Tag Archives: Chinook salmon

Spring Chinook take on high flows because of ‘early-migration gene’

It’s a bit mind-boggling to think that a single, tiny fragment of genetic material determines whether a Chinook salmon chooses to return to its home stream in the spring or the fall.

Photo: Ingrid Taylar (CC BY-NC 2.0) https://flic.kr/p/dmbyre

I’ve been following the scientific discoveries about spring chinook since 2017, when Mike Miller’s lab at the University of California, Davis, published research findings showing the location of this “early-migration gene” on chromosome 28.

In a story published this week in the Encyclopedia of Puget Sound, I wrote about some of the latest discoveries surrounding spring Chinook. I also thought it worthwhile to describe the importance of these fish to the ecosystem and to the native people of the Puget Sound region.

Up until the past two years, I never gave much thought to spring Chinook, nor apparently have most people, including many biologists. These are the salmon that often struggle to reach the upper reaches of the rivers when the streams are swollen with spring snowmelt. Much of these upper spawning grounds have been destroyed by human activity, and more than half the spring chinook runs in Puget Sound have gone extinct.

The more I learned about spring Chinook the more fascinated I became. The southern resident killer whales used to arrive in Puget Sound in April or May to feast on spring Chinook from Canada’s Fraser River, but those salmon runs have declined along with many fall runs of chinook. The result is a major change in behavior and migration patterns by the whales.

Spring Chinook were at one time an important food for bears coming out of hibernation, for eagles who had scavenged for food through the winter, and for native people who looked forward to fresh fish after a season of dried foods.

As I researched this story, I learned about the history of spring Chinook in the Skokomish River of southern Hood Canal and how a once-plentiful fish became extinct. I was pleased to describe the success of current efforts to create a new run of spring Chinook with the help of a hatchery in the North Fork of the Skokomish, where adult spawners are showing up nearly a century after the fish disappeared.

Spring Chinook in Salmon River, California
Photo: Peter Bohler, via UC Davis

Genetics is a fascinating field, and advances are coming rapidly in the studies of many species, including humans. The idea that a single gene can completely change the migration timing of a Chinook by four months raises many scientific and legal questions — including whether spring Chinook should get their own protection under the Endangered Species Act. As things stand now, Chinook salmon in Puget Sound — both spring and fall together — are listed as threatened under the ESA. But that could change as things shake out with the ESA in Oregon and California.

Ongoing genetic studies — including those involving various salmon species — are causing biologists and legal experts to re-examine the criteria for listing populations as threatened or endangered, as they teeter on the edge of extinction. No matter what the extinction risk is judged to be, spring Chinook are now recognized as something very special.

Orcas hunting for salmon: Not worth the effort in Puget Sound?

Trying to understand what motivates Puget Sound’s killer whales is difficult enough when the orcas are nearby. But now that they have abandoned their summer home — at least for this year — researchers are not able to easily study their behaviors, their food supply or their individual body conditions.

L-84, a 29-year-old male named Nyssa, was thought to be in good health when he went missing.
Photo: Center for Whale Research

Not so many years ago, we could expect the orcas to show up in the San Juan Islands in May, presumably to feast on spring chinook returning to the Fraser River in British Columbia and to streams in northern Puget Sound. Those chinook have dwindled in number, along with other populations of chinook in the Salish Sea, so it appears that the orcas may not come back at all.

Apparently, they have decided that it isn’t worth their time and effort to set up a summer home in the inland waterway. They have gone to look for food elsewhere, such as off the west coast of Vancouver Island, where it is harder for researchers to tell what they are eating and exactly where they are going.

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Three more orca deaths take census count down to 73 Southern Residents

Four orca deaths and two births over the past year brings the official population of southern resident killer whales to 73 — the lowest number since the annual census was launched in 1976.

