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

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

The District of Lake Country saw its number of overdose calls double in 2020 over the previous year. (Black Press file photo)
Overdose calls doubled in Lake Country in 2020: report

The district’s protective services annual report shows there were 47 overdose calls last year

Interior Health reported 33 new COVID-19 cases on March 5. (Black Press Files)
Interior Health reports 33 new COVID-19 cases on March 5

Over 300,000 vaccine doses have been administered provincewide.

Vernon husband and wife Jan (top) and Ken Waldon (with B.C. Lt.-Gov. Janet Austin), were among 44 provincial recipients of the Governor General’s Sovereign’s Medal for volunteerism. The awards were presented at a special ceremony earlier in September in Victoria. (Government House Victoria photos)
Fintry heritage site champion loses battle with illness

Ken Waldon was the leading proponent behind the creation of Friends of the Fintry Provincial Park Society

A lawyer wears a face mask and gloves to curb the spread of COVID-19 while waiting to enter B.C. Supreme Court, in Vancouver, B.C., Friday, Aug. 28, 2020. British Columbia’s highest court has sided with the land owner in a dispute over public access to public land. THE CANADIAN PRESS/Darryl Dyck
B.C. high court finds in favour of large landowner in fight over access to Stoney and Minnie lakes

The Nicola Valley Fish and Game Club launched legal action after the cattle company blocked road and trail access

RCMP search the vehicle after pouring out what appeared to be alcohol, onto the highway. (Phil McLachlan/Capital News)
UPDATE: Kelowna woman arrested after alleged erratic driving, suspected impairment

RCMP say no injuries reported and investigation is ongoing

About 50 people gathered Friday, March 5, 2021 in Penticton to protest city council’s decision to close a temporary winter shelter. (Jesse Day - Western News)
WATCH: Protest over Penticton shelter draws large crowd

People are gathering in Gyro Park to protest the closure of a winter shelter

Malawian police guard AstraZeneca COVID-19 vaccines after the shipment arrived in Lilongwe, Malawi, Friday March 5, 2021. Canada is expecting its first shipments of AstraZeneca vaccine next week. (Associated Press/Thoko Chikondi)
B.C.’s daily COVID-19 cases climb to 634 Friday, four more deaths

Currently 255 people in hospital, 66 in intensive care

A crashed helicopter is seen near Mt. Gardner on Bowen Island on Friday March 5, 2021. Two people were taken to hospital in serious but stable condition after the crash. (Irene Paulus/contributed)
2 people in serious condition after helicopter goes down on Bowen Island

Unclear how many passengers aboard and unclear where the helicopter was going

Surrey Pretrial in Newton. (Photo: Tom Zytaruk)
B.C. transgender inmate to get human rights hearing after being held in mostly male jail

B.C. Human Rights Tribunal member Amber Prince on March 3 dismissed the pretrial’s application to have Makayla Sandve’s complaint dismissed

Supporters rally outside court as Pastor James Coates of GraceLife Church is in court to appeal bail conditions, after he was arrested for holding day services in violation of COVID-19 rules, in Edmonton, Alta., on Thursday March 4, 2021. THE CANADIAN PRESS/Jason Franson
‘Law remains valid:’ Pastor accused of violating health orders to remain in jail

The Justice Centre for Constitutional Freedoms is representing the pastor

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

The Princeton Traditional Music Festival, normally held in August, was denied a grant due to COVID. (File photo)
COVID makes some of the 2021 grant decisions for Princeton council

Municipality doles out funds while striving to meet policy

The Netflix logo on an iPhone. B.C. delayed imposing sales tax on digital services and sweetened carbonated beverages as part of its response to COVID-19. Those taxes take effect April 1, 2021. THE CANADIAN PRESS/AP, Matt Rourke
B.C. applies 7% sales tax on streaming, vaping, sweet drinks April 1

Measures from 2020 budget were delayed due to COVID-19

Most Read