Abstract

The recently discovered Fraser’s dolphin is one of the less studied dolphin species in the world, due to its overall low density and offshore ecology. However, during our last two years of surveys in the entire Lesser Antilles, the Fraser’s dolphin was the 3rd most observed species. Presence was confirmed all along the arc which confirms the importance of oceanic archipelagos for this species. Therefore, our study area represents a unique opportunity to learn more about its habitat use and intriguing association behavior. Indeed, 78% of Fraser's sightings occurred in association with other cetacean species. The nature of those interactions is misunderstood. However, interspecific foraging behavior has been observed and could explain most of those associations. Curiously, this deep diving dolphin was not only found in association with pelagic species like the sperm whale and the short-fin pilot whale but also with more coastal species like the bottlenose and pantropical spotted dolphin. This could imply that the Fraser’s dolphin opportunistically forages in the entire water column as hinted by previous studies. However, this species is exposed to an increasing level of threats in the Lesser Antilles due to fishing activities, small cetacean hunting and augmentation of marine traffic. The analysis of a poll of 87 Fraser’s images revealed that 33% of the 31 pictures featuring wounds had an anthropogenic origin. Using our results, we aim to promote conservation in the Lesser Antilles in cooperation with the different actors to ensure the sustainability of the Fraser’s dolphin and other cetaceans’ populations.