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

Photo: pixabay.com
Morning Start: Why do dogs like squeaky toys?

Your morning start for Tuesday, April 20, 2021

People are shown at a COVID-19 vaccination site in Montreal, Sunday, April 18, 2021, as the COVID-19 pandemic continues in Canada and around the world. THE CANADIAN PRESS/Graham Hughes
211 new COVID-19 cases in Interior Health over the weekend

Currently, there are 875 active cases of the virus in the region

A nurse prepares a dose of the COVID-19 vaccine in Kelowna on Tuesday, March 16. As of April 19, more than 230,000 doses have been administered across the Interior Health region. (Phil McLachlan/Black Press)
More than 230K doses of COVID-19 vaccine administered across Interior Health

A total of 220,216 first doses and 13,775 second doses have been given to residents across the B.C. Interior

A new non-profit after school program starts in Revelstoke. The Revelstoke Afterschool Society focuses on spending time outside. school (Liam Harrap/Revelstoke Review)
Columbia Basin Trust doles out funds for child care providers

Sixteen Revelstoke providers received money

FILE – NDP Leader John Horgan, right, and local candidate Mike Farnworth greet one another with an elbow bump during a campaign stop in Coquitlam, B.C., on Friday, September 25, 2020. THE CANADIAN PRESS/Darryl Dyck
B.C. won’t be using random individual road stops to enforce travel rules: Safety Minister

Minister Mike Farnworth says travel checks only being considered at major highway junctions, ferry ports

A man drowned while out swimming near the Peach and the children statue in Penticton on Monday, April 19, 2021. (Monique Tamminga Western News)
Penticton man drowns swimming in Okanagan Lake

A witness brought him to shore and performed CPR but the man later died in hospital

FILE – Health-care workers wave to people clapping and yelling thank you to the frontline workers during the 7 p.m.-tribute outside the Lions Gate Hospital in North Vancouver, B.C. Wednesday, April 8, 2020. THE CANADIAN PRESS/Jonathan Hayward
B.C. nurses issue plea for all to follow health orders as hospitalizations spike

Nurses worried about strain COVID-19 is having on hospital capacity, care

Join Black Press Media and Do Some Good
Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

The river channel north of Osoyoos Lake where a man and his dog were rescued on April 19. (Google Maps)
Man and dog rescued from South Okanagan river channel

The man had driven his Jeep into the river off of the dike roadway near Osoyoos Lake

Jasmyn Yakura’s 2004 Chevy Aveo ended up going off Cosens Bay Road Sunday, April 18, with her behind the wheel, and coming to rest down a steep cliff. Yakura suffered only minor injuries. She was helped back to the road by a friend travelling behind her when the car left the road. (Yakura family photo)
North Okanagan driver credits seatbelt with saving life

Jasmyn Yakura, 17, survived after car went off Cosens Bay Road over a cliff, flipping ‘five or six times or more’

University of Victoria rowing coach Barney Williams is photographed in the stands during the Greater Victoria Invitational at CARSA Performance Gym at the University of Victoria in Victoria, B.C., on Friday, November 29, 2019. The University of Victoria says Williams has resigned effective immediately. (THE CANADIAN PRESS/Chad Hipolito)
University of Victoria women’s rowing coach resigns by mutual agreement

Lawsuit filed last summer accused Barney Williams of verbal abuse

Former B.C. premier Christy Clark. (Black Press Media files)
Former B.C. premier to testify at money laundering hearing today

Attorney General David Eby has been added to the witness list as well

Most Read