Reducing vessel activity is key to the survival of Southern Resident Killer Whales

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Reducing vessel speeds and noise levels would increase the likelihood that endangered South West Coast Resident Killer Whales will spend more time hunting chinook salmon, according to a new study from Simon Fraser University.

The research, published in the journal Marine Pollution Bulletin, provides information to guide conservation efforts and protect the remaining 73 whales estimated in the population.

Research shows that these whales spend between 70 and 84 percent of their time foraging for food in the absence of ships and boats to meet their daily energy needs.

“Killer whales rely on echolocation to hunt chinook salmon, and ship noise interferes with their ability to send ‘clicks’ and locate their prey,” says Ruth Joy, study collaborator, statistical ecologist and assistant professor at SFU’s School of Environmental Sciences.

Researchers studied the foraging behavior of whales in Haro Strait during a voluntary slowdown of ships in 2018, as part of a larger effort to reduce human-induced noise nuisance. The Strait is a critical summer foraging habitat for endangered whales.

The ECHO program was led by the Vancouver Fraser Port Authority and followed an earlier successful trial, which had 55% of vessels voluntarily reducing their speed to 11 knots while crossing the Strait, resulting in an overall reduction in noise from 2.5 decibels.

Using a surveying instrument known as a “theodolite tracking” to determine the positions of the whales, researchers observed and categorized the group’s behavior as traveling, resting, socializing, or foraging. during each five-minute sweep.

The research also recorded the number, type and position of vessels in the area, then combined data collected from vessels and whales with a sound propagation model, to predict the noise level of vessels and boats. whales were exposed to when they surfaced.

As noise levels increased, whales were less likely to start feeding and more likely to stop activity. Researchers suggest that reducing vessel speeds, lateral displacement in shipping lanes, replacing the noisiest vessels in the fleet, and re-routing shipping lanes are steps the industry can take to help these. Marine mammals.

Taking immediate action is more crucial than ever, following recent reports of three pregnant J pod whales now eating for two and raising their young for years to come.

“These three pregnant females and members of the J-pod cast a much needed silver lining for the future of the Southern Resident Killer Whales,” Joy said.

The researchers’ work continues as the school’s graduate students, Kaitlin Baril and Azadeh Gheibi, use the same theodolite tracking methods to study underwater ambient noise and its impact on killer whales in Boundary’s Canadian waters. Pass between British Columbia and Washington State.

The study is a collaboration between researchers from SFU, the Oceans Initiative in Seattle, the University of California and the University of Bielefeld in Germany.

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