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

Police presence in Chemainus in an actual building is limited to South Island Highway Patrol on Chemainus Road. (Photo by Pete Cavanaugh)
Petition calls for policing commitment in Chemainus to be honoured

Former detachment member leads the charge in making the municipality and RCMP accountable

Khowhemun Elementary is one of two Cowichan Valley schools that announced possible COVID-19 exposures last week. (Google Street View image)
Two Cowichan Valley schools announce possible COVID-19 exposures

Positive tests at Khowhemun, Quamichan; Superstore confirms more cases

Members of the 4-H Horse Club enjoy the annual horse camp at the Cowichan Exhibition grounds. (submitted)
Farm Credit Canada supports Cowichan 4-H club with cash

On the list of recipients is the Cowichan 4-H Horse Club out of Cobble Hill.

Flanked by CVOLC staff members Kevin van der Linden, Nate Boersen, Lisa Kellar and Neil Ellingson, Ryan Linehan receives his Student of the Month award from Rotary representatives Gregg Perry and Kim Barnard. 
(Kevin Rothbauer/Citizen)
Cowichan Valley Open Learning Collective ‘ambassador’ named Student of the Month

Ryan Linehan earns award for demonstrating natural leadership

(The Canadian Press)
‘Worse than Sept. 11, SARS and financial crisis combined’: Tourism industry in crisis

Travel services saw the biggest drop in active businesses with 31 per cent fewer firms operating

Montreal Canadiens right wing Paul Byron (41) fights for control of the puck with Vancouver Canucks defenceman Quinn Hughes (43) during first period NHL action in Vancouver, Monday, March 8, 2021. THE CANADIAN PRESS/Jonathan Hayward
Captain Clutch: Horvat nets shootout winner as Canucks edge Habs 2-1

Vancouver, Montreal tangle again on Wednesday

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

A special committee has been appointed to look at reforming B.C.’s police act and is inviting the public to make submissions until April 30, 2021. (Black Press media file)
Have thoughts on B.C.’s review of the provincial Police Act?

Submissions will be accepted until April 30

Cottonwoods Care Home in Kelowna. (Google Maps)
New COVID-19 outbreak at Kelowna care home includes fully vaccinated seniors: Henry

Two staff and 10 residents tested positive at Cottonwoods Care Centre

Excerpts from a conversation between Bria Fisher and the fake truLOCAL job. Fisher had signed a job agreement and was prepared to start work for what she thought was truLOCAL before she learned it was a scam. (Contributed)
B.C. woman warning others after losing $3,000 in job scam

Bria Fisher was hired by what she thought was a Canadian company, only to be out thousands

Provincial health officer Dr. Bonnie Henry and Health Minister Adrian Dix provide a regular update on the COVID-19 situation, B.C. legislature, March 2, 2020. (B.C. government)
B.C.’s COVID-19 cases: 545 Saturday, 532 Sunday, 385 Monday

Focus on Prince Rupert, Lower Mainland large workplaces

Rising accident rates and payout costs have contributed to billion-dollar deficits at ICBC. (Comox Valley Record)
B.C. appealing decision keeping ICBC injury cases in court

David Eby vows to ‘clip wings’ of personal injury lawyers

Most Read