Fourth International Orca Symposium and Workshop - CEBC - CNRS

SIGHTINGS OF KILLER WHALES OFF THE ANTARCTIC PENINSULA FROM
1997/98 TO 2001/02
Dalla Rosa, L. 1 , Danilewicz, D. 2 , Bassoi, M. 3 , Moreno, I.B. 2 , Santos, M.C.O. 4 & Flores, P.A.C. 5
1 Projeto Baleias/Brazilian Antarctic Programme, Marine Mammals Laboratory, Museu
Oceanográfico “Prof. Eliézer C. Rios”, Fundação Universidade Federal do Rio Grande, Cx. Postal
379, Rio Grande, RS, 96200-970, Brazil. E-mail: pgobldr@furg.br
2 Grupo de Estudos de Mamíferos Aquáticos do Rio Grande do Sul (GEMARS), Rua Felipe Neri,
382/203, Porto Alegre, RS, 90440-150, Brazil.
3 School of Ocean and Earth Science, Southampton Oceanography Centre, European Way, SO14 3ZH,
Southampton, United Kingdom.
4 Instituto de Biociências, Universidade de São Paulo, Rua do Matão 321, São Paulo, SP, 055088-900,
Brazil.
5 International Wildlife Coalition Brazil, Cx. Postal 5087, Florianópolis, SC, 88040-970, Brazil.
INTRODUCTION
Killer whales, Orcinus orca, are a common species around Antarctic waters (e.g. Jehl
et al., 1980; Mikhalev et al., 1981), however information on their abundance, distribution,
population identity and taxonomic status remains to be better assessed. Mikhalev et al. (1981)
proposed a new species of killer whale, Orcinus nanus, for the Southern Hemisphere, based
on morphological and biological data. Berzin and Vladimirov (1983) also proposed a new
species of killer whale, Orcinus glacialis, for Antarctic waters, based on morphological and
ecological differences in relation to O. orca. Both proposals probably refer to the same
population of smaller individuals. Antarctic killer whales commonly present lighter
pigmentation with a conspicuous dorsal “cape” (Jehl et al., 1980; Thomas et al., 1981; Evans
et al., 1982).
Since the 1997/98 austral summer, the Projeto Baleias/Brazilian Antarctic
Programme (PROANTAR) has conducted ship surveys in the Antarctic Peninsula region with
the following objectives: (1) photo-identify humpback whales for comparison with
international catalogues; (2) biopsy humpback whales for DNA and pollution analyses; (3)
determine cetacean distribution and density estimates; and (4) record all cetacean sightings. In
this paper we present data on killer whales observed off the Antarctic Peninsula in the
summer seasons of 1997/98 through 2001/02.
MATERIAL AND METHODS
During five consecutive summer seasons (1997/98 – 2001/2002), cetacean research
was conducted in the waters of the Antarctic Peninsula region, especially in the Gerlache and
Bransfield Straits, from the 75m Oceanographic and Supply Ship (NApOc) ‘Ary Rongel’. In
the Gerlache Strait, cetacean dedicated surveys were performed for distribution studies and
density estimates. A total of 20 transects were performed. Whale search was made with naked
eye and with 7X50 binoculars. The observers watched from the exterior wing bridges
approximately 14m above sea level. Data recorded on the killer whales included date, time,
coordinates, pod size/composition and behavior. Whenever possible, individuals were photoidentified
from the ship or from a small inflatable boat, following Bigg et al. (1987).
FOURTH INTERNATIONAL ORCA SYMPOSIUM AND WORKSHOPS
SEPTEMBER 23-28 2002, CEBC-CNRS, France
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