In this January 2014 file photo, endangered orcas from the J pod swim in Puget Sound west of Seattle as seen from a federal research vessel that has been tracking the whales. A new study from federal researchers provides the most detailed look yet at what the Pacific Northwest’s endangered orcas eat. (Elaine Thompson/The Associated Press, File)

In this January 2014 file photo, endangered orcas from the J pod swim in Puget Sound west of Seattle as seen from a federal research vessel that has been tracking the whales. A new study from federal researchers provides the most detailed look yet at what the Pacific Northwest’s endangered orcas eat. (Elaine Thompson/The Associated Press, File)

Study reinforces importance of Chinook to Pacific Northwest orcas

Data confirms how central the big salmon are to the orca’s diet year-round

  • Mar. 5, 2021 11:30 a.m.

For more than a decade, Brad Hanson and other researchers have tailed the Pacific Northwest’s endangered orcas in a hard-sided inflatable boat, leaning over the edge with a standard pool skimmer to collect clues to their diet: bits of orca poop floating on the water, or fish scales sparkling just below the surface.

Their work established years ago that the whales depend heavily on depleted runs of chinook, the largest and fattiest of Pacific salmon species, when they forage in the summer in the inland waters between Washington state and British Columbia.

A new paper from Hanson and others at the NOAA Fisheries Northwest Fisheries Science Center provides the first real look at what the whales eat the rest of the year, when they cruise the outer Pacific Coast.

The data reaffirm the central importance of chinook to the orcas and the importance of recovering chinook populations to save the beloved mammals.

RELATED: First orca baby of the year in B.C. named Ne’nakw

RELATED: Rare white orca spotted near Sooke two weeks after hunting in Alaska

By analyzing the DNA of orca feces as well as salmon scales and other remains after the whales have devoured the fish, the researchers demonstrated that, while the whales sometimes eat other species, including halibut, ling cod and steelhead, they depend most on chinook.

And they consumed the big salmon from a wide range of sources — from those that spawn in California’s Sacramento River all the way to the Taku River in northern British Columbia.

“Having the data in hand that they’re taking fish from this huge swath of watershed across western North America was pretty amazing,” Hanson, the study’s lead researcher, said Wednesday.

“We have to have hard data on what these whales are actually doing.”

There are officially 74 individuals in the three groups of endangered orcas, known as the J, K and L pods of the Southern Residents.

Three calves have been born since September, but those are not yet reflected in the count because only about half of the babies survive their first year.

Facing a dearth of prey, contaminants that accumulate in their blubber, and vessel noise that hinders their hunting, the whales are at their lowest numbers since the 1970s, when hundreds were captured — and more than 50 were kept — for aquarium display.

Scientists warn the population is on the brink of extinction.

The paper, published Wednesday in the journal PLOS One, suggests that efforts to make chinook more abundant off the coast in the non-summer months could especially pay off, and that Columbia River chinook hatchery stocks are among the most important for the orcas.

It also suggests that increasing the numbers of non-salmon species could help fill the gaps for the orcas when chinook aren’t available in the open ocean.

NOAA has already used some of the data, which has been available internally as scientists awaited the study’s publication, in proposing what areas to designate as critical habitat for the orcas.

Officials could use it in prioritizing certain habitat restoration efforts or in timing hatchery production of salmon to best benefit the orcas, said co-author Lynne Barre of the National Marine Fisheries Service’s Protected Resource Division.

This September 2008 photo provided by the Center for Whale Research taken near Washington state’s San Juan Islands shows scientists looking for clues about the diet of the Pacific Northwest’s endangered orcas using a pool skimmer to collect the scales or other remains of salmon the whales had eaten. A long-term study published Wednesday reaffirmed the importance of Chinook salmon to the whales even when they cruise the outer Pacific Coast, where the fish are harder to find. (Ken Balcomb/Center for Whale Research via AP)

This September 2008 photo provided by the Center for Whale Research taken near Washington state’s San Juan Islands shows scientists looking for clues about the diet of the Pacific Northwest’s endangered orcas using a pool skimmer to collect the scales or other remains of salmon the whales had eaten. A long-term study published Wednesday reaffirmed the importance of Chinook salmon to the whales even when they cruise the outer Pacific Coast, where the fish are harder to find. (Ken Balcomb/Center for Whale Research via AP)

The information could also be key in setting limits for fisheries; the Pacific Fisheries Management Council has recommended that NOAA curtail fishing if chinook abundance is forecast to drop below a certain level.

The researchers encountered the orcas 156 times from 2004 to 2017, with most of the fecal and prey samples from the outer coast being collected in 2013 and 2015, when the animals were easier to find because they were satellite tagged.

There were big runs of chinook those years, which might have been reflected in their findings; since then, chinook numbers have fallen up and down the coast due to drought in California and warmer ocean conditions.

