Federal Court Orders Navy to Limit Sonar Use Around Marine Mammals

Sea Technology, Mar 2008

The U.S. Federal Court, Central District of California, ordered the Navy to take additional measures when training with mid-frequency active sonar off the California coast.

On January 3, the court issued a preliminary injunction that requires sonar to be shut down any time marine mammals are within 2,200 yards in a 12-nautical mile California coastal exclusion zone.

The court's order requires the Navy to conduct additional monitoring for marine mammals, reduce power on sonar when surface ducting conditions exist and take additional monitoring steps prior to and during sonar exercises.

It also restricts the Navy from using sonar altogether in the Catalina Basin and requires helicopters to monitor for whales for 10 minutes before using active dipping sonar.

However, no injuries to marine mammals have been attributed to sonar use since the U.S. Navy began taking additional steps to minimize harm to them in January 2007, the Navy said.

The Navy employs 29 mitigation measures to assure that it does not hurt marine mammals when conducting sonar exercises. To determine how sonar affects marine life, the Navy funds universities and nonprofit organizations, contributing between $10 and $14 million annually-about 50 percent of the research funding worldwide.

Statistically, the number of marine-mammal strandings due to sonar is extremely low compared to those caused by nature and the commercial fishing industry, officials said. Sonar was implicated in 50 strandings over 10 years versus an average of 3,600 strandings per year due to natural causes and about 600,000 per year linked to the commercial fishing industry.