International Gulf of Alaska Expedition

Tag: International Gulf of Alaska Expedition

Salmon expeditions challenge old beliefs

Long-held assumptions about where salmon go during their years of swimming in the Pacific Ocean may need to be revised, according to Dick Beamish, a Canadian salmon researcher who helped organize two scientific expeditions into the Pacific Ocean.
For example, sockeye salmon have been caught in nets farther south than conventional wisdom would suggest, Beamish said, while fishing was hit-and-miss in the same area at different times, suggesting that pink and chum salmon were schooling more than expected.
The second International Gulf of Alaska Salmon Expedition ended Tuesday after nearly a month of travels, mostly off the coast of British Columbia. Findings at this point are fairly general, since key data have not yet been analyzed. In fact, conclusions from the first expedition a year ago are still being worked up by many researchers.
The two expeditions provide distinct pieces of a much larger puzzle about where the salmon go and what they eat during the majority of their lives, Beamish said.
“We need to do more science,” he said, “then it’s just a matter of time before we understand what the mechanisms are.”
The ocean is often described as a mysterious “black box” where little is known about the fate of salmon after they leave the inland streams and head out to sea. Yet the ocean is where most salmon spend the majority of their lives.
It has taken a little time for analysis, Beamish said, but it appears that the ages of the chum salmon caught in the ocean a year ago provided an early hint that last fall’s chum run would be lower than forecast by salmon managers — which is what occurred. While the expedition caught more chum this year, an age analysis is needed to determine whether more chum can be expected to come back this fall. (The majority of chum return when they reach 4 years old, with some 3-year-olds in the mix).
Last year, some of the fish were found to be unusually thin, but that was not observed this year, according to Beamish.
Indirectly, the coronavirus had a major effect on the expedition, including a revised route for the Pacific Legacy, a trawler rigged for scientific investigations. About midway through the cruise, all three American scientists on board left the ship and were not replaced out of concern that they might not be allowed to return home to Alaska amid the COVID-19 outbreak.
Six Canadian and three Russian scientists continued on, but the absence of Americans meant that the ship was not allowed to fish in U.S. waters off Alaska, Beamish said. Rather than spending time traveling farther off the coast, the ship returned to the same area that was fished during the first half of the expedition.
Surprisingly, the results were quite different, with far more pink and chum salmon caught during the first half of the expedition than in the same areas during the second half.
“Scientifically, to me that’s huge,” Beamish said. “Catching nothing is as relevant as catching something. It tells us that there had to be huge schools of pink and chum.”
That’s not what Russian researchers have seen during their years of sampling in the western Pacific Ocean, he said. There, the catches seem to be more uniform across broad areas.
By the way, the three Russians on the latest expedition were waylaid on their trip home because of a travel ban imposed by the Russian government during the COVID-19 outbreak. The three are waiting in Nanaimo, B.C., for approval to return to Russia.
“Nothing like these two expeditions (in the eastern Pacific) have ever been done before,” Beamish said. “The overwhelming conclusion, according to me, is that we need to see a bigger picture.”
While salmon returns to British Columbia and Japan are at all-time lows, Alaska and Russia are seeing unusually high numbers of sockeye. Clearly something is changing, and it could be related to global warming. To improve the overall picture, the expeditions not only sample for fish but also for temperature, ocean chemistry and other physical conditions as well as observing the entire food web — from plankton to the top predators. Few predators, however, have been seen during either expedition.
Funds for this year’s research cruise were raised privately with strong support coming from commercial fishing groups interested in understanding why salmon abundance may be high or low for any given year.
All the data from these expeditions are provided to anyone who wishes to study these problems, Beamish said, adding that he hopes that the best scientific minds will bring together other pieces of the puzzle to help explain what conditions are driving salmon populations. His working hypothesis is that salmon survival generally depends on getting enough food early in life.
An expedition being planned for next year by the North Pacific Anadromous Fish Commission could involve several ships in an effort improve the picture. The idea is to sample different parts of the ocean at the same time. The research is being conducted as part of the International Year of the Salmon.
Previous blog posts on this topic:

