The world's first hybrid sharks have been discovered in substantial numbers off the coast of Australia, and scientists say it may be an indication the creatures are adapting to climate change.
Australian researchers say they've found 57 animals that are a cross between the Australian blacktip shark and the common blacktip shark, two closely related but genetically distinct species.
"Hybridization could enable the sharks to adapt to environmental change as the smaller Australian black tip currently favors tropical waters in the north while the larger common black tip is more abundant in sub-tropical and temperate waters along the south-eastern Australian coastline," researcher Jennifer Ovenden of the University of Queensland said in a press release.
Ovenden said the discovery is a first for sharks, and it could indicate that other shark and ray species may interbreed in reaction to climate change.
The findings were confirmed using DNA testing and measurements. Scientists from the University of Queensland, James Cook University's Fishing and Fisheries Research Center, the Queensland Department of Employment, Economic Development and Innovation, and the New South Wales Department of Primary Industries will conduct further studies to determine the fitness of the new hybrids, according to the press release.
The hybrids were found along a 2,000-kilometer (1,243-mile) stretch of the eastern Australian coast from Queensland to New South Wales. The breadth of their distribution and their numbers impressed researchers.
"Wild hybrids are usually hard to find, so detecting hybrids and their offspring is extraordinary. To find 57 hybrids along 2,000 kilometers of coastline is unprecedented," Ovenden said.
Jess Morgan, another University of Queensland researcher, told The Australian newspaper that hybrid species are common in fish because their eggs are fertilized in the water.
"Sharks physically mate, which is usually a good way to make sure you don't hybridize with the wrong species," The Australian quoted him as saying.
"The results of this research show that we still have a lot to learn about these important ocean predators," Colin Simpfendorfer from James Cook University's Fishing and Fisheries Research Center said in the press release.