Researchers have identified five distinct subspecies of humpback whales in the North Pacific Ocean in an in-depth genetic study.
The humpbacks are widely found all over the world but those from the North Pacific are distinctly different in terms of DNA and therefore could be classified as a humpback subspecies. Researchers from the Oregon State University led by Prof. Scott Baker were able to study the North Pacific humpbacks further and classified them into five distinct subspecies.
The study covered different populations from a wide area that includes Hawaii, Mexico, Central America, Okinawa, the Philippines and another in the West Pacific.
Baker told LiveScience.com: "Even within these five populations, there are nuances. 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 three-year study calledStructure of Populations, Levels of Abundance and Status of Humpbacks (SPLASH) differentiated the five distinct humpback whale populations by studying the genetic make of up to 2,200 whale tissue samples from the winter-breeding grounds and the feeding grounds of these mammals.
It is important to study the different breeding and feeding areas of these mammals because it is what makes each subspecies distinct from whale populations from locations.
Like human culture, mother whales pass down migration methods, feeding and breeding regions to their young. This goes far through several generations which allow the distinctive genetic signatures to develop and distinguish them from other subspecies.
Aside from distinguishing these five separate populations from the North Pacific humpbacks, the team also raised a concern regarding the population of these whales in their respective locations.
Currently, the humpback whales are considered an endangered species by the U.S Endangered Species Act. However, the International Union for the Conservation of Nature only considers the humpbacks in the Arabian Sea and in the Oceania as endangered.
"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 to LiveScience.com.
The study was published in the Marine Ecology-Progress Series journal.