Salmon expeditions challenge old beliefs

Long-held assumptions about where salmon go during their years of swimming in the Pacific Ocean may need to be revised, according to Dick Beamish, a Canadian salmon researcher who helped organize two scientific expeditions into the Pacific Ocean.
For example, sockeye salmon have been caught in nets farther south than conventional wisdom would suggest, Beamish said, while fishing was hit-and-miss in the same area at different times, suggesting that pink and chum salmon were schooling more than expected.
The second International Gulf of Alaska Salmon Expedition ended Tuesday after nearly a month of travels, mostly off the coast of British Columbia. Findings at this point are fairly general, since key data have not yet been analyzed. In fact, conclusions from the first expedition a year ago are still being worked up by many researchers.
The two expeditions provide distinct pieces of a much larger puzzle about where the salmon go and what they eat during the majority of their lives, Beamish said.
“We need to do more science,” he said, “then it’s just a matter of time before we understand what the mechanisms are.”
The ocean is often described as a mysterious “black box” where little is known about the fate of salmon after they leave the inland streams and head out to sea. Yet the ocean is where most salmon spend the majority of their lives.
It has taken a little time for analysis, Beamish said, but it appears that the ages of the chum salmon caught in the ocean a year ago provided an early hint that last fall’s chum run would be lower than forecast by salmon managers — which is what occurred. While the expedition caught more chum this year, an age analysis is needed to determine whether more chum can be expected to come back this fall. (The majority of chum return when they reach 4 years old, with some 3-year-olds in the mix).
Last year, some of the fish were found to be unusually thin, but that was not observed this year, according to Beamish.
Indirectly, the coronavirus had a major effect on the expedition, including a revised route for the Pacific Legacy, a trawler rigged for scientific investigations. About midway through the cruise, all three American scientists on board left the ship and were not replaced out of concern that they might not be allowed to return home to Alaska amid the COVID-19 outbreak.
Six Canadian and three Russian scientists continued on, but the absence of Americans meant that the ship was not allowed to fish in U.S. waters off Alaska, Beamish said. Rather than spending time traveling farther off the coast, the ship returned to the same area that was fished during the first half of the expedition.
Surprisingly, the results were quite different, with far more pink and chum salmon caught during the first half of the expedition than in the same areas during the second half.
“Scientifically, to me that’s huge,” Beamish said. “Catching nothing is as relevant as catching something. It tells us that there had to be huge schools of pink and chum.”
That’s not what Russian researchers have seen during their years of sampling in the western Pacific Ocean, he said. There, the catches seem to be more uniform across broad areas.
By the way, the three Russians on the latest expedition were waylaid on their trip home because of a travel ban imposed by the Russian government during the COVID-19 outbreak. The three are waiting in Nanaimo, B.C., for approval to return to Russia.
“Nothing like these two expeditions (in the eastern Pacific) have ever been done before,” Beamish said. “The overwhelming conclusion, according to me, is that we need to see a bigger picture.”
While salmon returns to British Columbia and Japan are at all-time lows, Alaska and Russia are seeing unusually high numbers of sockeye. Clearly something is changing, and it could be related to global warming. To improve the overall picture, the expeditions not only sample for fish but also for temperature, ocean chemistry and other physical conditions as well as observing the entire food web — from plankton to the top predators. Few predators, however, have been seen during either expedition.
Funds for this year’s research cruise were raised privately with strong support coming from commercial fishing groups interested in understanding why salmon abundance may be high or low for any given year.
All the data from these expeditions are provided to anyone who wishes to study these problems, Beamish said, adding that he hopes that the best scientific minds will bring together other pieces of the puzzle to help explain what conditions are driving salmon populations. His working hypothesis is that salmon survival generally depends on getting enough food early in life.
An expedition being planned for next year by the North Pacific Anadromous Fish Commission could involve several ships in an effort improve the picture. The idea is to sample different parts of the ocean at the same time. The research is being conducted as part of the International Year of the Salmon.
Previous blog posts on this topic:

