Why Are Leatherback Sea Turtles Endangered?
Unfortunately there are many reasons why leatherback sea turtles are endangered. Through this article we will delve into all the factors which surround this tragic topic. We will look into threats such as Pollution, Fisheries, Loss of Habitat and many more factors which you may not have even considered. So why are leatherback sea turtles endangered? Let’s take a closer look and find out more.
Why Endangered Leatherback Sea Turtles Matter
Leatherback sea turtles represent a group of reptiles that have been roaming the earth since the time of the dinosaurs. They have been travelling thousands of miles across the oceans for one hundred million years.
Similar to all types of sea turtles, the leatherback sea turtle finds itself at the top of many marine ecosystems. They intervene in different stages of the food chain. Like all megafauna they help to keep the oceans in healthy conditions. One of the leatherbacks favourite foods is jellyfish and they play an important role in keeping the population of the marine organisms in check.
Leatherback sea turtles also play an important role in ecotourism in coastal communities, providing them with a much needed source of income through ecotourism. In particular coastal communities in Indonesia, Malaysia, Papua New Guinea, the Philippines, the Solomon Islands and Timor-Leste. This group of countries and sovereign states located between the Pacific and Indian oceans is know as the Coral Triangle. The Coral Triangle is recognised as a global centre of marine biodiversity and a global priority for conservation.
Threats To Endangered Leatherback Sea Turtles
Pacific populations of leatherback sea turtles have declined over the last twenty years. There is only an estimated 34,000 to 36,000 nesting females left alive worldwide. The best estimates from scientists, are that approximately only one in every thousand survive. This is as a result of over harvesting and from interactions with fisheries. As Atlantic leatherbacks migrate vast distances across the ocean they are at great risk of getting caught in longline fisheries. With jellyfish being their main prey of choice, leatherbacks are particularly prone to swallowing plastic bags which can be lethal and even kill. Some leaatherbacks have been found to have almost 11 pounds of plastic in their stomachs.
Bycatch in Fishing Gear
All across the world hundreds of thousands of sea turtles are accidentally caught in fishing gear every year. This is known as ‘bycatch’. The main types of gear that cause bycatch are shrimp trawl nets, fishing gillnets, longline hooks and buoy lines attached to pot or traps. Sea turtle bycatch is a serious problem that can lead to serious injury and even death. When sea turtles become caught in the fishing gear for too long they are unable to reach the surface in time to breath and can drown. Sometimes they can swallow fishing hooks.
Loss and Degradation of Habitat
Leatherback sea turtles will swim to the coast to lay their eggs on the beach. Due to vehicle traffic and more human activities on beaches, sea level raises and increasing coastal developments, leatherbacks have had their nesting beaches disturbed and even destroyed.
Nutrient run-off from agriculture and sedimentation from clearing of land is destroying and damaging sea turtle feeding grounds like sea grass beds and coral reefs.
Other human-related affects include beachfront lighting, which can lead to nesting females being deterred from coming ashore to nest. Beachfront lighting can also disorient hatch-lings from finding the sea once they leave their nests.
Shoreline armouring, which is things like sea walls and other structures designed to prevent flooding leaves sea turtles without any dry sand. Leatherback sea turtles need dry sand so that they can lay their eggs and make a nest somewhere suitable.
Direct Harvest of Turtles and Eggs
Throughout recent history all sea turtles, including leatherbacks were killed for their meat and eggs for consumption all over the world. With leatherback sea turtles being officially recognised as an endangered species they are protected in many countries, sadly in some countries however their eggs are still collected. Additionally they are still killed for meat and other reasons such as for their leathery skin to make clothes and accessories.
On developed coastlines their is an increased threat of boats and watercraft causing injury or even death to leatherbacks. This happens when the leatherbacks come to the surface to feed, rest or breath. Vessel strikes are the cause of a significant amount of leatherback stranding’s with some reports suggesting as much as one third.
Ocean Pollution/Marine Debris
Another reason why leatherback sea turtles are endangered is from the vast amounts of increasing pollution and marine debris. As mentioned above with the bycatch fishing they can also get tangled in fishing gear once it has been discarded. This with other marine debris can seriously injure and kill leatherbacks. Additionally they may die after ingesting fishing line, balloons or plastic bags, plastic pieces, and other plastic debris which they can mistake for jellyfish, their favourite food.
