Sea turtles mistake plastic bags for jellyfish.

Ecology: Why Are Sea Turtles Listed as an Endangered Species?

Turtles, which have existed for millions of years, survive against a lot of odds. However, as resilient as they are, they have fared extremely poorly in recent times. Many of the factors that are slowly killing off turtles are human-made ones. Most of the species of sea turtles are in need of conservation to save them from extinction. Pollution, loss of habitat and overexploitation are some of the factors that humans have been familiar with and responsible for for ages. On top of these, climate change too has been playing a major role in wiping out these animals.

How are sea turtles endangered?

Right from the day they’re hatched, it is a constant struggle for the sea turtles to survive. According to studies, out of every 1000 sea turtle eggs that are laid, only around one of them makes it to adulthood, due to both natural and man-made causes. And those who do survive are under constant threat from humans. For instance, in some regions, they’re hunted for their eggs, meat and shells. Beaches, which are some of their habitats, are developed. Oil spills and marine debris pollute their waters.

For the past few years, another threat that has cropped up is climate change. Stronger storms and rising sea levels erode and destroy beaches. Ocean currents change due to warmer temperatures of the water, which introduces the sea turtles to new predators. In addition, it also harms the coral reefs that some species of turtles need for survival. The warmer temperatures of the beach sand also affect the population of the sea turtles. The temperature of the sand influences the gender of the offspring when the eggs are laid. Scientists claim that warmer temperatures may create a shortage of male offspring, thus adding to the factors that may lead to the turtles’ extinction. All the population of sea turtles in the US have been listed as endangered or under threat by the US Endangered Species Act (ESA).

Many of the increasing threats that the sea turtles face is created by the actions of humans, like those listed below.

Artificial lighting

Artificial lighting is one of the greatest threats to the sea turtles’ survival. When they hatch, the sea turtles’ evolutionary instinct pushes them to move towards the brightest light in view. Naturally, this would be the moon or the sun, which leads them towards the ocean horizon, taking them to their natural ecosystem. But now, with the continuous expansion of cities, construction of hotels and condos on the coasts has shot up exponentially.

Thus, the artificial lighting of these buildings creates chaos when the baby sea turtles hatch. Natural light is replaced with artificial light. Thus, the turtles’ natural source of guiding light is now replaced, and the tiny hatchlings move towards the artificial light. With most of the coasts of the beaches where the sea turtles nest brightly lit with buildings, it is easy for the hatchlings to become confused. Now, very few of them make successful trips to the oceans. Most of them head towards the city lights into the traffic.

Sea turtles' first instinct is to follow the brightest light.
Sea turtles’ first instinct is to follow the brightest light. credit@ Yahoo

Since artificial lighting has been proven to be extremely harmful to the offspring, there have been many significant conservation efforts taken up by conservation groups and Marine Life programs. They seek to educate the public about conserving sea turtles. Communities living in the beach areas have been warned of the effects the bright lighting has on the sea turtles. Hence, there have been significant efforts to darken the beaches. One of the ways this is done is by replacing the harmful and bright artificial lighting with turtle-safe-lights. Some of the communities have taken up official sea turtle protection regulations, like Florida’s ‘Lights out’ policy. On the east coast of Florida, some parts of the beach where sea turtles nest are protected by fences. Moreover, conservationists monitor the tiny turtles and relocate the lost sea turtles back to the beach.

Bycatch

Imprecise fishing methods leading to bycatch is one of the contemporary and significant threats to sea turtles. Long-lining is one of the major causes of the accidental death of sea turtles. The black-market demand for tortoiseshell has shot up, both for decoration and supposed health benefits.

 When sea turtles are caught in fishermen’s nets, it is impossible for them to surface.
When sea turtles are caught in fishermen’s nets, it is impossible for them to surface. credit@ atmo.uk

Sea turtles must surface from time to time for breathing. When they are caught in fishermen’s net, it is impossible for them to surface. Thus, they drown to death. Studies conducted in 2007 show that nearly a thousand sea turtles were killed over the course of a few months in the Bay of Bengal due to netting.

However, a few relatively inexpensive changes made to fishing techniques can dramatically bring down the mortality rate of sea turtles. These include using slightly larger traps and hooks from which the turtles can escape. Sea turtle bycatch can also be reduced with the use of turtle excluder devices (TEDs).

Magnetic interference

Ferrous metal wire mesh screens are set up for protecting sea turtle nests.
Ferrous metal wire mesh screens are set up for protecting sea turtle nests. credit@ newfloridians

Ferrous metal wire mesh screens are set up with the good intention of protecting sea turtle nests from their natural predators by excavating and eating the eggs and the babies. However, this comes with its own set of problems. A new concern arising from the wire mesh screens is that it interferes with the development of the tiny sea turtles’ delicate magnetic sense. Due to the magnetic field interference from the mesh screens, the turtles’ magnetic field may not develop at the normal rate. Some turtle species and their hatchlings could also be affected due to the presence of magnetic fields from iron debris, steel seawalls, power cables and other human activities which locally alter the earth’s magnetic field.

Poaching

The black-market demand for the meat and eggs of sea turtles has brought down its population at a dangerous rate
The black-market demand for the meat and eggs of sea turtles has brought down its population at a dangerous rate. Credit@ Philippines Daily Encounter

What animal isn’t harmed by poaching? The black-market demand for the meat and eggs of sea turtles has brought down its population at a dangerous rate. While this is a growing problem around the world, it is more pronounced in the Philippines, China, Indonesia, India and the coastal nations of Latin America. According to estimates, around 35000 sea turtles are killed a year in Mexico. The same number amounts in Nicaragua too. In an attempt to save the sea turtles, conservationists in the US and Mexico have launched ‘Don’t Eat Sea Turtle’ campaigns.

