No injuries to marine mammals have been attributed to sonar use since the Navy began taking additional steps to minimize harm to such animals, a Navy official said Dec. 19.
"Right now, the Navy employs 29 mitigation measures to assure that we don't hurt marine mammals when we're out doing our sonar exercises," said Rear Adm. Lawrence S. Rice, director of Naval Operations Environmental Readiness, in a conference call with online journalists and "bloggers."
Navy officials said the 29 additional measures were put into place in January.
Rice acknowledged there's legitimate concern over sonar causing marine mammals to "beach." However, the ability to detect enemy submarines is essential to national security, and active sonar is the only existing technology capable of tracking modern diesel-electric and fuel-cell submarines, he said.
"Imagine if al Qaeda got their hands on a submarine and started sinking tankers exiting the Persian Gulf, where about 14 million barrels of oil leave every day, what that would do to the world's economy," he said.
To combat negative effects on sea life, the Navy funds research by universities and nonprofit organizations into how sonar affects marine life. Over the past couple of years, the Navy spent between $10 million and $14 million on research annually, Rice said.
"We fund about 50 percent of marine mammal research worldwide," he said.
Statistically, the number of marine-mammal "strandings" -- beached whales, for example -- due to sonar is extremely low compared to those caused by nature and the commercial fishing industry. Sonar was implicated in 50 strandings over 10 years, Rice said.
This averages out at a rate of five sonar-related strandings per year, vs. an average of 3,600 standings per year due to natural causes and about 600,000 per year linked to the commercial fishing industry, he explained.
"The numbers are still single-digit numbers of marine mammals stranding per year attributed to sonar," he said.
Despite the low numbers, the Navy is expanding its marine mammal program and will increase its funding of independent institutions' research to $18 million annually over the next five years, Rice said.
The research focuses on the locations and abundance of marine mammals, physiological and behavioral effects of sonar, and protective tools the Navy can use to manage its impact, he explained.
Also, the Navy has taken action through NATO to extend worldwide its 29 mitigation measures that have reduced incidence of sonar injury to mammals to zero.
"We gave those (29 mitigation measures) to NATO, and there's a move to incorporate those in the NATO planning document," Rice said.