The world's most isolated and distinct whale population? Humpback whales of the Arabian Sea

A clear understanding of population structure is essential for assessing conservation status and implementing management strategies. A small, nonmigratory population of humpback whales in the Arabian Sea is classified as ‘‘Endangered’’ on the IUCN Red List of Threatened Species, an assessment constrained by a lack of data, including limited understanding of its relationship to other populations. We analysed 11 microsatellite markers and mitochondrial DNA sequences extracted from 67 Arabian Sea humpback whale tissue samples and compared them to equivalent datasets from the Southern Hemisphere and North Pacific. Results show that the Arabian Sea population is highly distinct; estimates of gene flow and divergence times suggest a Southern Indian Ocean origin but indicate that it has been isolated for approximately 70,000 years, remarkable for a species that is typically highly migratory. Genetic diversity values are significantly lower than those obtained for Southern Hemisphere populations and signatures of ancient and recent genetic bottlenecks were identified. Our findings suggest this is the world’s most isolated humpback whale population, which, when combined with low population abundance estimates and anthropogenic threats, raises concern for its survival. We recommend an amendment of the status of the population to ‘‘Critically Endangered’’ on the IUCN Red List.

The Environment Society of Oman, Shell Oman Marketing, Petroleum Development Oman, The UK Foreign and Commonwealth Office, Ford Middle East, Veritas Geophysical, Salalah Port Services, Five Oceans LLC, Tawoos LLC, The Peter Scott Trust for Education Research in Conservation, Marina Bandar al Rowdha, DHL, Mustafa Sultan Communications, The ABA School Muscat, The British School Muscat, The Sultan School Muscat,The Embassy of the United States in Muscat,Emirates Airlines, Oman Air, Cathay Pacific,KPMG, Muscat Pharmacy, OHI Marine, Truck Oman, W.J. Towell and Co., Han Padron Associates, Mark Rental Cars, WS Atkins and the Wildlife Conservation Society.

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hb2015