Turtle populations round the world are endangered. Of the seven species of sea turtles, five are listed on the IUCN Red List of Endangered Species as either "endangered" or "critically endangered". Globally, the Kemp's ridley, hawksbill, and leatherback sea turtles are listed as "Critically Endangered", the loggerhead and green as "Endangered", the olive ridley as "Vulnerable" and the flatback as "Data Deficient".
The conservation and recovery of sea turtles requires national and international multi-lateral cooperation and agreements to ensure the survival of these highly migratory animals. For example, it is proposed that a regional programme of activities, involving all countries bordering the Bay of Bengal that come under the BOBLMEP is developed for the conservation of endangered marine turtles.
Human action presents both intentional and unintentional threats to the species' survival. Intentional threats include continued hunting, poaching and egg harvesting. More dangerous are unintentional threats, including boat strikes, fishermen's nets that lack turtle excluder devices, pollution and habitat destruction. Chemical pollution may create tumours; effluent from harbours near nesting sites may create disturbances; and light pollution may disorient hatchlings. Habitat loss usually occurs due to human development of nesting areas. Beach-front construction, land "reclamation" and increased tourism are examples of such development.
The greatest threat to turtles is a result of human activity. Eggs are often taken by humans from nests to be consumed for subsistence or as aphrodisiacs. Many turtles fall victim to fishing lines and nets, or are struck by boats. They also can die if they ingest floating plastic debris easily mistaken for their favourite food: jellyfish.
Plastic shopping bags look like squid or jellyfish to turtles so please be careful that the bags don't get into the rivers or the sea. Many plastic bags have become stuck in sea turtle intestinal tracts causing serious health problems and death. In addition, plastics of any kind that make their way out to sea will finally disintegrate and be consumed by turtles and other marine life that will never digest in their stomachs.
Natural predators at sea include predatory fish such as sharks and barracuda (Sphyraena sp.), estuarine crocodiles and orcas. Natural predators on the beach include ants, feral dogs, mongoose, water monitors, crabs and raptors. Wild boar are also known to attack nests. Crows, gulls, terns and raptors attack hatchlings as they emerge from the nest and head to the sea.
Importance to Ecosystems
Sea turtles play key roles in supporting ecosystems in the ocean as well as on land. Besides being a source of protein and nourishment to well being of wildlife at sea as well as on the beaches there are other benefits to ecosystems.
Sea turtles and dugongs act as grazing animals that constantly cut the grass short and help seagrass beds spread across the sea floor. Sea grass beds provide breeding grounds for numerous species of fish, shellfish and crustaceans. Without sea grass beds, many marine species harvested by fishermen would be lost, as would the lower levels of the food chain. This could result in many more marine species eventually becoming endangered or extinct.
Sea turtles have been found to support healthy reefs by controlling sponges which would otherwise out-compete reef-building corals for space.
Dune and beach vegetation are nourished and grow healthier and stronger as a result of nutrients from egg shells, unhatched eggs, trapped hatchings and carcasses. Healthy vegetation with strong root systems prevent beach erosion.
You may be interested in taking a look at further information about sea turtles in Sri Lanka and the best locations to go turtle watching.