Adding more conditions will reduce the realism and scope of the training, Alex Stone, who directs the Navy program, testified before the California Coastal Commission.
Stone also said he believes the program has sufficient protections for sea life — an argument disputed by environmentalists who packed the meeting.
The Navy estimates that the proposed training program, scheduled to begin next January, will kill 130 animals and cause hearing loss in 1,600 over five years.
“We think these are underestimates,” Michael Jasny with the Natural Resources Defense Council told the commissioners.
The Navy’s testing area encompasses 120,000 nautical square miles of the Pacific off the Southern California coast and includes a corridor between the state and Hawaii, among other areas.
The commission’s staff has recommended that approval be contingent on a list of conditions. They include requiring that the Navy create safety zones that would guarantee no high-intensity sonar activity near marine sanctuaries and protected areas and in spots that experience a high concentration of blue, fin and gray whales seasonally. The staff says a kilometer from shore should also be off-limits to protect bottlenose dolphins.
The commission set out similar conditions to the Navy in 2007 and 2009, but the Navy refused to accept them both times.
The commission sued the Navy over the matter, leading to a preliminary injunction in 2008, though then-President George W. Bush gave an exemption for the training. The U.S. Supreme Court later overturned the lower court’s decision.
Jasny’s organization and three dozen others say they want the Navy to avoid important habitat for vulnerable species, including endangered blue and fin whales, beaked whales, and migrating gray whales. They also want the Navy to not use sonar training and underwater detonations at night, when marine mammals are extremely hard to detect. And they want the Navy to be required to use its own acoustic monitoring network to help detect marine mammals.
They also say that from May through October ships should slow to 10 knots in areas with baleen whales, to avoid hitting them.
Scientists say there is still much to be learned about how much sonar activity affects marine animals. Studies have shown some species such as beaked whales may be adversely affected by some forms.