Uncovering the secret lives of salmon

Researchers aim to find where Pacific salmon spend their winters

An international team of scientists is heading to the Gulf of Alaska for a ground-breaking research survey to uncover the secret lives of Pacific salmon in the winter.

Discoveries coming out of a 25-day research cruise using a trawler in the North Pacific are expected to help countries do a better job of managing, conserving and restoring salmon stocks, including improving forecasting of returns.

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“I say it’s the great black box because we basically lose track of the salmon after they leave our coastal waters,” said Brian Riddell, president and chief executive of the Vancouver-based Pacific Salmon Foundation, a key backer of the endeavour.

“We talk about marine survival, but we only cover a small portion of their life in the marine environment.”

All North Pacific countries with Pacific salmon carry out research in coastal waters and near their shores. But there’s never been a comprehensive survey of this scope in the winter in the Gulf of Alaska, Riddell said.

Renowned scientist Richard Beamish is spearheading the organization of the $1-million-plus research survey, funded by non-profit organizations, the private sector and governments. It is a key project of the International Year of the Salmon initiative from the North Atlantic Salmon Conservation Organization and other groups.

New information collected in the Gulf of Alaska will be shared and made public.

“We will produce scientific information that has never been available before,” Beamish said from Nanaimo.

An emeritus scientist with Fisheries and Oceans’ Pacific Biological Station in Nanaimo, Beamish retired in 2011 but remains active in fisheries science. “I like to say to people that after 100 years of research, we know a lot about salmon, but what we need to know most, we mostly don’t know.

“Which means, we can’t forecast how a changing ocean ecosystem is going to affect salmon.”

New knowledge will lead to better forecasting of returns and better understanding of what affects the fish when they are out in the open ocean.

“The basic hypothesis that we are testing is that the abundance of Pacific salmon — all species — is mostly determined by the end of the first ocean winter. What that means is that processes that regulate the abundance of salmon happen in the ocean and happen in the first few months in the ocean.”

An estimated one-third of all Pacific salmon are believed to go to in the Gulf in the winter, Beamish said. Hence the timing of the survey, and, yes, ocean conditions can be rough.

Pacific salmon abundances are at historically high levels, with pink and chum salmon doing well. But no one knows why, he said.

“Russia got its highest catch of salmon in its history this year,” he said. But scientists do not know the reason stocks were so strong.

The research cruise is intended to illustrate the value of international teams of researchers working together as they investigate various factors regulating Pacific salmon.

It was a decade ago when Beamish and Riddell first talked about the need for this kind of multi-faceted research cruise.

And it was while drinking vodka with a Russian scientist after a Vancouver workshop that Beamish said: “Just for fun: ‘How about if I just arrange it?’ ”

Now it’s happening. A chartered Russian trawler, with a crew experienced in carrying out similar surveys off the coast of Russia, leaves Vladivostok on Feb. 1 for Dutch Harbour in the Aleutian Islands, where Russian scientists will be joined by the rest of the team. The survey then starts and the ship will arrive in Vancouver in March.

The plan is to use a net, 40 metres by 40 metres, to fish for one hour at a time at each of 60 to 70 locations in the Gulf, each about six hours apart.

A total of 19 top scientists from five countries have volunteered to be on the ship.

The team is made up of six Canadian scientists, eight from Russia, three from the U.S., and one each from Japan and South Korea.

The project’s three chief scientists are Evgeny Pakhomov, director of the University of B.C.’s Institute for Oceans and Fisheries, Vladimir Radchenko, of the international North Pacific Anadromous Fish Commission, and Laurie Weitkamp, a research fisheries biologist with the U.S. National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Centre. All have experience on research expeditions.

Pakhomov is a biological oceanographer who studies tiny ocean creatures to investigate potential food for salmon. It is the years salmon spend in the open ocean where they grow and accumulate reserves that allow them to successfully reproduce.

However, “We know little about this ecosystem,” he said in an article for the Anadromous Fish Commission.

The research cruise will help understand “how robust or resilient the North Pacific ecosystem is to climate change, which is relevant in predicting salmon population long-term trends,” he said.

Radchenko anticipates “breakthrough” findings on salmon ecology and said data collected in 2019 will be crucial for future comparisons.

The cruise will also provide “inexhaustible opportunities for outreach and education.” He expects that various aspects of salmon biology, such as feeding, growth and maturation, would change in a warmer ocean.

A review of the impact of predators on salmon — one of the research areas — in the eastern North Pacific is long overdue, he said.

New technologies will allow scientists to find out more than ever.

For example, the project is aiming for on-board DNA testing to pinpoint through genetics not only the river where a particular salmon is from, but which stock it belongs to. “That is huge,” Weitkamp said.

“In the Columbia River, we can distinguish, I think it is, at least eight stocks of chinook salmon.”

Such information is critical for the U.S. and for Canada. Both countries, for example, are closely watching chinook salmon stocks. Chinook salmon are the main food of the 74 remaining endangered southern resident killer whales and a prized catch for sport fishermen because of their size, but their numbers are declining along the Pacific coast.

Sockeye salmon returns to the Fraser River have ebbed drastically and are of particular interest for Canada.

As well, new information from the cruise will help hatcheries better time the release of the millions of young salmon they turn out every year. For example, researchers are hoping to learn when food in the ocean is most available to young chinook, thus giving them a better chance at survival.

All the researchers have their own specific fields, Beamish said. These include oceanographic measurements, plankton, ocean studies, fish diet, major predators and more.

“[These are] all of the things we need to know more about because none of this stuff has really been looked at in the Gulf of Alaska in the winter.”

cjwilson@timescolonist.com

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