The new concrete evidence was recently published by Peter Tyack of the Woods Hole Oceanographic Institution in the PLos One journal. Dr. Tyack and his colleagues describe a study in the Bahamas where they used underwater microphones to monitor “clicks” emitted by Blainville’s beaked whales while hunting. The whales that were hunting around Navy’s test range started to emit fewer “clicks” as soon as the sonar exercises began and then swam away miles away from the sound. They did return to the same spot a few days later.
The problem is that sometimes the whales are unable to get out of the way of sonar quickly enough. The mid-frequency sonar blasts may drive certain whales to change their dive patters in a way their bodies can’t handle, causing fatal injuries. In fact, many of the beached whales have suffered physical trauma, including bleeding around brain, ears and other tissues. These are symptoms similar to “the bends”- the condition that can kill scuba divers if they surface too quickly.
On the occasions listed below testing of mid-frequency to low-frequency active sonar was conducted in the area.
- 1996: 12 Cuvier’s beaked whales beached in Greece
- 1999: 4 beaked whales beached in the US Virgin Islands
- 2000: 3 beaked whales beached in Madeira
- 2002: 14 different whales beached in the Canary Islands