The boom and bust cycle of Chinook salmon in Oregon

This post by Jay Nicholas is a response to the recent, thought provoking post on the dilemma faced by those of us who live to fish for wild chinook salmon on the Oregon Coast each fall:

You may recall Oregon’s chinook boom in the late eighties. I know you remember 2002, 2003, and 2004. Those were big run-years, and we all felt like fly fishing heroes. In contrast, the last three years have almost brought us to our knees. Of course, it’s the fish that have really suffered. Most California and Oregon rivers have recently seen the lowest chinook returns in six decades.

How is it that this could have happened? Can we blame the seals? Nope. The bad-boys fishing off Canada and Alaska? Probably not. Foreign fishing factories? Don’t think so. Degraded freshwater conditions in spawning or rearing areas? Doubt it. All of these factors could be taking a little whack at our coastal chinook, but I don’t think, even collectively, they are the principle cause of our depressed runs.

Jay Nicholas Rogue

Enter that mysterious and hard to describe “ocean conditions” factor.

Although this villain may seem like a fish biologist’s dream excuse, it is the most likely explanation for the collapse of chinook populations from Sacramento clear up the Oregon Coast during the last several years.

So just what are ocean conditions? While I am not the expert here, I know they include water temperatures, upwelling, primary production at the bottom of the food chain, predators, actual salmon feed, and perhaps even the ominous “dead zones” that we’ve all read about in recent years.

Salmon are best suited to relatively cool water temperatures, so warmer-than-usual water is not good. It elevates metabolic rates into the not-so-good range for salmon. If this gets bad enough, salmon can experience direct mortality of adults, a phenomenon rarely seen except in severe El Nino conditions.

Upwelling is generally good, because it brings cool, nutrient rich water from deep layers to the surface, jump-starting primary production that provides for everyone in the food chain. Upwelling can be not-so-good if it brings up warm water, or cool, nutrient-poor waters.

Upwelling can also be a problem if it brings up a ton of nutrients, which creates a huge primary production bloom, and then dies. If a pile of bottom-of-the-food-chain critters is suddenly swimming in a nutrient poor environment, it can result in a sea of dead little critters that decay and suck all the oxygen from the water, creating “dead zones”. These anoxic areas cannot be good for salmon, but I do not think we completely understand whether or not the salmon can escape these zones.

Predators just need to make a living, like any other critters. If ocean waters are warmer than usual, it may allow oceanic predators to expand their range into salmon waters, preying directly on the salmon or on the salmon’s food.

Getting back to the problem of not enough chinook to make us happy fly anglers, the kings from the Sacramento to the Columbia have differences in their timing of ocean entry, live in different parts of the ocean, and as far as I am aware, have never ALL crashed at the same time in the last 60 years. Rivers like the Sacramento are heavily stocked with hatchery fish, but almost all of our Oregon Fall Chinook are wild fish – and ALL crashed at the same time.

Jay Nicholas Clousers

The most optimistic signs I am aware of are 1) sampling by NOAA in the ocean in the last two years have indicated that the abundance of juvenile salmon and salmon food has been much higher than the previous several years; and 2) friends fishing Oregon coastal rivers the last two years have caught a lot of jack Chinook. Both observations point to increasing runs in the next several years. Good numbers of jacks in the last two years should mean that we will see more two- and even three-salt males this fall.

I’m going to close this rant with several observations that the previous post hinted at:

First, the run this year could be very low, so use discretion when fishing for and releasing fish. There are likely to be good numbers of wild silvers in the bays and if you can dial these fish in, it could be a great opportunity to catch and release bright coho in the lower estuaries where cool water will be the norm.

Second, be prepared to go easy on the kings, but be open to the possibility that there may be relatively more males in the three- to ten-pound range. These make great table fare. PLEASE discourage everyone you know from keeping the big females. Those eggs should go in the gravel, not in the bait bucket.

Third, advocate for protection of our home-water rivers and the wild fish they still support. If the ocean turns around, we could still have some glory seasons ahead.

Jay Nicholas Chinook

Finally, and this is really important, don’t ever believe that hatchery fish are capable of producing consistently high runs of chinook in our coastal rivers. The Rogue River produced a return of close to a hundred-thousand wild kings in 2003 and 2004. Wild kings! The Sacramento run crashed even though there are zillions of hatchery chinook stocked there. In short, our best path to good chinook fishing on the coast is to limit our impacts, keep an eye on the Pacific Salmon Treaty monitoring information, refrain from expanding hatchery production, and make sure that the habitat in these wild-fish factories is adequately protected from development like urbanization, dam building, water withdrawals, logging, agricultural practices, and river-side trophy homes.


