Turtles - Why Are They Important?

As a scuba diver there is something magical about seeing a turtle during a dive, it could be an awful dive; zero visibility, currents, cold and miserable until you see a turtle. Everything else that has gone before it seems to melt away into the background and you focus on the graceful creature that seems to make moving through the water look so effortless. There’s no denying it, we love turtles and everything about them but they face an increasingly uncertain future because of mankind. We take a look at some of the challenges faced by turtles, what can be done about it and some of the great work being done by charities and conservation organisations to better protect their future

Types of Sea Turtle

There are 7 different species of sea turtle globally that range from the glorious reefs of the coral triangle here in southeast Asia to the seagrass beds of the Indian ocean and all the way through to the sand strewn beaches of the eastern pacific. Unfortunately over the last 200 years with the rise in human activity on an industrial scale sea turtles have found that their habitat is being destroyed at an alarming rate, accidental capture in longline fishing nets, face challenges from the amount of plastic in our oceans and are slaughtered for their meat and eggs. With so much against them its a wonder they still manage to survive at all. The 7 species of sea turtle are:

Leatherbacks

The largest of the sea turtles they range in size from 1-2.5m and can weight anywhere from 225 - 900 kg! Unlike their relatives, Leatherbacks do not have a hard shell but rather have a smooth, leathery skin that covers a flexible network of bone, hence their name. They are also the most widely distributed of all turtle species with their range extending from as far north as Alaska to the southern tip of New Zealand. They feed almost exclusively on soft bodied invertebrates such as jellyfish and tunicates. They are currently classified as vulnerable by the IUCN Red List.

Green Turtles

The second largest of sea turtle species after the Leatherback turtle, they can grow up around 1.2m in length and weigh up to 225kg. The adults are herbivores, preferring to feed on seagrass, seaweed and algae. Their beak is sharp and serrated which is perfectly suited to grazing on sea grass and scraping algae off of hard surfaces such as corals. Considered a keystone species they are responsible for helping to maintain healthy sea grass beds as they tend to just feed on the tops of the grass blades rather than pulling out the whole root, this allows the seagrass to grow back healthier and faster. They can be found in the sub tropical and tropical regions around the world and are particularly populous here in southeast Asia. Their names is derived from the colour of their fat and not their shell. They are currently listed as Endangered.

Hawksbill Turtles

A Hawksbill Turtle in the Perhentians Islands, Malaysia

Named after their bird like beak that is perfectly formed for feeding on coral sponges, hawksbill turtles tend to feed on little else. It is estimated they can consume over 500kg of sponges per year which is great for the health of coral reefs as otherwise the sponges would overgrow the them. They are often confused with Green turtles due to their similar shape and colour, however their shells can often be more highly coloured which leads them to often be considered as the most beautiful of turtle species. They can grow up to around 1m in length and weigh up to 90kg. Their habitat is generally in the tropical regions but they can be found in some sub tropical regions in the Atlantic, Pacific and Indian oceans. They are the most endangered of all turtle species and are listed as Critically Endangered due to the fact that their populations has declined by more than 80% in the last century as their shells were highly sought after for the ride in “tortoise shell” products.

Loggerheads

Another of the larger species of Turtle Loggerhead turtles are named after their large head and strong jaws which all them to eat hard shelled food such as crabs, weeks and conchs. Growing up to a length of around 1.2 meters and weighing up to 180kg they are comparable in size to the Green Turtle. Found in every ocean around the world, only the larger Leatherback turtle has a wider distribution than the Loggerhead. The highest concentration of nesting occurs just off the coast of Oman on Masirah Island in the middle east and are the most common species of turtle found in the Mediterranean sea. The biggest threat to Loggerhead turtles is entanglement in fishing nets which the turtle eventually ends up drowning. Currently the species is listed as Vulnerable.

Olive Ridley

Olive Ridley turtles are the second smallest species of marine turtle after the Kemp’s Ridley growing up to around 60cm in length and weighing in at around 35-45kg. They are considered to be the most abundant type of sea turtle and can be found in most tropical regions such as the Pacific, Indian and southern Atlantic Oceans. They are primarily a pelagic species, spending most of their time out in the open ocean which does lead to them being caught up in fishing nets as by-catch. In fact it is estimated that approximately 60,000 turtles, mainly the Olive Ridley are caught up and drowned in shrimp trawl nets each year. Olive Ridley turtles are omnivorous and eat a variety of prey such as lobster, crabs, jellyfish, sea urchins algae and fish. Although they are the most abundant their numbers have decreased by around 50% over the past 50 years and are listed as Vulnerable.

