Study: Sleeper sharks may kill Steller sea lion
SEAFOODNEWS.COM [AP] - Oct. 29, 2014
(Photo courtesy of the National Marine Fisheries Services/Oregon State University)
ANCHORAGE, Alaska – Scientists researching the severe decline in Alaska's Steller sea lion population have a fingered a new possible suspect for the drop: Pacific sleeper sharks, a species previously thought of as a scavenger and fish-eater.
A study led by Oregon State University researcher Markus Horning concludes that three juvenile sea lions tracked with implanted data transmitters were killed by a cold-blooded predator, and the likely culprits were sleeper sharks, which can grow to 20 feet long.
Transmitters surgically implanted in the sea lions that died indicated a sudden change in temperature of warm to cold but no exposure to water or light, indicating they were eaten by something cold-blooded.
The recorded temperatures ruled out a kill by a killer whale, Horning said by phone. "It would have been at the same temperature as the Steller sea lion," he said.
Likewise, known sea lion predators such as great white sharks and salmon sharks have body types that would have reflected higher temperatures, he said, if they had consumed a sea lion.
The western population of Steller sea lions, which live in Alaska from Cordova...
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