There is some interesting ongoing work in AK that shows salmon getting smaller with age. Some appears to be due to either being outcompeted by other species (Pinks) or switching to less nutritious food.

The second, less nutritious food, has a real hidden pitfall. In order to survive in warmer water, salmon need to burn more calories-being poikilothermic. With less energy per bite, a full stomach supports smaller size because a large fish does not have the energy for metabolism.

So, if our waters are warming, the salmon need more nutritious food to maintain (or recover-see Elwha and Kenai) "lost" size. Which means if we want more and larger salmon we need to leave more of the lower levels of the food chain in the ocean.

Couldn't nets be selectively harvesting the big fish genes out of the population as well?

I think that in many of the AK stocks the primary fishery is hook and line but the problem is sowing up across species. Except some pinks, who seem to be the one of the "bad guys" in this story.

AK does its Chinook damage in the ocean ( just as they do PNW fish ). Manage rather well otherwise. Just can"t turn loose of that commercial bowl offshore. Yes the pressure of trollers in the ocean places extreme genetic pressures on the fish as you remove a greater % of 4,5,6 year fish from the pool. Absolutely known as to cause and effect but not talked about much. It does not fit the harvesters talking points.

I appreciate the discussion about the damage that the marine mixed stock salmon fisheries do to age, size, numbers, future, and so on. But what the ocean is trying to tell us, in the way in which sizes are now changing, species are vanishing, and so on is that the whole damn ocean is in trouble.

If salmon managers continue to look only at salmon the fish are lost. We (all managers) have to consider the ecological consequences of what harvesting "their" resource does. Taking too many herring cuts down salmon food. Taking too many Chinook removes Killer Whale food, allowing too few salmon spawners takes away bear food. And the list goes on and on.

The long term health of our salmon runs depends on taking and doing a holistic view of the oceans and uplands that will include the future of humans and natural resources. It's linked. And ignored.

That's why I use superbaits. I'm a conservationist. Sometimes I do trick them in to eating their ovum.

That broadens the conversation CM. That size is dependent on food is true. Take the recent Coho crash. From what I observed about 2/3 came normal but about 1/3 were undersized. You always have what are called dinks but not in that portion. You can not harvest the food chain top to bottom and think that those at the top will not be effected. So long term yeah the food chain will come home to bite us. That said again since the post Boldt times the non treaty commercial fishers and Rec fisheries moved North to Alaska and took the PNW fish there in front of the tribes. The massive impacts of all forms of commercial harvest in the Bering Sea and Gulf of Alaska are the primary driver for the crash of Chinook. Long term yup the food chain thing will come home to be sure but that pressure in the marine area is the primary thing that is simply continuing to do what it has for 30 years. Decimate salmon.

But as long as we all stay in our secure silos we don't have to think about the bigger issues.

We fish down the food chain, which works if everything in the chain is reduced by the same amount. But when you want to expand human use, Killer Whales, pinnipeds, cormorants and terns then you put more pressure on a resource that your management is making smaller.

One of my better bosses (although the bar for bosses generally was on the ground or buries, some were way above ground level) said that salmon were abundant in the past because salmon were abundant. What he meant was that we had a lot of salmon to catch when we had lots of them spawning. We now go the other way, like good Wall Street Bankers. What is the minimum investment I am forced to make in order to maximize my return to myself.

Interesting word for the day,

Depensation/critical depensation:

When the level of depensation is high enough that the population is no longer able to sustain itself, it is said to be a critical depensation. This occurs when the population size has a tendency to decline when the population drops below a certain level (known as the "Critical depensation level"). Ultimately this may lead to the population or fishery's collapse (resource depletion), or even local extinction.

There is another aspect that goes the other way. That is, the resource has different stability levels.

Say, originally, Skagit steelhead were stable with run of and an escapement of 150000-pre-human removals and all the salmon.

During tribal times the run was 130K with 10K removed along with some of the salmon.

Now, we are to about 10K more or less along with a few salmon.

Each time the fishery, or habitat destruction, changes productivity the steelhead adopt a new level. They are relatively stable at that level so long as the rest of the conditions such as salmon, stream temp, flows, ocean temps, estuarial quality remain rather constant.

One of the lessons that I learned early, but fought against for a long time, was that there is no single MSY, or optimum population, or even optimum escapement goal because there are so many conditions that go into it. Unfortunately, our fish find themselves in a very unstable situation where the only constant is kill as many as we think we can today.

"Each time the fishery, or habitat destruction, changes productivity the steelhead adopt a new level. They are relatively stable at that level so long as the rest of the conditions such as salmon, stream temp, flows, ocean temps, estuarial quality remain rather constant.

One of the lessons that I learned early, but fought against for a long time, was that there is no single MSY, or optimum population, or even optimum escapement goal because there are so many conditions that go into it. Unfortunately, our fish find themselves in a very unstable situation where the only constant is kill as many as we think we can today."

Can I get an, Amen!?

AMEN

I agree with Spokey. Selective harvest has been removing the largest genetics for generations before non Indians got here.
Salmon have continued to get smaller, just at a way faster rate in recent times. Their is no maximum size limits in Washington, so sport and commercial harvest has also has contributed.
If anything, Pink Salmon are a example of this. Because of there fixed life cycle, they have shrunk less. Our harvest model attacks the multi year class fish most.
The average Alaskan chum this year is less than 8 pounds.

Lol I was just asking the question. I believe all the bottom of food chain harvesting is hurting lots of fish populations in ocean. How many tons of krill are harvesting just so yuppies can feel younger & healthier by ingesting powdered or oil krill products? Also I'd bet the scent market does it's fair share of damage. By far I'd think (and not t sound all alt right or anything lol) the Asian markets are by far the biggest problem since the shear amount & variety of sea life that gets sold or bought there. Ain't nobody in the US gonna stand up and slow that down. The snowflakes might create a "spafe space" right in the front yard of any politician that tried.

I am not a scientist but from a purely observational standpoint I think salmon populations were most impacted when the herring roe harvest started up.

I apologize for assuming. To answer your question, selective harvest of the largest fish is the most significant reason for decline in size.

If the Chinook salmon lived 7-8 years they would work up the food chain and eat our precious hatchery fish of all salmonids.
They do not grow large enough, and very little predation takes place.

From NOAA webpage regarding what forage fish are used for.

“The small, open-ocean fish that are caught in industrial fisheries are consumed directly, used as bait in commercial and recreational fisheries and in lobster traps, used as ingredients in the feed for aquaculture, pigs, poultry, cattle, and pet food; and are converted into fish oil pills.”

It is the larger fish competing with humanity for their food. No surprise how that will end----- BURP.

Which gets back to the point that all of of our natural resource problems trace back to humans and their population. If we want salmon in the future, or deer, or bears, or ducks, or whatever we will need to face the population issue head on.

Not to decide is to decide.

As they continue to lose habitat through development.

Anybody from California know what deer harvest in the state was in 1960 versus today?

Not a lot new in this discussion, W. E. Ricker in 1981 published a paper where he pointed out chinook had been decreasing in size since 1920. The reasons were all of the ones discussed in this thread. All salmon species and populations have been changing size and age, increasing and decreasing over time. I think of it as evolution, adapting to a changing environment. Animals with a short life cycle do it faster. We humans in some populations are slowly getting larger and older but it is not in all populations.