Cake and balloons were abundant at the annual fish ladder appreciation day last week, but one important thing was in very short supply.
There were hardly any chinook salmon to actually appreciate.
Anyone angling for a view of the holding tank, usually packed with salmon, was in for disappointment, said Lawrence Vano, operations manager at the Whitehorse Rapids Salmon Hatchery.
Few fish have passed through the ladder this year.
“This year is horrible. Horrible, horrible, horrible,” said Vano. “Anything less than 1,200 salmon (coming through the ladder) is not a good year.”
Only about 150 fish passed through as of the August 14 appreciation night. About 500 to 600 salmon have usually passed through by mid-August.
“It might be late,” said Vano. “Usually we’re at a peak right now, so I’m not sure if we’re still going to peak or if there’s a delay.”
This year’s low salmon run could be the low part of a natural cycle.
“It valleys and peaks. But even if the salmon wasn’t overfished, you’re still looking at a low run.”
It has not been an easy year for salmon fishers in the Yukon. The Fisheries and Oceans department closed the commercial and domestic chinook salmon fisheries on the Yukon River earlier this month.
This year’s salmon run is estimated at 25,000 to 30,000.
Low salmon runs could be more of a trend than an anomaly, according to an Alaskan researcher.
Fewer salmon are swimming up the Yukon River and those that do are smaller than ever before, said Chris Stark, an Institute of Marine Sciences researcher at the University of Alaska-Fairbanks School of Fisheries and Oceans.
A combination of environmental factors is most likely responsible for low salmon runs, he said.
Early ice-ups are causing streams to warm up earlier, which means salmon are using more energy than usual to get around. Using more energy is physically harder on the salmon, said Stark.
“You have to eat more or grow less, or both,” he said. “But smaller fish don’t do as well as larger fish, we believe.”
Global warming could be changing salmon habitats but little research has been done to confirm this, said Stark.
“If ice comes off too early and those salmon are living in water that heats up early, those juveniles may not be in sync with the bugs they feed on or, cued by the ice breakup, they go downstream and hit ice jams pushing them off the river channel,” said Stark.
“Once they’re off the river channel, they’re in big trouble. They go a little further, get stuck in a pond and that’s the end of that.”
Chinook salmon have increased competition from other salmon species once they reach the ocean, said Stark.
While salmon production in Canadian hatcheries increased, the US has produced incredible numbers of pink salmon and the Japanese are releasing huge amounts of chum salmon into the ocean, said Stark.
“It’s likely those fish are competing directly for food sources with the chinook salmon from our region,” he said. “We now know when the chinook salmon are smaller when they return.”
In the last 20 years, the average size of a chinook salmon has decreased 20 per cent, from 22 pounds to 16 pounds. Smaller salmon have less chance of surviving than larger fish, said Stark.
Two things could also be contributing to the size decrease, said Stark.
The average salmon coming back is younger and smaller and small salmon reproduce small salmon.
More significantly, larger salmon are fished out of the population, taking their genetics with them, said Stark.
“The change in size has been perpetrated probably by selectively taking out larger fish from the rivers,” said Stark.
“Everybody from the bottom of the river to the top are targeting those larger fish. We’re slowly taking those genetics out of the population.”