Scientists from WCS (Wildlife Conservation Society), the American Museum of Natural History (AMNH), the Environment Society of Oman, and other organizations have made a fascinating discovery in the northern Indian Ocean: humpback whales inhabiting the Arabian Sea are the most genetically distinct humpback whales in the world and may be the most isolated whale population on earth. The results suggest they have remained separate from other humpback whale populations for perhaps 70,000 years, extremely unusual in a species famed for long distance migrations.
Scientists from WCS (Wildlife Conservation Society), the American Museum of Natural History (AMNH), the Environment Society of Oman, and other organizations have made a fascinating discovery in the northern Indian Ocean: humpback whales inhabiting the Arabian Sea are the most genetically distinct humpback whales in the world and may be the most isolated whale population on earth. The results suggest they have remained separate from other humpback whale populations for perhaps 70,000 years, extremely unusual in a species famed for long distance migrations.
Known for its haunting songs and acrobatics, the humpback whale holds the record for the world’s longest mammal migration; individuals have been tracked over a distance of more than 9,000 kilometers between polar feeding areas and tropical breeding areas.
“The epic seasonal migrations of humpbacks elsewhere are well known, so this small, non-migratory population presents a wonderful and intriguing enigma,” said WCS researcher and study co-author Tim Collins. “They also beg many questions: how and why did the population originate, how does it persist, and how do their behaviors differ from other humpback whales?”
Previous studies on humpback whales, including several published by WCS, have revealed a great deal of population structure among humpback whales of the Northern Hemisphere and many areas of the Southern Hemisphere, particularly on breeding grounds. At the ocean basin scale, scientists are gaining an understanding of humpback whale gene flow, including in the Southern Indian Ocean. The dynamics and movements of animals in the Arabian Sea, however, are poorly understood.
“We have invested lots of energy working to clarify the population structure of several large whale species around the world,” said Dr. Howard Rosenbaum, Director of WCS’s Ocean Giants Program and senior author on the study. “The levels of genetic differences for Arabian Sea humpback whales are particularly striking; they are the world’s most distinct population of humpback whales and might even shed some light on the environmental factors that shape cetacean populations.”
The study appears in the online journal PLOS ONE. The authors include: Cristina Pomilla of the the Sackler Institute for Comparative Genomics at the American Museum of Natural History; Ana R. Amaral of the Universidade de Lisboa; Tim Collins of WCS; Gianna Minton of WWF-Gabon; Ken Findlay of the University of Pretoria; Matthew Leslie of AMNH and WCS; Louisa Ponnampalam of the University of Malaysia; Robert Baldwin of the Environment Society of Oman; and Howard Rosenbaum, Director of the Ocean Giants Program at WCS.
Continue reading at the Wildlife Conservation Society.
Humpback whale image via Shutterstock.
