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Will climate change disorientate fish?

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Shanta Barley | 13:01 UK time, Monday, 20 July 2009

Humans are regularly lost at sea but what about fish? New research suggests that climate change could disorientate fish by enlarging their ear bones, which they use to navigate.

seabass.jpg

Previous studies found that seawater rich in carbon dioxide (CO2) shrinks the shells of corals and shellfish by reducing the availability of the bio-mineral aragonite, a form of calcium carbonate and key constituent of shells.

The ear bones (otoliths) of fish are made of aragonite, too. David Checkley at Scripps Institution of Oceanography and his colleagues therefore expected the otoliths of fish reared in CO2-rich seawater to shrink.

To their surprise, the opposite happened. The more carbon dioxide they added to the water, the larger the fishes ear bones grew.

Checkley's team reared the young of white sea bass in seawater containing three levels of CO2: low (380 uatm), medium (993 uatm) and high (2559 utam).

The medium concentration here is approximately 2.5 times the current CO2 concentration, and is likely to occur in the atmosphere by the year 2100, the study notes.

The weight of ear bones rose by 10-14% in fish reared at the medium concentration of CO2, and by as much as 26% at the highest level.

It is hard to overstate the importance of ear bones: when small but perfectly formed, in humans as in fish they help us navigate, stay upright and survive. And studies show that fish with asymmetrical ear bones have difficulty navigating and are less likely to survive than normal fish.

Will fish with larger ear bones suffer a similar fate? It's too soon to tell, but right now there's no conclusive evidence that fish with larger ear bones fare worse than normal fish.

Comments

  • 1. At 3:01pm on 20 Jul 2009, Gates wrote:

    Species already affected by climate change:
    Plankton

    Warmer-water plankton has moved further north by 600 miles, with a similar retreat of cold- water plankton.

    Fish

    Warm-water species such as tuna, stingrays and triggerfish have increased in the waters of southern Britain. Cold-water species have retracted north in some regions, such as the North Sea.

    Marine Mammals

    Experts suggest that they are no more vulnerable than other wildlife, but as top predators they will be affected by changes in the distribution of fish.

    Seabirds

    Climate change has been linked with the poor breeding success, reduced survival and population decline of the kittiwake. Warmer winters have probably affected its main source of food, sandeels. Sea-level rise may affect breeding sites for shoreline-nesting species such as terns.

    Intertidal Species

    Southern, warm water species on rocky shores have increased in abundance and range as temperatures have risen. The purple acorn barnacle, for example, has extended its range by 100 miles, while cold-water species such as the tortoiseshell limpet have decreased in numbers. Some new species are likely to become established, displacing existing organisms.

    Source:http://www.independent.co.uk/environment/climate-change/climate-change-already-affecting-uks-marine-life-426245.html

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  • 2. At 4:20pm on 20 Jul 2009, SheffTim wrote:

    Fish are odd in that only their ear bones (otoliths) are formed from calcite material (Most fish skeletal structure is formed from Phosphates, hence fishmeal is used as fertilizer.); fish will only be affected by any ocean acidification though dissolution of microscopic life at the bottom of the food chain having a knock-on effect upwards.

    These fish were only seven and eight days old when dissected, so the next stage is to let them grow to maturity and see if its affects their stability etc.

    Could these fish be taking CO2 directly from their bloodstream to form their ear bones, rather than relying on calcite minerals in the seawater?
    There is a relationship between the amount of CO2 and the size of the otolith in these fish:

    "The researchers began their experiment by incubating the eggs of White Sea bass in seawater that contained more than six times the normal amount of carbon dioxide. When the fish were between seven and eight days old, the scientists measured their otoliths and were met with quite a surprise.
    Contrary to the researchers assumptions, the young fish had otoliths that were 15 to 17 percent larger than normal. They repeated the experiment, only to receive the same results.

    The Scripps team then performed another experiment by reducing the carbon dioxide in the water to only 3.5 times the normal level. In contrast to the first experiments results, the otoliths in these fish were only 7 to 9 percent larger than normal."
    http://blog.biodata.com/2009/6/30/carbon-dioxide-affects-fish-ear-structure

    I think that's what they are getting at with: "We hypothesize that CO2 moves freely through the epithelium around the otoliths in young fish, accelerating otolith growth while the local pH is controlled."
    In other words the blood, or fluid in the ear, doesn't become acidic as it takes in CO2, only the seawater is.
    Any fish specialists in da house?

    Also
    http://www.sciencedaily.com/releases/2009/06/090625141450.htm

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  • 3. At 6:08pm on 20 Jul 2009, MangoChutney wrote:

    Given the rise in CO2 to the level suggested wouldn't happen overnight, surely the fish would evolve with any rise in CO2 level, and wouldn't evolution mitigate the problem?