L-84, a 29-year-old male named Nyssa, is among three southern resident orcas newly listed as deceased. Here he is seen catching a salmon. // Photo: Center for Whale Research

This evening, the keeper of the census — Ken Balcomb of the Center for Whale Research — sadly announced the deaths of three orcas who have not been seen for several months.

In past years, Ken waited until he and his staff have several opportunities to search for any whales that appear to be missing. But this year the whales have stayed almost entirely away from their traditional hunting grounds in the San Juan Islands, where they once stayed for nearly the full summer.

In an unusual move this year, Ken relied on reliable observers from the Canadian Department of Fisheries and Oceans as well as other biologists along the west coast of Vancouver Island. The missing whales were not seen during multiple encounters with the Canadians, Ken told me.

The reason the whales have not spent any time in Puget Sound is fairly obvious, Ken said. Their primary prey, chinook salmon, have not been around either.

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Orcas gain increasing clout during fishing season discussions

Puget Sound’s endangered killer whales are becoming fully integrated into annual planning efforts that divide up the available salmon harvest among user groups — including sport, commercial and tribal fishers.

An orca mother named Calypso (L-94) nurses her young calf Windsong (L-121) in 2015.
Photo: NOAA Fisheries, Vancouver Aquarium under NMFS and FAA permits.

The southern resident killer whales should be given priority for salmon over human fishers, according to a fishing policy adopted for 2019-2023 by the Washington Fish and Wildlife Commission. The new policy calls for “proper protection to SRKW from reduction to prey availability or from fishery vessel traffic …”

The problem with allocating a specific number of salmon to the orcas is that the whales cannot tell us when or where they would like to take salmon for their own consumption. The result, now in the planning stages, is to limit or close fishing in areas where the orcas are most likely to forage during the fishing seasons.

As revealed yesterday during the annual “North of Falcon” forecast meeting, fewer chinook salmon — the orcas’ primary food — are expected to return to Puget Sound this year compared to last year, but more coho salmon should be available for sport and tribal fishermen. The challenge, according to harvest managers, is to set fishing seasons to take harvestable coho without unduly affecting the wild chinook — a threatened species in Puget Sound.

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Sharing info and solving mysteries: International Year of the Salmon

Nearly a decade in the planning phase, it appears that the International Year of the Salmon couldn’t come at a better time for Northwest residents.

More and more people are beginning to recognize the importance of chinook salmon to the long-term survival of our Southern Resident killer whales. Legislation designed to improve the populations of salmon and orcas has gained increased urgency as these iconic creatures continue to decline.

Many countries throughout the Northern Hemisphere have joined together in a campaign to raise public awareness about salmon this year and to increase the support for scientific research and restoration projects that might save endangered salmon from extinction.

One exciting aspect of the International Year of the Salmon, or IYS, is a scientific expedition involving 21 researchers from five countries. This international dream team will depart Sunday from Vancouver, British Columbia, to engage in a month of research into the secrets of salmon survival. I described this long-anticipated endeavor in an article published today in the Encyclopedia of Puget Sound.

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Salmon treaty designed to boost spawning count and feed the orcas

Allowable fishing for chinook salmon in the waters of Canada and Southeast Alaska will be cut back significantly this year as a result of a revised 10-year Pacific Salmon Treaty between the United States and Canada.

Chinook salmon // Photo: NOAA Fisheries

The goal of the updated treaty is to increase the number of adult chinook returning to Washington and Oregon waters, where they will be available to feed a declining population of endangered orcas while increasing the number of fish spawning in the streams, according to Phil Anderson, a U.S. negotiator on the Pacific Salmon Commission.

Most chinook hatched in Washington and Oregon travel north through Canada and into Alaska, making them vulnerable to fishing when they return. Changes to the treaty should reduce Canadian harvests on those stocks by about 12.5 percent and Alaskan harvests by about 7.5 percent, Phil told me. Those numbers are cutbacks from actual harvests in recent years, he said, so they don’t tell the complete story.

