Pink salmon returns throughout the north Pacific Ocean rim have in recent years been extraordinarily large, so much so that fishery experts are gathering at month’s end in Vancouver, British Columbia, to ponder recent production trends and to identify future research needs.
But what is, quite possibly, the greatest surge is not likely be considered during the Oct. 30-31 North Pacific Anadromous Fish Commission’s international workshop on “Explanations for the High Abundance of Pink and Chum Salmon and Future Trends.” That’s because the pink salmon run being witnessed this year in the Columbia River basin, though six times the previous record, is tiny in total number when compared to those in the Puget Sound, Alaska, Canada, Russia and Japan.
But the overall abundance of pink salmon may be contributing to the newfound wealth in the Columbia River.
“Maybe we’re starting to see some strays that are poking into the Columbia, starting to colonize,” according to Lisa Seeb, a research professor in the University of Washington’s School of Aquatic and Fisheries Science.
Or, she said, maybe small spawning populations that originated in the Columbia River basin have blossomed for the same reasons -- most likely favorable ocean conditions -- that pink and chum salmon populations around the rim are returning at record rates.
“Whatever is going on in the ocean is good for pink salmon,” Seeb said.
The southernmost extent of the pink salmon species is generally considered to be just north of the Columbia River in west-central Washington’s Nisqually and Puyallup rivers. But over time the Pacific region’s most abundant species has indeed poked its nose into the Columbia. Small numbers are often seen during redd surveys for other species. And pinks are seen and recorded passing through Columbia and Snake river hydro project fish ladders.
The record annual pink count at Bonneville had been established at 637 in 2003. The record goes back to 1938 when construction of the dam was completed.
But that record was surpassed this year with a total count through Wednesday of 3,827 adult pink salmon. So far in 2011 there have been 18 daily counts of more than a100 pink salmon at Bonneville. In the past there have only been seven annual counts of more than 100.
A total of 11 pink salmon have been counted at the lower Snake River’s Little Goose Dam, which is more than 400 river miles from the mouth of the Columbia. The fact pink salmon are passing over Bonneville, at river mile 146 -- and more surprising, reaching the Snake River dams -- is perplexing for biologists. Pinks elsewhere tend to tend to spawn nearer a freshwater-saltwater nexus. Pink juveniles forsake freshwater rearing, choosing instead to swim toward the ocean almost immediately after they emerge from their eggs.
“They spend so little time in freshwater that they don’t imprint” as well as other salmon species on their natal stream, said Washington Department of Fish and Wildlife geneticist Sewall Young.
That fact would seem to support theories that the Columbia River pinks are fish that strayed from their roots in the Puget Sound or elsewhere.
Both Young and Seeb said they would like to gather genetic samples from the Columbia pink spawners for analysis and comparison with other populations to the north.
The 2011 pink salmon returns to the Columbia are being found far and wide. WDFW redd surveys, conducted primarily to monitor fall chinook salmon spawning, have turned up pink salmon carcasses in such streams as the Kalama and North Fork of the Lewis rivers and Mill Creek downstream of Bonneville, and the Wind and White Salmon rivers and Drano Lake above the dam.
“Every place we’ve looked for chinook we’ve found pinks,” the WDFW’s Joe Hymer said of fall redd surveys. Numbers however have been small, a half dozen here and a half dozen there.
“I don’t think anyone really has a handle on it,” the WDFW’s Jeremy Wilson said of the extent of spawning in the Columbia River basin and/or where the pinks originated. Because the pinks have been relatively rare in the Columbia system, managers pay little attention to them.
Pinks are the smallest, ranging up to about five pounds, and most abundant of the Pacific salmon species. During their spawning migration, males develop a pronounced humped back, hence their nickname "humpies".
The commercial harvest of pink salmon is a mainstay of fisheries of both the eastern and western North Pacific; over 100 million have been taken in recent annual harvests in Alaska alone. More than 20 million harvested pink salmon are produced by fishery-enhancement hatcheries, particularly in the northern Gulf of Alaska. The fish are often canned, smoked or salted. Pink salmon roe is also produced commercially for caviar, which is a particularly valuable product in Asia.
According to background information regarding the NPAFC workshop, “total commercial catches of Pacific salmon (Oncorhynchus spp.) in the Subarctic North Pacific are at historic high levels, with recent catches over one million tons.
“High catches were caused by an increase of pink and chum salmon production, which represented over 80 percent of the total catch. At the same time chinook, coho, and masu salmon have been decreasing in abundance.
“These trends in Pacific salmon catches are generally recognized to result from processes within the ocean that appear to improve the capacity to produce pink and chum salmon, perhaps decrease the capacity to produce chinook and coho salmon, and contribute to recent extreme variability in sockeye salmon production. Understanding how future trends in ocean production capacity will change is particularly important for hatchery programs.”