National Oceanic and Atmospheric Administration (Ocean Today)
Seven different species of sea (or marine) turtles grace our ocean waters, from the shallow seagrass beds of the Indian Ocean, to the colorful reefs of the Coral Triangle and the sandy beaches of the Eastern Pacific. While these highly migratory species periodically come ashore to either bask or nest, sea turtles spend the bulk of their lives in the ocean.
Over the last 200 years, human activities have tipped the scales against the survival of these ancient mariners. Slaughtered for their eggs, meat, skin, and shells, sea turtles suffer from poaching and over-exploitation. They also face habitat destruction and accidental capture—known as bycatch—in fishing gear. Climate change has an impact on turtle nesting sites; it alters sand temperatures, which then affects the sex of hatchlings. Nearly all species of sea turtle are now classified as endangered, with three of the seven existing species being critically endangered.
Kemp's Ridley Turtle
Olive Ridley Turtle
Threats to Sea Turtles
Sea turtles are a fundamental link in marine ecosystems. They help maintain the health of seagrass beds and coral reefs that benefit commercially valuable species such as shrimp, lobster, and tuna. Sea turtles are the live representatives of a group of reptiles that have existed on Earth and traveled our seas for the last 100 million years. Turtles have major cultural significance and tourism value.
Five of the seven species are found around the world, mainly in tropical and subtropical waters. The remaining two species, though, have relatively restricted ranges: Kemp's Ridley is found mainly in the Gulf of Mexico and the Flatback turtle around northern Australia and southern Papua New Guinea.
Loggerhead and hawksbill turtles are particularly vulnerable. Nearly all species of sea turtle are classified as Endangered. They are killed for their eggs, meat, skin and shells. They also face habitat destruction. Climate change has an impact on turtle nesting sites. As fishing activity expands, this threat is more of a problem.
Sea turtles journey between land and sea and swim thousands of ocean miles during their long lifetimes. They wait decades until they can reproduce, returning to the same beaches where they were born to lay their eggs. Females can lay hundreds of eggs in one nesting season, yet few will yield hatchlings that survive their first year of life. Beyond these significant natural challenges, sea turtles face multiple threats caused by humans as noted below.
Fisheries: Sea turtles virtually everywhere are affected by bycatch from fisheries. Worldwide, hundreds of thousands of sea turtles a year are accidentally caught in shrimp trawl nets, on longline hooks and in fishing gill-nets. Sea turtles need to reach the surface to breathe, and therefore many drown once caught.
Direct Take: Sea turtles and their eggs are killed by people throughout the world for food, and for products including oil, leather and shell.
Coastal Development: Sea turtle habitats are degraded and destroyed by coastal development. This includes both shoreline and seafloor alterations, such as nesting beach degradation, seafloor dredging, vessel traffic, construction, and alteration of vegetation.
Climate change: Climate change will increase the frequency of extreme weather events, result in loss of nesting beaches, and cause other alterations to critical sea turtle habitats and basic oceanographic processes. It may impact natural sex ratios of hatchlings and increase the likelihood of disease outbreaks for sea turtles.
Marine pollution is anything from a discarded plastic to a lost fishing net. Every ocean in the world is littered with some form of debris which resembles food for marine life. Many animals accidentally eat marine debris causing internal injury, intestinal blockage, and starvation. Once ingested, the plastic piles up in the turtles's stomach and can then obstruct bowels, preventing turtles from digesting food and leading them to starve to death. Light pollution disrupts nesting behavior and causes hatchling death by leading them away from the sea. Chemical pollutants can weaken sea turtles’ immune systems, making them susceptible to disease.
Habitat loss uncontrolled coastal development, vehicle traffic on beaches, and other human activities have directly destroyed or disturbed sea turtle nesting beaches around the world. Sea turtles are dependent on beaches for nesting. Lights from roads and buildings disorient hatchlings away from the sea, and vehicle traffic on beaches compacts the sand, making it impossible for female turtles to dig nests. Turtle feeding grounds such as coral reefs and seagrass beds are damaged and destroyed by activities onshore, including sedimentation from clearing of land and nutrient run-off from agriculture. Beach restoration projects for protecting seaside buildings have also been found to be harmful, through dredging and sand filling.
How You Can Help Protect Sea Turtles
Minimize beachfront lighting during the sea turtle nesting season by turning off, shielding, or redirecting lights.
Close blinds and draperies in oceanfront rooms at night during the nesting season to keep indoor lighting from reaching the beach.
Do not construct campfires on the beach. Sea turtle hatchlings are known to be attracted to the light emitted by campfires and crawl into fires and die.
Use your natural vision when walking on the beach at night. The use of flashlights and flash photography can deter turtles from coming ashore to nest or cause them to abort nesting attempts.
If you encounter a turtle on the beach at night, remain quiet, still, and at a distance, otherwise she may become frightened and return to the ocean without nesting.
Leave the tracks left by turtles undisturbed. Researchers use the tracks to identify the species of turtle that nested and to find and mark the nests for protection.
Properly dispose of your garbage. Turtles may mistake plastic bags, styrofoam, and trash floating in the water as food and die when this trash blocks their intestines.
Celebrate events without the use of helium balloon releases. Like plastic trash, balloons end up in the ocean, especially when released near the coast. Sea turtles mistakenly eat the balloons and die.
Remove recreational equipment, such as lounge chairs, cabanas, umbrellas, and boats, from the beach at night. Their presence can deter nesting attempts and interfere with the seaward journey of hatchlings.
Protect beach vegetation that stabilizes sand and the natural coastline.
When boating, stay alert and avoid sea turtles. Propeller and collision impacts from boats and ships can result in injury and death of sea turtles. Also, stay in channels and avoid running in seagrass beds to protect this important habitat from prop scarring and damage. Avoid anchoring boats in seagrass beds and coral reefs, which serve as important foraging and resting habitats for sea turtles.