Abstract This study represents the first quantitative
analysis of the characteristics of the distribution areas and
stomach contents of common minke whale Balaenoptera
acutorostrata, sei whale B. borealis, and Bryde’s whale
B. edeni in relation to oceanographic and prey environments
in mid summer in the western North Pacific. Common
minke whales were distributed within subarctic
regions and the northernmost region of the transitional
domain, coinciding with the main habitat of their preferred
prey, Pacific saury Cololabis saira. Sei whales were mainly
found in the northernmost part of the transition zone and
showed prey preference for Japanese anchovy Engraulis
japonica, which was significantly more abundant in the
main distribution area of the whale than in its adjacent
areas. ‘‘Hot spots’’ of Bryde’s whales were found in several
regions of the transition zone between the subarctic
boundary and the Kuroshio front. This whale species preferred
Japanese anchovy as prey, for which the distribution
density was significantly higher in the main distribution
area of the whale than in the adjacent areas. These results
indicate that the summer distributions of Pacific saury and
Japanese anchovy greatly influence the distributions of
these whale species, suggesting that the whales’ habitat
selection is closely related to their prey selection.