Deaths Attributed to Newly-Named Acoustic Syndrome
LOS ANGELES (March 17, 2006) -- In a preliminary scientific study released today, a team of investigators found that man-made ocean noise -- "most probably" noise from military sonar -- was the most likely cause of a recent mass stranding of beaked whales off the Almeria coast in southern Spain. Their findings were based on necropsies, or animal autopsies, carried out on four of these rarely-seen animals.
According to investigators, all four whales had suffered injuries "very similar" to those seen in some prior mass mortalities involving mid-range military sonar. Whales that died in earlier events appeared healthy, but on closer examination were found bleeding around the brain and ears with a host of lesions in their livers and other organs.
The pathology is now so well established in some species of whales that investigators have given it a name: "Gas and Fat Embolic Syndrome." It was this severe set of injuries that investigators believe led to the strandings and deaths of the Almeria whales on January 26, 2006.
"The investigation has produced hard evidence of the connection to sound--like seeing a bullet wound, but needing to identify the shooter," said Michael Jasny, a senior consultant for the Natural Resources Defense Council (NRDC). "In light of today's findings, it's incumbent on navies and on industry to divulge what activities they were conducting in the area."
The Almeria event is only the latest in a long and growing series of mass strandings attributed to ocean noise in the Canary Islands, the Bahamas, North Carolina, Alaska, Hawaii, Japan, Greece, and other sites around the globe. Most have been linked to high-intensity mid-range sonar used by navies in training exercises, but some have been connected to other sources of man-made noise, like the airguns used by industry for oil-and-gas exploration.
Apart from injury, mid-frequency sonar has been shown to provoke dramatic behavioral responses in a range of marine mammal species, causing them to panic, abandon their habitat, or strand. It has also been blamed by commercial fishermen in some parts of the U.K. and the United States for declines in their catch rates.
Download a preliminary report on the strandings, produced by investigators from the University of Las Palmas de Gran Canaria.