Thanks to whales, oceans used to be as loud as a rock concert

Industrial whaling appears to have had an unexpected consequence: It turned down the volume in the oceans, according to research presented this week at the annual meeting of the Acoustical Society of America in Kansas City, Mo.

The effect of man-made sound underwater, from speedboats to submarine sonar, is a topic of great concern for marine researchers. That’s because many worry that the sounds we have injected into the underwater environment may be disrupting animals’ acoustical landscape. That may make it difficult for them to migrate, hunt or mate.

But the new study, conducted by Michael Stocker and Tom Reuterdahl of Ocean Conservation Research in Lagunitas, Calif., suggests that the oceans were actually much louder in the past because of whale vocalizations.

To determine that, they needed to use old records of Soviet whalers to calculate just how many whales were present in the past. That type of data hasn’t always been available, said Stocker and Reuterdahl. Because the whalers were taxed for their catch, they kept two sets of books: One that actually reflected the number of whales pulled in, and another that they showed the taxman.

Once they had amassed trustworthy data from true catch logs, Stocker and Reuterdahl assigned the whales “sound generation values,” modeling just how loud it might have been underwater back in the day.

According to the researchers, going underwater in the North Atlantic as recently as the early 19th century would have sounded as loud as a rock concert, with measures reaching as high as 126 decibels.

So do these results mean we can start holding underwater concerts without fear of upsetting the locals? Hardly. It turns out that many human-made sounds have different acoustical properties than the ones that exist naturally underwater. As a result, it still may well be that today’s quieter oceans pose a serious threat to underwater life nonetheless.

Stocker and Reuterdahl said the question remains “a topic of intense research.”

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