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.