Early lives of Alaska sockeye salmon accelerating with climate change

I may have to add an “every silver lining has a cloud” category. The number of hypothetical bad outcomes is impressive ~ctm

University of Washington

Adult sockeye salmon returning to spawn in the lakes of Bristol Bay, Alaska. Credit: Jason Ching/University of Washington
Adult sockeye salmon returning to spawn in the lakes of Bristol Bay, Alaska. Credit: Jason Ching/University of Washington

An ample buffet of freshwater food, brought on by climate change, is altering the life history of one of the world’s most important salmon species.

Sockeye salmon in Alaska’s Bristol Bay region are skipping an entire year in freshwater because climate change has produced more favorable conditions in lakes and streams, which allow the young fish to grow and put on weight much faster. Previously, these fish would spend up to two years in their birth lakes before heading to the ocean, where they feed and reach maturity two to three years later. Now they are more likely to head out to sea after only one year.

These findings were published May 27 in Nature Ecology & Evolution by University of Washington researchers.

“Climate change is literally speeding up the early part of their lifecycle across the whole region,” said senior author Daniel Schindler, a UW professor in the School of Aquatic and Fishery Sciences. “We know climate warming is making rivers more productive for the food juvenile salmon eat, meaning their growth rate is speeding up. That puts the salmon on a growth trajectory that moves them to the ocean faster.”

But this “jumpstart” in freshwater doesn’t necessarily benefit salmon in the long run. The same fish are now spending an extra year in the ocean, taking longer to grow and mature. This extra year at sea is likely caused by climate stressors, as well as other fish: In the ocean, wild sockeye compete for food with close to 6 billion hatchery-raised salmon released each year throughout the North Pacific Ocean. That number has grown steadily since the 1970s, when only half a billion hatchery salmon were released.

“Hatchery fish have really changed the competitive environment for juvenile salmon in the ocean,” said lead author Timothy Cline, a postdoctoral researcher at the University of Michigan who completed this work as a doctoral student at the UW. “In Bristol Bay, the habitat is totally intact and fisheries management is excellent, but these fish are living in lakes warming with climate change, then competing with other salmon for food in the ocean.”

The researchers drew on nearly 60 years of Bristol Bay sockeye data to tease out these changes over time, including information gathered by scientists and students in the UW’s Alaska Salmon Program. Close to half of the world’s wild sockeye is caught from this region, and more than 40 million fish usually return each year to Bristol Bay’s nine river systems to spawn.

Higher temperatures in the region have caused lakes and rivers to warm up earlier each spring, fueling the growth of tiny plankton that young sockeye eat. This extra food essentially fattens up the fish a year earlier, triggering their migration to the ocean.

This trend could negatively impact the resiliency of the Bristol Bay sockeye population, the authors said. Before, not every fish in a particular “age class” would migrate to the ocean in the same year, and any given year would see fish of different ages moving out to sea. This diversity of ages has helped the species navigate risks and survive.

But now, most sockeye are migrating at the same time, as 1-year-olds. This could devastate an entire age class if the ocean conditions happen to be poor one year. Additionally, scientists don’t know how many salmon the North Pacific can actually support.

“With climate change, is there a limit to how productive the ocean will become? We just don’t know where there’s a tipping point, especially as we fill the ocean with hatchery competitors,” Schindler said. “We need to be really cognizant about overstressing the marine resources that support wild salmon.”

Co-author on the study is Jan Ohlberger, a research scientist at the UW School of Aquatic and Fishery Sciences.

The study was funded by the National Science Foundation and the Gordon and Betty Moore Foundation.


From EurekAlert!

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Tom Halla
June 4, 2019 6:19 pm

On actual science, sockeye salmon migrate to salt water at a certain weight, rather than a certain age. So if they are well fed in fresh water, they migrate at an earlier age.
Somehow, that is to be a bad thing, as all changes are bad. As the Church of Climate Change has as an item of doctrine, the Little Ice Age was a golden age, and any changes from that state is the essence of evil.

Scouser in AZ
Reply to  Charles Rotter
June 4, 2019 10:47 pm

How do we know that the rivers are getting warmer?
Is there any actual data? Or is it an assumption?

Reply to  Scouser in AZ
June 5, 2019 6:17 am

More CO2 means more dissolved CO2, which means more algae and water plants.
Which in turn means more of everything all the way up the food chain.

Most of the world considers this a good thing. Except for climate scientists who are trained to believe that all change is evil.

Reply to  MarkW
June 13, 2019 12:16 pm

Wouldn’t more aquatic plants and algae have similar effect on water temperatures (i.e. cooling) as cloud cover has on the eart? Cooler water should slow development of fish and their food supply.

