Leatherback turtles are threatened by many human-caused hazards, including fishing, development of coastal beaches, climate change, hunting and pollution.
Most people don't think about where their seafood comes from. In fact, unlike beef, chicken and pork, most seafood is taken straight from the wild. Fisheries use many techniques to entangle, hook, corral, and trap marine animals for human consumption, including longlines, gillnets, and trawls. But these methods don't just catch fish, they also catch sea turtles, dolphins, seabirds, and other vulnerable marine life. This is called "bycatch" or incidental capture.
ARTICLE: Not Such a Fine Kettle of Fish.
Thousands of leatherbacks are hooked or entangled in longlines and gillnets each year. Encounters with this fishing gear can result in severe injuries or can cause turtles to drown if they are unable to surface to breathe.
Sea turtle habitats are degraded and destroyed by coastal development. Commercial development – such as hotels and houses – and beach armoring projects – such as jetties and sea walls – along shorelines damage the beaches that sea turtles rely on for nesting, while ship traffic and sea floor dredging alter the vegetation of their undersea habitats.
Leatherbacks tend to nest on high-energy beaches with extensive, wide sandy areas between the high tide line and vegetation. Human-made alterations of these beach characteristics can drive away leatherbacks looking for a place to nest.
One of the less well-known effects of climate change is that it may upset the natural ratio of male to female sea turtle hatchlings. Rather than being determined by specific chromosomes such as in humans, the sex of leatherback sea turtles (and other sea turtles) is determined by the temperature of the sand surrounding the eggs. Higher temperatures during incubation tend to produce more females. Over time, if leatherbacks are unable to respond to rising sand temperatures by moving to cooler nesting beaches, the natural sex ratio of their populations might become almost completely female with no males produced.
Melting ice caps as a product of climate change can also cause sea levels to rise, resulting in more erosion and changing shorelines, which will affect viable nesting beaches. Ocean acidification, coral bleaching, changing ocean currents and extreme weather patterns all cause adverse effects on sea turtle habitats and the fundamental oceanographic processes on which sea turtles rely.
Marine pollution has a direct impact on sea turtles. Many leatherbacks die when they ingest or become entangled in discarded items, including plastics, abandoned fishing gear, harmful by-products of hydrocarbon (i.e. oil and gas) extraction, and other debris.
Leatherbacks' diet is composed primarily of jellyfish, and because of this dietary preference they sometimes confuse floating plastic bags and other debris for a tasty meal. When a leatherback ingests a piece of plastic, it often blocks the turtles' intestines, making it impossible to continue eating.
|With a leatherback's poor vision, a delicious jellyfish and a plastic bag look the same in the ocean.|
ARTICLE: There’s a Future in Plastics.
Other pollutants, like light and chemicals are also dangerous. Light pollution disrupts nesting behavior by adult female turtles as well as hatchlings' ability to find their way to the sea, which may lead to their death. Chemical pollutants can weaken sea turtles' immune systems, making them more susceptible to disease.
IN DEPTH: Learn about threats to all sea turtles.