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Thread: Weirs and Dams

  1. #11

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    Quote Originally Posted by Ian Alex View Post
    Do you know the reasoning behind this scheme, why do they want another weir ?
    Heritage apparently. Tourism somehow as well. They swear they will put a proper fish pass in place and have offered a fish counter as a juicy, and admittedly very tempting, bribe.

  2. #12
    Join Date
    Sep 2010
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    One of the challenges of putting in a fish counter is getting most of the fish close enough for it to "see". That's easier if you make the other possible routes impassable so a weir that's designed with a good fish pass should make installation of a counter easier. You do still need someone to cover the ongoing costs and put in the time involved running a counter.

    The big question is whether knowing how many fish you have is more important than allowing them unhindered passage. I've yet to come across a weir with a fish pass that doesn't hinder fish at some flows but there has to be a fighting chance that a weir designed from the outset with a pass will be better than retrofitting a pass to an existing weir.

  3. #13
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    Default Monks

    Quote Originally Posted by MCXFisher View Post
    Try removing one built by Cistercian monks in the 9th (?) century! The next one upstream is attached to a Grade 1 listed stately home. Now we will have to negotiate in minute detail with English Heritage on fish pass design, permissible materials and scheme of work, all greatly increasing the cost. Back to the fundraising
    Is that on one of our local rivers?
    "Don't hate the black, don't hate the white,if you get bitten just hate the bite"

  4. #14
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    Yes indeed, Kirkham Abbey on the Derwent.

  5. #15

    Default Weirs and Dams

    Quote Originally Posted by Loxie View Post
    Heritage apparently. Tourism somehow as well. They swear they will put a proper fish pass in place and have offered a fish counter as a juicy, and admittedly very tempting, bribe.

    Heritage.......I find that is a kind of unnecessary throwback. Well, I wish you well, if it goes ahead.
    The stream of consciousness is just looking for an ocean in which to open itself

  6. #16
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    Aug 2008
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    Yorkshire (were there a god it'd be god's own country)
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    Quote Originally Posted by NEbody View Post
    One of the challenges of putting in a fish counter is getting most of the fish close enough for it to "see". That's easier if you make the other possible routes impassable so a weir that's designed with a good fish pass should make installation of a counter easier. You do still need someone to cover the ongoing costs and put in the time involved running a counter.

    The big question is whether knowing how many fish you have is more important than allowing them unhindered passage. I've yet to come across a weir with a fish pass that doesn't hinder fish at some flows but there has to be a fighting chance that a weir designed from the outset with a pass will be better than retrofitting a pass to an existing weir.
    Good points. I think it was Walleye who previously posted this link to all manner of counting mechanisms including sonar.

    Technical, Logistical, and Economic Considerations for the Development and Implementation of a Scottish Salmon Counter Network: Scottish Marine and Freshwater Science Vol 7 No 2

    Lots are expensive and of course the ongoing monitoring is less than a priority for our cash-strapped Agencies under Austerity. All have their own issues. The main one IMHO is often that exploitation rates (ER) on escapement above the counter is not specifically recorded and have seen some hint that certain ER guesstimates don't factor in exploitation (and CLs don't consider spawning below) below the counter... Then there's all the QA/QC that isn't done...


    It's becoming crystal clear now that weirs can have such an adverse affect on down-migrating smolts, [(new hydro is a smolt shredder) which of course may not find any fish pass entrance in a flood] timing, physically and predation wise, that the stock standard may be to remove them as a matter of course. Legal challenge due here?

    Personally, I think it should be blindingly obvious that dam removal should be the preferred mechanism to aid passage, and where no counter exists, to take rod effort into consideration when assessing catches...

    But as ever, if you're not measuring them (nets and rods and counters) how do you know they're not there?* The best river data available has all three and the results there are a bit clearer than some dodgy over-abstracted over-anthropogenically degraded river on the edge of the salmon's range without two of the three.



    *Maybe we need to invent a "Twining Quotient"
    "...hooking mortality is higher than you'd expect: further evidence that as a numbers game, catch-and-release fishing isn't always as straightforward as it seems"
    John Gierach


    Fed up of debating C&R - see Hidden Content

    Unless otherwise stated, data used in any graph/figure/table are Crown copyright, used with the permission of MSS and/or EA and/or ICES. MSS / EA / ICES are not responsible for interpretation of these data by third parties

  7. #17
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    Quote Originally Posted by MCXFisher View Post
    Try removing one built by Cistercian monks in the 9th (?) century! The next one upstream is attached to a Grade 1 listed stately home. Now we will have to negotiate in minute detail with English Heritage on fish pass design, permissible materials and scheme of work, all greatly increasing the cost. Back to the fundraising
    Alternatively, you could go in early some morning with a JCB , make a few alterations and if anyone notices , just plead ignorance. That`s what a local "developer" did with some old buildings that were supposedly protected in the town I live in, many moons ago.The fine that was imposed on him was paltry compared to the money he made after supposedly putting things back together.
    You won`t catch anything if you don`t keep your bugs in the water!

  8. #18
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    Default Ignorance

    Ingonrance will get yer a hefty owld fine or maybe even prison......
    "Don't hate the black, don't hate the white,if you get bitten just hate the bite"

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