Advanced Search

Please click here to take a brief survey

Seeing Through Salmon
Alex Steffen, 17 Mar 08
Article Photo

To get a sense of how complex and tangled the task is of managing the planet, consider Chinook salmon.

The Sacramento River fall Chinook salmon run, which had been recovering in recent years, has suddenly collapsed, and no one seems to know why:

The almost complete collapse of the richest and most dependable source of Chinook salmon south of Alaska left gloomy fisheries experts struggling for reliable explanations — and coming up dry.

...Fishermen think the Sacramento River was mismanaged in 2005, when this year’s fish first migrated downriver. Perhaps, they say, federal and state water managers drained too much water or drained at the wrong time to serve the state’s powerful agricultural interests and cities in arid Southern California. The fishermen think the fish were left susceptible to disease, or to predators, or to being sucked into diversion pumps and left to die in irrigation canals.

But federal and state fishery managers and biologists point to the highly unusual ocean conditions in 2005, which may have left the fingerling salmon with little or none of the rich nourishment provided by the normal upwelling currents near the shore.

The life cycle of these fall run Chinook salmon takes them from their birth and early weeks in cold river waters through a downstream migration that deposits them in the San Francisco Bay when they are a few inches long, and then as their bodies adapt to saltwater through a migration out into the ocean, where they live until they return to spawn, usually three years later.

What wiped out the run? Climate change? Water diversions? Something we don't understand? The answer may well be all three, which illustrates the difficulty of trying to manage a complex natural system through highly political processes (which in the real world is essentially the only way they ever are managed).

Why care so much about the salmon? Well, fall Chinook are a $150 million fishery, first of all. That's a lot of fish missing from a lot of tables, and a lot of fishermen looking at hard times.

But there's another reason we should care: river and mountain ecosystems throughout the North Pacific depend on salmon to remain healthy. Here's how Ed Hunt explains it:

Pacific salmon do a strange thing. After they spawn, they die. ...After spawning, they leave their nutrient-rich carcasses behind. Many of the microscopic creatures that nibble on the carcasses eventually become prey for the next generation of fish. And so the parents nourish the young.

But salmon provide more than an indirect food source for baby salmon. At least 137 different species — from grizzly bears to gray wolves — depend on salmon for part of their diet. Even trees and plants benefit from the nutrients brought back by salmon from the seas.

Indeed, salmon used to transport so many marine nutrients to terrestrial ecosystems that environmental historian Richard White compared them to a conveyor belt. As Richard Manning explains:

Salmon are born, leave the stream as a pencil-sized fish, spend a few years fattening on ocean's bounty, then return with a gift to the natal stream, as much as 60 pounds of body mass made of not just carbon, but of the other nutrients the entire system needs. They import nutrients to landlocked life. This is the measure of the power of salmon.

Scientists now estimate that the Columbia River system once gained about 400 million pounds of nutrients from each year's salmon runs, before the dams broke the cycle. ... Samples of salmonberry bushes growing streamside reveal as much as 18 percent of their nutrients are ocean-derived, making it one of the more aptly named plants around. The same is true of trees. Plants are fed when carcasses decay and fertilize the soil, or when the dead salmon enter the food chain and eventually return to the soil as droppings. The faunal section of the chain contains at least 20 vertebrate species, including, of course, bears, but also surprisingly, deer and elk, which during spawning season are known to feed directly on salmon carcasses.

The upshot is that when the wrong forces combine -- when upwelling fails, ocean dead zones spread, streamside habitats are logged or developed and rivers are diverted to farmers' fields -- what is lost is not just a whole bunch of big fish, but the fundamental health of the ecosystems of an entire region.

If we're going to take our obligations as planetary managers seriously, we need to start being able to see through two lenses simultaneously -- a human lens and an systems lens -- and bring them into focus together. Despite decades of really smart, committed people trying to do that in Western North America, our vision's still blurry.

What might clear it up?

(If you want to learn more about salmon, by the way, I highly recommend browsing around over on the excellent Salmon Nation website.)

Creative Commons photo credit

Bookmark and Share


we have a moment of economic vulnerability, natural collapse, resource scarcity, and wide agreement about infrastructure neglect, combined with a ticking clock. i don't know what else a person could ask for.

Posted by: hapa on 18 Mar 08

meaning, "hey everybody! let's talk about the future."

Posted by: hapa on 18 Mar 08

Great post. I just happen to be reading Water: A Natural History, by Alice Outwater, which provides an extremely readable explanation of the life & history of North America's waters, describing the myriad ways water percolates through our continent (& presumably elsewhere) as well as how we have, for the last 500 years managed to do everything we can to un-do this extraordinary resource. Outwater specifically discusses the impact of human activity on the life cycles of salmon, rivers, lakes, forests, prairies and wetlands. A must read.

Posted by: Mal Gormley on 18 Mar 08

Cheap and universal data logged about the ecosystem + computers with the right type of simulation environment might clear it up.

Remember, you can't reason about something which you can't measure. Science began when people stopped philosophizing about the world--and started measuring things and doing experiments. When you have real facts to reason with, the results you get get better and better.

Until we have a way to measure the health of the various players in the ecosystem, we can't reason about what the impacts of our decisions will be.

Posted by: Hasan Murtaza on 18 Mar 08

oh, in that correct sense of the question, i agree with hasan, but hope there's another way because who knows when good-enough or that-much-better data will accumulate, even in a devoted hurry, with fabulous sensors and lots of eyes on it. i'd vote for the conservationist process of elimination to get there -- take as much of our load off as possible -- because i'm not sure what even the best science has to offer can learn from a royally overtaxed system's current function. 's'like trying to figure out the maximum theoretical human speed by observing a TB patient.

Posted by: hapa on 18 Mar 08



MESSAGE (optional):

Search Worldchanging

Worldchanging Newsletter Get good news for a change —
Click here to sign up!


Website Design by Eben Design | Logo Design by Egg Hosting | Hosted by Amazon AWS | Problems with the site? Send email to tech /at/
Architecture for Humanity - all rights reserved except where otherwise indicated.

Find_us_on_facebook_badge.gif twitter-logo.jpg