In the summer, when the orcas forage in the inland waters of the Salish Sea, their diet is almost entirely chinook — mostly those that return to spawn in Canada’s Fraser River, the paper said.

By September, as coho salmon return to spawn in the region’s rivers, they make up about half of the orcas’ diet, with a mix of chinook, chum and coho providing sustenance through the fall.

In the winter, when the orcas spend more time on the outer coast, they turn to non-salmon species, apparently because chinook are more spread out and harder to find.

Barre said it may be surprising that the orcas focus so much on chinook when there are so many other fish in the sea, but research has also suggested that the whales might target them because the nutritional value of the big, fatty fish is worth the calories burned catching them.

“It would certainly make our lives easier if they were eating a lot more of the other things that are available,” she said.

— Gene Johnson, The Associated Press

State News

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

The report prepared by Independent Investigations Office of BC said that no offence was committed by the police officer from Lisims/ Nass Valley RCMP detachment while responding to a stabbing incident that led to an in-custody death. (Black Press file photo)
Nass Valley RCMP officer cleared in October 2020 police-involved death

Independent Investigations Office of B.C. concludes no offence committed by police officer

Back Row, Left to Right: Laura Archibald, (teacher), Sarah Engdahl, Victoria Cho, Bronwen Bennett, Briana Simms, Jalynn Gibson, Sydney Harris, Braya Kluss, Valentina Protheroe, Isabella Gibson, Emily Hart, (teacher). Front Row, Left to Right: Collin Maillet, Hannah Hansen, Layla Loutitt, Isabella Kossler, Zadie Kietzmann, Izzie Croot, Deanna McDicken, Hope Misner. Missing: Brianna Onstein, Makenna Harris. (Submitted Photo/Tracey Hart)
Terrace’s Art in Motion Dance earns accolades at Prince George Dance Festival

The group earned a total of 21 trophies during the competition

A temporary fix to erosion problems on Lanfear Hill has been approved. (Ben Bogstie/Terrace Standard)
City to spend $360,000 on temporary hill fix

Will restore pedestrian and cycle use of Lanfear Hill

Terrace Community Fund was able to set up the Dare to Dream Fund with a significant donation from Trumpeter Donnie Clark. (File photo)
Dare to Dream Fund set up after a large donation from musician Donnie Clark

The fund will provide financial support for the Dare to Dream music program in Terrace and Thornhill

A person receives a COVID-19 vaccine at a vaccination clinic run by Vancouver Coastal Health, in Richmond, B.C., Saturday, April 10, 2021. THE CANADIAN PRESS
B.C. sees 873 more COVID-19 cases Tuesday, decline continues

Hospitalizations up to 377, two more deaths for 1,515 total

B.C. Premier John Horgan speaks at the B.C. legislature. (B.C. government)
Tougher COVID-19 restrictions in B.C., including travel, still ‘on the table’: Horgan

John Horgan says travel restrictions will be discussed Wednesday by the provincial cabinet

Protesters occupied a road leading to Fairy Creek Watershed near Port Renfrew. (Submitted photo)
B.C. First Nation says logging activist interference not welcome at Fairy Creek

Vancouver Island’s Pacheedaht concerned about increasing polarization over forestry activities

Flow Academy is not accepting membership applications from anybody who has received a dose of the vaccine, according to a password-protected membership application form. (Submitted image)
B.C. martial arts gym refusing patrons who have been vaccinated, wear masks

Interior Health has already issued a ticket to Flow Academy for non-compliance with public health orders

Guinevere, lovingly referred to by Jackee Sullivan and her family as Gwenny, is in need of a gynecological surgery. The family is raising money to help offset the cost of the procedure. (Jackee Sullivan/Special to Langley Advance Times)
Langley lizard’s owners raise funds for gynecological surgery

The young reptile is scheduled for operation on Tuesday

Facebook screenshot of the sea lion on Holberg Road. (Greg Clarke Facebook video)
VIDEO: Sea lion randomly spotted on remote B.C. logging road

Greg Clarke was driving home on the Holberg Road April 12, when he saw a large sea lion.

Defence counsel for the accused entered two not guilty pleas by phone to Grand Forks Provincial Court Tuesday, Jan. 12. File photo
B.C. seafood company owner fined $25K for eating receipt, obstructing DFO inspection

Richmond company Tenshi Seafood is facing $75,000 in fines as decided March 4 by a provincial court judge

B.C. Finance Minister Selina Robinson speaks in the B.C. legislature, March 2, 2021. (Hansard TV)
B.C. NDP ministers defend ‘air tax,’ latest COVID-19 business aid

Empty home tax doesn’t apply to businesses, but space above them

In Ontario, COVID-19 vaccine clinics have been set up at local mosques. (Submitted photo: Rufaida Mohammed)
Getting the vaccine does not break your fast, says Muslim COVID-19 task force

Muslim community ‘strongly’ encouraging people to get their shot, whether or not during Ramadan

Most Read