Sea turtle populations have been seriously reduced worldwide through a number of human influences including artificial lighting, plastic and marine debris, beach erosion and coastal armoring and commercial fishing. Other influences include illegal sea turtle shell trade, oil spills, harvest for consumption, marine pollution, beach activities and climate change. Natural pressures on sea turtles include predation. For these reasons all species of sea turtle are in an imperiled state that warrants legal protection.
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Beach furniture can obstruct and entangle nesting sea turtles, but there are some simple steps to take that can reduce these potential impacts:
Although sea turtles can be agile in the water, on land they are not very mobile making them more susceptible to predation. Even in a natural environment, sea turtles, particularly eggs and hatchlings, face a myriad of threats from predators. Before even hatching, eggs are exposed to predators such as raccoons, crabs, ants, coyotes and boars, which raid nests and destroy eggs. In certain “hot spots” throughout the United States up to 50 percent of all sea turtle nests are destroyed as a result of predation, however natural predation impacts less than 10 percent of the nesting population in Escambia County. Humans sometimes unwillingly contribute to this problem by leaving trash/food on commonly nested beaches, attracting raccoons and other potential predators. Additionally, dogs have dug up sea turtle nests and can attack hatchlings, so it is important to keep them on a leash during nesting season.
When hatchlings enter the ocean, predation threats remain high as they make convenient snacks for birds, crabs, certain fish and other oceanic creatures. Young sea turtles have been known to use the seaweed they feed on as shelter from these potential predators. Once reaching the adult stage, a difficult task in itself, sea turtles are comparably far less vulnerable to predators besides the occasional shark attack. Specifically, tiger sharks have been known to eat sea turtles occassionally, while killer whales have been known to sometimes attack leatherback sea turtles. Overall, these natural threats are not the predominant reason why sea turtle populations have been diminishing, as they have endured predation for over 100 million years.
Climate change is one of the main threats facing sea turtles today. Increased air and water temperatures, as well as sea level rise, have the potential to do irreversible harm to current sea turtle populations. Negative impacts from climate change include habitat loss, coral bleaching, alterations to vital sea grass beds and the potential to change turtle sex ratios drastically.
Turtle nesting habitat is already being diminished from coastal erosion and overdevelopment of coastal areas. Rising sea levels will reduce nesting habitats even further. Climate change also has an effect on sea grass beds which juvenile turtles use to hide from predators, stay warm and also feed on these beds and the other marine life that call these beds home. As temperatures rise, so do toxic algal blooms. Toxic algal blooms are killing off sea grass beds by blocking out the sunlight and creating oxygen deficient zones which the grasses need to survive. Toxic algal blooms can also be fatal to turtles by creating large anaerobic zones and releasing a harmful mixture of other gases above the surface of the water. This can cause turtles to suffocate because when they come up for air they breathe in this toxic mixture of gases instead of the fresh air needed to survive while underwater for long periods of time.
The sex of sea turtles is determined by the temperature of the sand that the eggs are laid in and slight fluctuations in temperature, only a few tenths of a degree, can make the difference between turtles being born male or female. Male turtles develop in slightly cooler temperatures and females develop in warmer temperatures. If overall atmospheric temperatures rise anywhere from 1-3 degrees centigrade that could mean the vast majority of hatchlings would be born female, threatening future turtle populations even more.
The main reason sea turtle populations are in the state that they are now in is due to human activity. It is now our responsibility to do all that we can to conserve these magnificent creatures. We must work to undo the damage that has been done and do everything in our power to restore sea turtle populations and prevent them from dwindling into extinction.
To learn more about the impact that global warming is having on sea turtles, and the various other threats turtles face, click here.
The ever growing presence of plastic and other trash in Earth's oceans have and will become an increasing threat to the survival of sea turtles. Sea turtles have inward facing spines in their mouths that prevent prey from escaping. This evolutionary advantage has now become a disadvantage in many instances because it prevents a turtle from being able to regurgitate if it mistakenly eats trash resembling food.