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  • 4. At 6:55pm on 20 Jul 2009, MangoChutney wrote:

    @gates23

    you should add these examples of climate change do not prove or disprove the existance of AGW

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  • 5. At 6:58pm on 20 Jul 2009, U13900240 wrote:

    " and wouldn't evolution mitigate the problem?"

    How quickly do you think things evolve???

    http://en.wikipedia.org/wiki/Timeline_of_evolution
    http://www.ecotao.com/holism/bp.htm

    The answer would be "no".

    The only upside would be all the other fishes would be in the same boat and the huge reduction of population from the changes would help defensive organisms better than aggressive ones.

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  • 6. At 7:06pm on 20 Jul 2009, shantabarley wrote:

    One thing to make clear is that the medium concentration experienced by the fish is likely to occur by 2100 in the atmosphere, not the ocean.

    That said, the ocean does soak up a lot of the CO2 humans add to the atmosphere, according to the study: 'a large fraction (0.3 to 0.5) of the CO2 added to the atmosphere by human burning of fossil fuels enters the ocean'

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  • 7. At 7:07pm on 20 Jul 2009, U13900240 wrote:

    "In other words the blood, or fluid in the ear, doesn't become acidic as it takes in CO2, only the seawater is."

    I don't know about fish ears but ours lets quite a bit of water leech in. And some significant number have perforations that leave bubble trails when they go underwater.

    Remember: in no animal are the ear bones so deep inside that they are protected from all outside interference by, for example, blood.

    Some links may help. Don't know how useful, but they should give you a "feel" for it.

    http://news.nationalgeographic.com/news/2002/12/1209_021209_TVFishEarBones.html
    http://www.life.umd.edu/biology/popperlab/background/anatomy.htm
    [Unsuitable/Broken URL removed by Moderator]

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  • 8. At 7:22pm on 20 Jul 2009, U13900240 wrote:

    "you should add these examples of climate change do not prove or disprove the existance of AGW "

    Why?

    They are part of the evidence. That they are consistent with observations is perfectly acceptable truth.

    Tell me, have you ever seen gravity?

    No.

    But you can see the RESULT of it.

    The apple falling from the tree proves gravity since if it didn't exist, the apple wouldn't have wanted to fall down. It may have gone to Skegness.

    So these ARE proofs of AGW.

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  • 9. At 7:35pm on 20 Jul 2009, U13900240 wrote:

    Chutney, what on EARTH was wrong with that post #7?

    Did it make you weep 'cos I wasn't saying you're right, it'll be A-OK 'cos evolution will kick in to overdrive???

    No. Fish do not evolve that quickly.

    They may on your planet, but not on this one.

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  • 10. At 9:53pm on 20 Jul 2009, Jack Hughes wrote:

    This is the money quote:

    "To their surprise, the opposite happened."

    And this is in their own field of study: fishbones. Their projections and assumptions were completely wrong.

    The rest of the piece is a farrago of assumptions, projections, and chicken-little stuff from outside their area. But it gets presented as established fact.

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  • 11. At 10:08pm on 20 Jul 2009, U13900240 wrote:

    Strange.

    Everything he accuses others of seem to be in the very same post he accuses with.

    He assumes that projection is invalid. He chicken-littles his way to his parrot meme: "it's not happening, it's not happening".

    And places his post as if it was self-evidently true.

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  • 12. At 11:02pm on 20 Jul 2009, LarryKealey wrote:



    If I read the article correctly, particulary the last line - we get "this might be bad - but we don't know".

    We do know that decimating entire species and collapsing fisheries are bad. Why not focus our efforts where we can have a real impact - close fisheries for 5-10 years, allow species and the food chain to recover. In ten years time - after no fishing in areas, we could obtain sustainable yields many times the unsustainable yields we get today.

    The US has made great strides in better management of our fisheries - its too bad the rest of the world lags behind. We need international agreements, rigorously enforced to protect the seas (Headline: US Navy & Royal Navy uses illegal fishing trawlers for target practice...LOL).

    #1 - By the way, Tuna are found in all the oceans and seas of the world - including those around Britain - unfortunately, they are being decimated.

    Many species of marine life migrate - they care not for "international boundries", yet they are in dire need of our protection. Imagine a world where we have restored fisheries to the levels of 3-400 years ago. We could take a sustainable yield many times greater than the (unsustainable) yield we get today. We could also do it in an economically attractive fashion...without a lot of pain.

    Oh, but who am I kidding? Its all about greed and the "quick buck" - like windmills...(where is Don Quixoti when you really need him?)

    Cheers.

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  • 13. At 06:59am on 21 Jul 2009, MangoChutney wrote:

    @yeah_whatever

    1 Evolution doesn't happen in all species at the same rate, nor at the same rate within the same species. For example, it has been shown that the Galapagos finches beaks evolved to be larger in times of food shortage and smaller in times of abundance. Food shortages, what does that tell you?

