Posted by: The ocean update | June 14, 2015

‘A deaf whale is a dead whale’ : US navy sonars could be cause of strandings

Portuguese-beach-California-WhaleJune 14th, 2015. Marine researchers speculate noise pollution in the Pacific is disrupting whales’ vital abilities to hear and migrate – and driving them ashore at an alarming rate

Twelve whales have washed ashore in northern California in the past two months, prompting headlines around the world and attracting droves of tourists, curious about the massive mammals so suddenly out of their natural element.

According to a California Academy of Sciences (CAS) necropsy one of those whales, a 32ft female humpback that washed ashore in Pacifica, a 20-minute drive from San Francisco, had “signs of trauma consistent with blunt force”.

Suggested causes of death have included being hit by a ship and an attack by an orca. But while those might have been the final blows for the whales, other issues are being raised by environmental groups such as Earthjustice, the National Resources Defense Council (NRDC) and Greenpeace. These issues include the US navy’s use of sonar.

Moe Flannery, a stranded marine mammal responder and manager of the CAS Department of Ornithology and Mammalogy, declined to give a cause of death shortly after conducting the necropsy on the first Pacifica whale. But she did say the whale showed signs of muscle hemorrhaging, an injury which research has shown to be consistent with sonar-related deaths.

Other researchers who participated in the necropsy, including those from the Marine Mammal Center (MMC), corroborated such findings and pointed out that hemorrhaging does not necessarily mean blunt force trauma from a ship. The MMC, which is currently focusing most of its resources on the problems facing starving sea lions, declined to comment on whether sonar was involved.

Although it is difficult to determine sonar-related injuries and deaths, Earthjustice attorney David Henkin argues hemorrhaging should not be used as a reason to dismiss sonar as a potential culprit. Possible evidence of sonar contributing to whale deaths, such as emaciation, hemorrhaging and bleeding of the brain, was present in the Pacifica humpback stranding and in stranding in Santa Cruz of two grey whales.

“That difficulty [in determining cause of death] should not be misinterpreted as raising questions about whether sonar is a likely cause of many strandings and associated marine mammal deaths,” Henkin said.




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