Sonar Called Likely Stranding Cause
Friday, April 28, 2006
Federal marine specialists have concluded that Navy sonar was the most likely cause of the unusual stranding of melon-headed whales in a Hawaiian bay in 2004.
The appearance of as many as 200 of the normally deep-diving whales in Hanalei Bay in Kauai occurred while a major American-Japanese sonar training exercise was taking place at the nearby Pacific Missile Range Facility.
The report is the latest in a series of scientific reviews linking traditional mid-frequency naval sonar to whale strandings. Sonar has been used for decades, but it was only recently that the apparent connection to strandings was established.
While the National Oceanic and Atmospheric Administration scientists said they could not definitely state that sonar caused the strandings, they said extensive study led them to the conclusion that there was no other likely cause.
"Our analyses indicate there was no significant weather, natural oceanographic event or known biological factors that would explain the animals' movement into the bay nor the group's continued presence in the bay," said Teri Rowles, NOAA Fisheries Service's lead marine mammal veterinarian and lead author of the report.
NOAA concluded that sonar was "a plausible, if not likely, contributing factor" to the stranding.
The Navy has said it was virtually impossible for its sonar to have led to the Hanalei Bay stranding, and officials maintained that position yesterday. "I think that if you look at the report, there are just so many unknown factors at work that to say sonar was a plausible if not likely cause is erroneous," said Lt. Commander Christy Hagen of the U.S. Pacific Fleet in Hawaii.
The Navy is planning another major sonar testing maneuver in the same area in July and -- for the first time -- NOAA has formally asked the Navy to use expanded measures to protect whales from the possible effects of its sonar.
The active sonar used by navies sends out loud pings of sound that seem to frighten and disorient whales, especially deep-diving species such as the beaked and melon-headed whales. The effect was documented off Greece in 1996 and established later during naval exercises in the Bahamas, off the Canary Islands and off Spain.
The findings have complicated the Navy's efforts to set up a 500-square-nautical-mile sonar training facility off the coast of North Carolina. Naval officials say the sonar training is essential, especially now that possibly hostile foreign navies have developed diesel submarines that are not detected by the kind of passive sonar used to follow large nuclear submarines.
Rowles said that the melon-headed stranding in Hawaii was highly unusual, and only the second recorded in the United States in modern times. The other occurred off Florida earlier this year, and Rowles said NOAA is trying to determine if any naval activity occurred in the area.
In the 2000 Bahamas stranding, a local marine biologist collected some of the whales that died onshore and froze them for later study -- which helped NOAA conclude that sonar was the likely cause. In Hanalei Bay, the whales were ultimately led back to sea and one young animal died, apparently of starvation. So there was no physical evidence of injury to examine.
Yesterday's NOAA conclusion was based instead on the lack of other possible causes, the unusual nature of the whale movement, and an analysis that concluded the extensive sonar use occurred close enough to Hanalei Bay for the whales to swim there by early July 3.
A number of environmental groups have become increasingly concerned about the effects of sonar, and the Natural Resources Defense Council has sued the Navy a number of times on the issue. Michael Jasny, a senior consultant with NRDC, said the NOAA report was worrisome.
"This was by far the largest stranding of melon-headed whales ever recorded in Hawaii," he said. "Once again, the Navy's denial has been contradicted by the official government investigation. It's time for the Navy to stop this needless infliction of harm."