Reducing vessel activity key to southern resident killer whales' survival, B.C. study suggests

Vancouver -

A new study from a group of biologists, acousticians and statisticians from around the world suggests reducing vessel activity is key to the survival of B.C.'s endangered southern resident killer whales.

Experts from Oceans Initiative, in collaboration with a Simon Fraser University professor, say killer whales rely on echolocation to hunt for chinook salmon, but noise from ships interferes with their ability to send out clicking sounds to locate their prey.

Researchers studied whales in Haro Strait in 2018 during a voluntary vessel slowdown. Just over half of vessels chose to lower their speed to 11 knots in that area, which reduced noise by 2.5 decibels. They also tracked how many vessels there were.

When noise levels increased, researchers discovered the whales were less likely to start looking for food.

"When vessels move slower there's an observable effect in terms of the probability of killer whales foraging. So that's just sort of filling in the picture, if you will, of what we can do in terms of mitigations for the shipping lanes for trying to protect some of the resident killer whales in their habitat," said Ruth Joy, a co-author of the study.

Researchers say taking immediate action is more important than ever, following reports of three pregnant J-pod whales.

"These three pregnant females and members of J-pod cast a ray of much-needed hope on the future of southern resident killer whales," Joy said.

The paper was recently published in Marine Pollution Bulletin and is a partnership between the Oceans Initiative, Simon Fraser University, the University of California and Bielefeld University in Germany.