Padrão de ocorrências do lobo-marinho-subantártico Arctocephalus tropicalis (Gray 1872) no sul do Brasil: associação com fatores climáticos e ambientais

Abstract

The study presents the pattern of occurrences of subantarctic fur seals, Arctocephalus tropicalis, in the southern Brazilian coast and their association with remote and local patterns of climatic variability and anomalies in the concentration of chlorophytes and sea-surface temperature in the region of the breeding colonies of Gough and Tristan da Cunha Islands. The date, sex and age category of 254 records of the species between 1992 and 2013 were analyzed. The representative indexes of the patterns of climatic variability and environmental variables were obtained from four and five months before the records, were assumed as time lapse for displacement for species between their closest breeding colonies and the southern Brazilian coast. As a result, we found a pattern of predominance of adult males, registered mainly in 2002 (n = 92) and 2003 (n = 21) during July, August and September months. The Mixed Generalized Linear Model explained the association between the patterns of climatic variability and the occurrences of A. tropicalis (R² = 0.73) involved the effect of the interaction between the Southern Annular Mode, the South Atlantic Ocean Dipole, the Subtropical Indian Ocean Dipole, the Indian Ocean Dipole and El NiñoSouthern Oscillation with four months lag. A significant association was also observed between the decrease in the concentration of chlorophytes five months earlier in the vicinity of their breeding colonies on the Gough and Tristan da Cunha Islands.