Estrutura populacional e influência ambiental na abundância de tubarões-baleia (Rhincodon typus Smith 1828) no Arquipélago de São Pedro e São Paulo, Brasil

Abstract

Saint Peter and Saint Paul´s Archipelago (SPSPA) is an important site of Whale shark observations in Brazil as it has the highest frequency of sightings knows in the country. In the present work, data from sightings during scientific expeditions carried out between 2005 and 2018 (13 years) were computed and analyzed. Information on sightings was grouped by month, calculating the relative monthly frequency which was then compared with the environmental variables (temperature and chlorophyll a) obtained by remote sensing, with the objective of inferring their influence on the frequency of occurrence of the species in the archipelago. Photos and videos of the whale sharks were also collected. The images that presented satisfactory quality were processed using the semi-automated program called I³S (Interactive Individual Identification System). The results obtained so far are of great importance for the understanding of population structure, behavioral, feeding habits and migratory movements of the whale shark in the Atlantic Ocean, as they strengthen the hypothesis that sightings may be related to environmental variables such as sea surface temperature (SST) and chlorophyll-a concentration, including a possible loyalty to the archipelago since by photo-indentification we confirmed five re-sightings, three within a few days each other, one with about a year and an individual re-visited three times in different years.