Twenty-two varieties of beaked whales roam the seas, feeding on bottom-dwelling squid and small fish on the dark ocean floor. Shy and seldom seen by man, they are among the least understood large creatures on Earth.
But in recent years, these deepest-diving whales have sent out an unexpected distress signal, alerting researchers and marine mammal advocates, through their confused behavior and beachings, to an environmental hazard that until 10 years ago was not known to exist.
The threat comes from very loud noises, especially from Navy sonar, that on at least several occasions have proved fatal to the whales.
The realization that sonar can disorient or frighten whales sufficiently to leave them beached and dying has spurred protests and lawsuits, and has given the Navy a problem that it first denied but now, to some extent, acknowledges. Navy officials, however, have strenuously resisted efforts to limit testing of their sonar, saying it is essential to national security.
In response to angry protests, as well as some pressure from Congress and the marine mammal scientific community, the Navy has now funded an ambitious, $6 million project to learn more about beaked whales and their response to sonar and other loud ocean noises. The research began in earnest last month in the Bahamas under the leadership of the National Oceanic and Atmospheric Administration, not far from the spot where, in 2000, the stranding of 17 beaked whales after a Navy sonar exercise first brought the issue to public attention. At least six of those animals died.
The goal is to learn about beaked whales by attaching sophisticated motion detectors to the very few that can be spotted and approached during their brief stays on the surface. The instruments are being used to record the timing, depth and angles of their dives and ascents and to see how the animals react when exposed to sounds approaching (but never reaching) the intensity of sonar signals.
It is a clinical trial of sorts, trying to scientifically determine how very loud, man- made sounds may be affecting the elusive creatures.
“The Navy and we as regulator have been really struggling with this issue,” said NOAA ocean acoustics specialist Brandon Southall, a principal investigator. “So far, we’ve been able to make only educated guesses about what might be going on from the whales that come ashore. We really want some direct measurements from live beaked whales … about their reactions to sound.”
