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

Four young women prepare to model Magic Wand dresses at a fashion show. Magic Wand provides grad dresses and tuxedos for a nominal fee. (Submitted File Photo)
Nominations available for Cindrella Dreams Program in Vanderhoof

New organizer excited to help graduates with formal wear

Photo collage of loved ones lost to substance use and overdose. (Photo courtesy Moms Stop The Harm)
B.C. overdose deaths still rising 5 years after public health emergency declared

Moms Stop the Harm calls on B.C. to provide safe supply in response to deadly illicit drug use

District of Vanderhoof municipal office. (Aman Parhar/Omineca Express)
Vanderhoof district rejects FOI request for business name

Officials will release more information about the restaurant on May 21

Demonstrators at the legislature on April 14 called on the province to decriminalize drug possession and provide widespread access to regulated safe supply across B.C. (Jake Romphf/News Staff)
Rally calls for decriminalization, safe supply on 5th anniversary of overdose emergency declaration

From 2016 to the end of February, 7,072 British Columbians died due to overdose

(Government of Canada)
Liberal MP caught stark naked during House of Commons video conference

William Amos, in Quebec, appeared on the screens of his fellow members of Parliament completely naked

Provincial health officer Dr. Bonnie Henry updates B.C.’s COVID-19 situation at the B.C. legislature, Feb. 1, 2020. (B.C. government)
B.C.’s COVID-19 case count jumps to 1,168 Wednesday, nearly 400 in hospital

Now 120 coronavirus patients in intensive care, six more deaths

Moss covered branches are seen in the Avatar Old Growth Forest near Port Renfrew on Vancouver Island, B.C. Thursday, Sept. 29, 2011. THE CANADIAN PRESS/Jonathan Hayward
B.C. blockades aimed at protecting old-growth forests reveal First Nation split

Two Pacheedaht chiefs say they’re ‘concerned about the increasing polarization over forestry activities’ in the territory

Richmond RCMP Chief Superintendent Will Ng said, in March, the force received a stand-out number of seven reports of incidents that appeared to have “racial undertones.” (Phil McLachlan/Capital News)
‘Racially motivated’ incidents on the rise in B.C’s 4th largest city: police

Three incidents in Richmond are currently being invested as hate crimes, says RCMP Chief Superintendent Will Ng

Commercial trucks head south towards the Pacific Highway border crossing Wednesday (April 14, 2021). The union representing Canadian border officers wants its members to be included on the frontline priority list for the COVID-19 vaccine. (Aaron Hinks photo)
CBSA officers’ union calls for vaccine priority in B.C.

Border officers at ports including, YVR and land crossings should ‘not be left behind’

A still from the video taken of a violent arrest on May 30, 2020 in downtown Kelowna. (File)
Kelowna Mountie charged with assault for caught-on-camera violent arrest

Const. Siggy Pietrzak was filmed punching a suspected impaired driver at least 10 times during an arrest

A screenshot from a Nuu-chah-nulth healing song and performance created in collaboration between Hjalmer Wenstob and Timmy Masso. (Screenshot from YouTube)
VIDEO: Tla-o-qui-aht First Nation brothers produce COVID-19 healing song

Hjalmer Wenstob and Timmy Masso share dance and inspiration.

Most Read