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

Prime Minister Justin Trudeau will issue an apology for Canada’s treatment of Itaian-Canadians during the Second World War. (CPAC)
COLUMN: Apologizing for an uncomfortable wartime decision

Canada’s government will apologize for its treatment of Italian-Canadians during the Second World War

Kimberley case counts not at the point for 18 years and older community vaccination, says Interior Health. (File photo)
Many factors considered for smaller community-wide vaccination: Interior Health

East Kootenay resort town’s COVID-19 situation not at the point of community-wide vaccination, say officials

The BC Wildfire Service is urging caution amid forecasts of strong winds throughout the Kamloops Fire Centre. (BC Wildfire Service photo)
Strong winds forecasted for Kamloops Fire Centre, BC Wildfire service urges caution

“Wind can cause grass fires to spread very quickly,” says the BC Wildfire Service

Richard Cannings
Penticton MP weighs in on federal budget

Budget caters to the wealthy, but Richard Cannings is happy with $10/day childcare

Are you considering any ambitious home renovation projects? The Okanagan Regional Library can help. (Black Press file photo)
COLUMN: Redecorate your home with help from the library

Plenty of resources in place for home decoration projects

Canadian Prime Minister Justin Trudeau and United States President Joe Biden smile as they say farewell following a virtual joint statement in Ottawa, Tuesday, February 23, 2021. THE CANADIAN PRESS/Adrian Wyld
Trudeau pledges to cut emissions by 40% to 45% by 2030, short of U.S. goal

Trudeau announced target during a virtual climate summit convened by U.S. President Joe Biden

Vernon RCMP are seeking the public’s help in identifying a man who allegedly pointed a firearm at two people outside a downtown business Saturday, April 10, 2021. (Contributed)
Man who brandished firearm in downtown Vernon sought by police

Video surveillance image shows man pointing what investigators believe to be a handgun April 10

MLA Shirley Bond, right, answers questions during a press conference at Legislature in Victoria, B.C., on February 19, 2019. THE CANADIAN PRESS/Chad Hipolito
Former B.C. gaming minister says she wasn’t told directly about dirty cash flowing to casinos

Shirley Bond said Thursday civil forfeiture, gang violence and gambling addiction were also major concerns in 2011

RauDZ pop-up patio located on Pandosy Street in front of The Okanagan Table. (Contributed: Audrey Surrao)
Kelowna restaurant gets creative to adjust to new health orders

The owners of RauDZ Regional Table open ‘pop-up patio’ to adjust to health order banning indoor dining

RCMP Constable Etsell speaks to tourists leaving the area at a police roadblock on Westside Road south of Fintry, B.C., Thursday, July 23, 2009. THE CANADIAN PRESS/ Yvonne Berg
B.C. police say they take ‘exception’ to conducting roadblocks limiting travel

Asking the police to enforce roadblocks exposes officers to further risk and possible COVID-19 infections, says federation president Brian Sauve

The City of Vernon has placed 30th in Macleans.ca’s poll of the 415 best communities to live in Canada. (Jennifer Smith - Morning Star)
Okanagan city high on Macleans’ list of best places to live in Canada

Vernon ranked No. 30, fifth-highest in province and best ranking outside Vancouver Island; Halifax No. 1

Waterfront owners on Kalamalka Lake might want to check their docks, as one was spotted floating around the Oyama end of the lake Thursday, April 22. (Nick Clements photo)
‘Anyone lose a dock?’ in North Okanagan

Wooden structure spotted at south end of Kalamalka Lake

As part of the province’s strategy to combat the opioid overdose crisis, take-home naloxone kits have been distributed throughout the province. (Courtesy of Gaëlle Nicolussi)
Vancouver Island could be at its worst point of overdose crises yet: medical health officer

Island Health issued overdose advisories for Victoria, various communities in the last two weeks

BC Hydro released a survey Thursday, April 22. It found that many British Columbians are unintentionally contributing to climate change with their yard maintenance choices. (Pixabay)
Spend a lot of time doing yard work? It might be contributing to climate change

Recent BC Hydro survey finds 60% of homeowners still use gas-powered lawnmowers and yard equipment

Most Read