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Increase in harbor porpoises shifts Puget Sound’s food web

Most of us have heard that harbor seals eat Chinook salmon, which are the preferred food for our beloved Southern Resident killer whales, an endangered species whose long-term survival could hinge on getting enough Chinook.

The number of harbor seals in the inland waters of Washington state now totals somewhere around 10,000 or slightly higher, according to the latest estimates by Steve Jeffries, a marine mammal biologist with the Washington Department of Fish and Wildlife.

Harbor porpoise surfing in a boat wake in Burrows Pass, off Fidalgo Island.
Photo: ©Cindy R. Elliser, Pacific Mammal Research

But did you know that harbor porpoises, which eat many of the same things as harbor seals, now number around 11,000 in the same general area? That’s according to a recent study for the Navy led by research consultant Tom Jefferson.

I have to say that those numbers came as a major surprise to me, and I began to ask questions about what all these porpoises in Puget Sound might be doing to the food web, which involves complex interactions between salmon, seals, porpoises, orcas and many other species.

The result of my inquiry is a story published this week in the Encyclopedia of Puget Sound.

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Focus on chinook salmon creates troubles for Southern Resident orcas

I’ve often wondered how well Puget Sound’s endangered orcas would be doing today if these whales had not grown up within a culture of eating chinook salmon.

Photo: NOAA Fisheries

In Iceland, some killer whales apparently feed on both fish and seals, depending on the time of year, according to researcher Sara Tavares of the University of St. Andrews in Scotland. The same animals have been seen among large groups of orcas as they pursue schools of herring in the North Atlantic, she writes in her blog, Icelandic Orcas.

The Icelandic whales have a different social structure than the fish-eating Southern Resident killer whales that frequent the Salish Sea. Both groups are also quite different from the marine-mammal-eating transient killer whales that have been visiting Puget Sound more frequently in recent years.

It is now widely accepted that groups of killer whales each have their own culture, passed down from mothers to offspring, with older relatives playing an integral role in the lessons. Culture is simply learned behavior, and the message delivered from the elders to the young is: “This is the way we do it.”

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Getting lost in the tangle of connections called the Puget Sound food web

I’m increasingly amazed at the interwoven nature of the Puget Sound food web. Whenever I become focused on a specific species — Chinook salmon, for example — one of the first questions I ask is: What is this species eating?

I soon learn that the answer depends on the size of the individual doing the eating. Prey for a baby salmon is much different from prey for an adult.

If you really want to learn about why a species is doing well or poorly, you need to look beyond prey availability for your species of interest and find out what the prey are eating as well. Healthy prey must be abundant for any species to do well, so the prey of the prey must also do well.

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The lives of salmon are complex, leading to threats but also hope

Salmon have a tough life. Not only must they escape predators and find enough food to eat — as do all wild animals — but they must also make the physiologically taxing transition from freshwater to saltwater and then back again to start a new generation.

In a four-part series being published in the Encyclopedia of Puget Sound, I explain some of the latest research findings about how chinook, coho and steelhead are struggling to survive in the waters of Puget Sound.

Chinook salmon // Photo: Zureks, Wikimedia commons

The first part is called “Opening the black box: What’s killing Puget Sound’s salmon and steelhead?” It describes the Salish Sea Marine Survival Project, a major research effort involving more than 200 scientists in the U.S. and Canada. The effort is coordinated by Long Live the Kings in the U.S. and by the Pacific Salmon Foundation in Canada.

The second part, titled “Size means survival for salmon,” takes a look at salmon and steelhead’s place in the food web from the “bottom up,” as they say. Specifically, what are the fish eating and what is limiting their access to a healthy food supply?

Still to come are discussions about predation (“top down”) in Part 3, and other factors that affect survival, such as disease and chemical exposure, in Part 4.

Our goal for this project has been to describe the important research findings in careful detail without getting lost in complex scientific analysis. I also describe, at the end of Part 1, some new findings regarding potential competition among salmon for food in the Pacific Ocean.

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