Hatchery Fish Struggle To Reproduce In Wild

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Here’s another surprise from the unpredictable frontlines of biology. A new study from Oregon State University finds that steelhead trout raised in hatcheries face a dramatic and unexpectedly rapid drop in their ability to reproduce in the wild—nearly 40 percent per captive-reared generation. Fish reared in a hatchery for two generations had around half the reproductive fitness of fish reared for a single generation. The effects appear to be genetic, and probably result from evolutionary pressures that quickly select for characteristics that are favored in the safe, placid world of the hatchery, but not in the comparatively hostile natural environment. The study, to be published Friday in the journal Science, raises serious questions about what happens to wild populations when they interbreed with hatchery fish, and the wisdom of many hatchery practices.

Julia Whitty is Mother Jones’ environmental correspondent. You can read from her new book, “The Fragile Edge,” and other writings, here.

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SIX TRUTHS

Reclaiming power from those who abuse it often starts with telling the truth. And in "This Is How Authoritarians Get Defeated," MoJo's Monika Bauerlein unpacks six truths to remember during the homestretch of an election where democracy, truth, and decency are on the line.

Truth #1: The chaos is the point.

Truth #2: Team Reality is bigger than it seems.

Truth #3: Facebook owns this.

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Truth #5: It's about minority rule.

Truth #6: The only thing that can save us is…us.

Please take a moment to see how all these truths add up, because what happens in the weeks and months ahead will reverberate for at least a generation and we better be prepared.

And if you think journalism like Mother Jones'—that calls it like it is, that will never acquiesce to power, that looks where others don't—can help guide us through this historic, high-stakes moment, and you're able to right now, please help us reach our $350,000 goal by October 31 with a donation today. It's all hands on deck for democracy.

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