Blue Whale Requiem

But two years after the experiment, the the report says, the anonymous diver still takes antiseizure medication for his acquired condition, as well as antidepressants.

The Natural Resources Defense Council got a permanent injunction against what it calls “unbelievably loud” LFA sonar in 2003. But at 235 decibels, midrange sonar, useful in rooting out “silent” submarines that may prowl the seas — is much louder than what disabled the Navy diver. How exactly it would affect a blue whale — or the grays that migrate south along our coasts later in the year and return north to Alaskan waters each spring — is a mystery. Of the 83 species of whale known to roam the ocean, scientists know the hearing range of only 11.

“With the big baleen whales, we don’t really know which frequencies they can hear,” not to mention physically withstand, says Dave Mellinger, an expert in marine acoustics at Oregon State University. “You can’t catch one and put it in a tank and test its hearing.” But “we assume they can hear [up to] a few kilohertz frequency.” The calls of blue whales in the Atlantic Ocean speak in “a different dialect” from Pacific blues, but both are below human hearing range.

“I remember hearing a blue whale for the first time,” says Mellinger, who has often submerged microphones into the ocean. “It’s a very low pulsing sound. They really sound impressively big.”

It has been said that a blue whale in the middle of the ocean can build in its mind’s eye a picture of the entire ocean, simply by sending out that sound and registering the echo. But what happens when the echo comes back muddied by a flood of noise?

“That’s an open question,” Mellinger says. “It could be akin to looking into a fog — the noise obscures things at great distances. We don’t know what effect it has on their migrations or ability to find mates.”

In fact, only in the early 1990s did anyone make a connection between human-generated sound and marine mammal strandings, even though such strandings have occurred since 1963, when Cuvier’s beaked whales, a smaller species, washed up on the shores of Sagami Bay, Japan, after U.S. naval maneuvers there.

According to a California Coastal Commission report in 2005 on the environmental impact of marine noise, that 40-year period of ignorance “underscores how easy it is to miss the connections between noise and a variety of impacts on marine mammals.” It also underscores one of the report’s key points: Humans know so little about marine mammal hearing that they would be wise to err on the side of caution.

In early November, the 9th Circuit Court of Appeals will convene to decide whether to continue to allow the Navy’s midrange sonar testing. Joel Reynolds, an attorney for the NRDC, one of the groups suing the Navy, is optimistic that the tests will be halted. The Navy itself estimated the exercises would cause permanent injury or death to 170,000 marine mammals and 4,000 beaked whales — violating California’s coastal-protection laws.

“I just have to shake my head over why it is that these remarkable creatures have to be subjected to this kind of treatment,” Reynolds says. “This is an amazing coast that we have, with a spectacular abundance of species. It’s a very odd place for the Navy to be using as a training area.”