Abstract

The aim of this paper is to report the different species of cetaceans sighted between Valparaiso and Easter Island (Rapa Nui), during five cruises made during winter seasons of 1993 to 1995, to explain their spatial distribution during the winter months. The cetacean species sighted were Balaenoptera musculus intermedia, Balaenoptera physalus quoyi, Balaenoptera borealis schlegelii, Balaenoptera edeni, Balaenoptera bonaerensis, Megaptera novaeangliae australis, Physeter catodon, Ziphius cavirostris, Mesoplodon densirostris, Orcinus orca, Pseudorca crassidens, Globicephala melas edwardii, Delphinus delphis, Tursiops truncatus, Lissodelphis peronii and Lagenorhynchus obscurus. The distribution of the records showed three subareas of animal concentration. First, between 112° and 91° W. Second, between 90° and 77° W. Third, between 75° W and Valparaiso (71°37?W). The possible indicative species of each subarea were: Subarea 1. B. bonaerensis, M. densirostris, P. crassidens and Z. cavirostris. Subarea 2. B. borealis schlegelii, B. edeni and M. novaeangliae australis. Subarea 3. G. melas edwardii, L. peronii and L. obscurus. The first records of the following cetaceans species in the study area are: B. musculus intermedia, B. bonaerensis, M. densirostris and Z. cavirostris in the waters of the first subarea; B. musculus intermedia and B. edeni in waters of the second subarea. The species mostly sighted was P. catodon (1.65 sights per day), which also had the wider range of distribution during those winter seasons, followed by B. physalus quoyi (1.27), D. delphis (1.01), B. bonaerensis (0.89), T. truncatus (0.76) and B. borealis schlegelii (0.51). However, as it was expected, the most abundant species, expressed as animals per day, were the small odontocetes D. delphis (212.78) and T. truncatus (54.55), followed by P. catodon (3.91).