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

A memorial to Hudson Brooks outside the South Surrey RCMP detachment. (File photo)
Officer who fatally shot Hudson Brooks recounts ‘absolutely terrifying’ incident

Const. Elizabeth Cucheran testified at coroner’s inquest Tuesday morning

Single-family houses like these, under construction in Willoughby, are now 20 per cent more valuable than a year ago, according to recent real estate numbers. (Matthew Claxton/Langley Advance Times)
‘Great Congestion’ hits Langley real estate as buyers vie for houses

Townhouses and single-family homes are in high demand and prices are up

Riverside Calvary Church in Walnut Grove. (Langley Advance Times file)
B.C. is ‘stereotyping’ churches as riskier for COVID than other spaces, lawyer argues

Judge said that freedom of expression, religion are not at issue in the case

Which came first? Actually, you might not need the chicken at all pretty soon. (Black Press Media File Photo)
Painful Truth: Eggs without chickens?

What does that do to poultry farmers?

A player is checked in prior to the start of play in a North Langley Softball video produced to demonstrate COVID-19 safety measures are in place (Danica Reed video/special to Langley Advance Times)
Playing it safe: North Langley Softball produces COVID safety video

Intended to answer parental concerns about precautions while practicing during a pandemic

Older rental apartments are prime candidates for renovations, and could result in lost affordable housing stock. (Zoë Ducklow photo)
B.C.’s renoviction overhaul a good start, but won’t preserve affordable stock, lawyer says

And still no protection for people who can’t pay rent due to COVID-19

(Photo by Marissa Baecker/Shoot the Breeze)
B.C. WHL teams to hit the ice with Kelowna, Kamloops hub cities

Kelowna, Kamloops centres chosen to host B.C. WHL teams for 24-game regular season

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 machines are akin to ATMs and allow drug users at risk of overdose to get hydromorphone pills dispensed to them after their palm has been scanned to identify its unique vein pattern. (CANADIAN PRESS)
Feds dole out $3.5M for ‘vending machines’ to dispense safer opioids in B.C.

The machines are located in four cities across Canada, including Vancouver and Victoria

Kelowna’s lakefront visitor centre is one of 130 around the province. Tourism businesses have been hardest hit by COVID-19 restrictions on travel. (Destination B.C.)
Tourism, small business getting COVID-19 help, B.C. minister says

$300M grant program has delivered $50 million so far

The incident happened in downtown Castlegar. Photo: Betsy Kline
Castlegar teen recounts stabbing after stranger breaks into grandmother’s house

The unnamed teen survived a terrifying attack Feb. 21

(Black Press file photo)
Agassiz boy, 11, dies from ‘extensive injuries’: Homicide team

Agassiz RCMP were called out Friday to assist with a child in medical distress

Most Read