Impacts of Ocean Noise

Whales face many natural and human-derived risks to their health throughout their lives. Here we describe four threats that gray whales face while feeding in Oregon waters: entanglement in fishing gear, vessel strike, elevated ocean noise, and changes to their habitat.
Imagine living your life at a rock concert where you can barely hear your friends talking to you and they can barely hear you. This would be really stressful, and many medical studies show that increased stress in humans is linked with increased health risks, like heart disease. We are concerned the same situation may be happening to whales living in an increasingly noisy ocean.

Listen to these two sound clips recorded off the Oregon coast to compare what it sounds like underwater with and without boats nearby.

Without boats nearby

With boats nearby

Since light does not travel well in the ocean, whales rely on sound to communicate with each other, listen for predators, find food, navigate, and find mates. However, noise levels in the Pacific Ocean have increased dramatically over the last few decades, meaning that the ability for whales to do all these important life activities is much harder now, and this may be increasing their stress levels.
Image courtesy of NOAA | Click Image for More Info
To study this relationship between ocean noise and whale stress, we record the soundscape near gray whales using hydrophones (underwater sound recorders) and we collect whale poop to examine the hormone levels of that individual, including its stress level. With this data, we have documented an increase in whale stress levels with an increase in ocean noise and an increase in boat traffic. Ocean noise increases with increased boat traffic, so we do not know yet if this rise in whale stress is related to increased collision risk or increased noise or both, but we continue to research this question.