Reducing vessel activity key to southern resident killer whale survival

Photo Credit: SFU grad students Azadeh Gheibi & Kaitlin Baril - Reducing ship speed and noise levels would increase the probability that endangered West Coast southern resident killer whales will spend more time hunting for Chinook salmon, a new Simon Fraser University study has found. The research, published in the journal Marine Pollution Bulletin , provides insights to guide conservation efforts and protect the estimated 73 remaining whales in the population. Research shows that these whales spend between 70 and 84 per cent of their time foraging in the absence of ships and boats to meet their daily energy needs. "Killer whales rely on echolocation to hunt for Chinook salmon and ship noise interferes with their ability to send out 'clicks' and locate their prey," says study collaborator Ruth Joy, a statistical ecologist and assistant professor in SFU's School of Environmental Science. Researchers studied the whales' foraging behaviour in Haro Strait during a 2018 voluntary vessel slowdown, as part of a broader effort to reduce human-generated noise disturbance. The strait is a critical summer foraging habitat for the endangered whales. The ECHO program was led by the Vancouver Fraser Port Authority and followed a successful earlier trial, which saw 55 per cent of vessels voluntarily reduce their speed to 11-knots when transiting through the strait, resulting in an overall noise reduction of 2.5 decibels.