Navy sonar cited in beaching

A probable link leads federal officials to call for preventive steps

HANALEI, Kauai » Navy sonar used during the 2004 Rim of the Pacific exercises likely caused 150 melon-headed whales to strand themselves in Hanalei Bay over the Fourth of July weekend, federal officials announced yesterday.

While one calf died in the area the day after the stranding, that death was caused by malnutrition and not by the six U.S. and Japanese subs training around Kauai during RIMPAC, scientists with the National Oceanographic and Atmospheric Administration said.

The NOAA scientists, who released a final report on the incident, could not determine the exact causes of the stranding, but said that sonar was "a plausible if not probable" factor, said Brandon Southall, Acoustics Program director for the NOAA Fisheries Service.

He added that no other reasons were found -- meteorological, physical or otherwise -- that would have caused the stranding, but too many factors are unknown to say that sonar was a definitive cause.

The conclusions have helped prompt NOAA to request that the Navy take steps to prevent such effects during similar exercises scheduled for this summer.

The Navy has applied for an Incidental Harassment Authorization for this year's RIMPAC, scheduled for 21 days of sonar use between June 26 and July 28. It is the 19th time since 1968 that RIMPAC, the largest international maritime exercise, has been held in Hawaii waters.

This year, for the first time, NOAA is asking the Navy to restrict sonar use and monitor its effect on sea life.

The Navy is planning to implement safety zones around their vessels using sonar, and will reduce power or shut down sonar operations if marine mammals are nearby, according to NOAA officials.

The Navy downplayed the inferences that could be read from the report.

"There are data limitations and the report is inconclusive," said Lt. Cmdr. Christy Hagen, a spokeswoman for the U.S. Pacific Fleet. "There are so many unknown factors that you cannot come to any definitive conclusion at this point."