Endangered Leatherback Sea Turtle Vital Statistics
We formally know this species as Leatherback Turtles, however their scientific name is a little harder to pronounce. The Leatherback species actual name is ‘Dermochelys Coriacea’. Yes, we prefer ‘Leatherback’ as a name too. It is however the only living species of the Dermochelys or Dermochelyidae family.
The leatherback sea turtles status is currently Highly Vulnerable. Over the last decade leatherback sea turtle numbers have been rapidly decreasing, mainly due to factors raised by humans. Destructive human activities are the reason why leatherback sea turtles may be endangered.
Length & Weight
The leatherback sea turtle is the largest of all living turtle species. Measuring between 1.4–2.2 m (4.5–7.2 ft), it’s no wonder these animals are the largest. They can grow to sizes bigger than most humans, but their size is only really appreciated up close. The scale of this turtle species is huge, and swimming next to one of these gentle giants in the oceans may still be a little intimidating.
Leatherback sea turtles weight varies for every individual, however their weight can vary between 250kg – 998kg (550 to 2,200 lb). To put this into comparison, the average human population weight is 62kgs per person. So the leatherback species can weight anywhere between 4 times – 15 times the weight of an average human.
Major habitat type
Open water and coastal habitats.
Carnivores, their diet consists exclusively of jellies and other soft-bodied invertebrates like tunicates and sea squirts.
The leatherback is the largest sea turtle in the world and one of the largest living reptiles. Their skin is rubbery and mostly black with pinkish-white coloring on it’s belly. Also they are the only species of sea turtle that lack scales. Leatherbacks have the largest front flippers of all sea turtles proportionally. They have paddle-shaped back flippers.
Unique to leatherbacks their bony shell is not visable. Instead it’s covered by a leathery layer of black or brown skin, this is where they get their leatherback name from. The leatherback is the only sea turtle that lacks a hard shell. Their carapace (shells) are dark with white spots. The carapace consists of small, interlocking dermal bones beneath the skin that overlie a supportive layer of connective tissue and fat and the deeper skeleton. Their carapace has seven ridges along its length and tapers to a blunt point.
Leatherback sea turtles that are juveniles will remain near the coast in tropical waters that are typically warmer than 26°C. Once they grow to the point where they exceed 100 cm in curved carapace (the hard upper shell of a tortoise) length they become adults. Once adults they will become pelagic meaning that they can live in the open ocean, even in temperatures that are below 10°C.
Previous Population and Distribution
As recent as 1982 the estimated global population was around 115,000 adult females. In 1996 it had declined to 30,000 to 40,000. Leatherback populations in the Pacific and Indian Oceans have undergone dramatic declines in the past forty years. For example, the nesting colony at Terengganu, Malaysia went from more than 3,000 females in 1968, to 20 in 1993, to just 2 in 1993 – there are no signs of recovery.
Current Population and Distribution
Leatherbacks have been recorded as far north as Alaska, and as far south as Africa’s Cape of Good Hope.
The Pacific may now have as few as 2,300 adult females.
Leatherback populations have not declined all over the world. Certain regions in South Africa have been protecting leatherbacks for thirty years and have subsequently seen the nesting population increase fourfold. Reports estimate that west African regions house between 10,000 to 11,000 turtles every nesting season.
The most important nesting beaches remaining in the Atlantic are found in Suriname, French Guiana, and Gabon. In the Pacific, the few remaining important beaches are in Indonesia, Mexico and Costa Rica, with other rookeries found in Nicaragua, Panama and Guatemala.
Mediterranean Sea, Northeast Atlantic Shelf Marine, Southern Australian Marine, Benguela Current, Humboldt Current, Agulhas Current, Western Australia Marine, Gulf of California, Canary Current, Sulu-Sulawesi Seas, Bismarck-Solomon Seas, Banda-Flores Sea, Great Barrier Reef, Palau Marine, Andaman Sea, East African Marine, West Madagascar Marine, Mesoamerican Caribbean Reef, Southern Caribbean Sea, Northeast Brazil Shelf Marine.
Scientists are using satellite telemetry to track leatherbacks migration patterns feeding areas and more importantly where they may come into contact with fisheries and their dangerous fishing gear. Scientists achieve this by placing small satellite tags on the turtles. These tags are completley harmless and will eventually fall off.