The case of the disappearing chinook salmon
Capital Press 11/19/2020
A pair of chinook
salmon. The populations of chinooks along the West Coast are
down by about two-thirds of previous levels, a study says. Dams
appear not to be a factor
Scientists know a lot about West Coast chinook salmon and the
rivers where they spawn before their progeny head downstream to
the open ocean.
What happens during those two to three years in the North
Pacific is less well-known and, in fact, may hold the key to the
survival of all of the region’s chinook.
For decades, fisheries biologists have closely studied the
chinook, which is prized by the commercial and sports fishing
fleets — so much so that they are known as “king” salmon in
Alaska for their high value.
For example, at Seattle’s Pike Place Market, the prices for
whole chinook salmon range from $14.99 to $37.50 a pound. That
makes a single 40-pound chinook worth upwards of $1,500 at
Chinooks have been tagged and counted and hauled over and around
dams to increase their survival rates. For years, scientists
have assumed the numbers of chinooks returning from the ocean to
spawn have been decreasing because of the dams on major rivers
and other impediments such as culverts on smaller rivers and
But a new study poses a question for which fisheries biologists
and managers appear not to have an answer: Why are chinook
salmon returns decreasing not only in rivers that have dams but
also in those that don’t?
That’s an important question. It challenges many of the
assumptions that scientists and activists have made, and even
makes one wonder whether dams are the problem at all.
The study, by David Warren Welch, Aswea Dawn Porter and Erin
Leann Rechisky of Kintama Research Services in Nanaimo, British
Columbia, found that the returns of chinook salmon in rivers and
streams along the Strait of Georgia were falling. The strait is
between Vancouver Island and mainland British Columbia.
Problems faced by the southern population of orcas, which feed
primarily on chinook salmon, would appear to back up that
observation despite the constant chatter that the Snake River
dams are the problem.
But the case of the disappearing chinook is even more
“We discovered that chinook survival in many rivers of the
Strait of Georgia region had fallen to levels well below those
reported for Snake River chinook,” the authors wrote.
They put together a study and found that, sure enough, all along
the West Coast of the U.S. and Canada and across Alaska, chinook
populations are shrinking by two-thirds of previous levels. Even
more curious: nearly all of those salmon rivers are pristine,
with no dams or other impediments.
This begs the question: What is going on here, and why? This
study appears to call into question the assumption that four
Snake River dams are to blame for the struggling chinook
Activists and a few politicians say they are ready to sacrifice
those dams to “save” the salmon.
This recent study shows that researchers have a lot more work to
do before those — or any other — dams are sacrificed.
It would be folly to destroy the region’s river transportation
system, irrigation system, power generation and economy and
still not help the chinook.
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