Reply to  Scouser in AZ
June 5, 2019 7:59 am

Quit with the pesky questions. What are you, a climate denier or something?

Reply to  Charles Rotter
June 5, 2019 3:39 am

They have looked for the cloud in the silver lining- and found it!

Smart Rock
Reply to  Susan
June 6, 2019 7:08 am

They have to find the cloud. The science is settled. “All change is bad” is the First Law of Climate Science; it’s the consensus, and it’s accepted by 97% of climate scientists who believe that all change is bad.

Plus, “all change is caused by human activity” is the Second Law of Climate Science. It’s a bit more shaky, and only has 96% of adherents.

June 4, 2019 7:15 pm

“Tipping point”

It’s getting to the point, where I just tune out when some article about global warming speaks of an unknown “tipping point”. Yeah, right … nature has exhibited NO resilience over billions of years … yeah … nature, or some biosphere, or some species is just gonna “tip over and DIE” … sheesh. Add this to the list of … “what you must believe to be a warmist”

Bryan A
Reply to  Kenji
June 4, 2019 8:44 pm

Only those species specific to Guam as their niche biome

Reply to  Kenji
June 5, 2019 6:19 am

This morning I was reading an article about the sun reaching solar minimum. Of course they had to include a line about how solar minimums cool the atmosphere and how climate deniers are using this cooling to proclaim that CO2 won’t kill us all.

J. Parsons
Reply to  Kenji
June 5, 2019 12:43 pm

If I followed the article correctly, the “tipping point” of concern is when the oceans become Too hospitable and productive for salmon?

Reply to  J. Parsons
June 6, 2019 11:10 am

The Horror … The Horror

Dave Fair
June 4, 2019 7:51 pm

There are more hatchery raised salmon, so the world will end. Did I read that wrong?

Reply to  Dave Fair
June 4, 2019 10:39 pm

That’s what I read. Here’s an idea! Have ALL the indigenous peoples of the West Coast dip net every last hatchery salmon … seine net them all … as is your “tribal right” … and eradicate all the “manmade” salmon. Problem solved! Eh ichtelologist geniuses!? Puhleeze.

Reply to  Dave Fair
June 5, 2019 6:21 am

Man doing something to return salmon levels to what they were before man started to heavily fish the salmon, is now treated as a bad thing.

Reply to  MarkW
June 5, 2019 9:48 am

“We” are (mistakenly) trying to return the salmon to levels that were observed during a small time period.

The brief time period AFTER man wiped out the west coast salmon predators, and when large numbers of Europeans started living on the west coast observing the swarming returns.

(The original fish ladder (human carried basket) at Oregon falls was less efficient than the current scenario … but “we” still think the Willamette basin runs are lower than “historic”.)

Joel Snider
Reply to  MarkW
June 5, 2019 12:53 pm

Actual solutions are usually frowned on, in not out-and-out criminalized by the progressive left.

June 4, 2019 8:11 pm

Release less hatchery Salmon because the natural Salmon are doing well would seem to be the correct action. No?

Dave Fair
Reply to  Bruce
June 4, 2019 8:37 pm

Based on this study, logic would so dictate, Bruce.

Reply to  Dave Fair
June 5, 2019 3:05 am

yeah but but thatd be the sane move…and would ruin their sobstory.
and if theyre doing well in warmer? lakes/rivers…thenwouldnt the supposedly warmer oceans make them happy at sea too?
one yr earlier out but EXACTLY the same time to catch size it seemed to me
whole lot of fluff and nonsense and they got paid for it.

Sky King
June 4, 2019 8:17 pm

Data-free assertions of speculations. Fake news.

Dave O.
June 4, 2019 8:25 pm

This world can only stand so much food productivity before it completely disintegrates.

Clay Sanborn
June 4, 2019 8:54 pm

What climate change? If those fish are leaving the lakes earlier, what do you want to bet there is another reason than climate? How would they know the reason? Did someone ask the fish?

Tom Abbott
Reply to  Clay Sanborn
June 5, 2019 3:51 am

“If those fish are leaving the lakes earlier, what do you want to bet there is another reason than climate?”

My guess is the increased CO2 in the atmosphere is stimulating extra growth in the lakes which increases the amount of food the salmon have available to them.

Bryan A
June 4, 2019 8:54 pm

But this “jumpstart” in freshwater doesn’t necessarily benefit salmon in the long run. The same fish are now spending an extra year in the ocean, taking longer to grow and mature.

Higher temperatures in the region have caused lakes and rivers to warm up earlier each spring, fueling the growth of tiny plankton that young sockeye eat. This extra food essentially fattens up the fish a year earlier, triggering their migration to the ocean.

