1. Unexpected Discovery
Baleen whales, like this right whale mother and calf, communicate using low-frequency acoustic signals. Underwater noise from large ships overlaps communication sounds used by whales, and these noise levels have significantly increased, leading to concerns about effects on whales. This study shows that reduced ship traffic in the Bay of Fundy after September 11, 2001, resulted in a significant decrease in underwater noise.
Reduced noise was associated with decreased levels of faecal stress hormones in right whales. (Here’s how the researchers get those faecal samples.) This is the first evidence that exposure to ship noise is associated with chronic stress in whales, and has implications for baleen whales in heavy ship traffic areas.