Beware: Informal Blog Post Ahead.
Thank you, John Oliver, for making the world aware of the salmon cannon. If you have not yet become enlightened about this fascinating and hilarious means for transporting fish, stop reading. Click on the above link… Are you done? Great. Now we can all agree it is comical, but it also is a creative solution to the wide-spread problem of dams preventing access to historic salmon spawning habitat, including California’s Sacramento River winter-run Chinook salmon. Whether or not a salmon cannon will be installed at Shasta Dam, it’s mere existence lets me highlight ambitious plans to save this fantastic fish. If you’re not familiar with the saga of the winter-run Chinook, check out my previous post, and if you’re on a role, look at Casey’s great discussion of how deep history shapes the world we see around us today. But if you don’t feel the need to read another post, take my word for it that these fish are a fine specimen of evolutionary adaptation and yet are holding on to existence by a pinky-fin in the face of the numerous changes humans have made in the world.
The winter-run evolved to use the network of cold, spring-fed creeks in the Mt. Shasta region. During the summer months, these streams have cool enough water for salmon eggs to incubate and newly-hatched fry to develop. Yet ALL of this historic spawning habitat was lost when Shasta Dam was completed in 1945, forcing salmon to spawn in a small region of habitat in the mainstream Sacramento River, ultimately leading to epic declines in the population (now at about 3% of historic levels). In the future, climate change and increasing water demands will only continue to exacerbate the problem.
An obvious solution is to recreate some level of connectivity between the creeks upstream of the dam and the river below the dam. However, removal of Shasta Dam, which is central to much of California’s water-infrastructure, is not politically feasible. And traditional methods used to move fish around dams, such as fish-ladders, are an incredibly expensive and difficult, if not impossible, solution for allowing fish passage at a 602 foot wall like Shasta Dam. This leaves us with…the salmon cannon?
Unfortunately for John Oliver fans, the salmon cannon has not yet been mentioned as a solution at Shasta Dam. Overcoming this fish barrier is a problem with huge logistical challenges and any solution will have an uncertain probability of success. Both of these are common issues that often contribute to conservation inaction and political stale-mate. However, (and I think this is the exciting part!) the predicament of the winter-run has actually catalyzed an ambitious reintroduction program that is going on right now. There is an interagency group which is devising a plan to re-establish connectivity, beginning by reintroducing eggs and juveniles into one of two major tributaries within the year (Upper Sacramento and McCloud Rivers - see map below). Work has already been devoted to determine the feasibility of reintroduction, which includes evaluating the potential for historical spawning areas to support salmon, fostering discussions with local land-owners who will host the returning fish, and battling with the logistical challenges of moving both adults and juveniles past the dam and its reservoir. This is exciting because it goes beyond band-aid fixes and piece-meal solutions and directly addresses a major source of the problem.
To date, there have been no decisions on long-term fish passage. In the short term it is likely that a trap-and-haul program will be put in place. Systems for trapping adult fish swimming upstream already exist as part of a long-running hatchery program that uses these fish as breeding stock in a conservation hatchery (Livingston Stone National Fish Hatchery). In the initial reintroduction these same adults will likely be trucked above the dam and released to spawn, then the next year’s juveniles would be collected as they swim downstream and into the Shasta reservoir to be trucked back down below the dam and released to continue their migration to the ocean. However past experience with this system in other rivers has shown that trap-and-haul programs tend to be expensive and difficult to maintain in the long term. Thus it should be a stop-gap plan until something else can be put in place. This begs the question once again…can we use the salmon cannon?
Which brings me to my final point: Punkin Chunkin. Bear with me for a minute. This is a contest where teams compete to shoot a pumpkin as far as possible with a pneumatic air canon or catapult, which makes a great topic for procrastination. But Punkin Chunkin is also an insightful example of what happens when you accelerate an organic object very rapidly. This problem, called ‘pie-ing’ in the Punkin Chunkin competition world, is described well by an article in Wired by Rhett Allain. In short, when you shoot a pumpkin from a cannon with a very large force, the acceleration puts pressure from the air on only one side of the pumpkin, causing it to flatten, or ‘pie’, and effectively explode in mid-air. It is a clear reminder that on earth we are still limited by the laws of physics, and shooting a salmon through a cannon over a 600 foot tall dam might run into a few physics problems. So, while the salmon cannon has the potential to be a great solution in certain circumstances, I’m honestly not expecting a large cannon to be the final fish-passage option for winter-run Chinook. However, it does provide a great reason to blog about salmon cannons and Punkin Chunkin, and to get readers to think creatively about how we might save our amazing winter-run Chinook in the face of drought, climate change, and increasing human population.
While there are plenty of uncertainties and likely imperfections in the reintroduction plan, it is difficult to see any long-term improvement for the winter-run salmon population without providing access to historic habitat. I think it is encouraging that in the face of a pressing conservation problem where the only potential solutions require massive inputs of time, sustained money, will-power, and creativity, the bureaucratic beast is moving forward. So keep your eyes and ears out for more information, and be an educated and vocal public! If you agree or disagree with anything I’ve said here (other than the indisputable fact that the John Oliver piece on the Salmon Cannon made your day a little brighter), please make a comment and start a conversation.
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