Movement patterns of acoustically tagged reef manta rays (Mobula alfredi) in Raja Ampat MPA network, West Papua

Little is known about the movements and habitat range of reef mantas within the 5 million hectare marine protected area (MPA) network in Raja Ampat, West Papua. Here we report on the movement patterns of reef mantas among... [ view full abstract ]

Little is known about the movements and habitat range of reef mantas within the 5 million hectare marine protected area (MPA) network in Raja Ampat, West Papua. Here we report on the movement patterns of reef mantas among their known feeding and cleaning aggregation sites across the region. Twenty-four VR2W acoustic receivers were deployed in known aggregation sites across the Raja Ampat region, distributed within all seven MPAs. A total of 44 mantas were acoustically tagged in six locations with Vemco V16 transmitters. They consisted of 31 females, 12 males, and 1 individual of unknown sex. The ratio of chevron to melanistic mantas tagged was 1:1.9. In the two-year period of monitoring (1 Jan 2016 – 31 Dec 2017), the cumulative number of visitations recorded by individual mantas ranged from 1 to 156 days (25±5). Of the 15 receivers detecting mantas, Kofiau was the most frequently visited site, with 301 days of visitations. Visitation of melanistic mantas (average of 39 days) was significantly different from that of chevron mantas (average of 17 days), while visitation rates between males and females were not statistically different. The furthest distance between two receivers visited by an individual manta was approximately 270 km, which was between Magic Mountain (Misool) and Sepatu (Waigeo). This provides the first evidence of reef manta movement between the northern and southern region. Overall, results indicate strong site fidelity and very little crossover between the several isolated reef areas in Raja Ampat, including Misool, Kofiau, and Waigeo island groups.