So…Salmon are fattening up faster due to warmer water plankton populations having more mass, yet they are growing slower in the ocean with an extra year there.
A couple of generations will show if this causes them to be affected negatively of if the extra year in the ocean proves beneficial and produces larger fish.
IF the increased quantity of hatchery fish affects the ocean population negatively, simply release fewer hatchery fish into the population

Mark Lee
Reply to  Bryan A
June 5, 2019 9:15 am

“…IF the increased quantity of hatchery fish affects the ocean population negatively, simply release fewer hatchery fish into the population.”

Exactly. There is no negative. If wild Sockeye Salmon are getting to the ocean in increasing numbers, then you don’t need to supplement the population with hatchery salmon, thus reducing your expenses. The purpose of hatchery salmon should be to maintain a desired ocean population level. More wild = less hatchery. Less wild = more hatchery. This seems to be simple math to me.

June 4, 2019 10:12 pm

This is interesting, and having fished for Sockeyes I have a modest answer. While there may or may not be something about higher protein levels in fresher water, what i think is going on is that bear and seal/sea lion predation has increased tremendously. The fish are tending to stay farther upstream, returning earlier from the ocean and running up earlier or later to adapt to predators. That’s a more logical answer to me than the fish figured out the Democratic Party Platform.. My suggestion is to shoot more bears, seals and sea lions to give the fish a chance.

Mark H
June 4, 2019 10:13 pm

“Higher temperatures in the region have caused lakes and rivers to warm up earlier each spring, fueling the growth of tiny plankton that young sockeye eat.”

Could it not also be that higher levels of CO2 are fertilizing the plankton in the lakes, leading to an increase in the amount of food available for the Salmon fingerlings? Either way, it seems like not such a bad time to be a Sockeye Salmon

June 4, 2019 11:28 pm

I don’t like fish*, so I’m not sure how to take this one.

Are we doomed or not?

(*To eat, that is. Nothing against them personally, as long as they stay in the water where they belong.)

Reply to  RoHa
June 5, 2019 6:28 am

What about flying fish?

James Schrumpf
Reply to  MarkW
June 5, 2019 7:45 am

Sharknadoes? How is climate change affecting the frequency of sharknadoes?

Bryan A
Reply to  James Schrumpf
June 5, 2019 7:50 pm

Not well…the increased dissolved CO2 is making the Sharks teeth weaker and resulting in Toothless Sharknadoes

June 4, 2019 11:39 pm

Their data for the warming is at
Unfortunately they don’t chart it, but eyeballing the data I would say that there is no general warming, just two warm years 2014 and 2015 (no more recent data).

June 5, 2019 12:02 am

In their Supplementary Data 1
There is little or no data for “brood year” after 2011, so it’s difficult to see how they can associate any changes in fish behaviour with temperature. Maybe someone would like to take a look at the data? I’m travelling and can’t analyse it on an iPhone.

Bob boder
Reply to  Mike Jonas
June 5, 2019 4:20 am

Because we all already know about the warming, no need to show it to establish that it is the cause.

June 5, 2019 1:24 am

“Should the worst-case scenario of rainfall from a budding tropical feature in the western Gulf of Mexico become involved, levels on the lower Mississippi could approach that of the Great Flood of 1927.”
High pressure in the Eastern Pacific may increase the amount of tropical storms in the Gulf of Mexico.

June 5, 2019 3:16 am

In the UK those rivers with good feeding for (Atlantic) salmon parr often had runs of larger fish which had a longer time at sea feeding.
The general principle seems to be that Atlantic salmon return to spawn at 6 to 7 years of age.
If the nursery streams are fertile, then they go to sea at 2 years of age, in other rivers they may take 3 to 4 years before running to sea as smolts.
Thus the fish returning to spawn can have had 3 to 4 years at sea, with some rivers producing salmon of up to 40 lb.
Unfortunately Atlantic salmon are undergoing a serious drop in numbers, possibly due to high seas fishing, the industrial fishing of sand eels which are a major source of food for salmon, pollution of spawning streams and infestations of sea lice from intensive salmon farms.
As an aside, the feeding grounds of Atlantic salmon were unknown until the US submarine Nautilus discovered salmon feeding off the coast of Greenland. Commercial fisherman then took advantage of this information and proceeded to catch large numbers of part grown salmon, thus reducing the numbers returning to spawn.
As another aside, the Guardian is pushing the story of flooding in the Mid West USA.
I feel very sorry for those affected by the flooding, which is similar to the flooding here in Somerset a few years ago, but on a much larger scale.
Is this something that happens very rarely, or is it becoming more frequent? I see that extensive flooding in 1943 is quoted in the article.

