IMIS

Nesting turtle populations have been well documented in the Middle East, but scant information exists on foraging populations in the region. 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 Chelonia mydas or Eretmochelys imbricata on sex ratios in the wild or on the dynamics of turtle populations with regard to growth, survival and sex ratios and no descriptions of non-adult components of the populations. These data are crucial and among the top research priorities for understanding the status of turtles in those life stages least studied by modern science (NRC 2010). Particularly lacking for the Gulf are long-term estimates of population abundance trends that are needed to model sea turtle demography (sensu Chaloupka 2002) and to develop a better understanding of long term ecological processes (Inchausti & Halley 2001). 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 detailed sex and age-class-specific demographic information (Limpus & Chaloupka 1997, Chaloupka & Limpus 2001, 2002, Pilcher 2010a). Mean global surface temperatures are reported to have warmed by approximately 0.6°C in the last century at a an unprecedented rate (IPCC 2001, Brohan et al. 2006) and modeled projections for climate change in the next 100 years predict further accelerated warming (IPCC 2001). 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 (reviewed in Walther et al. 2002), 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). Over eighty percent of species (from plants to vertebrates) reviewed by Parmesan & Yohe (2003) exhibited shifts in phenology related in some way to climate change. We suggest that the Arabian Gulf offers a ‘living laboratory’ for understanding impacts on population demographics as a result of climate extremes, and that marine turtles are ideal study subjects.