The geographic distribution of reef and oceanic manta rays in the south-east Indian and south-west Pacific Oceans

Abstract

AbstractThe reef manta ray,Mobula alfredi, occurs in tropical and warm temperate coastal waters, and around islands and reefs in the Pacific and Indian Oceans. Published records that relate to the distribution ofM. alfrediin the south-east Indian and south-west Pacific Oceans are largely restricted to locations where there is a focus on manta ray ecotourism, with little information from elsewhere. Even less is known about the circumglobally distributed oceanic manta ray,Mobula birostris, for which there are few published sighting records. We collatedn =11,703 sighting records from Australian waters and offshore territories forM. alfredisourced from scientific image databases (n= 10,715), aerial surveys (n= 375) and online reports (n= 613). From collated records, we confirm that the species shows an uninterrupted distribution within Australian coastal waters north of 26°S on the west coast to 31°S on the east coast, with a southernmost record at 34°S. Confirmed locations forM. birostrisencompass a latitudinal range of 10-40°S. Records from more southerly locations relate to warm-water events. Sightings ofM. birostriswere rare, but were confirmed at several geographically separate locations, probably reflecting its preference for offshore waters. The study clarifies the occurrence and range of each species within coastal waters of the south-east Indian and south-west Pacific Oceans, and highlights regions in northern Australia that are of specific interest for future research into possible movements of individuals between international marine jurisdictions.