New England Aquarium, Associated Press
In this Sept. 10, 2007 photo released by the New England Aquarium, a right whale dives near a ship in Canada’s Bay of Fundy. A study published in London Feb. 8, 2012 shows that reduced ship traffic in the Bay of Fundy after Sept. 11, 2001 resulted in a significant decrease in underwater noise and a corresponding reduction of stress hormones in right whales.

BOSTON — Researchers say 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.

The analysis was led by a New England Aquarium researcher. It showed a drop in the stress-related hormone in right whales following the attacks.

The drop coincided with a period of significantly lower ocean noise after ship traffic came to a near-standstill for security reasons following the terror attacks.

The analysis combined data from two experiments that happened to be going on simultaneously. One involved acoustic recordings of right whales in Canada's Bay of Fundy. The other collected samples of whale feces, which contain stress-indicating hormones.

It wasn't until 2009 that a researcher realized the data existed for the analysis.