Marine turtles have survived on Earth for more than 100 million years. There are seven species, living in open seas and coastal habitats. Many of them migrate for thousands of kilometres, even across entire oceans, between feeding and nesting grounds.
Six of the seven species are classified as endangered or critically endangered on the IUCN Red List of threatened species.
Male turtles don't leave the sea, but female turtles come ashore to lay their eggs on sandy beaches during the nesting season - during which she can lay hundreds of eggs
But relatively few young turtles reach maturity. Hatchlings are often killed by predators such as crabs, foxes and birds as they make their way from the nest to the sea. Once in the sea, many more small turtles are taken by fish.
The long time to reach maturity and the many natural dangers faced by hatchlings and juveniles mean that as few as 1 in 1,000 turtle eggs will survive to adulthood.
Why turtles need help
The drastic decline in marine turtle populations around the world is due in part to hunting and poaching for their meat, eggs, skin and shell.
In many countries, young marine turtles are caught, stuffed and sold to tourists as curios. International trade still exists despite all seven species being listed on Appendix I of CITES, which prohibits international trade in rare species like turtles.
Tens of thousands of marine turtles die each year when they become trapped in fishing and shrimping nets and on hooks. Known as bycatch, this accidental capture is one of the greatest threats to marine turtles.
Like many endangered species, marine turtles are vulnerable to the changes in their habitat. The coral reefs and seagrass beds where they like to feed are being damaged and destroyed by unsustainable fishing practices and sedimentation as a result of human activities on land.
Disturbance on nesting beaches can also make it impossible for female turtles to dig nests.
It's a natural part of the marine turtle life cycle that few of the eggs laid will hatch into turtles and survive to adulthood - but the disturbances caused by people either harvesting turtle eggs, or damaging nesting beaches and feeding grounds means the scales have become tipped even more heavily against marine turtles.
What we're doing - and how you can help
WWF works on many aspects of marine turtle conservation, such as reducing the loss and degradation of marine turtle habitats, reducing the negative impact of bycatch on marine turtles.
We're also helping reduce the unsustainable use and illegal trade in marine turtles and turtle products, working with TRAFFIC (the wildlife trade monitoring network) to help governments enforce restrictions on the trade in live animals, shells and other products.
Colombia, where WWF is working to increase the number of marine and coastal areas under protection, is one example of our marine turtle conservation work.
Colombia has coastlines on both the Pacific ocean and the Caribbean sea and is home to five of the seven species of marine turtle.
We're also supporting fishermen in using equipment and fishing methods that are less harmful to turtles.
Turtle populations are being monitored to increase our knowledge of different species. This information will help us create conservation strategies that reduce the deterioration and fragmentation of species’ habitats.
It will also help us persuade the Colombian government to incorporate marine conservation considerations into development policies, tourism and the fishing sector.