Sea turtles face threats on nesting beaches, in their feeding grounds and in the open ocean. Many of the greatest threats to sea turtles are caused by humans. But there are things we can do to help.
Sea turtles were once intensively hunted for their meat and eggs. Laws and education efforts all over the world have decreased the number of turtles being eaten by humans. Unfortunately, turtle meat and eggs are still consumed in countries where laws are not strictly enforced.
The commercial fishery that accidentally kills the most sea turtles is bottom trawling to catch shrimp in the Gulf of California. Unattended fishing gear is also a problem, especially in the open ocean. Turtles often become entangled in longlines or gillnets. They also become stuck in traps, pots and dredges. Turtle excluder devices (TEDs) for nets and other traps have helped reduce the number of sea turtles being accidentally caught.
Trash. Turtles eat a wide array of the 24,000 metric tons of floating trash dumped in the ocean each year. This includes such items as bags, sheets, pellets, balloons and abandoned fishing line. Sea turtles may mistake the floating plastic for jellyfish, a common food item. When turtles eat plastic, it causes many health concerns, including blocked intestines, malnutrition, suffocation, ulcers and starvation. Ingested plastics also release toxins that accumulate in the turtles tissues. These toxins lead to thinner eggshells, tissue damage and unusual behavior.
Artificial lighting. Artificial light impacts nesting females and hatchlings. Females appear to prefer nesting on beaches free of artificial lighting or shadowed. Hatchlings automatically move towards the ocean using reflected moonlight or starlight on the water as a guide. Artificial light is brighter and can confuse them so they navigate inland towards that light and away from the ocean. Artificial lighting causes tens of thousands of hatchling deaths per year.
Changes in global temperatures can affect the turtles in many ways.
- Since the sex of sea turtle hatchlings depends on the temperature at which the eggs were incubated, high sand temperatures may change sex ratios resulting in too few males to sustain the population.
- As water levels rise, a number of good nesting beaches will be lost.
- The areas where sea turtles feed may be dramatically altered by climate change.
Habitat destruction and intrusion on the habitat by humans is a serious threat to sea turtles. Beach development for people deprives the turtles of good nesting areas, forcing them to leave or nest closer to the water.
Growth of cities often leads to the siltation of sandy beaches and the construction of docks and marinas can destroy near-shore habitats. Boat traffic and dredging damages habitat and can also injure or kill turtles when boats collide with turtles at or near the surface.
Sea turtles face different predators as they age.
Eggs and hatchlings are the most vulnerable. They may be eaten by a wide range of coastal predators, such as crabs, large lizards, small mammals (e.g. raccoons, coatis, dogs, coyotes, etc.) and a variety of birds of prey and shorebirds. They are also threatened by many types of insects and worms. The most destructive nest predator in the United States is the raccoon.
Young greens sea turtles can be eaten by cephalopods, sharks and other large fish once they are in the ocean.
Adults face fewer serious predators, although large marine predators such as sharks, seals and orcas will occasionally attack and eat adult sea turtles. Flatbacks are sometimes attacked by saltwater crocodiles. Nesting females are attacked by flies, feral dogs and humans.
Green turtles are also threatened by a disease known as fibropapillomatosis (FP). FP is a disease where the turtles develop multiple tumors on the skin and internal organs. It is a significant cause of death that has affected green turtle populations in several parts of the world. FP has also been seen in flatbacks, and may occur in other species as well.
All over the world the sea turtles continue to decline. Their conservation and recovery requires international cooperation in order to address all of the threats to these species. Most sea turtles are considered to be endangered.
In the U.S., the National Oceanic and Atmospheric Administration (NOAA) Fisheries and the U.S. Fish and Wildlife Service (USFWS) protect sea turtles. NOAA monitors the turtles while they are in the ocean and USFWS while they are on land. Federal and state agencies have developed regulations to eliminate or reduce threats to sea turtles. For example, NOAA works closely with the shrimp trawl fishing industry to develop turtle excluder devices (TEDs) and reduce the death of sea turtles accidentally caught in shrimp trawl gear. TEDs that are large enough to exclude even the largest sea turtles are now required in shrimp trawl nets. The USFWS, in partnership with other organizations, provides protection for sea turtles and their nests during the nesting season.
You can help too. Our lack of knowledge about the population and life history of sea turtles makes it very difficult to understand what these species need to survive and thrive. That’s why it’s important that students like you learn about sea turtles and take actions. In many places, workers and volunteers from many different organizations help protect the turtles during the nesting season. Volunteers help locate and protect nests, relocate nests threatened by disturbance or guide hatchlings to the ocean. Even after the eggs hatch, these volunteers can assist scientists as they uncover and count eggs and hatchlings left in the nest.
There are many other ways that we can help:
- Limit our use of plastics
- Refuse, Reduce, Reuse, Recycle
- Use only turtle friendly products
- Respect sea turtles beaches and nests
- Support sea turtle research
- Volunteer with a recommended sea turtle conservation organization
- Support your local sea turtle conservation organizations