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 Oliver Municipal Aiport runway will be extended in spring 2021. (Oliver Municipal Airport / Facebook)
Oliver airport runway to be extended

The extension will be funded through a provincial grant

A dose of COVID-19 vaccine is prepared at a vaccination clinic in Montreal’s Olympic Stadium on Tuesday, Feb. 23, 2021. THE CANADIAN PRESS/Paul Chiasson
39 new cases of COVID-19 in Interior Health region

The total number of cases in the region since the pandemic began is now at 7,334

BC Housing has proposed that the emergency winter shelter at Victory Church at 352 Winnipeg Street be extended as a shelter until March 31, 2022. It was originally intended to be open until April 1, 2021. (Jesse Day - Western News)
One more year of ‘temporary’ homeless shelter in Penticton?

BC Housing has applied to extend Victory Church as a shelter for those experiencing homelessness

The Wrong Turn Tavern in Keremeos is for sale. (Facebook)
Popular Keremeos tavern up for sale

Owner Liza Sanders is selling The Wrong Turn Tavern for $800,000

Walter Makepeace was shocked to find two of his beehives were missing from his Keremeos acreage Feb. 20, 2020. (Contributed)
Allegedly stolen beehives create buzz in Keremeos

Walter Makepeace was shocked to see two beehives had gone missing from his property

NorKam secondary student Karis Wilson in the outfit that got her sent home from school on Feb. 23, 2021
Black Press Media Weekly Roundup: Top headlines this week

Here are the stories that made waves in the Okanagan-Shuswap

Staff from the Marine Mammal Rescue Centre, passersby, RCMP and Nanaimo Fire Rescue carried a sick 300-kilogram steller sea lion up the steep bluff at Invermere Beach in north Nanaimo in an attempt to save the animal’s life Thursday. (Photo courtesy Marine Mammal Rescue Centre)
300-kilogram sea lion muscled up from B.C. beach in rescue attempt

Animal dies despite efforts of Nanaimo marine mammal rescue team, emergency personnel and bystanders

Gina Adams as she works on her latest piece titled ‘Undying Love’. (Submitted photo)
‘Toothless’ the kitty inspires B.C. wood carver to break out the chainsaw

Inspired by plight of a toothless cat, Gina Adams offers proceeds from her artwork to help animals

B.C. Finance Minister Selina Robinson presents bill to delay B.C.’s budget as late as April 30, and allow further spending before that, B.C. legislature, Dec. 8, 2020. (Hansard TV)
How big is B.C.’s COVID-19 deficit? We’ll find out April 20

More borrowing expected as pandemic enters second year

The first of 11 Dash 8 Q400 aircraft's have arrived in Abbotsford. Conair Group Inc. will soon transform them into firefighting airtankers. (Submitted)
Abbotsford’s Conair begins airtanker transformation

Aerial firefighting company creating Q400AT airtanker in advance of local forest fire season

Arrow Lakes Caribou Society said the new caribou pen near the Nakusp Hotsprings is close to completion. (Submitted)
Maternity caribou pen near Nakusp inches closer to fruition

While Nakusp recently approved the project’s lease, caribou captures are delayed due to COVID-19

The Canada Revenue Agency says there were 32 tax fraud convictions across the country between April 2019 and March 2020. (Pixabay)
Vancouver man sentenced to 29 months, fined $645K for tax evasion, forgery

Michael Sholz reportedly forged documents to support ineligible tax credits linked to homeownership

Then-Liberal leader Andrew Wilkinson looks on as MLA Shirley Bond answers questions during a press conference at Legislature in Victoria. (Chad Hipolito / THE CANADIAN PRESS)
B.C. Liberal party to choose next leader in February 2022

Candidates have until Nov. 30 to declare whether they are running

NorKam secondary student Karis Wilson in the outfit that got her sent home from school on Feb. 23, 2021
Kamloops-Thompson school district drafts new dress code policy after students sent home

The new policy is being created after a NorKam secondary student was sent home because of what she was wearing

Most Read