Document: Article
Abstract: The relationships between cetaceans and remoras are still poorly known, especially those involving the species commonly referred to as the whalesucker (Remora australis), which attaches to cetaceans only. We report here on the association between resident common bottlenose dolphins (Tursiops truncatus) and whalesuckers at the remote São Pedro and São Paulo Archipelago (SPSPA) in the equatorial Atlantic Ocean. The study was conducted during four field expeditions between 2011 and 2013. A total of 13,720 photographs of the common bottlenose dolphins were taken from a small inflatable boat. From the analysed pictures, 141 were of dolphins with attached remoras, 70 of which were from 12 photo-identified dolphins (i.e., about 50% of the estimated population). The number of whalesuckers per dolphin, the size classes of these remoras, and their favoured attachment sites on the dolphins’ bodies largely resemble the association of the same fish species with spinner dolphins (Stenella longirostris) at Fernando de Noronha Archipelago (FNA) in the Southwestern Atlantic Ocean. It is noteworthy that we found more similarities than differences in the relationships between the dolphins and the whalesuckers at both these oceanic islands, despite the dolphins belonging to different species, having marked differences in body size, and the great disparity in their numbers: about 25 individuals at SPSPA vs hundreds (sometimes up to 2,000) at FNA. The present study strengthens the view that this remora takes advantage of the association with small swift cetaceans that congregate regularly in offshore areas and confirms the common bottlenose dolphin as a cetacean host for the whalesucker.
Key Words: remora, Echeneidae, cetacean, Delphinidae, marine association, Saint Paul’s Rocks, Brazil
DOI: https://doi.org/10.1578/AM.47.6.2021.585
Page Numbers: 585-598