Long-term persistence of large dugong groups in a conservation hotspot around Hawar Island, Kingdom of Bahrain

1. Predictable aggregations of large marine mammals are valuable conservation targets, but aggregated populations can also be exposed to site-level threats. 2. The globally vulnerable Dugong dugon has a wide distribution but is found in large numbers mainly in Australia and the Arabian Gulf. Though Australian dugong populations are well studied, much less is known of the dugongs in the Arabian Gulf. 3. The spatial and temporal persistence of dugongs around Bahrain, with a focus on large dugong groups (>50 dugongs), was determined using an occupancy modelling framework supported by historical records, structured interviews, citizen science network reports, and small-scale boat and unmanned aerial vehicle surveys. 4. Historical records and current distributional studies confirmed that large dugong groups have been reliably sighted around Hawar Island (Bahrain) since at least 1986, forming large, clumped groups that persist almost year round. The largest recorded so far in the world, these fluid groups (maximum of similar to 700 dugongs) account for similar to 60% of the dugongs found in Bahrain and similar to 12% of all dugongs in the Arabian Gulf. 5. The delineated occupancy core area of large dugong groups (similar to 145 km(2)) straddles the Bahrain-Qatar border, reflecting the transboundary nature of these groups. 6. Careful management of human-induced stressors (in particular, fishing, boating, and coastal development) combined with regular monitoring of Hawar Island's large dugong groups and their seagrass habitat is critical to safeguard this globally important population. 7. The effectiveness of any conservation management is predicated on strengthening cooperation among all range states in the Arabian Gulf. A key recommendation of this study is to establish a regional network of marine protected areas encompassing core aggregation sites for dugongs, particularly the Hawar Islands in Bahrain, the north-western waters of Qatar, Marawah Island in the United Arab Emirates in addition to the shallow waters between Saudi Arabia, Qatar, and United Arab Emirates.