oa An overview of whale shark movement ecology projects in the Red Sea Research Center

Background The Red Sea Research Center is part of a relatively new university on the Saudi Arabian Red Sea coast, the King Abdullah University of Science and Technology (KAUST). KAUST officially opened in 2009 but began global collaborative research projects in 2007. Among the early discoveries arising from these collaborative projects was the identification of a whale shark aggregation site in the Red Sea. KAUST researchers have been studying this aggregation site since 2008. Approach KAUST researchers have employed various methods and technologies to track whale sharks, including acoustic tagging, satellite tagging technologies, genetics, and some technologies integrating the use of autonomous vehicles. Our whale shark studies include determining the population demographics of the sharks visiting our sites, the site fidelity of the sharks, and any potential connections with populations outside of the Red Sea. In 2012, KAUST began a collaborative effort with colleagues in the Marine Megafauna Foundation to study a whale shark aggregation at Mafia Island, Tanzania. Results The results from our movement studies highlight the pros and cons of various methodologies, and overall emphasize the importance of using multiple methods simultaneously to maximize the clarity of results. In Saudi Arabia, the whale sharks are very near to 50% male and 50% female, unusual compared to most aggregations. Satellite tracking suggests that the Saudi sharks migrate away from the site in the “off-season” and some are confirmed to have left the Red Sea. However, the majority of the sharks remain within the southern half of the Red Sea. Acoustic tracking of whale sharks at Mafia Island, in Tanzania, shows unexpected cryptic residency with many sharks being detected year-round despite a clear seasonal pattern in the sightings of whale sharks in boat-based surveys. These and brief summaries of our findings from other methods will be discussed. Conclusions The results from the Saudi aggregation are strikingly different from results of an aggregation we have been studying at Mafia Island, Tanzania. Future studies of plankton dynamics and fine-scale analysis of whale shark behavior may reveal fundamental differences in the sites that explain these differences in residency. Many emerging technologies hold great promise for improving our ability to learn more about the world's largest fish.