Distribution of minke whales in the Bellingshausen and Amundsen Seas (60°W–120°W), with special reference to environmental/physiographic variables

Abstract

The relationship between the distribution of minke whales (Balaenoptera acutorostrata) in the Bellingshausen and Amundsen Seas (longitude between 60°W and 120°W), and environmental and physiographic variables (sea‐surface temperature, sea‐ice extension, and sea‐floor‐slope type), was studied to determine whether these environmental and physical factors affect the distribution and density of minke whales. The analysis was based on sightings data obtained from the 1989/90 and 1982/83 IWC/IDCR cruises. The mean sea‐surface temperatures for comparable areas were significantly higher in 1989/90 (2.04°C) than in 1982/83 (1.12°C), and the area where the sea‐surface temperature was greater than 1°C in the 1989/90 study was approximately twice that of the 1982/83 study. Additionally, during the surveys, the extent of the sea ice in 1989/90 was less than that in 1982/83, with the mean ice edge about 92.6 km (50 nautical miles; 1 nautical mile ≈1.852 km) farther south in 1989/90 than in 1982/83. This is consistent with the sea ice extent observed in winter, when the sea ice extent was less in 1989 than in 1982. The distribution of minke whales was substantially different between the two surveys, with the density and abundance of minke whales being greater in 1982/83 than in 1989/90. The warmer sea‐surface temperatures, fewer cold‐water intrusions, and the smaller extent of sea ice in 1989/90 may be related to the difference in distribution of minke whales from 1982/83, possibly owing to the shift in availability of prey.

The summer distribution of coastal minke whales (Balaenoptera acutorostrata) in the southern outer Moray Firth, NE Scotland, in relation to co-occurring mesoscale oceanographic features

“…However, due to problems of low sample size of data, few significant patterns or correlations have been observed. Kasamatsu et al (2002) managed to show strong correlations between the presence Antarctic minke whales (B. bonaerensis) and ice edges areas in the Bellinghausen and Amundsen Seas in the Antarctic. Although no significant correlations were found between minke whale density and sea surface temperature, it was observed that densities appeared to be higher during the surveys conducted during 1982/1983 when the region was experiencing intrusions of colder water (Kasamatsu et al, 2002).…”

The distribution and habitat preference of coastally occurring minke whales (Balaenoptera acutorostrata) in the outer southern Moray Firth, northeast Scotland

“…Certainly factors such as water depth, sea bottom sediment and even the extent of sea ice have all been shown to influence minke distributions across a range of different habitats (e.g. Kasamatsu et al 2000a;Naud et al 2003;Macleod et al 2004;Cecchetti 2006), but the interplay between these different factors evidently varies from one geographic region to the next (Tetley April 2007). Consequently fluctuations in both fine and large-scale physiography are believed to be significant for the distribution of minke whales within the Moray Firth, and thus a greater understanding of their habitat preferences in this region is considered to be important not only for the improvement of abundance estimates and interpretations of population trends here, but also for the establishment of protected areas for the long-term coastal management of the species in these waters.…”

Whale distribution in relation to prey abundance and oceanographic processes in shelf waters of the Western Antarctic Peninsula

“…Studies concerning whales in the Antarctic have largely been limited to describing distribution patterns in relation to large scale oceanographic features (Uda 1954, Tynan 1998 or coarse surveys of prey across broad spatial scales (Kasamatsu et al 2000a,b, Nicol et al 2000, Reid et al 2000, Murase et al 2002. Such relationships have not been assessed at smaller spatial extents (10s of km) (Thiele et al 2004).…”