Until recently nothing was known of hawksbill at-sea habitat in the Arabian region other than the location of nesting sites and inferences drawn from their spongivorous diet which suggested they inhabited only coral reef habitats. MRF served as the lead scientific authority for a four-year effort spearheaded by the Emirates Wildlife Society to understand sea turtle habitat use in the Arabian region alongside partners from Iran, Oman, the United Arab Emirates and Qatar.
The Arabian region comprises the Arabian Gulf (also known as the Persian Gulf, along with the Gulf of Oman and Arabian Sea. It supports large green turtle populations on Karan and Jana Islands in Saudi Arabia, and at Ras Al Jinz / Ras Al Hadd in Oman. Smaller nesting aggregations are found in Iran and Kuwait, and recently a nest was found in the UAE. There are hawksbill turtle nesting rookeries in Saudi Arabia, Iran, Kuwait, Qatar, Oman and the United Arab Emirates. Masirah Island, Oman supports one of the largest loggerhead rookeries in the world of thousands of nesting females along with hawksbill turtles and a small population of olive ridley turtles.
The Gulf is a unique environment which undergoes extreme water and air temperature fluctuations; as a result this climate has a profound impact on marine species development and distribution. Surface waters typically exceed 30°C for sustained periods and the Gulf can be likened to a natural living laboratory for understanding thermoregulatory behaviour by marine species in the face of climate change and elevated global temperatures.
Temperature is important because marine turtles are ectotherms and regulate internal body temperatures through behavioural responses to temperature shifts. Negative influences of changes in climate regimes include habitat availability and nesting success, nesting timing and periodicity, incubation success, gender ratios and hatchling fitness among others. Thus, the ability for turtles (and other species) to respond to temperature shifts may become more relevant in the face of rising global temperatures.
Marine turtles play valuable ecological roles as consumers and prey and they are indirectly linked to seabed and fisheries stability. Marine turtles can be indicator species of the relative health of habitats that support commercial fish and invertebrates (found in seagrass beds, open oceans and coral reefs among others) that are valued by mankind. Marine turtles also have non-consumptive uses such as tourism, education and research.
Satellite tracking data for 90 post-nesting female hawksbills (75 tracked by the project and 15 contributed by partners) from nesting sites in Iran, Oman, Qatar and the United Arab Emirates (UAE) were used to identify key foraging grounds, temporal activity patterns and potential migration bottlenecks.
The satellite tracks showed that turtles tended to stay near their nesting sites for varying periods of time, thus allowing us to estimate that they laid between three and six clutches of eggs per season. As they left their nesting grounds, most turtles moved south or southwest toward the corner of the Gulf shared by Qatar, Saudi Arabia, and the UAE, with only a few traveling into the Gulf of Salwa (between Qatar and Saudi Arabia). Even fewer went northward toward Saudi Arabia and Kuwait. Surprisingly, no turtles headed east toward Iran and the eastern reaches of the UAE, an area that receives the cleaner waters entering the Persian Gulf from the Sea of Oman. Outside the Gulf, Omani turtles headed south from the Damaniyat Islands, hugging the coast of Oman, rounding Ras Al Hadd toward foraging sites along the mainland coast between Masirah and Yemen. Masirah turtles were the laziest of all, moving just a few kilometers across to the mainland.
The most important results of this study, though, were the identification of the feeding grounds where turtles spend most of their time. Once they reached their destinations, the Gulf turtles occupied discrete and isolated foraging grounds that are dispersed across a huge swath of the southwest Gulf, then usually returned to the same areas following two- to three-month summer migrations. Their home ranges varied in size but overall were relatively small – and each turtle essentially lived on its own little feeding patch consisting of shallow areas with sparse hard substrate.
As a result of our findings, we have suggested (a) that industrial development (particularly urban and industrial infrastructure) of shallow water areas should be limited, thereby maximizing available foraging habitats for hawksbills, and (b) that fishery activities should be controlled to limit their effect on hawksbills. In Oman, the identification of ITAs was clearer, with Shannah and Quwayrah identified as being key foraging habitats for most turtles and with the waters off Ras Al Hadd—specifically a 20 km band along the shores between Damaniyat, Muscat, and Masirah—constituting an important bottle-neck for hawksbill turtles.
These data and analyses are expected to improve the overall understanding of hawksbill habitat and behaviour in a climate-challenged environment, contribute to our understanding of Important Turtle Areas in the Arabian region, and support sea turtle conservation-related policy decision-making at national and regional levels.
Seed funding for this work was provided by the Emirates Wildlife Society–World Wild Fund for Nature office in the UAE. Subsequent funding was provided by the numerous private sponsors: 7Days, Abu Dhabi Urban Planning Council, Bridgestone, CASP, College of the North Atlantic, Qatar, Deutsche Bank, Dubai Electricity & Water Authority, Dubai Festival City, Emirates Palace, Environment & Protected Areas Authority, Sharjah, Environment Agency – Abu Dhabi, Fairmont, Géant, Gulftainer, HSBC, INtercontinental, Dubai Festival City, Jebel Ali Golf Resort & Spa,
Jumeirah Etihad Towers, Linklaters, Momentum Logistics, Mubadala, Murjan Marinas, Nokia, Sheikha Salama bint Hamdan Al Nahyan Foun- dation, The Club, TimeOut Dubai, and the Young Presidents Organisation.