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Thread: Physiological response of smallmouth yellowfish to angling.

  1. #21
    Join Date
    Jul 2009
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    Work in Zambia... live in Notties, KZN Midlands.
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    Two weekends ago I was fly-fishing for both SM Yellows and Bass. What was very obvious was the difference in the time it takes for a SM Yellow to recover and a bass. Caught a good size SM yellow, did not play it long and released it under water using a barbless hook. The next cast I caught a decent size bass and was in two minds about killing it or not, gave it to my son who "tormented" it for the next hour. He built a small pond and left it there half covered while he looked for a better place. He then carried it for about two mins outside water dropped it a few times and then moved it from pool to pool like that for the next 50min. Finally I couldn't take watching the bass suffering anymore and released it. The next morning the first fish we hook was the bass, the SM yellow (had a mark on its side) cruised up and down for two days without looking at anything.
    "Ex Africa simper aliquid novi" - Pliny the Elder

  2. #22
    Join Date
    Sep 2007
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    Durbanville
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    Quote Originally Posted by JCD View Post
    I assume you mean "fail to see the point of using a stomach pump in any kind.." and not "I fail to see the point in any kind of fishing if you are practicing C&R"
    Yes indeed

  3. #23
    Join Date
    Sep 2007
    Location
    Durbanville
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    513

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    Quote Originally Posted by William Ewels View Post
    Unassailable logic!

    Next issue - what exactly are these "handling towels" being recommended? Texture/properties, cleaning, and research please?
    I'll clarify my point of view with a 40 page scientific dissertation...next time

  4. #24

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    Quote Originally Posted by Jean Bence View Post
    I'll clarify my point of view with a 40 page scientific dissertation...next time
    Exec summary will suffice thanks (Why is there no "cheekybugger" smilie on here?)
    The highest form of existence is play.

  5. #25
    Join Date
    Jan 2007
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    Azania
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    OK let me try and explain this.

    Yellowfish caught and released may die for various reasons. Apart from the fish getting injured the other cause as illustrated in the study relates to stress. Dying from stress relates to the fish trying to get away, what we call "fighting the fish" after being hooked. Internally, the effort by the fish causes an oxygen deficit in the tissues due to exertion. This forces the muscles of the yellowfish to function without any oxygen (anaerobically) which causes serious lactic acid build up in the muscle tissue, which diffuses into the blood. Lactic acid acts as an acid in the blood, causing the pH of the blood to drop. A slight change in pH can cause serious disruptions of the metabolic processes, resulting in released fish dying. The blood Ph of released fish normally returns to normal if the fish was not on the other end of your line for too long and released quickly as there was not a serious amount of lactic acid build up.

    Often releasing fish after a long battle we see them swimming away "strongly" - however, the imbalance in the blood chemistry may kill them days later. We often see this in released fish that hang around the edges or around your fishing area hours after being released.

    The study presented illustrated in Appendix A - Tips for sustainable catch, revive and release practices for yellowfish flyfishing in the Vaal river.

    Reviving Yellowfish
    "Help revive the fish. If a released fish do not swim away, hold it in a normal swimming position and gently move it back and forth in the water to move water over the gills and allow oxygen to enter its blood."

    Now from all the research that was done I ask the following: Is moving a fish "back and forth in the water" the right way to revive a fish?

    Have you ever seen a fish swimming backwards?

    Moving a fish back and forth, like so many of the Pro's show on TV and as proposed by the researchers of this study does not optimize oxygen uptake and can even be detrimental to recovery of the yellowfish! We all agree that for a yellowfish to efficiently transfer oxygen from the water to the blood stream, water must pass over the gill surfaces in a front-to-back direction, but this should happen in a natural way. Holding a fish steady allow the fish to naturally pulse the gills inducing flow over the gill surfaces.

    It would have been better if the researchers proposed that in effectively reviving a yellowfish the fish should be held steady and upright or alternatively gently move in an 'S' or 'figure 8 pattern. To propose moving the fish in a back-and-forth motion is ridiculous.

  6. Default

    Quote Originally Posted by William Ewels View Post
    Unassailable logic!

    Next issue - what exactly are these "handling towels" being recommended? Texture/properties, cleaning, and research please?
    I guess some thing like this is what they meant http://www.orvis.com/store/product.a...ubcat_id=15819

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