Incidence of a solitary bottlenose dolphin, Tursiops truncatus, and interactions with spinner dolphins, Stenella longirostris, in the Fernando de Noronha Archipelago, Brazil
The Projeto Golfinho Rotador (PGR, Spinner Dolphin Project) has systematically monitored the distribution, ecology, and behavior of cetaceans in the Fernando de Noronha Archipelago (FNA) since 1990. During this period, the presence of spinner dolphins (Stenella longisrostris) was recorded in 93% of the days of the year, and occasionally another nine species of cetaceans. As of November 2021, the presence of a solitary bottlenose dolphin (Tursiops truncatus), known as Kai, was observed in the FNA. This work aims to describe the frequent presence of the solitary bottlenose dolphin in the FNA, as well as the interactions between that individual and the spinner dolphins. The records were made from two land-based platforms on the main island, and by collecting information and images from collaborators, such as sailors and divers. From 10 November 2021 to 23 July 2022, between the first and last sightings, in 223 days of study and 2,210.22 h of sampling effort, 49 sightings of the bottlenose dolphin were recorded. It was an adult, offshore ecotype, of unidentified sex and apparently healthy. On days when Kai was sighted, the spinner dolphins stayed an average of 5.84 h in the area (SD ± 3.02), while on days without sightings the average permanence was 6.20 h (SD ± 2.65). There was no effect of the presence of Kai on the permanence of the spinner dolphins (Mann-Whitney, U = 1042; p = 0.678), with a predominance of neutral interactions. According to the habituation stages currently adopted, Kai was in stage two, in which it was already known by the local population, followed some boats, but still kept its distance from humans. The existence of legislation to protect cetaceans and the action of the PGR in the community may have helped with the non-progression of the habituation stage.
How to Cite
LicenseAuthors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).