Knowledge of the interrelationships between habitats and life-stage development in marine turtles requires an understanding of recruitment, size and age at maturity, sex ratios, growth and sexual development rates, survivorship and nesting probabilities. These data may be used to determine the status and survival of turtle populations during earlier life stages and for the development of appropriate conservation strategies.
Nesting populations have been well documented in the Arabian Gulf, but scant information exists on foraging populations. Data on this dominant phase of their live cycle are critical to determine how turtle populations will be influenced by various natural (e.g. climate change) and anthropogenic (e.g. fishery pressure) stresses. Unfortunately, there is no published information for Arabian Gulf turtle sex ratios in the wild or on the population dynamics with regard to growth, survival and sex ratios, and no descriptions of non-adult components of the populations. These data are crucial for understanding the status of turtles in those life stages least studied by modern science.
Particularly lacking for the Gulf are long-term estimates of population abundance trends that are needed to model sea turtle demography and to develop a better understanding of long term ecological processes. Population abundance estimates, such as those based on foraging ground capture–mark–recapture programs, which we aim to conduct in the present study, can provide these detailed sex and age-class-specific demographic information.
And all of this is linked to climate change: Mean global surface temperatures are reported to have warmed by approximately 0.6°C in the last century at a an unprecedented rate and modeled projections for climate change in the next 100 years predict further accelerated warming. Biodiversity conservation strategies must therefore look to the future and plan for potential outcomes over a range of possible changes in global, regional and local climate, but anticipating species’ reactions to climate change is problematic given the time frames and temperature gradients. There is a growing body of literature documenting advances in the annual phenology (timing of seasonal activities) of many animal and plant species in concert with observed climate change, and a common result is that spring events occur earlier (such as arrival at nesting grounds). If marine turtles are not able to adapt to changes such as these, this could have notable repercussions for turtles nesting in the Gulf (where nesting might continue so that nests are exposed to lethally high incubation temperatures). We suggest that the Arabian Gulf offers a ‘living laboratory’ for understanding impacts on population demographics as a result of climate extremes, and that our findings will inform governments and conservation agencies to develop effective and efficient management interventions.
Funded by Qatar Foundation and in a three-way partnership between the Environmental Studies Center at Qatar University, the Marine Research Foundation in Sabah, Malaysia, and the Environmental Futures Centre at Griffith University, Australia, this project is pioneering in-water reproductive biology studies of sea turtles in the Gulf. This is the first time work has been done on foraging turtles in the entire region – up to now all knowledge of sea turtles has been derived from the nesting beaches. But nesting beaches only host adult female turtles. What about the males? And what about the juveniles? Are there enough males and females to keep the population robust? With turtle sex determined by temperature – warmer leads to more females – what will happen to turtle populations in the face of climate change? The Gulf offers an opportunity to study real-time climate change firsthand.
This work was funded by the Qatar Foundation.