Researcher calls Low-frequency sounds being emitted in an ocean study off North Kauai aren't keeping whales away or deterring them from reproducing, says researcher Joseph Mobley.
sonar tests OK
The study finds that
underwater noise does not
drive away marine mammalsBy Helen Altonn
haltonn@starbulletin.comOverall, he said, "Our findings were basically benign, so it's likely the National Marine Fisheries Service will have no problem with it."
Mobley conducted eight aerial surveys this year to monitor effects on marine mammals of underwater noise from the Scripps Institution of Oceanography's North Pacific Acoustic Laboratory on Kauai. He then compared the findings with results of an aerial survey last year when the sound source was off.
The University of Hawaii-West Oahu psychology professor is the lead UH researcher for marine mammal monitoring studies conducted for the Acoustic Thermometry of Ocean Climate (ATOC) project.
The five-year program is designed to study ocean temperatures with sound transmissions over long distances. Testing began in January with final Navy approval and is done every four days with six 20-minute transmissions in one day.
The research has been controversial because of concerns about effects of the sounds on humpback whales, although scientists reported no significant effects in two years of preliminary tests.
Paul Achitoff, attorney with the Earthjustice Legal Defense Fund -- a major critic of the program -- said he doesn't think the monitoring studies provide any useful information because they're not looking at psychological or behavioral impacts caused by the sound source.
He also thinks "having the sound source there is unjustified because the supposed basis for it is to measure the ocean temperature and therefore tell us whether there is global climate change occurring and only an idiot at this point of time would seriously doubt that we are experiencing global warming.
"We don't need someone using Navy equipment and funding to do some kind of project that is long out of date."
Mobley said the monitoring group is looking for changes in the number of whales and marine mammals in general and any changes in distribution.
"If sound bothers them, locally they should be found further away when it's on."
However, he said they found significantly more marine mammals north of Kauai with the sound on this year than when it was off.
The increase was about 10 to 15 percent, both for whales and dolphins, he said. Whales are naturally increasing at a rate of 7 percent a year based on the surveys, he said.
In studying distribution changes, Mobley said the researchers focused mostly on humpback whales, the species that probably can hear the sound.
"It's a little to low for dolphins to hear based on what we know about their hearing." The humpbacks were slightly further away with the sound on, "but not significantly so," he said.
"I was trying to find significant effects and unable to find them."
Mobley noted that the sound is in deep water, about 1,640 feet, about 8 miles north of Kauai and it has to travel upslope to get to shallow water where the whales are.
It loses a lot of its energy as it travels up and by the time it reaches the whales it's barely above ambient noise, he said, "so it's probably something whales can barely hear." Broadcast at 190 decibels, it's a low rumble sound, he said.
Mobley's report was submitted to National Marine Fisheries Service and the state Department of Land and Natural Resources, both of which approved the project. It's also available on the Web site npal.ucsd.edu.
ATOC home page
North Pacific Acoustic Laboratory
Earthjustice