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

Jack Emberly is the host of a podcast on CEED Pod. (The News files)
CEED Centre in Maple Ridge launches new podcast

Available on CEED Centre website

The Ridge Meadows Flames are hosting an under-15 development skate this summer. (Facebook)
Ridge Meadows Flames announce under-15 development camp

Junior B club to host eight skates in July

BC Hydro is allowing the water levels on the South Alouette River to be higher this spring, to allow a study of sockeye smolt out-migration. (Special to The News)
Maple Ridge river higher for sockeye smolt study

Sockeye salmon smolt migration in South Alouette studied

Last year T’s, with the help of UPlan, the Youth Planning Table subcommittee, made up of about 20 students from the Maple Ridge Pitt Meadows school district, decorated their front window with the names of all the graduates. (The News files)
Parent doesn’t want 2021 grads to be forgotten

Letter from superintendent of Maple Ridge Pitt Meadows School District explains grad guidelines

A bullet hole is seen in the windshield of an RCMP vehicle approximately 4 km from Vancouver International Airport after a one person was killed during a shooting outside the international departures terminal at the airport, in Richmond, B.C., Sunday, May 9, 2021. THE CANADIAN PRESS/Darryl Dyck
Homicide team IDs man in fatal YVR shooting as police grapple with spate of gang violence

Man, 20, charged in separate fatal shooting Burnaby over the weekend

Keith MacIntyre - BC Libertarian
Penticton’s Keith MacIntyre new leader of the B.C. Libertarian Party

The Penticton businessman was voted in by members of the party on May 8

RCMP are searching for Philip Toner, who is a 'person of interest' in the investigation of a suspicious death in Kootenay National Park last week. Photo courtesy BC RCMP.
Man sought in suspicious Kootenay death found in Lake Country

Philip Toner is a person of interest in the death of Brenda Ware

Vernon North Okanagan RCMP reported to 287 mental health calls between Jan. 1, 2021, and May 1. (Black Press files)
‘It’s not the police’s responsibility to deal with mental health calls’: Vernon RCMP

RCMP remind public to take care of mental health and well-being, while better solutions are sought

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

Thompson Rivers University campus is in Kamloops, B.C. (KTW file photo)
Thompson Rivers the 1st B.C. university to supply free menstrual products

The university will offer the products this September

Fraser Health is using ‘targeted’ vaccination clinics in high-risk areas of the Lower Mainland. (Fraser Health photo)
B.C.’s COVID-19 decrease continues, 515 new cases Tuesday

426 seriously ill people in hospital, up from 415 Monday

The site of Sunfest, Laketown Ranch, will be open for camping this summer. (Citizen file)
Sunfest country music bash won’t be shining on B.C. in 2021

Annual Vancouver Island Festival cancelled due to COVID-19, along with Laketown Shakedown

Tla-o-qui-aht First Nation elected chief councillor Moses Martin, who was also Chantel Moore’s grandfather, speaks to media in Port Alberni on Aug. 16, 2020, during a visit from NDP leader Jagmeet Singh following the police shooting of Chantel Moore. (Elena Rardon photo)
Mother of 2 shot by police in critical condition, says B.C. First Nation chief

Community ‘devastated’ by third member of 1,150-person Vancouver Island nation shot in less than a year

Most Read