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

Image Surrey.ca
Surrey council resurrects, fast tracks 84th Avenue connection at Bear Creek Park

The city put the brakes on this project in 2007 because of community opposition

(Delta Police Department photo)
North Delta youth calls 911 after accruing $7K in online gaming charges

‘Police spoke with the student about appropriate times to call 911’

Brady
‘Don’t give up’: Surrey man touts RAAC clinic for opioid addiction

Fraser Health has opened a second Rapid Access to Addiction Care clinic in the region

Multiple firearms were among items seized by Surrey RCMP from a Whalley condo this week. (Surrey RCMP photo)
Firearms, drugs among items seized by police from Whalley condo

Investigation began after report of vehicle robbery with use of firearm, RCMP say

Provincial health officer Dr. Bonnie Henry updates B.C.’s COVID-19 situation at the B.C. legislature. (B.C. government)
B.C. reports 10 additional deaths, 395 new COVID-19 cases

The majority of new coronavirus infections were in the Fraser Health region

“Our biggest challenge has been the amount of vaccine,” said FNHA acting chief medical officer Dr. Shannon McDonald. (First Nations Health Authority Facebook photo)
All First Nations on reserve to be vaccinated by end of March: First Nations Health Authority

Vaccinations continuing for B.C. First Nations amid shortages

Site C will go ahead, one year later and $5.3 billion more, the NDP announced Feb 26. (BC Hydro image)
B.C. NDP announces Site C will go ahead with new $16B budget

Reviews recommend more oversight, beefed up foundation stability work

The last three wild northern spotted owls live near the Spuzzum Watershed outside of Hope. The province recently ordered a halt to logging for at least a year to give the owls a chance to survive.  (Photo/Jared Hobbs)
Logging halted in northern spotted owl habitat near Hope

Halt will last at least a year, gives time to formulate survival plan for Northern Spotted Owl

Several BC Ferries sailings are cancelled Friday morning due to adverse weather. (Black Press Media File)
Tsawwassen to Swartz Bay ferry sailing cancelled due to high winds, sea state

Adverse weather causes cancellations across several BC Ferries routes

The BC Prosecution Service announced last year that it was appointing lawyer Marilyn Sandford as a special prosecutor to review the case, following media inquiries about disclosure issues linked to a pathologist involved in the matter. (Black Press Media files)
Possible miscarriage of justice in B.C. woman’s conviction in toddler drowning: prosecutor

Tammy Bouvette was originally charged with second-degree murder but pleaded guilty in 2013 to the lesser charge

A kid in elementary school wearing a face mask amid the COVID-19 pandemic. (Metro Creative)
Union asks why an elementary school mask rule wouldn’t work in B.C. if it does elsewhere

B.C. education minister announced expansion of mask-wearing rules in middle, high school but not elementary students

A pharmacist prepares a COVID-19 vaccine at Village Green Retirement Campus in Federal Way on Jan. 26. (Olivia Sullivan/Sound Publishing)
Canada approves use of AstraZeneca’s COVID-19 vaccine

The country joins more than a dozen others in giving the shot the green light

A new survey has found that virtual visits are British Columbian’s preferred way to see the doctor amid the COVID-19 pandemic. (Unsplash)
Majority of British Columbians now prefer routine virtual doctor’s visits: study

More than 82% feel virtual health options reduce wait times, 64% think they lead to better health

Most Read