Foley Creek in Oregon is as ideal as a non-wild stream can get. Cold water, limited human interaction, complex, flows directly into the lower Nehalem River not more than a few miles from the Pacific ocean. The headwaters are managed for private timber production while the lower reaches meander between private rural houses and cow pastures. There is even a berry farm or two but it is far from heavy use. There isn't one culvert! I have seen many streams in Oregon. There are salmon in the craziest places. They can become stranded in a puddle no longer than myself and only a few inches deep as high flows recede. They can jump through perched culverts that make me want to get a tetanus shot just by looking at them. They can hang out in warm bacteria ridden waters for days before succumbing to stress related deaths. They are even found in road and pasture ditches. They are an amazingly resilient genus. For some reason though, Foley Creek is missing salmon. They are not present in the numbers one would expect. The gradient is perfect, the gravels and pools are there, it isn't too flashy, but for some reason, year after year, I have yet to see one fish either adult or juvenile in this stream. I know they are there from Fish and Wildlife counts, but the numbers are limited. My neighbors saw one spawning Coho, once. What is the problem? Coho, Steelhead, and Chum can live in warmer waters than Foley. They can make it through almost any barrier on other streams while Foley's passage is unbarred. They make it to the top of the Nehalem River despite a waterfall, sediment flushes, and high temperatures. One would think that Foley Creek, both by proximity and by nature would be flush with salmon and trout. Not one cutthroat though. I know how to look too. I have been doing this for the better part of a decade. I see the most ideal gravel bed and associated pool almost on a daily basis. Where are they?
I have several hypotheses:
- There are numerous steep gravel roads that intersect Foley Creek, some of which deliver sediment during heavy rains. These bury those pristine gravel beds that could be ideal for spawning.
- There is limited wood which is needed for gravel sorting and cover.
- There are some reaches that have no riparian cover and temperatures could become elevated.
The return is low. Even if smoltification failed and every cohort was killed as the result of one of these three reasons then strays would recolonize the stream, but they don't to the degree they need to in order to sustain a viable population.
I have a second hypothesis, one that runs deeper and faster to the point. A hypothesis I, as a restoration biologist, avoid like a plague-ridden alley because it is too sad for me to comprehend.
The oceans are dying. This hypothesis is supported by a great deal of evidence (mostly through process of elimination). If the dams along the Columbia were the limiting factor then we would see more salmon in coastal streams where passage is not barred. If heat were the limiting factor the same would be true. If habitat complexity was the limiting factor then the restoration work which has occurred over the past twenty to thirty years or so would make such a difference that we could see a correlation between our work and salmon populations.
While dams definitely cause direct and indirect mortality, as does temperature and habitat simplification, the adult returns are almost always dependent on 'a good ocean year'. What does that mean? A good ocean year refers to ideal temperatures, currents, food, and limited take from all predators including humans.
There is more evidence that our dying oceans are the primary limitation to salmon populations; the pH is changing, the currents are changing, the temperature swings are increasing, the freshwater inputs are increasing, the food web is shifting. These are preventing our freshwater restoration work from being as effective as it can be. We can keep the young ones alive but we can't do anything to increase their adult survival once they hit the salt water.
I would call myself crazy, if it wasn't just salmon. Then there is the coral, the turtles, the whales, the multitude of tiny fishes, and a host of other creatures I can't name, all dying at faster-than-historical rates.
What can one do? I don't know.
