Descrição da distribuição espaço - temporal de machos cantores da Baleia Jubarte (Megaptera Novaeangliae) em Abrolhos

Abstract

To approach a phenomenon that one wishes to investigate, it is first necessary to recognize its characteristics in space and time. In sequence, we present an analysis of data from 24 years of scientific observations regarding humpback whales (Megaptera novaeangliae) at their breeding site at the Abrolhos bank, Brazil. Data were collected consecutively from 1992 to 2015, between July and November, totaling 6 456 sightings, in a total of 15 100 specimens, of which 2 522 (16,7%) were pups. To compare the effort employed in each sighting, an index was constructed relating the number of sightings by the time spent. With it was estimated the existence of a population growth of the species. Was found an average annual success rate of 4.76 (± 1.14) sightings / day, with a higher propensity between the months of August and September, with 95.09% (4 916) at depths lower than 36m, and 86, 60% (4,477) at distances shorter than 63km from the Abrolhos archipelago. The humpback whales groups with female and cub were 50.03% of all registered groups, and have been found at relatively small depths closer to the islands. For males singers humpback whales records were made of 139 specimens (2.15%), with an average distance of 25 km and an average depth of 20m. It was found a spatial cluster of male singers whose location did not correspond to the Abrolhos national park area, providing further studies about the dissociation of these areas. In addition, the study of causality for this cluster should be investigated.