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Whale Racket: Sounding Out How Loud The Oceans Were From Whale Vocalizing Prior To Industrial Whaling

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LAGUNITAS, California -- Concern is growing that human-generated noise in the ocean disrupts marine animals that rely on sound for communication and navigation. In the modern ocean, the background noise can be ten times louder than it was just 50 years ago. But new modeling based on recently published data suggests that 200 years ago prior to the industrial whaling era -- the ocean was even louder than today due to the various sounds whales make.

California researchers Michael Stocker and Tom Reuterdahl of Ocean Conservation Research in Lagunitas, Calif., present their findings at the 164th meeting of the Acoustical Society of America (ASA), held Oct. 22 26 in Kansas City, Missouri. Using historic population estimates, the researchers assigned "sound generation values" to the species for which they had good vocalization data. "In one example, 350,000 fin whales in the North Atlantic may have contributed 126 decibels about as loud as a rock concert to the ocean ambient sound level in the early 19th century," Stocker notes. This noise would have been emitted at a frequency from 18 22 hertz.

According to the researchers, use of whaling records to determine just how many whales were harvested from the ocean over the course of industrialized whaling is difficult because the captains were taxed on their catch and therefore had an incentive to "fudge" the numbers. Some captains kept two sets of books. After the collapse of the Soviet Union, some of the real reports began surfacing. In one example the Soviets initially reported taking approximately 2,710 humpback whales from the late 1950s to the mid-1960s. The newer data reveal the actual number was closer to 48,000.

This more accurate data was supported by population estimates using mitochondrial DNA, which does not change through female lines of a species. Thus the current diversity in DNA can serve as a proxy for historic population numbers.

While their estimates suggest there was a whole lot of whale racket a couple centuries ago, Stocker says "we can assume that animals have adapted to biological noise over the eons, which may not be the case with anthropogenic noise. Anthropogenic noise is often broader band and differently textured than natural noise, so the impacts are likely different as well. Investigating these differences and their impact on marine life is the topic of intense research."

Views expressed in this article do not necessarily reflect those of UnderwaterTimes.com, its staff or its advertisers.

Reader Comments

2 people have commented so far. cloud add your comment

Sounds very interesting. I wonder if these sounds would be heard above the surface. I don't recall any reports of people hearing sounds from the deep. People adrift in life boats or something like that.
   comment# 1   - Jon · Porterville, USA · Oct 26, 2012 @ 3:30pm

Having seen Humback whales it really makes one wonder how such a singl whale could ever be removed from its home as, they are the shoe off as far as whales are concered. I wish they could all be returned (turn back the clock) to sing another day.
   comment# 2   - Tony DeMaio · USA · Oct 29, 2012 @ 6:34pm
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