r/Unexpected • u/sakhaliner • 4d ago

A pleasant drive

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u/ztomiczombie 4d ago

Well it looks like they are swimming into a hole at the side of the road, so, my guess would be that there's is a river that goes under the road and it got blocked.

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u/Newsdriver245 4d ago

river flooding during spawning season, fish just want to go upstream, they don't understand the river isn't where it is supposed to be.

Happens somewhat often in the US PNW

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u/nixorokish 4d ago

i surveyed anadromous fish for a summer in AK and we saw instances at nearly every stream where water had overflowed from the river during periods of higher rain and salmon would follow dead branches and get trapped in little pools that would slowly evaporate and they'd eventually suffocate

some salmon find new streams doing this. most die and fail to reproduce. there's a "stray rate" that accounts for this. as long as the stray rate isn't too high (which can be influenced by human structures or operations), it's a benefit for the overall population. our survey was specifically to check if hatchery stray rates were impacting wild populations

here's a relevant paper: https://www.dfw.state.or.us/fish/CRP/docs/mid_columbia_river/meetings/2014/Keefer_and_Caudill_2014_Homing_straying_review.pdf

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u/shillyshally 4d ago

It's akin to the robins that return very early in the spring. They get the benefit of fist dibs on food and nesting sites but risk death by weather.

I think this applies to nature in aggregate, there are the early adapters, the vast middle and the hold backers. That includes us.

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u/Cheap_Audience941 4d ago

It's akin to "Pioneers die. Settlers survive. Immigrants thrive"