Marine debris

For years, we have been warned of the harm that marine debris can do to marine animals. Sea turtles are threatened by every way in which human beings use plastic. While recycling is encouraged, not everyone does it. The amount of plastic in the beaches and oceans is growing at an alarming rate.

Sea turtles mistake marine debris, especially plastics, for jellyfish and eat it, only to end up in a dire state. For each species of sea turtle, the consumption of plastic is different. But when they do eat them, it clogs their intestines, leading to internal bleeding and eventually killing them. Turtles have also been found with plastic straws lodged in their noses and coins stuck in their throats. The chemicals present in the plastic also clog their airway and damage their internal organs. Moreover, the chemicals that the turtles ingest from the plastic can seep into their eggs, thus affecting their newborns. It is extremely unlikely that with so much of chemicals present in their system, the babies would survive.

Sea turtles mistake plastic bags for jellyfish
Sea turtles mistake plastic bags for jellyfish. Credit@ recycles.com

The abandoned fishing nets dumped on the beaches are no help either-the sea turtles easily become tangled in them. And when the baby turtles hatch on the beach, they have to find their way from land to the water by themselves. Scattered on their way are innumerable amounts of plastic. Many of them get trapped in plastic, and perish from lack of resources and the heat of the sun.

With the growing number of sea turtle deaths comes the growing concern regarding their endangerment. Research conducted regarding plastic consumption by sea turtles shows that each of the turtles had plastic in them. The research states that the most common items found in the turtles were fishing equipment, cigarette buds, tires and plastic in other forms.

Climate change

Climate change is something we’ve been more than familiar with for the past few years. The effects of climate change are felt all over the world, with temperatures fluctuating to the extreme, ice melting at a dangerous rate, severe droughts and heavy rainfalls and floods.

Rising temperature of the sand

Rising temperatures of the sand may result in an increased number of female offspring.
Rising temperatures of the sand may result in an increased number of female offspring. Credit@ Science

So how are sea turtles affected by climate change? Well, the temperature of the beach sand where the turtles lay their eggs determines the sex of the newborns. Studies show that when they are developing in their eggs, the rising temperature may result in too many females. This affects their life cycle and reproduction, thus affecting their population as a whole. This isn’t common with other animals. Warmer beach sand means more females, while cooler sand usually results in an equal number of males. Climate change has resulted in hotter temperatures, and it keeps getting hotter when the time comes for the sea turtles to lay their eggs.

While animals generally do adapt according to their environment, it would take generations for the sea turtles to adapt to the changing temperature. And it is important to keep in mind that the temperature keeps changing and rising, which makes it all the more difficult for the marine animals to adapt.

Rising sea levels

The fluctuating temperature of the sand isn’t the only thing that affects the turtles. The rising of the sea levels affects the animals’ memory. The sea turtles have an imprinted map in their memory. This map guides them as to where they usually nest and lay eggs. With the rising sea levels comes dire affects that mess up their memory, thus making it difficult for them to nest. The rising water also takes away the turtles’ nesting areas. . The three most vulnerable areas in the US are southern Florida, Louisiana and Chesapeake Bay. Florida’s beaches are some of the most vital nesting habitats of the sea turtles.

In addition, with the temperature of the water rising, the sea turtles’ diet is also affected. These animals usually feed on coral reefs, which are impacted in disastrous ways when the temperature shoots up. Many marine animals need the coral reefs for survival. With the death of the reefs comes damage to countless marine life.

Increased storms

Climate change also results in an increased number and severity of storms. The storms wipe out the nesting grounds and the eggs that the turtles may have already laid. And with the rising sea levels and destruction of nesting grounds, these animals have to hunt for safer and new nesting grounds, which may take a while. The result is that reproduction and life cycles are affected.

Changing currents and migration

Migration is important for any animal species for their survival. Climate change alters the ocean currents. The ocean currents are the usual highways that turtles use when migrating. Changes in the ocean circulation mean that sea turtles have to change their movements, possibly shifting their migration and also the timing of their nesting periods.

Oil spills

All marine animals are affected by oil pollution. When oil spills occur, the oil lingers on the surface of the water, endangering sea turtles. The oil also affects the turtles at every stage of their life cycle. It poisons the sea turtles when it enters their digestive systems.  

 The oil poisons the sea turtles when it enters their digestive systems
The oil poisons the sea turtles when it enters their digestive systems. Credit@ Discovery

Sea turtles have a life cycle that depends on the sex of the turtle. They follow this cycle all through their life. Their life cycles start when, after hatching, they make their way to the water. When they reach their adult phase and mate, the females head over to their nesting grounds to lay the eggs. The males go back to feeding after mating. Oil spills affect this cycle. When the females ingest oil and lay their eggs, it has dire effects. Either the eggs won’t survive the chemicals and break, or the baby turtles are born with chemicals present in their system, thus leading to poor development. The oil spills also affect the diet of the sea turtles. If oil seeps into the things they consume, then the ingestion can lead to their internal organs being damaged.

Conclusion

Due to a variety of factors, the population of sea turtles has been ebbing lower. They have been added to the endangered species. While they may have survived millions of years, the modern human-dominated world has turned things around, making it a struggle for them to survive. Climate change, habitat loss, oil spills, poaching and beach development have rapidly increased the decline of the population of sea turtles. And their conservation history shows that they are unable to adapt to rapid changes. While the turtles did outlive the dinosaurs, it remains to be seen if they can survive in the modern day.

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