Science  02 Mar 2007:
Vol. 315, Issue 5816, pp. 1199d
DOI: 10.1126/science.315.5816.1199d

Research on cosmic neutrinos has led to the discovery of a sperm whale hot spot in the Mediterranean.

The Italian National Institute of Nuclear Physics plans to build a giant neutrino detector, called NEMO, 3500 meters deep off the coast of Catania, Sicily. Ordinary detectors look for the elusive Embedded Imageerenkov-light signature. But in 2005, Italian physicists decided to test a new method: acoustic sensing. They deployed an array of four sensors off Sicily to see whether background noise is low enough to allow for acoustic detection.

As it happens, sound frequencies of interest for neutrino detection overlap with those from sperm-whale and dolphin calls. So marine biologists from the University of Pavia piggybacked a sea mammal-monitoring experiment on the array. The ensuing log, which is still being analyzed by both biologists and physicists, indicates hundreds of sperm-whale transits per year over an area of about 1000 square kilometers—far more than have been supplied by visual sightings. Scientists are thrilled with the new tool. Cruise-based missions provide data from only a small time window, points out Giuseppe Notarbartolo di Sciara of the conservation agency ACCOBAMS. “We still don't know how many whales live in the Mediterranean,” he says. “But listening posts like this would be great for monitoring their seasonal movements.”

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