Study: Ocean dolphin groups don't mix

WASHINGTON, March 24 (UPI) -- Conservationists say groups of dolphins in the Indian Ocean do not mix freely with one another, apparently kept apart by currents and other invisible factors.

Researchers from the Wildlife Conservation Society and the American Museum of Natural History say genetically distinct populations of the Indo-Pacific humpback dolphin may be formed in part by currents, surface temperature differences and other environmental barriers, a WCS release reported Thursday.

Scientists made the discovery using both genetic data from dolphins and environmental information from remote-sensing satellites.

The study is one of the first examinations of how environmental factors in marine environments may influence population structure in marine species and can potentially provide an understanding of how environmental factors may drive the evolution of new species, the researchers said.

"Examining how environmental factors affect the population structure of marine species is a complex task. Doing this over entire regions is a challenge," Martin Mendez of the Sackler Institute for Comparative Genomics at the American Museum of Natural History said.

"Unlike studies of terrestrial species in easily observable environments, marine species are difficult to follow and the barriers they encounter are often invisible to us."