Kemp’s Ridley

The smallest of all of the 7 sea turtles species the Kemp’s Ridley turtle can grow up to around 60cm and weight around 35-40kg. Until recently they were on the brink of extinction but thanks to strict laws protecting them and their nests on beaches in Mexico and Turtle excluder devices in fishing nets. During the 1940s an arribada of approximately 40,000 turtles was filmed, however due to hunting for their meat and eggs this had dropped to around only 200 nesting turtles in the 1980s. Thanks to the conservation efforts this has slowly but steadily recovered to around 7000 - 9000 nesting turtles today. They are found nesting primarily on the beaches of Mexico, particularly in the state of Tamaulipas and have been seen all along the Atlantic coast from the gulf of Mexico all the way up to Nova Scotia. They are known for their triangular shaped head and hooked beaks which allow them to forage for their favourite prey crabs. They are considered Critically Endangered.

Flatbacks

Flatback turtles are named after their distinctive carapace or shell which unlike the curved shell of other species is flattened. They can grow up to around 1m in length and weigh up to 90kg and have the smallest distribution of all marine turtles only being found in Australia. Often preyed on by saltwater crocodiles even whilst nesting their numbers are also affected by other predators such as Night Herons, Pelicand and feral pigs that feast upon the eggs in their nest to which they are especially susceptible as they only lay around 50 eggs per east compared to an average of 100-200 with other species. Despite being limited to a small area they are probably the least studied of all turtle species and are currently listed as Vulnerable.

A baby turtle is rescued from a nest by a Lang Tengah Turtle Watch Volunteer

How Can We Help?

Turtles are considered to be what is known as a keystone species and are considered critical to helping ensure our oceans and reefs stay healthy. For example, Leatherback turtles help to control the number of jellyfish in the ocean, Hawksbill turtles are key to maintaining healthy coral reefs by keeping sponge populations in check and Green sea turtles help to maintain healthy sea grass beds which can lock away huge amounts of carbon thus helping control global warming. Turtle nests are beneficial for beaches around the world as hatchlings that don’t survive and make it out of the nest provide an important source of nutrients to coastal vegetation and where there are turtles they play an important economic role by attracting tourists and scuba divers. However, they face a number of threats to their populations such as getting caught in fishing nets as by-catch, in the USA fishing nets are required by law to have Turtle Excluder Devices, but unfortunately this isn’t the case in many other parts of the world. Other threats include being hunted for their meat and eggs, in fact in some parts of southeast Asia such as Terengganu in Malaysia it is still legal to collect and sell turtle eggs which decimates local turtle numbers. But what can be done to help them? Thankfully there are numerous turtle conservation charities and projects to help educate and conserve these beautiful marine creatures. Some fantastic examples are Lang Tengah Turtle Watch which has outposts on Pulau Lang Tengah and also a partnership with the luxury YTL hotel, Tanjung Jara in Kuala Dungun. As locals will buy the concession to a beach for the right to collect and sell turtle eggs, Lang Tengah Turtle Watch will buy the eggs from the locals and hatch them thus providing an economic income for the concession holder and saving the eggs.

Sponsored turtle nests at Lang Tengah Turtle Watch, Tanjung Jara

Although nests are protected and sponsored, providing money to fund the efforts, only an estimated 1 in 1000 hatchlings will survive into adulthood so it is so important that this great work is continued. Other charities in Malaysia include the Perhentian Turtle Project and a new trend is growing where high end hotels such as The Taaras in Pulau Redang and Batu Batu Resort in Johor will have their own turtle hatcheries. I would particularly recommend visiting the Batu Batu resort to see the fantastic work being done there - they promise to ring your room if turtles start to hatch in the night and won’t hold them back and release them during the day like some other hotels so maximises the chance of the hatchling surviving.

So, hopefully you have managed to learn a little about sea turtles, the threats they face and how we can help them. Next time you’re scuba diving and see one, just think about how lucky you are and help to spread the word about what needs to be done to save them.

A Green Turtle at Pulau Sipadan, Malaysia