2020 Volume 2 Issue 1 Pages 15-38
This paper examined the geographical distribution of several whale species in the Indo-Pacific region of the Antarctic during the austral summer. The analyses were based on sighting data collected systematically by JARPA and JARPAII surveys in the longitudinal sector of 35°E–145°W, south of 60°S, between 1987/88 and 2008/09. The searching effort comprised a total of 353,134 n.miles. The Antarctic minke whale was the species most frequently sighted, followed by killer, humpback, unidentified beaked, fin, sperm, southern bottlenose, blue, southern right and sei whales. Density index of whales (DIW: no. of individuals sighted/100 n.miles) was calculated using all primary effort and sightings data and its geographical distribution plotted on maps with Lat. 1 degree × Long. 1 degree squares for each species. These maps are more detailed compared to those of the previous maps which used 5° × 5°squares in the 1960s. The geographical distribution was described for each whale species together with some features of their distribution. For example, sei, dwarf minke, humpback and southern bottlenose whales were not sighted in the Ross Sea, distribution areas of southern right whales were limited to the sector 80°E and 135°E, and high-density areas of humpback whales were observed between 80°E and 110°E. The large scale and long-term sighting data set has made a substantial contribution to understanding the geographical distribution patterns and habitat use of whales in the Antarctic ecosystem.
