GEOGRAPHIC-VARIATION IN VENTRAL FLUKE PIGMENTATION OF HUMPBACK WHALE MEGAPTERA-NOVAEANGLIAE POPULATIONS WORLDWIDE

Ventral fluke patterns of humpback whales Megaptera novaeangliae were assessed to determine if pigmentation shows geographical variation acr oss different breeding areas. Fluke photographs (n = 3854) were collec ted from 7 major breeding grounds worldwide and were ranked into categ ories 1 (white) through 5 (black) based on the proportion of white and black pigment on the ventral surface. Average coloration varied prima rily between oceanic populations, with the Southern Ocean stocks (Area IV, western Australia, and Area V, eastern Australia) characterized b y significantly more light-colored flukes, while the North Pacific sub populations consisted of individuals with significantly more dark-colo red flukes. Results of statistical analyses revealed that all populati ons differed significantly from one another in the distribution of pig mentation classes, with the exceptions of Hawaii vs Japan, Mexico vs J apan, Mexico vs Hawaii, eastern Australia vs western Australia, and We st Indies vs Colombia. Results of pigmentation analyses reveal histori c and current interactions among oceanic subpopulations of humpback wh ales and reflect population sub-division in this species.