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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Pingers: Alarms or Dinner Bells?
10 May 1999 6:00 pm
It seemed simple: To prevent marine mammals from becoming ensnared in fishing nets, scare them away with high-pitched noisemakers. But a paper published in the spring issue of the Marine Technology Journal suggests that for some species, acoustic "pingers" do more harm than good.
Each year some 80,000 dolphins and thousands of other marine mammals snag in nets worldwide; most die. Two years ago, a report in Nature suggested that pingers, which emit periodic high-frequency underwater bursts, had markedly reduced the accidental catch of harbor porpoises in the Gulf of Maine's groundfish fishery. Why they work is still a mystery: They may cause discomfort, interfere with marine mammals' echolocation, or become associated with nets. Nonetheless, at least 14 more fisheries around the world have recently adopted the devices.
Now one of the authors of the Nature paper warns that pingers may produce "a whole array of unintended consequences." For example, writes Scott Kraus, research director of the New England Aquarium's Edgerton Research Laboratory, at one mid-Atlantic shad fishery pingers drove away shad as well as porpoises even though the shad weren't supposed to be affected by the sounds. In the Pacific Northwest, salmon aquaculturists found that devices intended to fend off marauding seals instead became seals' "dinner bells." And Kraus cites preliminary evidence that New Zealand's endangered Hector's porpoises may actually be attracted to the pings. "Every fishery is different," writes Kraus, "and every ... species has different hearing and sound production abilities."
How ocean sounds affect different marine species "is something we are only just beginning to understand," says Greg Early, associate scientist with the Edgerton Research Lab. He agrees with Kraus and his Duke University colleague Andrew Read that it's best to play it safe and run a trial at every fishery where pingers are under consideration.