Marine Resources Assessment for the Marianas Operating ... - SPREP

AUGUST 2005 FINAL REPORT
Figure 3-1. General major and minor migratory patterns of humpback whales in the North Pacific
Ocean. Humpback whales migrate between summer feeding grounds in temperate or near-polar
waters and winter calving grounds in shallow tropical waters. Regions depicted with solid shading
are defined by current observations of seasonal return by naturally marked individuals. Regions
depicted with striped shading are defined by historical patterns of distribution during periods of
commercial whaling. Few individuals have been sighted on both the Hawaii and Mexico calving
grounds during alternate years indicating a possible interchange betweeen the two seasonal
subpopulations. Interchange is also possible between the Japan and Hawai'i calving grounds.
Source information: Baker et al. (1990) and Calambokidis et al. (2000, 2001).
tested. Also, it seems reasonable to assume that the aggregation of humpbacks that feeds around
Kodiak Island (Waite et al. 1999) may represent largely individuals from the Western North Pacific
stock.
The humpback whale has one of the longest migrations known for any mammal; individuals can travel
nearly 8,000 km from feeding to breeding areas (Clapham and Mead 1999). The exact migration
corridor of whales moving between the Hawaiian breeding ground and the Alaskan feeding ground is
not known, although it is clear that whales migrate through deep, oceanic waters. Similarly, the
specific migration route of whales between Japanese breeding grounds and the apparent Aleutian
Island/Bering Sea/Gulf of Alaska feeding grounds is not clear. Migratory transits between Hawai’i and
southeastern Alaska have been documented to take as little as 36 to 39 days (Gabriele et al. 1996;
Calambokidis et al. 2001). Based on Japanese whaling records, the migratory sequence of arrival on
the Ryukyu Islands grounds is that immature whales arrive first, following by adult males and nonpregnant
females, while late pregnant females and those with newborn calves arrive last (Nishiwaki
1966).
3-13