Arabian Sea Humpback Has Been Isolated for 70000 Years
Despite being a migratory mammal, the Arabian Sea humpback is possibly the most isolated whale population on the planet, according to a new study.
This currently endangered species hasn't left its home in all this time, preventing it from interacting with other humpback whales and making it genetically distinct from populations in the Southern Hemisphere and North Pacific.
Reported in the journal PLOS ONE, researchers were able to analyze tissue samples from 67 Arabian Sea humpbacks, focusing on both mitochondrial and nuclear DNA. The animal's gene flow suggests that the while the Arabian Sea humpback originated in the Southern Indian Ocean, it found its way to the Arabian Sea and stayed put for 70,000 years - a fact that's "remarkable" considering this species has reportedly migrated more than 9,000 kilometers (5,592 miles) at a time.
"The epic seasonal migrations of humpbacks elsewhere are well known, so this small, non-migratory population presents a wonderful and intriguing enigma," study co-author Tim Collins, of the Wildlife Conservation Society (WCS), said in a statement.
Researchers speculate that this separation could be contributed to various glacial episodes in the late Pleistocene Epoch and associated shifts in the strength of the Indian Monsoon. Not to mention that Arabian Sea humpback whales are on a different breeding schedule than population in the Western Indian Ocean, only increasing their isolation.
And given this humpback's lonely existence, it's particularly vulnerable to factors that could drive it further towards extinction. There are currently fewer than 100 individuals in the wild, with threats from humans and the whale's slow reproduction.
"The known and growing risks to this unique population include ship strikes and fishing net entanglement," noted senior author Dr. Howard Rosenbaum, "threats that could be devastating for this diminished population."
Researchers are recommending that the whale be designated as "critically endangered" on the IUCN's Red List.
Humpback whales are a type of baleen whale, which are characterized by "plates" in their mouth that filter out food, rather than teeth. Adults can grow up to 60 feet long, the NOAA says, and weigh as much as 80,000 pounds or 40 tons. And like all humpbacks, the Arabian Sea humpback whale is known for its haunting songs and acrobatics.
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