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

(Phil McLachlan/Capital News)
Murder charge laid in February 2020 stabbing death of Smithers man

Michael Egenolf is charged with the second-degree murder of Brodie Cumiskey

Island Health chief medical officer Dr. Richard Stanwick receives a first dose of Pfizer vaccine, Dec. 22, 2020. (B.C. government)
COVID-19: B.C. seniors aged 90+ can start to sign up for vaccination on March 8

Long-term care residents protected by shots already given

A health care worker prepares to test a Coastal GasLink field worker for COVID-19. (Coastal GasLink photo)
Coastal GasLink begins COVID screening of pipeline workers

Construction is once again ramping up following Northern Health approval of COVID management plan

FILE – A COVID-19 vaccine being prepared. (Olivia Sullivan/Sound Publishing)
B.C. seniors 80 years and older to get COVID vaccine details over next 2 weeks: Henry

Province is expanding vaccine workforce as officials ramp up age-based rollout

Fisheries and Oceans Canada released it's 2021 Pacific Herring Integrated Fisheries Management Plan Feb. 19. (File photo)
Northern herring opportunities kept to a minimum

2021 management plan caps Prince Rupert fishery at 5 per cent

Health Minister Adrian Dix looks on as Dr. Bonnie Henry pauses for a moment as she gives her daily media briefing regarding COVID-19 for British Columbia in Victoria, B.C. THE CANADIAN PRESS/Jonathan Hayward
7 additional deaths and 542 new COVID-19 cases in B.C.

Provincial health officials reported 18 new COVID-19 cases linked to variants of concern

The City of Vancouver estimates there are 3,500 Canada geese in the city right now, and that number is growing. (Bruce Hogarth)
Help tame Vancouver’s Canada goose population by reporting nests: park officials

The city is asking residents to be on the lookout so staff can remove nests or addle eggs

Chief Justice Christopher Hinkson (Office of the Chief Justice)
Judge questions whether B.C.’s top doctor appreciated right to religious freedom

Lawyer for province says Dr. Henry has outlined the reasons for her orders publicly

A sample of guns seized at the Pacific Highway border crossing from the U.S. into B.C. in 2014. Guns smuggled from the U.S. are used in criminal activity, often associated with drug gangs. (Canada Border Service Agency)
B.C. moves to seize vehicles transporting illegal firearms

Bill bans sale of imitation or BB guns to young people

BC Housing minister David Eby is concerned that Penticton council’s decision to close a local homeless shelter will result in a “tent city” similar to this one in Everett, Wa. (Olivia Vanni / Black Press file)
‘Disappointed and baffled’ B.C. housing minister warns of tent city in Penticton

Penticton council’s decision to close a local homeless shelter could create tent city, says David Eby

Join Black Press Media and Do Some Good
Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

The first of Fisheries and Oceans Canada’s long-range maritime patrol aircraft—the Dash-8—becomes operational. (Photo supplied by PAL Aerospace)
Fisheries and Oceans Canada’s new De Havilland Dash-8-100 long-range surveillance air craft is capable of staying aloft for eight to 10 hours for a variety of missions up and down the B.C. coast. (Photo supplied by PAL Aerospace)
New plane will double DFO’s surveillance capacity in B.C.

The Dash-8 will fly out of Campbell River for enforcement, conservation missions

A recently published study out of UBC has found a link between life satisfaction levels and overall health. (Pixabay)
Satisfied with life? It’s likely you’re healthier for it: UBC study

UBC psychologists have found those more satisfied with their life have a 26% reduced risk of dying

A vial of some of the first 500,000 of the two million AstraZeneca COVID-19 vaccine doses that Canada has secured through a deal with the Serum Institute of India in partnership with Verity Pharma at a facility in Milton, Ont., on Wednesday, March 3, 2021. THE CANADIAN PRESS/Carlos Osorio - POOL
Federal panel recommends 4-month gap between COVID vaccine doses due to limited supply

The recommendation applies to all COVID-19 vaccines currently approved in Canada

Most Read