The World Conservation Union (IUCN) Red List Classifications for Sea Turtles



Species Red List Category Year Assessed











Critically Endangered


Olive Ridley



Kemp's Ridley

Critically Endangered



Data Deficient


Currently, all sea turtle species except the Australian flatback Natator depressus are included in the IUCN Red List as endangered or critically endangered (IUCN, 2007). Conserving sea turtles is particularly complex as it requires knowledge of different aspects of the sea turtle life-cycle such as biology, breeding, migration and foraging. As sea turtles spend more than 99% of their lives at sea they are relatively inaccessible and constrained largely to when females return to natal beaches to nest.

The IUCN Red list, a prioritised compilation of endangered wildlife species, can be a powerful tool for conservation planning, management, monitoring and for placing pressure on decision-makers and politicians, highlighting the vulnerability of endangered species.

IUCN Red List is widely considered to be the most objective and authoritative system for classifying species in terms of the risk of extinction. The IUCN aims to have the category of every species re-evaluated every 5 years if possible, or at least every ten years. This is done in a peer reviewed manner through IUCN Species Survival Commission (SSC) Specialist Groups, which are Red List Authorities responsible for a species, group of species or specific geographic area. See IUCN’s Marine Turtle Specialist Group: .

Reference and links:

Tomas, J., Aznar F., Raga, A. (2001) Feeding ecology of the loggerhead turtle Caretta caretta in the western Mediterranean. J. Zoology (2001) 255, 525-532.

IUCN Red Lists:


Pitfalls of the Red Listing for Sea Turtles

In the review of sea turtles and IUCN Red Listing, Seminoff and Shanker have identified some key shortcomings of the Red Listing for the conservation of sea turtles (Seminoff and Shanker, 2008).

  • A scientific or campaign tool? The influential nature of the IUCN Red Listing Status has meant that many species have been claimed to be on the ‘brink of extinction’ and used to fuel conservationist campaigns. This has meant that variations between populations, regions and abundance means that confusion has arisen over what populations are doing well and what are in danger of disappearing.
  • Regionally distinct populations: For a globally distributed species such as the sea turtle needs conservation listings need to recognize the existence of regionally distinct populations to effectively convey extinction probabilities
  • Longevity: IUCN criteria for assessing over a 10-year or 3-generation time frame. Long-lived species like the sea turtle use the 3-generation time frame, but with a single sea turtle generation being as much as 40 years this could mean 150 years to determine population changes.
  • Flexible criteria still problematic: Additional criteria and strategies for making status designations have included: geographic range (Criteria B); absolute number of mature individuals in the population (Criteria C and D) and quantitative analysis to determine probability of extinction in the wild (Criteria E). However these are all problematic for applying to sea turtle status for the reasons of: continued migrations despite potentially reduced populations, difficulty in measuring population size, inter-annual variability and inter-generational ‘time-bomb’ from egg harvest over multiple decades.
  • Shifting baselines and data deficiency: Other problems facing sea turtle listing include the ‘shifting baseline syndrome’ (Pauly, 1995 in Seminoff and Shanker, 2008) which means that some populations have been characterized as stable or increasing even if they are depleted relative to historic levels; and data availability, especially with historic data.
  • The journey is as valuable as the destination: The IUCN Red List is highly influential and ‘policy relevant’ and the assessment process is of exceptional value. However ‘the amassing of data from around the world that has taken countless hours to access and organize, and the resultant knowledge of differences among populations is overshadowed by the single status listing’ (Seminoff and Shanker, 2008: 59).
  • Solutions identified by Seminoff and Shanker suggest modifying existing IUCN Red List criteria, undertake regional assessments and establishing a new of conservation assessment.

Source: Seminoff, J. and Shanker, K. (2008). Marine turtles and IUCN Red Listing: A review of the process, the pitfalls, and novel assessment approaches. Journal of Experimental Marine Biology and Ecology (356) pp: 52-68.

Case Study- Change Of IUCN Status For "Mediterranean" Green Turtle

MEDASSET Considers Change a 'Step Backwards' for Conservation, Scientists see the IUCN Red List Status as an objective tool

The IUCN Marine Turtle Specialist Group (MTSG) has recently changed the IUCN Red list (World Conservation Union) status of the green turtle in the Mediterranean from a regional critically endangered status, to only an endangered global listing. The IUCN Red List, a prioritised compilation of endangered wildlife species, can be a powerful tool for conservation planning, management, monitoring and for placing pressure on decision-makers and politicians, highlighting the vulnerability of endangered species. At this time there is "insufficient and improper justification" for the green turtle to be classified as a subpopulation within the Mediterranean, according to listing criteria. MEDASSET considers that this devalued status could potentially jeopardize conservation efforts in the region.

MTSG's decision may be a step backward for green turtle conservation in the Mediterranean as it may jeopardise regional conservation efforts of a population estimated at only 250-500 nesting females! So far, the "critically endangered" status of the green turtle in the Mediterranean has been crucial for pushing the very few protection measures and political support available, to salvage and recover the species. To determine suitable listing for the green turtle in the Mediterranean, appropriate documentation to meet special IUCN subpopulation criteria is needed. Considering that these studies take several years and IUCN listing procedures are rather slow, by the time the process is complete there may be no turtles left to protect! The fact that they nest primarily in non-EU member states, restricting the influence of strong EU Environmental legislation, further exacerbates the problem.

MEDASSET proposed that during this 'data deficient period', the green turtle population in the Mediterranean retain its listing with a time allowance for research and conservation reasons, before such a sudden devaluation takes place. The IUCN Red list has been increasingly powerful and relevant for "concentrating minds on true priorities", let’s hope that this devalued status of the green turtle in the Mediterranean does not distract from its critical conservation need.

Scientists argue that...

The IUCN must base its decisions on fact not feeling and at present sufficient data is not available to support the green turtle in the Mediterranean as a separate sub-population.

Genetic studies are the only way forward to determine true listing of the species in the Mediterranean.

If the Mediterranean green turtle is listed as a subpopulation, it could potentially affect green turtle's listing globally. Obviously the green turtles in the Mediterranean needs far more help than those in other parts of the world, but with the listing change they both have an endangered status. It works both ways - if Mediterranean greens are at a later date declared a separate sub-population, should we consider listing others as only vulnerable?
A system is needed that allows conservationists to prioritise their efforts; the current system certainly needs refining!

Source: MEDASSET (2006) Change of IUCN Status for ‘Mediterranean’ green turtle. Turtle Dives newsletter. Available online: