Worldwide declines in mammal, bird, reptile, amphibian, and fish abundance have prompted concerns that the planet is experiencing a sixth mass extinction. Factors implicated in these declines include over-exploitation, habitat loss, disease, introduction of invasive species, and climate change. Set against this backdrop, conservation measures have been introduced at various levels. Although these measures often lead to conservation success stories, it is more difficult to reverse population declines of broadly distributed groups (i.e. migratory species) of conservation concern like sea turtles.

This study presents the population status, size and tendencies of the seven species of sea turtle globally. For this purpose, 299 time series (ranging from 6 to 47 years) of annual nesting abundance were analyzed.

The obtained results show that the tendency for published estimates of population size in sea turtles is increasing rather than decreasing across the globe. A prevalence of upward trends in levels of abundance at regional management units for each species was found. The same general tendency was found when looking at the individual series. Additionally, the authors show that even small sea turtle populations have the capacity to recover.

It is concluded that the positive trends in abundance are likely linked to the effective protection of eggs and nesting females, as well as reduced bycatch. However, authors highlight that conservation concerns remain, such as the decline in leatherback turtles in the Eastern and Western Pacific, and that often the available time series are too short to identify trends in abundance. It is stated that the findings of this study highlight the importance of continued conservation and monitoring efforts that underpin this global conservation success story.

Mazaris AD, Schofield G, Gkazinou C, Almpanidou V, Hays GC (2017) Global sea turtle conservation successes. Science Advances 3:e1600730