What the IUCN says

First appearing more than 100 million years ago, marine turtles represent an ancient and distinctive part of the world's biological diversity. As recently as the 18th and 19th centuries, marine turtles were highly abundant, with some populations numbering well into the millions. In the last several hundred years, however, humans have overwhelmed the species' ability to maintain their numbers. We capture them intentionally for food, skin, and shell. We capture them accidentally in fisheries. We destroy their foraging, nesting, and resting habitats. Most recently, we have been polluting the environment in which they live, the oceans. Today, few populations of marine turtles are unaffected. Most are declining, often seriously. Many are extinct.

Currently, seven species are clearly recognized. They are:

Green turtle (Chelonia mydas)
Loggerhead (Caretta caretta)
Flatback (Natator depressus)
Hawksbill (Eretmochelys imbricata)
Leatherback (Dermochelys coriacea)
Olive ridley (Lepidochelys olivacea)
Kemp's ridley (Lepidochelys kempii)

Flatback turtle returns to the water after laying her eggs

Marine turtles have a fascinating life history. They are long-lived species that mature late in life and move great distances during their lifetimes. Marine turtles are excellent navigators, frequently migrating hundreds or even thousands of kilometres between foraging and nesting grounds. They spend their lives at sea but return to land to reproduce.

Adult females nest in multiyear cycles, usually 2-4 years. They come ashore several times to lay hundreds of eggs during a nesting season. After about 50 to 60 days of incubation, the hatchlings emerge and head for the ocean to begin life as pelagic drifters. This period is often referred to as the "Lost Years". In most cases, we do not know where the hatchlings go, or how long this period lasts.

While maturing over the course of several decades, marine turtles move in and out of a variety of ocean and coastal habitats. This open ocean existence often frustrates our efforts to study and conserve them. Survival to adulthood is low.

Endangered and Vulnerable

Presently, all species except the Australian flatback are listed in the IUCN Red List as Endangered or Vulnerable. All marine turtles are included in Appendix I of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), and all species except the flatback are listed in Appendices I and II of CMS (the Convention on the Conservation of Migratory Species of Wild Animals). There can be no doubt that if these magnificent animals are to be safeguarded from eventual extinction, comprehensive, focused and integrated efforts must be undertaken on a global scale.

Mapoon elders, children and volunteers drag ghost nets up the beach

Today, thousands of individuals in volunteer and government-supported management and conservation programs throughout the world are working to conserve marine turtles. Although marine turtles spend the majority of their time at sea, these programs primarily focus on nesting beach activities, an emphasis that has resulted in large gaps in our knowledge about these animals. Furthermore, recent population modeling suggests that conservation of eggs and hatchlings, without concurrent conservation of the older life stages, might be of limited value. The lack of international coordination also hampers conservation efforts. This is unfortunate as marine turtles are under assault throughout their lives as they move from the waters of one nation to another.

To date, one shortcoming of activities to promote marine turtle conservation has been our failure to address conservation issues in a systematic and unified way. The concept of integrated management is crucial to marine turtle conservation in several ways:

Marine turtle management should be incorporated into coastal management regimes to ensure that habitat quality and ecosystem functions are maintained.
Marine turtle management should be included at local, regional and global levels so that those people directly affected by management, as well as those who have influence over regional and global activities, are involved.
Management of any marine turtle species or population should be integrated across its entire geographic range so that activities in one part of the range do not undermine conservation management in other areas of its range.

For a number of years many people have debated whether declining populations of marine turtles should be exploited. Most recognize the significance of marine turtles in the cultural and social lives of many coastal people and the importance of these animals and their eggs as a source of protein. Too frequently, however, wide use by a growing human population, coupled with the migratory nature and slow rates of natural increase of these animals, has resulted in most utilization being non-sustainable. Clearly, failure to stop or reverse these declines will result in the eventual extinction of marine turtle populations.

Although the MTSG recognizes that utilization of marine turtles occurs in many areas and does not oppose all use, it does not support non-sustainable use. There are many areas where complete protection has been necessary for the management of marine turtles, and this is an important option for conservation planning. Because there are inherent difficulties with exploitation, we emphasize the need to involve the local people who utilize marine turtles in their conservation and management.

Mapoon elders and scientists work together on the Western Cape Turtle Project

At the heart of the debate is making appropriate decisions about use, an issue which is hard to resolve given our incomplete knowledge of these species and the amount of time required for the effects of over-exploitation to be noted. The group advocates informing and involving local people in the decision-making process while continuing to base management decisions on science.

Marine turtles serve important functions in the ecosystems in which they are found, although the details of those functions can be hard to clarify where populations currently are seriously depleted. For example, seagrass beds where green turtles graze regularly are more productive, nutrients are cycled more rapidly, and the grass blades have a higher protein content, thus benefiting other species. Furthermore, some populations of marine turtles, whose feeding areas may be hundreds or even thousands of kilometres from their nesting beaches, serve an important role in nutrient cycling by transporting massive quantities of nutrients from these feeding grounds to typically more nutrient-poor coastal and inshore habitats in the vicinity of the nesting beaches.

Without active intervention and management, marine turtle populations are expected to continue to decline to extinction. With the resulting loss of productivity within marine ecosystems, we can expect a resulting decline in quality of life for human populations dependent on coastal ecosystems.

Information on this page was sourced from the Marine Turtle Specialist Group within the IUCN