There are five species of South African marine turtles out of the seven species found worldwide. The iSimangaliso Wetland Park with its pristine beaches comprises one of the last significant laying sites in Africa for loggerheads and leatherbacks.
Marine turtles have a heritage going back at least 110 million years, and fall into two main subgroups. We have the unique family Dermochelyidae, which consists of a singe soft-shelled species, the leatherback. The second family, Cheloniidae, comprises the remaining six species, all of which are hard-shelled.
Each turtle specie has its own prey they feed on. This ensures they don’t compete for food or space as they roam different areas to feed.
Marine turtles are air breathers, although they can remain submerged for long periods. Most of their time is spent out in the oceans, with only the females coming to shore to nest and lay their eggs, where they return with almost magical accuracy to the very same beach where they hatched.
Endangered world-wide, females are most at risk when they come to shore as their meat and eggs are still eaten in parts of the world. Factors such as ocean pollution and gill nets are also having a massive impact on their chances of survival.
The Largest Living Turtle
The Leatherback turtle (Dermochelys coriacea) is the largest living turtle, and the fourth heaviest reptile after three crocodile species. With its carapace covered in skin and oily fat, it is distinctly different from the other six species with their characteristic bony shells.
With their tear-drop shaped body they have the most streamlined shape, with a large pair of front flippers to power them through the water. Dark grey to black in colour, leatherbacks have scattered white blotches and spots to their upper body, with a lightly coloured underside.
Able to dive up to 100m, they can remain under for 35 minute at a time. Jelly fish being part of their diet, they are at particular risk to pollution as they often mistake plastic for their prey.
Loggerhead turtles (Cheloniidae) are found throughout the world. Although known to reach up to 2.8m in length, their average size recorded is under 1m. The largest specimen weighed in at a whopping 450kg, although on average they are closer to 135kg. Along with the leatherback, the loggerhead is the only other of the South African marine turtles to nest annually along the iSimangaliso Wetland Park coast.
Sexual maturity is reached between 17 to 35 years, with a lifespan of between 47 to 67 years. Their low reproductive rate makes them vulnerable, females laying up to four clutches only every 2 to 3 years.
Along with green turtles, loggerheads are the marine species most kept in captivity.
Green turtles (Chelonia mydas), also known as the black turtle, or Pacific green turtle, are found throughout tropical and sub-tropical oceans of the world. Its common name is derived from the layer of green fat found under its carapace, while its shell is olive to black in colour.
Preferring shallow water, green turtles are mostly found in lagoons, and being herbivorous, feed mainly on seagrass. They are known to live up to 80 years.
Critically Endangered Hawksbill
The Hawksbill turtle (Eretmochelys imbricata) are primarily found in tropical coral reefs feeding on sponges, crustaceans, algae and fish.
Critically endangered, hawksbill have been considered a delicacy for centuries, dating back to 5th century BC, China. Hunted for their beautiful shells since Egyptian times, products labelled ‘tortoiseshell’ are normally from hawksbill. Up until 1994, the Japanese trade in hawksbill shells was in the region of 30 000kg.
The Olive Ridley turtle (Lepidochelys olivacea) is the most abundant of sea turtle species, although seldom seen off our coast making them the rarest of the South African marine turtles. They weigh between 34 to 35kg, reaching only around 600mm in length. They get their name from their pale green carapace, or shell.
Have you dived with one of these ancient marine creatures of the sea? Maybe you have witnessed one of our South African marine turtles annual nesting ritual along our coast at iSimangaliso Wetland Park. Let us know what your experience meant to you, we would love to hear your story.