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Too close for comfort The research vessel Maurice Ewing sailed near the island in the Gulf of California where beaked whales beached.

Environmentalists Sue Over Whale Deaths

An environmental group has asked a federal judge to suspend an NSF-funded sea-floor mapping expedition off Mexico funded by the U.S. National Science Foundation (NSF), claiming that it led to the deaths of two whales. NSF rejects the claim, but the incident has curtailed an expensive international mapping project and reignited controversy over the impact of noise on marine mammals.

The controversy began 25 September, when five vacationing marine biologists sailing in Mexico's Gulf of California happened upon two freshly beached Cuvier's beaked whales (Ziphius cavirostris). The group soon discovered that the Maurice Ewing, a research vessel owned by Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York, was conducting a seismic survey nearby. The ship was using sound pulses to map the margins of the continental plate.

Human-created noise, including the sonar of military vessels, has been linked to other strandings of beaked whales (ScienceNOW, 7 January,). Although there is still no clear explanation of how sound might harm the whales, the gulf strandings "just seemed too coincidental, given the history, " says Barbara Taylor, one of the vacationers and a whale researcher with the government's Southwest Fisheries Science Center in La Jolla, California.

Five days after the incident, Lamont officials temporarily halted the $1.6 million, 6-week cruise to review environmental precautions. Lamont's director, Michael Purdy, says there is no clear link between the mapping and the strandings, noting that the Ewing appears to have been at least 50 kilometers away from the animals when they stranded. But cruise managers ultimately decided to reduce noise levels, drop about half the planned routes, increase efforts to spot and avoid whales, and end night work, when whale monitoring is impossible.

The additional precautions, however, don't satisfy some whale experts. The signals can travel 10 or more kilometers from the ship, they note, a distance far beyond the gaze of sentries. Beaked whales are notoriously difficult to spot. "The Ewing should cease operations; they don't have a workable plan," says John Hildebrand, a whale and acoustics specialist at the Scripps Institution of Oceanography in La Jolla.

The case was filed 17 October in San Francisco, by the Idyllwild-based Center for Biological Diversity. The judge is still deciding whether to halt the cruise, which is scheduled to end 4 November.

Related sites
Science article on debate about noise and marine mammals
Center for Biological Diversity
Lamont's marine seismology group