Deep-Diving Migrant of the Open Seas

What can dive deeper than a submarine, swims all by way of entire oceans, is roofed in polka-dots, and has a mouth straight out of a horror film?

It sounds much like the setup for a nasty joke, however leatherback sea turtles are all of this stuff and extra. Leatherbacks are probably finest acknowledged for his or her huge dimension and peculiar carapace. Nonetheless there’s further to those creatures than chances are you’ll understand. Be taught on to examine further regarding the world’s largest turtle.

Diving Deep

Leatherbacks are one among nature’s deep-diving superstars, able to descending to ocean depths that will crush completely completely different creatures instantly. The turtles typically glide down a complete lot of ft beneath the ocean’s flooring throughout the hunt for jellyfish, they usually can preserve submerged for spherical 90 minutes on a single breath.

The stress at these depths is immense, however leatherbacks can cope fairly merely on account of their distinctive carapace. Not like completely completely different sea turtle species, who’ve a inflexible, bony shell, a leatherback’s carapace is made up of small, interlocking dermal bones, referred to as osteoderms, coated by a thick, leathery pores and pores and pores and skin (subsequently the decide). From a distance, a leatherback’s pores and pores and pores and skin seems darkish gray, however rise up shut and as well as you’ll see that they’re coated in polka-dots, like some good reptilian dalmatian. This design permits their carapace to contract and broaden with altering stress on account of the turtle strikes between totally completely completely different depths.

Whereas dives a complete lot of ft down are the norm for leatherbacks, some turtles will often descend to extraordinary depths. A leatherback tagged by Nature Conservancy scientists in 2023 merely lately broke the doc for the deepest dive ever recorded by a marine reptile.

The turtle, nicknamed, Uke Sasakolo, was tagged all through the Solomon Islands in December 2023. After laying her eggs, the turtle swam southeast to her foraging grounds in New Zealand. At one diploma all by way of her journey, she dove on the very least 1,344 meters (4,409 ft) beneath the ocean’s flooring — a depth equal to these reached by US Navy submarines. (The tags doc depth inside an accuracy of 14.5 meters, so the true depth was between 1,329.5 and 1,358.5 meters.)

That individual turtle has a penchant for deep dives, reaching depths of bigger than 1,200 meters (>3,900 ft) on 4 completely completely different events. The earlier leatherback dive doc of 1,280 meters (4,199 ft) was recorded in 2006 southwest of Cape Verde, all through the Atlantic Ocean. 

Marathon Migrations

Uke Sasakolo was tagged as a part of a evaluation led by TNC, who labored with conservation rangers to tag 17 leatherback turtles all through the Solomon Islands to bigger perceive their migration routes and foraging grounds.

Plenty of the 17 tagged turtles swam south-east, to the chilly, productive waters of New Zealand. Quite a few took further adventurous routes. One turtle headed to the Good Barrier Reef after which onto Papua New Guinea, whereas one completely different turtle, named Aunty June, swam an astonishing 5,000 miles from the Solomon Islands to the waters off of Baja, California in lower than a yr. 

Leatherbacks have the widest worldwide distribution of any reptile, present in each ocean along with the Arctic and Antarctic Oceans. They undertake a few of the world’s longest migrations, and turtles from totally completely completely different populations have totally completely completely different migratory routes. The turtles that nest at TNC’s evaluation web site on-line all through the Solomon Islands swim to foraging grounds close to New Zealand, southern Australia, and California. Turtles that nest all through the Caribbean head northwards to forage off the coast of Nova Scotia. Japanese Pacific leatherbacks, throughout the meantime, nest on the coast of Mexico and Costa Rica and migrate south to waters off the west coast of South America. And the leatherbacks that nest in central Indonesia swim north to the South China Sea.

These distinctive journeys are what make defending this species so sturdy. Monitoring and defending turtles on their nesting seashores is crucial, nonetheless it completely’s all for naught if these turtles are hooked on a long-line fishery 1000’s of miles distant. TNC is working with scientists in New Zealand and Australia to aim to defend Haevo’s leatherbacks at their foraging grounds, which overlap with a wide range of long-line fisheries.

Little Mouth of Horrors

Take a peak down a leatherback’s throat, and as well as you’ll be greeted with a scene straight out of a horror film. Their esophagus is coated with backward-curved spines, referred to as esophageal pallipae, which like rhino horns and human fingernails are created from keratin.

Leatherback turtles swallow plenty of seawater as they chomp down on jellyfish, and the pallipae assist maintain their prey in place on account of the turtles expel that additional seawater as soon as extra out of their mouths. Fortuitously, leatherbacks aren’t liable to biting people, however I pity the jellyfish who face their final moments in that horrible maw.

A leatherback’s beak might also be notably designed to assist it chew down on slippy, squishy prey. Their beak has sharp edges and is curved in a zig-zag sample, paying homage to a jack-o-lantern’s grin. Their extended, wing-like flippers propel them by way of the water with beautiful grace, given how ungainly they’re above the bottom. (I do know, from private expertise, that being whacked on the shins by one among talked about flippers is a decidedly disagreeable expertise.)

Historic and Imperiled

The leatherback’s evolutionary origins stretch as soon as extra into deep time. Their ancestors swam all through the oceans 100 million years before now, whereas tyrannosaurs and triceratops roamed the shorelines.

As we talk, leatherbacks are thought-about a globally susceptible species, with plenty of their sub-populations declining shortly. The turtles all through the Western Pacific are thought-about critically endangered, with only one,400 breeding adults thought to outlive.

Nature Conservancy scientists are working with conservation rangers all through the Solomon Islands to look at leatherback nesting seashores. The rangers, which embody the nation’s first ladies rangers, collect knowledge on nests, acquire eggs and swap them to specific hatcheries, and assist defend the nesting females from poachers.

Hopefully, their efforts will assist guarantee these distinctive giants of the deep survive.