Mike Lowe
June 5, 2019 3:26 am

Since the Alarmists are wanting us to spend trillions of dollars to keep the warming below 1.5deg we can assume that they know it has not reached that “disastrous” level yet. But we are supposed to believe these academics when they say that one-half or one degree of warming will have had such a dramatic effect on the behaviour of salmon? Sorry, I just do not believe that, especially since each fish will experience far more than that small change when migrating from sea to river at different dates and climatic conditions. This is obviously yet another attempt to secure more funds for “critically needed further studies”! Have these people no morals or ethics at all?

Bruce Cobb
June 5, 2019 3:59 am

This “study” has a distinctly fishy smell. They have conveniently jumped on “climate change” as the reason for the salmon’s earlier departure, and possibly, somewhat earlier Springs is a factor. However I suspect a higher level of nutrients available for the plankton to eat is another.
The increased competition from much-increased hatchery populations is a totally different issue, having nothing to do with “climate change” (real or imagined), yet they lump it in. Ridiculous.

Steve O
June 5, 2019 6:15 am

A common logical technique is to consider the opposite. If lakes were getting colder, and fish were taking an extra year to reach the weight at which they migrated to the ocean, how would that be presented?

This is similar to the article on the Larch, which are experiencing higher than average growth in Northern regions. Whatever the change, researchers are presenting them in a negative way. Bad news is bad news. Good news is potentially bad news. There shall be no positive effects of warming.

Pamela Gray
June 5, 2019 6:21 am

Lake and river warming, at least those associated with the Pacific Ocean, is likely a function of El Niño and its teleconnection to atmospheric systems, particularly those systems that drive Arctic Oscillations leading to tightly confined or loosely spread out arctic air.

This paper isn’t worth a bird cage.

June 5, 2019 6:29 am

Once again, no attempt to actually establish as a fact, that the lakes and streams have gotten warmer.
Just assume that it must be the case and work from there.

June 5, 2019 6:34 am

Climate change “science” is all about correlation. A connection between things based on perception. When in doubt blame climate change. Actually there appear to be no pause in thought for any doubt with these people. Blaming the climate for all things is immediate and final.

June 5, 2019 7:34 am

It sounds as if this was an anti-hatchery paper when it started and turned into the evils of global warming. I assume to keep funding flowing in.

Several of the green leaders in Canada, today big into the CAGW religion, have been adamantly opposed to all hatcheries and salmon farming for decades, actually before CAGW became the issue de jour.

HD Hoese
June 5, 2019 7:44 am

https://www.nature.com/articles/s41559-019-0901-7.epdf?author_access_token=uy_g_AiZJc6ged_kpT6t_tRgN0jAjWel9jnR3ZoTv0NkxzMONJ75psPCrw4h0Yk-YeBWjIT-Abi4HkYOpND6ovQOaz5X7WAeXeH8jdorMkx2uiIgZzm4NLiC0ACvHD3UxyOgdgEtFhITfQuKmYu2Pg%3D%3D Not open access, but authors making it available.

I don’t have time to study this, but it looks very interesting. Their Fig. 2C, shows a great increase in salmon over the last half century along with hatchery releases but–“Recent estimates attribute 40% of Pacific salmon abundance to hatchery-produced fish, although this estimate is conservative as hatchery fish that spawn naturally are not counted.”

“ In the two systems where this age class was historically a small proportion, Kvichak and Egegik, the changes in life-history traits have increased diversity among age classes (Fig. 1).” Fig. 2a does shown irregular increases in T and decreases in “ice-out.” Fig. 2b shows ocean changes. “ Positive values of PDO (negative values of NPGO) are correlated with increased salmon productivity in Alaska..”

Pamela Gray
Reply to  HD Hoese
June 5, 2019 9:11 am

Interesting. If a hatchery fish (otherwise known as a wild fish grown in captivity) spawns in a wild river, what are the fingerlings called? What if they are put in a reservoir that does not have fish passage and spawn there? Are the fingerlings wild or still called hatchery fish?

June 5, 2019 8:58 am

The problem Alaska reds have is not what is going on in the fresh water, but rather having to compete with billions of pink fry in the salt when they get there. Alaska decided a few decades ago not to compete in the fish farming world, making it illegal in the state around 1990. Like all protectionist measures, it didn’t work at all. OTOH, they did get into the ocean ranching business, pumping out billions of pink fry from commfish supported hatcheries that are caught a year later by commercial fishermen. Turns out that pinks are great predators and are out-competing the longer lived fish for biomass in the North Pacific. Prince William Sound and Cook Inlet are particularly bad. This has in turn damaged returns of chinook, coho and sockeye. Chinook runs are in dire straits in a large part of the state. There is even science on this, roundly ignored by commfish as their solution is simply to catch everything in sight. The political fight is well under way.

