The sicklefin devil ray (Mobula tarapacana) is a large, pelagic ray which is listed as Endangered by the International Union for Conservation of Nature (IUCN). Mobula tarapacana is thought to have a circumglobal, yet patchy distribution, and has not been verified extant off the eastern USA. Here, we report 180 sightings of M. tarapacana with a total of 361 individuals, collated across five datasets from aerial survey operations and incidental sightings in the waters off the US East Coast and Gulf of Mexico, between 1996 and 2022. This study extends the northern range of M. tarapacana in the Gulf of Mexico to 29°N, and in the Atlantic to 40°N. Seasonal trends were observed off the north-eastern coast of the USA, with M. tarapacana only present in the summer months. Measurements from high resolution digital aerial imagery found M. tarapacana off the New York coast to be adults and subadults with an average disc width of 268 cm (±25, range 232–316 cm). This study provides important spatial and temporal data for management, as well as informing areas for future research on M. tarapacana in the western Atlantic.

An updated checklist of manta and devil rays (family Mobulidae) occurring in waters of the Azores archipelago is given based on new data from underwater images and on the re-evaluation of previous citations for the region. There are, at least, three species of mobulids occurring in the region, possibly four: giant manta Manta birostris; Chilean devil ray Mobula tarapacana; and one or both of the giant devil ray Mobula mobular/spinetail devil ray Mobula japanica species complex. These findings have direct implications for the known ranges of all these species and for the conservation of their North Atlantic populations.