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6 Responses to The boom and bust cycle of Chinook salmon in Oregon

  1. Karl Mueller says:

    Great post. I want to add though for the sake of habitat conservation that while the other factors you mention are not the principle cause of decline in recent years, they are a contribiting factor that has brought us to where we are today (our knees).

    Instream habitat carrying capacity plays a critically important role. As you and I discussed, (more like you explained I listened) if a river puts out 2 million smolts and 1 percent survive the “ocean conditions ” in a crappy ocean year you still have 20,000 adults. If the river is only able to support 200,000 smolts and 1% survive you get 2,000 adult salmon. That’s a big difference and in-river habitat remains an important factor in the size of our runs. On the flip side, if you take the same river with the same hypothetical carrying capacities but a great ocean survival rate of say 10 percent, the run ends up being 200,000 or 20,000. Take your pick folks.

    So this by way of saying, don’t give up on the instream habitat aspect. There is a real danger in just blaming the ocean (which I don’t think Jay is doing here). Keep the really big picture in mind. I’ve heard many times now people saying “there is nothing we can do”, that salmon run sizes are dependant on the the ocean. That is only part of the picture. These people don’t understand that ocean conditions affect smolt survival on an order of magnitude. As bad as things are, imagine how crappy they’d be if we hadn’t started doing a better job of restoring/protecting instream habitat in the last couple decades.

    The runs are historically bad. Used to be, using the way back machine, that a crappy year is what we now consider a banner year–that’s the instream habitat.

  2. jay nicholas says:

    Karl: THANK YOU!

    The importance of protecting and restoring the rearing capacity of freshwater and estuarine habitat is essential to sustaining our wild salmon populations and fisheries.

    The ocean can be kind or the ocean can be nasty to salmon, but unless the fish have reasonably decent habitat for spawning and rearing, the game is over. The ocean-driven, coast-wide swings in our Chinook runs are likely not amenable to our management programs, but the condition of our rivers and estuaries are a direct consequence of management decisions well within our control.

    The question is whether or not we have the political courage to do what is needed to protect the land and the waters that nourish salmon, our economy, and our spirits.

    In my opinion, protecting habitat functions that still work for wild salmon should be our highest priority; followed by investing in habitat restoration.

    As you rightly point out, every increment of freshwater and estuarine rearing capacity erodes the likelihood that we will occasionally have banner run years in the future, even if the ocean deals us and the fish a good hand.

    And lest anyone forget, we should not catch too many of the fish or degrade their productive capacity with our hatchery programs.

    Final thought: need to pay attention to the ALL the big and little injuries we deal the salmon body.


  3. Sam W. says:

    Granted, overfishing, hydroelectric, habitat and “ocean conditions” have all greatly contributed to the demise of the chinook. However, the erosion of “wild” stocks by hatchery fish has played perhaps even a larger role. Once the gene pool is eroded there is no getting it back. Keep that in mind as we all applaud the huge run of hatchery steelhead on the Columbia system this year. To the extent that we laud and otherwise support our steelhead success this year we also support the continued use of hatchery fish to solve the salmon “problem.”

  4. Karl Mueller says:

    Sam–I detest hatchery salmon more than the next guy and we have to keep them on our radar too . I don’t agree though that hatchery fish are the problem here. On the Oregon Coast excluding the Columbia, I can only think of the Elk, Umpqua, and maybe a couple small rivers that have hatchery salmon. What we have there, with regard to salmon, is not a hatchery problem though for steelhead that is another story.

    Hatchery fish are not any kind of acceptable solution and I agree with you that we definitely should not glamorize the steelhead fishing fishing that’s going off on the Big C and her tribs.

  5. al says:

    I’m new to this blog thing and have taken an interest in reading all the coments. Hear on willamett where I live i’ve helped with the tagging of the hatchery stock of our kings.
    And was really put out when I was told by EPA sight boys that some well to do folks along this river considered rotting salmon polution!! So no carcuses are returned to the water. Now I don’t have a dagree in anything but maybe stramside attendance. But without those dead fish what feeds the other stream bottom dwellers ? that my trout and smolts need for food?

  6. al says:

    Wow ! just reread my blog! My typing skills really need an overhaul . I’ll do better next time 1

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