Southern resident killer whales in B.C. waters. Research shows the population’s females are more negatively influenced by vessel traffic than males. (Photo supplied by Ocean Wise Conservation Association)

Southern resident killer whales in B.C. waters. Research shows the population’s females are more negatively influenced by vessel traffic than males. (Photo supplied by Ocean Wise Conservation Association)

Female orcas less likely to feed in presence of vessel traffic: study

Research the southern resident population raises concerns over reproduction capacity

Female orcas are more likely than males to stop eating when noisy vessels get too close to the pod, surprising new research indicates.

The study out of the San Juan Islands in Washington State, published recently in the journal Frontiers in Marine Science, looked at the foraging habits of the endangered southern resident killer whale population that shares its habitat in B.C. waters. The findings highlight the importance sex-specific responses to marine disturbances, and raises concerns over female reproduction capacity.

“A female’s decision to forego foraging states due to the close proximity of vessels could have cascading effects on the ability to meet energetic requirements to support reproductive efforts,” the study reads. “This is particularly concerning in an endangered population that is in decline.”

There are currently just 74 killer whales in the southern-resident population. The researchers hope the study will influence future management actions in preserving foraging opportunities and recovery efforts.

READ MORE: Coast Guard ramps up protections for B.C. whales

Between 2010 and 2014, researchers led by wildlife biologist Marla Holt with the National Oceanic and Atmospheric Administration attached temporary sensor-tags to members of the population to monitor their subsurface behaviour with prey capture in a critical habitat. Over the course of three seasons measurements were taken during variable vessel activity on the surface, including vessel counts, distance and speed.

Among the results, the findings showed the whales made fewer and shorter dives for prey when the vessels had an average distance of less than 366 metres.

The findings are consistent with other cetacean studies, but here researchers showed females were especially influenced by vessel activity.

It implies females experience risk to vessels differently than males. This is likely because they’re more attentive to the well-being of young offspring. Deep dives also put greater energy demands on the smaller female body.

“A female’s decision to forego foraging in the presence of close vessels could hinder her ability to meet energetic requirements to support reproductive efforts, including fetal growth in pregnancy and lactation costs after calving,” the study reads. “This is particularly concerning in an endangered mammalian population because recovery cannot occur without successful reproductive outcomes among breeding individuals, particularly in long-lived females with birthing intervals of 3–7 years.”

READ MORE: Victoria researcher finds ‘holy grail’ of killer whales

ScienceSouthern Resident Killer Whales

Just Posted

Ashcroft hospital emergency closed sign, 2016. Photo credit: Barbara Roden
Ashcroft Hospital emergency department closed this weekend

Closure due to unexpected limited physician availabiliy, says Interior Health

Residents line up outside the Vernon Recreation Complex for their COVID-19 vaccine Saturday, June 5. (Jennifer Smith - Morning Star)
No appointments necessary for first dose COVID-19 vaccine: Interior Health

People can just show up at clinics, register on the spot and get the shot

Heidi Roy of the Cariboo Jade Shop in Cache Creek with the 3,000 jade boulder, which is now on secure display inside the shop. (Photo credit: Barbara Roden)
Massive jade boulder returns to Cache Creek store six months after daring heist

The 3,000-pound boulder was stolen on Dec. 19, 2020 and found abandoned in the bush a week later

Dr. Albert de Villiers, chief medical health officer for the Interior Health Authority. (Contributed)
Child sex crimes charges against Interior’s top doc won’t impact pandemic response: Dix

Dr. Albert de Villiers is charged with sexual assault and sexual interference

Canadian Prime Minister Justin Trudeau participates in a plenary session at the G7 Summit in Carbis Bay, England on Friday June 11, 2021. THE CANADIAN PRESS/Adrian Wyld
Canada donating 13M surplus COVID-19 vaccine doses to poor countries

Trudeau says the government will pay for 87 million shots to be distributed to poor countries

Premier John Horgan speaks as provincial health officer Dr. Bonnie Henry, right, and health minister Adrian Dix look on during a press conference to update on the province’s fall pandemic preparedness plan during a press conference from the press theatre at Legislature in Victoria, Wednesday, Sept. 9, 2020. THE CANADIAN PRESS/Chad Hipolito
B.C. officials to provide details on Step 2 of COVID reopening plan Monday

Step 2 could allow for larger gatherings and a resumption of recreational travel

Indigenous Services Minister Marc Miller is seen during a news conference, Wednesday May 19, 2021 in Ottawa. THE CANADIAN PRESS/Adrian Wyld
Indigenous child-welfare battle heads to court despite calls for Ottawa to drop cases

Feds are poised to argue against two Canadian Human Rights Tribunal rulings

The Great Ogopogo Bathtub Race has been held in Summerland as a fundraising event. Do you know which Canadian city introduced this sport? (Black Press file photo)
QUIZ: A summer’s day at the water

How much do you know about boats, lakes and water?

Two-year-old Ivy McLeod laughs while playing with Lucky the puppy outside their Chilliwack home on Thursday, June 10, 2021. (Jenna Hauck/ Chilliwack Progress)
VIDEO: B.C. family finds ‘perfect’ puppy with limb difference for 2-year-old Ivy

Ivy has special bond with Lucky the puppy who was also born with limb difference

A million-dollar ticket was sold to an individual in Vernon from the Lotto Max draw Friday, June 11, 2021. (Photo courtesy of BCLC)
Lottery ticket worth $1 million sold in Vernon

One lucky individual holds one of 20 tickets worth $1 million from Friday’s Lotto Max draw

“65 years, I’ve carried the stories in my mind and live it every day,” says Jack Kruger. (Athena Bonneau)
‘Maybe this time they will listen’: Survivor shares stories from B.C. residential school

Jack Kruger, living in Syilx territory, wasn’t surprised by news of 215 children’s remains found on the grounds of the former Kamloops Indian Residential School

A logging truck carries its load down the Elaho Valley near in Squamish, B.C. in this file photo. THE CANADIAN PRESS/Chuck Stoody
Squamish Nation calls for old-growth logging moratorium in its territory

The nation says 44% of old-growth forests in its 6,900-square kilometre territory are protected while the rest remain at risk

Most Read