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  1. #1
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    Default Global warming and fish size.

    I seem to remember a long time ago reading that tench had increased in size due to a longer feeding period and more food availability down to longer hotter summers. My vague minds eye impression is that coarse species have got bigger in my lifetime although, possibly not more numerous. I seem to read about more 10lb, 12lb even 16lb + more barbel than I ever did. Roach seem to be fairly common over a 1lb than I ever remember. Big dace and perch, not as uncommon as they once were. I think the record bream is topped by 20lb+ fish, I would never had thought that possible once upon a time.
    I don't have any facts just my general impression, if I am right and this is down to global warming, what happens when it all stops and goes into reverse, will it get colder and this trend will be reversed, will we be wondering one day where all the big fish have gone.

  2. #2
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    Default Re: Global warming and fish size.

    Quote Originally Posted by markg View Post
    will it get colder and this trend will be reversed, will we be wondering one day where all the big fish have gone.
    We will probably be blaming (rightly or wrongly) the lack of big fish on the Otters

    Keith
    Happiness is fish shaped (It used to be woman shaped but the wife is getting on a bit now)

  3. #3

    Default Re: Global warming and fish size.

    Markg, re your post. I suppose if with global warming there is a longer feeding period then lots of species should grow bigger. However, I now catch fewer 1lb plus roach than 30 years ago but perch are much bigger.

  4. #4
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    Default Re: Global warming and fish size.

    Quote Originally Posted by peterjg View Post
    Markg, re your post. I suppose if with global warming there is a longer feeding period then lots of species should grow bigger. However, I now catch fewer 1lb plus roach than 30 years ago but perch are much bigger.
    I know it may be taking our climate change a little too far but have you thought that as the water temperatures start to get higher and higher the less oxygen it will hold (fact) and the less oxygen there is in the water the less the fish would probably feel like feeding and therefore not putting on as much weight?

    Plus the low levels in our rivers and stillwaters could become more of a permanent feature in a warmer climate and that can’t be a plus factor either.

    How many times have you fished during a heatwave where the only thing that seems to move in the constant heat are fish basking and gasping for air?

    And the reason that the Perch seem to be getting larger could possibly be because it’s prey is becoming a little more lethargic during the hotter days and becoming a little easier to catch in the sweltering heat?

    Climate change may not all be plusses.

    Just a thought.
    Last edited by Keith M; 05-12-2018 at 21:01.
    Happiness is fish shaped (It used to be woman shaped but the wife is getting on a bit now)

  5. #5
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    Default Re: Global warming and fish size.

    Lots of variables in this. Fish bigger by eating crays? Some species getting bigger as stated having longer feeding seasons? We may be catching up to what the more southern European countries were 30 years ago with regard to carp. More 1lb roach that in reality are mainly from commercials with plenty of grub going in?
    I just wish I had another 70 years to see it through!

  6. #6
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    Default Re: Global warming and fish size.

    The biggest factor I see, at least in the less managed fisheries, is the lower heads of fish being a contributing factor. A distinct lack of smaller fish, or gaps in year classes, allows existing fish to get bigger than they might otherwise. The snag with this is that once the big fish die off, you aren't left with a great deal. The monster Great Ouse barbel would be a fine example.

  7. #7
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    Default Re: Global warming and fish size.

    Thanks for the replies, I like to just ask what others think sometimes. All these climate change announcements lately just got me thinking about what happens after if the desired effect is achieved. No one ever seems to talk about that. I quite understand why we don't want it to get any hotter but do we want it to get colder. I take into account there are many reasons why fish may have got bigger but, at least part of that may have had something to do with since warming began especially in the last 50 years or so. If green house gas levels are reduced to the same levels as circa 50 years ago are we going to get the same weather of 50 years ago IE winters of 63 and 47. And how is the flora and fauna going to cope with that after it has adjusted itself to present climate conditions. In the case of fish it must have some affect if bigger sizes has at least in part been due to longer hotter summers. If zero emissions is achieved is the world going to become extremely cold?
    There doesn't seem to be any plan, talk, or any thought into how much green house gas should be reduced by and what it will lead to; the affect it will have on our lives, economies and flora and fauna.
    Last edited by markg; 06-12-2018 at 06:48.

  8. #8
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    Default Re: Global warming and fish size.

    Quote Originally Posted by markg View Post
    Thanks for the replies, I like to just ask what others think sometimes. All these climate change announcements lately just got me thinking about what happens after if the desired effect is achieved. No one ever seems to talk about that. I quite understand why we don't want it to get any hotter but do we want it to get colder. I take into account there are many reasons why fish may have got bigger but, at least part of that may have had something to do with since warming began especially in the last 50 years or so. If green house gas levels are reduced to the same levels as circa 50 years ago are we going to get the same weather of 50 years ago IE winters of 63 and 47. And how is the flora and fauna going to cope with that after it has adjusted itself to present climate conditions. In the case of fish it must have some affect if bigger sizes has at least in part been due to longer hotter summers. If zero emissions is achieved is the world going to become extremely cold?
    There doesn't seem to be any plan, talk, or any thought into how much green house gas should be reduced by and what it will lead to; the affect it will have on our lives, economies and flora and fauna
    .
    There have always been natural fires and volcanoes since the year dot which until now haven’t been a real problem; and there are still going to be natural fires and a few people living in remote places burning natural fuels like wood & coal etc. so I can’t see zero emissions ever happening realistically; although getting as far down in emissions that we can; without any unnecessary adding to it; can’t be a bad thing surely our Ice Caps might start to return, and climate changes might slow down, and the hole in our ozone layer may reduce or close up again.

    Whether our coarse fish would get smaller or not wouldn’t be a real issue as most of our larger fish would be lying on the bank with their eyes and throats eaten out by predators that us humans had decided to re-introduce well before then

    Keith
    Happiness is fish shaped (It used to be woman shaped but the wife is getting on a bit now)

  9. #9

    Default Re: Global warming and fish size.

    As a few have suggested I dont equate warmer tempreture automatically to increased fish size. In some cases I would expect the opposite to happen. Also with warmer tempreatures we would see other species begin to populate and perhaps impact some of the species we have now. Two examples I would expect to see more of if tempreatures went up would be Black bass and Catfish as well as explosions of fry leading to stunted stock on some waters.

    Obviously its a complex thing with allot of variables but higher temps dont always mean bigger fish imo.

  10. #10

    Default Re: Global warming and fish size.

    OK Tench got bigger with the large gravel pits and the high protein bait carp fishermen was spodding in and Roach for my money have shrunk, certainly in my local rivers anyway.

    I'm just going to chuck a question out because why not eh? Have fish got bigger or are we just better at catching larger fish due to technology advancements?
    The world is full of kings and queens who blind your eyes and steal your dreams!

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