How management authorities respond to the study identifying the distinct North Pacific humpback populations remains to be seen, Baker said, but the situation "underscores the complexity of studying and managing marine mammals on a global scale."
The five populations identified in the study are: Okinawa and the Philippines; a second West Pacific population with unknown breeding grounds; Hawaii, Mexico and Central America.
"Even within these five populations there are nuances," noted Baker, who frequently serves as a member of the scientific committee of the International Whaling Commission. "The Mexico population, for example, has 'discrete' sub-populations off the mainland and near the Revillagigedo Islands, but because their genetic differentiation is not that strong, these are not considered 'distinct' populations."
The SPLASH program has used photo identification records to estimate humpback whale populations. The researchers estimate that there are approximately 22,000 humpbacks throughout the North Pacific about the same as before whaling reduced their numbers. Although recovery strategies have been successful on a broad scale, recovery is variable among different populations.
"Each of the five distinct populations has its own history of exploitation and recovery that would need to be part of an assessment of its status," said Baker, who is a professor of fisheries and wildlife at OSU. "Unlike most terrestrial species, populations of whales within oceans are not isolated by geographic barriers. Instead, migration routes, feeding grounds and breeding areas are thought to be passed down from mother to calf, persist
|Contact: Scott Baker|
Oregon State University