Large-scale movement and habitat range of reef manta (Manta alfredi) in northern Raja Ampat waters, West Papua, Indonesia

Little is known about the habitat range and seasonal distribution of reef mantas in Raja Ampat, West Papua. The objectives of this study were to investigate the habitat range and to examine spatial and temporal movements of reef mantas for underpinning conservation efforts and management actions in Raja Ampat region. The mantas were tagged with Vemco V16 acoustic transmitters. In November 2013, Vemco VR2 acoustic receivers were deployed in eight listening stations throughout northern Raja Ampat waters, including Wayag Lagoon, Uranie, Eagle Rock, Yefnabi Kecil, Seprang, Dayan, Manta Ridge, and Wai. In total, 38 reef mantas were tagged in six locations. Tagging periods varied between 0 to 682 days (237±27 days). Meanwhile the days of visit ranged from 1 to 188 days (42±7 days). Moreover, Manta Ridge was the most popular site with 565 days of manta visits. It was followed by Yefnabi (434 days), Eagle Rock (287 days), and Wai (202 days). In addition, several mantas were detected in five different listening stations and most of them travelled to at least one listening station. Interestingly, results indicate that manta seasonal movements, based on the frequency of day visits, occurred within four main listening stations (Manta Ridge, Wai, Yefnabi Kecil, and Eagle Rock). Apart from this, nearly 90% of hourly visit frequency occurred during the day between 6 am to 6 pm. Overall, those results can be used to assist in the designation of manta conservation both spatially and temporally to ensure manta populations and manta tourism sustainability in Raja Ampat.