among its marine turtle cousins, but with an existence of 100 million years and counting, placing it in its selfsame body form among the famously toothy dinosaurs, the leatherback might beg to differ. What it lacks in armour it makes up for in fecundity and heft: a leatherback may attain a length of two metres from beak to tail and tip the scales at 1300 lbs. They are also long-lived, with a lifespan estimated at 45-50 years, or possibly up to 100 years, depending on the source consulted.
Fascinatingly, every adult leatherback turtle has a uniquely-shaped pink spot on the top of its head. This spot is thought to play a role in promoting migration by sensing seasonal changes in daylight.
4,000 feet under the surface
Here in the western Atlantic, leatherbacks that nest on tropical and subtropical beaches from French Guiana up to Florida make annual migrations north to dine on jellyfish and salps. More than a thousand leatherbacks are believed to visit the Maritimes every year, where they can be seen foraging in waters as shallow as a couple of metres, but more often go unseen offshore, where they are capable of diving as deep as 4000 feet (that’s more than a kilometre!) – deeper than most marine mammals – and of holding their breath on active dives for at least 85 minutes.
The leatherback has the widest global distribution of any reptile, nesting mainly on beaches in the tropics and subtropics, but feeding all over. Once common in all the world’s oceans save the Arctic and Antarctic, over the past few decades the global population has plummeted by an estimated 70%. Among the manifold reasons why this is bad news is the implications for commercial fisheries: the principal prey of leatherbacks—jellyfish—prey in turn on larval fish, the adults of which we find wrapped in cellophane at Sobeys. An adult leatherback may eat over 600 lion’s mane jellyfish per day, helping to keep their numbers in check.
Threats to the Leatherback Sea Turtles
In Atlantic Canada and throughout much of their range, leatherbacks are vulnerable to entanglement in longlines, buoy lines, mooring lines, floating lines and nets. Vessel collisions, marine pollution, acoustic disturbance and climate change are additional serious threats, as are turtle hunting, collection of eggs for human consumption, and loss and degradation of nesting habitat (females require soft-sand beaches for nesting as rocks can easily damage their soft underside).
Committee on the Status of Endangered Wildlife in Canada (COSEWIC) conservation status: ENDANGERED
You can help our leatherback sea turtles (not to mention very many of our now-endangered marine mammals) by forgoing net-caught seafood. Angling for abundant and/or invasive species in your area is a more sustainable alternative. You can also help by supporting charitable organizations like the Canadian Sea Turtle Network, which works to conserve endangered sea turtles in Canadian waters, and by lending your voice to calls to vastly expanded marine protected areas. More broadly, doing everything that is within your means to decarbonize your life benefits humanity and wildlife alike.