Data available for an assessment of North Pacific blue whales
Branch (convenor), Brownell, Donovan, Ivaschenko, Kato, Lang, Matsuoka, Mizroch, Rosenbaum, Sirovic, Suydam
International Whaling Commission
Blue whales in the North Pacific comprise at least two populations, and possibly three, based largely on song type. The best studied is the eastern North Pacific population that has a reliable catch time series and previous assessment; there are recent surveys and catch data for the lessâ€studied central and western North Pacific population; and there is a possible third population inhabiting an area around Japan. The area around Japan was the basis of substantial whaling, followed by a lack of sightings in jSV
data, and no catches for several decades, leading to the possibility of extirpation. This possible Japanese population off Hokkaido has since been sighted more regularly in the JARPN/JARPNII cruises, and a unique song type has also been recorded from a single location off Hokkaido. More acoustic recordings are needed to determine the extent of this possible third population. Assessments of the central and western, and possibly the Japanese population, will be possible when abundance estimates are obtained from the POWER and JARPN/JARPNII cruises.