Associated Press

BOSTON — An ocean experiment that was accidentally conducted amid the shipping silence after Sept. 11 has shown the first link between underwater noise and stress in whales, researchers reported Wednesday.

The analysis indicated that a drop in a stress-related hormone found in the right whales was tied to a dip in ocean noise that followed a near-standstill in ship traffic, due to security concerns following the attacks.

The work indicates whales and other sea life that use sound to communicate and travel can be harmed by the noise. That could prompt more research and eventually influence future ocean traffic and development, said New England Aquarium scientist Rosalind Rolland, the report's lead author.

"This is definitely a very important piece in the puzzle that lends credence to the idea that, yes, we potentially have a problem out there and we need to learn a lot more about it," Rolland said.

The report combined data from two unrelated experiments in Canada's Bay of Fundy that happened to be occurring simultaneously. One involved acoustic recordings of right whales; the other the collection of whale feces samples, which contained stress-indicating hormones.