
The downsizing of Chinook salmon - DoreenMichele
https://www.opb.org/news/article/chinook-salmon-size-shrink-orca-oregon-washington/
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bdwalter
As someone who has avidly fished for salmon in the NW for the last 30 years
(~75 days per year), I can at least give my opinion that this is mostly BS.

Pervasive, non-selective, commercial and tribal gill-netting that is optimized
to remove the largest specimens from the gene-pool is a big part of where I
point my finger. Throw in the dams and massive increases in non-native,
invasive California sea lions in the lower Columbia and you have a mess in the
making. Lots of factors but I believe most of the problems are in-river, not
in-ocean.

Also disclaimer, my opinions mostly come from experience on the Columbia (The
largest Chinook runs in the world), not the Sound or further north.

~~~
tastyfreeze
I wish I could find the selective breeding paper I read years ago. It is as
you say. The human practice of keeping the largest fish in both sport and
commercial catches is to blame. A 75 year king salmon derby here shows
progressively smaller fish winning every year. Its not really hard to reason
that if you kill the big fish before they breed the fish are going to get
smaller.

We even see short unnaturally fat fish that are just under the minimum length
that has been the same for 30+ years. The gene pool is being pressured to
shorter fish for survival.

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Scaevolus
Puget Sound's resident orcas basically refuse to eat anything other than
Chinook (King) salmon -- 97% of their diet is salmon, 78% is Chinook salmon. A
variety of old dams without salmon runs have been blocking their ideal
spawning grounds, but many of them are being demolished or upgraded to let the
fish pass.

[https://en.wikipedia.org/wiki/Southern_resident_killer_whale...](https://en.wikipedia.org/wiki/Southern_resident_killer_whales)

~~~
stevenwoo
This is true but doesn't address the why within one human generation the
population size change in salmon returning to spawn ( five years in Pacific
versus current two-three years in Pacific versus 10000 years prior history at
five years). Also I believe the article says that Alaska orcas are now feeding
on the salmon before they get to the Puget Sound orcas, and not in the article
but linked that marine mammal populations take a larger number of salmon than
orcas, so there is pressure on salmon population from all types of natural
predation/less habitat.

~~~
Scaevolus
The resident orcas have declined enough to be endangered, largely tracking the
decline in Chinook.

~~~
Tiktaalik
Yeah the Orcas are starving.

[http://www.cbc.ca/news/canada/british-columbia/low-orca-
birt...](http://www.cbc.ca/news/canada/british-columbia/low-orca-birth-rates-
linked-to-lack-of-chinook-salmon-1.4183609)

Ship traffic is also likely a factor in that it's likely disruptive to their
hunting.

Unfortunately the Canadian government is set on approving the TransMountain
diluted bitumen pipeline expansion, which will increase oil tanker traffic
through the Haro Strait 7 fold. This will probably be dangerously disruptive
to the orcas even if there's never any diluted bitumen spill

The orcas are probably doomed :(

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paulcole
> Fishermen stand next to chinooks almost as tall as they are, sometimes
> weighing 100 pounds or more.

This is a fish story. 100 pound chinooks have always been INCREDIBLY rare.
While there are records of very few fish that size being netted or trapped,
the world hook and line record is "only" 97 pounds.

And a salmon of 125 pounds would be about 62-65", certainly not "almost as
tall as a fisherman." The writer should learn about the fisherman's trick of
forced perspective- i.e. standing behind the fish to make it look bigger.

Hard for me to take a lot of the article seriously when they can't get a
pretty simple fact right.

~~~
quadrangle
Uh, 62-65" certainly is "almost as tall as a fisherman"!

You think fisherman are all well over six feet tall or something?? Even if
that were the case, "almost as tall" qualifies. They didn't say "as tall"
without the "almost".

~~~
paulcole
125 is bigger than all but maybe 2 or 3 of the biggest salmon ever caught. A
100 pound fish would be closer to 58”.

~~~
quadrangle
Yeah, but I was just using numbers from your post itself, not making a claim
about fish sizes in the world, and 58" is _still_ "almost as tall as a
fisherman" (the operative word being "almost").