Second Pacific salmon expedition gets a chance to see the effects of cooler water

A second research cruise to study the winter travels of salmon in the Pacific Ocean got underway today, when 12 scientists from three countries left Victoria, B.C., aboard the trawler Pacific Legacy.
Researchers say they have learned a great deal from the first salmon cruise a year ago, when 21 scientists from five countries ventured out into the Pacific to take samples of fish and other marine life. The samples are being shared with dozens of biologists trying to piece together the complex food web that supports five species of salmon struggling to find food, escape predators and survive a variety of environmental threats.
Lower water temperatures this year should allow researchers to draw some conclusions about how salmon respond to changing ocean conditions, said Ed Farley, who heads the Ecosystem Monitoring and Assessment Program for NOAA’s Alaska Fisheries Science Center.

Temperatures along the Pacific Coast of North America are close to normal, with waters slightly below average (blue). Farther offshore is slightly above (yellow). Temperatures are in degrees C.
Map dated March 10: NOAA / National Environmental Satellite, Data, and Information Service

Much of last year’s cruise is being replicated this year to figure out where each species of salmon go under different ocean conditions and whether their overall numbers have increased or declined. As with last year, key questions surround the type of food that different salmon are eating and whether the amount of prey is adequate to keep them healthy, Ed told me.
Preliminary findings from last year’s research can be found on the website of the International Gulf of Alaska Expedition, including a slideshow (PDF 4.4 mb). Also check out the story I wrote last year after talking with Laurie Weitkamp of the Northwest Fisheries Science Center, a member of last year’s research team.
Chum salmon tend to feed on different prey species than do pink salmon, Ed noted, but sockeye and pinks have a good deal of overlap in what they eat. Chinook generally eat small fish, which are higher on the food web than what is consumed by the other salmon species. Examining the stomach contents of various fish provides insight into their recent diets.
Genetic analysis of the salmon caught in the trawl net should allow researchers to tell where the fish originated, including streams in Washington, Oregon and California as well as Canada, Alaska and even parts of Asia.
“We don’t know what is killing these fish in winter,” Ed noted. “It is hard to starve a fish, but based on other winter surveys … it appears that their fat content is not so good.”
One hypothesis is that salmon in better shape with higher fat stores may be able to go without eating and find places to avoid predators, including salmon sharks. But if the salmon need food to survive, they may be forced to venture into areas with increased prey but also more predators.
Planned route of salmon expedition off the coast of British Columbia, first leg of survey shown in red, second leg in blue. Actual route will be chosen during cruise, based on weather and catch rates. Alternative stations are marked with black dots. Map: Gulf of Alaska Expedition

Another major question raised by some researchers is whether competition among salmon is causing problems for one or more species. Hatchery production of chum and pink salmon has reached an all-time high, and the effects of competition — especially during lean years — could be a factor in salmon survival.
Because the wide ocean holds so many life-or-death questions for salmon, researchers often call it the “black box” in the life cycle of the migrating fish.
Answers regarding salmon survival may be complex, Ed said, but a lot can be learned by studying the multitude of species caught in nets during these winter cruises. The International Gulf of Alaska Expedition, conducted as part of the International Year of the Salmon, is scheduled to end when the 121-foot Pacific Legacy returns to Victoria on April 4.
The 12 scientists on board are based in Canada, Russia and the United States, including two from the Alaska Fisheries Science Center, two from the Alaska Department of Fish and Game, and one from the Southern Regional Aquaculture Association.
Dick Beamish, a longtime Canadian salmon researcher who organized last year’s winter survey, helped raise more than $1.4 million for this year’s cruise. Money was provided by provincial and federal governments in Canada, the seafood industry as well as personal and business donations.
Plans are already underway for next year’s expedition, which will involve three to five vessels surveying areas where salmon migrate in various regions of the Pacific Ocean, from North America to Asia.
Twitter: @yearofthesalmon and #GoA2020