Generally, the larger the fry are when they hit the salt, the better their survival and the better their returns. Problem is that ocean ranching for pinks (and the Russians are doing it too on the other side of the Pacific) appears to be making sure the good news from nature does not go unpunished. Link is to the best outdoors writer in the state, an old news guy who does real good research. Cheers –


June 5, 2019 9:06 am

How can you say with good conscience that there is no climate change and then tout the benefits of climate change. I’m a skeptic and you cannot argue both sides of a coin and be credible.

Mark Broderick
Reply to  John
June 5, 2019 9:47 am

The Earth getting slightly warmer is not the same as CAGW !

Reply to  John
June 5, 2019 12:42 pm

The Earth is recovering from the devastatingly (to humans) cold period of the Little Ice Age. That period had record droughts and freezes recorded in history (e.g. summers with no summer). One and a half degrees warmer than those days is a really good thing (a recovery)…and another degree will be even better as it was during earlier warming periods during the Holocene…when civilizations flourished. With the AMO turning negative now (and quiescent sun), that extra warming probably won’t happen until later this century…but it is expected if you look at previous warming periods during the Holocene.

The warming since the LIA has not been liner. The warming from 1910 – 1940 was identical to the warming from 1970 – 2000 (ending only .25-.30 degrees warmer than the 1940’s peak…and inside the annual noise durong the whole period). The 1910 – 1940 warming was from natural unknown causes…but the later IDENTICAL and totally unremarkable warming period was all from CO2. Prove it.

So, yes, there was a wee bit of normal warming. This article did not prove that the more rapid salmon growth was from earlier lake melt-off from climate change (don’t know about the last decade, but that surely did not happen this year…still thawing out). Inland lakes are warmed some by air temperatures, but are warmed primarily by direct sunlight and very unevenly all over these lakes…raising up to several degrees per day when sunny…and not at all or declining on cold cloudy windy days.

Aside from registering and reporting on the earlier salomon maturation, this study is crap. There are lots of things that contribute to the growth of fish, and a possible half degree of global warming (which may not even have been reflected in higher lake water temperstures) is extremely unlikely to have caused this substantially increased growth.

Gary Pearse
Reply to  John
June 5, 2019 6:02 pm

John, No scientifically literate sceptic says that there is no climate change. Change has been a mainstay of climate throughout geological history. There is nothing unprecented about current temperatures (actually this is a relatively cold period compared to most of geological time), nor are CO2 levels presently high. Previous eras have had CO2 4000 to 9000ppm, 10 to 20 times what it is today

June 5, 2019 9:30 am

Darwin has been totally tossed out and humans are apparently aliens that do not belong on earth. Got it.

James Schrumpf
June 5, 2019 11:34 am

NOAA’s Global Historical Climatology Network’s Monthly summaries show that over the last four years, over 2000 stations in the US have reported flat or decreasing trends in temperature. Here’s a Google map showing the distribution:


However, there are 6,000 or so US stations, just as well distributed, that show a warming trend. What does that mean? Can any kind of global trend be claimed when individual stations show such a mix, and only by averaging does any kind of global phenomenon exist?

michael hart
June 5, 2019 1:30 pm

I spent some of the happiest years of my life sitting and walking around the salmon hatchery at The University of Washington.

Little did I realize that they were actually breeding climate-change idiots, not fish.

Gary Pearse
June 5, 2019 5:44 pm

“… this could devastate..

There is a pattern to all alarmist papers. A) If indeed there seems to be something negative happening (say budworms destroying coniferous forest), well they go full forward on alarm beyond any reasonable level of concern and blame cataclysmic anthropo global warming (More likely it is caused by activists blocking forest management paractices).

B) When what is clearly very good news they conclude that it’s bad. The “Great Greening of the Earth” from Anthropo CO2 and bumper crops are examples. First all we heard was ‘crickets’ and then they dreampt up all sorts of things that are terrible about this! Okay, habitat is increasing but this will be a bigger carbon exhalative source of CO2 when it stops and burgeoning crops are lower in nutrition and all this bount will cayse malnutrition! Sure, the plants are more drought proof but they will expand coverage and reduce water supplies!

Look folks, this bonanza for Sockeye salmon is a very good news story. Ya see, the oceans are getting more productive, too. Heck we are going to need bigger nets and and bigger boats!!

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