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Thread: fishing

  1. #1 fishing 
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    A recent study on the effects of human fishing activities and natural selection is most interesting.

    Human fishing is mostly aimed at large fish. This causes a selection for fish to stay smaller. After all, the big fish get fished out. Smaller

    The opposite selection pressure is present in the natural selection. Big fish get eaten less due to their size. Small fry is food for everything. Big fish eat other fish. A large fish can also produce more offspring.

    Hence there is a natural selection for fast growth aiming at a large sized fish quickly.

    The article in question examines both pressures on the evolution of pike to examine their recent history.

    in 1940s-60s the pressure of fishing was the overriding factor. Fish showed decreased somatic growth (the growth of their body).

    Then there was a phase of relaxed fishing. And the population bounced right back on the evolutionary path of increased size.

    However, it is never simple.

    However, our results point out that knowing the intensity and direction of artificial selection is not always enough to predict the response of populations to harvest. Instead, trait changes result from the combined forces of both the harvest and natural selection, and evolution of harvested populations is thus a process more complex than generally portrayed. Conservation plans that ignore this complexity could lead to improper management decisions.
    reference:
    http://www.pnas.org/cgi/content/abstract/104/40/15799

    Esox lucius


    "Kill them all and let God sort them out."

    - Arnaud Amalric

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  3. #2  
    Forum Professor sunshinewarrior's Avatar
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    Excellent stuff. Thanks for that. I remember reading somewhere that tuskless males are becoming more and more common amongst African elephants due to similar (poaching-related) pressures.


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  4. #3 Re: fishing 
    Time Lord zinjanthropos's Avatar
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    Quote Originally Posted by spuriousmonkey
    Esox lucius
    Too bad they never got smarter.
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
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