Thursday, September 9, 1999

Scientist says whales little
affected by noise testing

By Harold Morse


The Navy says it found little or no adverse response from whales to anti-submarine undersea sonar off Southern California, Central California and the Big Island of Hawaii in monthlong tests in each area concluded in 1998.

It made the point last night at an open house at the University of Hawaii Campus Center that whales seemed relatively unaffected in tests using low-frequency active sonar. The Navy, countering criticism the sonar sounds may harm whales, still left some guests skeptical.

"I don't fully understand what has been studied," said Jeff Mikulina, director of the Sierra Club, Hawaii chapter. "Have they done enough to say that this isn't going to have an adverse impact on marine animals? Is this absolutely necessary?"

Chris Clark, Cornell University scientist who shared investigation duties with two other scientists, said in an interview that he too was skeptical earlier. "I got involved because, like many other people, my concern was that the low-frequency active sound system could seriously affect whales."

He feared whales might stop breeding, mothers and calves might be separated and whale migration might be affected, but testing suggests otherwise, Clark said. "The surprising result is that the responses from the whales were very minor."

Blue whales didn't stop feeding off Southern California, Clark said. The test vessel went into a large feeding area and checked with sound both on and off. "We found no difference with the two conditions. We came out here and did it with humpbacks,too. We also did it with migrating gray whales off Central California."

Clark admitted that gray whales close in shore showed some avoidance response. "We put a boat right in the middle of the migration. The gray whales, as they approached the sound source ... would swim around it."

But this stopped when the sound source was moved farther off shore. "They went right by it. It made absolutely no difference."

Researchers also disproved a theory that the louder the sound the greater whales' response. How loud it was had no effect on gray whales off Central California, Clark said."This was very similar to what happened off Hawaii."

Sound tests were run on singing humpback males far off shore -- rather than disturb mothers and calves near shore.

"Offshore where we worked, the responses again were surprising. Some whales would definitely stop singing for tens of minutes -- or move away from the shore. But all these animals would resume normal activities in less than an hour," he said. "We had two populations of animals. Some -- they would pay no attention to the sound, no matter how loud it was -- and others, they would stop singing or move away even when the sound was not very loud. It's as though you have some animals that couldn't care less and other animals (that) are very sensitive."

Clark views data gathered as just a beginning. "We could overinterpret these results. "You can't make a blanket statement and say because we found no negative responses, the concern over man-made noise in the ocean is no longer an issue."

Joseph Johnson, project manager, said researchers took a conservative approach. "We tried to show there was an impact. I think that's important. Instead of trying to put data together that says we didn't have an impact, we tried to show that we did."

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