    2 This is not evidence of AGW. All you can say, based on the studies, is climate change has changed the pattern of the marine life studied. There is no evidence to support the conclusion that this is man made. To assert otherwise is disingenuous at best and deliberate lies at worse.

    3 I did not have your post removed - pleases check with the mods

    4 I am not going to be drawn into further discussion by you, until you apologise for lying on a previous thread

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  • 14. At 08:53am on 21 Jul 2009, U13900240 wrote:

    "1 Evolution doesn't happen in all species at the same rate, nor at the same rate within the same species. "

    It doesn't happen that fast in ANY fish.

    "2 This is not evidence of AGW"

    Yes it is.

    "There is no evidence to support the conclusion that this is man made"

    This is evidence of climate change and change still ongoing. Just like CO2 increases is ongoing.

    If your WAG that Spencer's graph showed we were back to the beginning again now, these species would be back at their original haunts.

    That they aren't shows that there is still genuine warming.

    And CO2 is the only thing that has changed with a profile that keeps up with the changes in the species.

    And you're the lying sack.

    "I don't use one month's data to determine a trend. And here's a graph where the one month figure shows the trend is back to normal" ring a bell?

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  • 15. At 10:39am on 21 Jul 2009, U13900240 wrote:

    "In other words the blood, or fluid in the ear, doesn't become acidic as it takes in CO2, only the seawater is."

    I don't know about fish ears but ours lets quite a bit of water leech in. And some significant number have perforations that leave bubble trails when they go underwater.

    Remember: in no animal are the ear bones so deep inside that they are protected from all outside interference by, for example, blood.

    Some links may help. Don't know how useful, but they should give you a "feel" for it.

    http://news.nationalgeographic.com/news/2002/12/1209_021209_TVFishEarBones.html
    http://www.life.umd.edu/biology/popperlab/background/anatomy.htm

    Another link to a PDF was killed and the post rejected.

    Yet there have been PLENTY of PDF's posted here.

    http://www.bbc.co.uk/blogs/climatechange/2009/07/anyone_seen_the_front_page.html#P83109717

    for example.

    Moderators, what are you on?

    And what's wrong with PDF? It's part of the HTML5 SPECIFICATION.

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  • 16. At 1:33pm on 21 Jul 2009, MangoChutney wrote:

    fish evolution rates:

    http://www.underwatertimes.com/news.php?article_id=17561029308

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  • 17. At 1:53pm on 21 Jul 2009, U13900240 wrote:

    "low-predation environment above the barrier waterfall had adapted to their new environment by producing larger and fewer offspring with each reproductive cycle."

    Any genetic change?

    No.

    This is adaption, not evolution.

    Humans are becoming sexually mature younger now. Not because of any genetic change but that the regulation of the bilogical clock remains unchanged and its "tick" is based on the nutrition of the growing human. If there's more food, it can reproduce earlier to take advantage of the food glut.

    A starving child will mature sexually much later than normal.

    No evolution.

    No genetic adaption.

    If the fish are moved back in to a poor environment, they will not die out because they aren't adapted to a niche environment.

    See the Panda vs other Bears.

    The Panda has adapted to the bamboo diet and cannot live without it. Bears cannot live off bamboo, but are generalists and adapt to many places. Not by evolving, but by being able to exploit it as they are.

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  • 18. At 1:54pm on 21 Jul 2009, U13900240 wrote:

    PS if you think that dressing down was bad, try taking that to a Christian Fundie site where they are saying there is no evolution and evolution needs to be proven to happen.

    Pop that link in there and call it proof.

    See how much nicer scientists are, even ones you despise?

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  • 19. At 2:11pm on 21 Jul 2009, MangoChutney wrote:

    "microevolution, which is smaller evolutionary changes, such as adaptations, within a species or population"

    http://en.wikipedia.org/wiki/Evolution

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  • 20. At 2:26pm on 21 Jul 2009, U13900240 wrote:

    "microevolution, which is smaller evolutionary changes, such as adaptations, within a species or population"

    Ah, well with THAT you'll get accepted on an ID site.

    But the link you point to isn't evolution.

    Where's the evolutionary change?

    Or do we evolve when summer turns up and we experience more heat?

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  • 21. At 5:41pm on 21 Jul 2009, MangoChutney wrote:

    i would suggest that readers draw their own conclusions

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  • 22. At 5:55pm on 21 Jul 2009, U13900240 wrote:

    Good advice.

    Doesn't help though when you repeat the same refuted arguments over and over again.


    Like repeats of "CO2 can't be warming because it is saturated".

    Which rather goes against the other common denialist: "H2O is far more potent". After all, that's also saturated. Therefore H2O cannot cause warming if CO2 cannot cause warming from saturation of absorption.

    the climate scientists know what they are talking about.

    Talking heads like CT, Laz, Jack and yourself do not, since you work at cross-purposes.

    Heck, Jack recently said that science of Ohms Law was 100% proven. Yet Larry says that science can never be proven, only disproven.

    Yet neither of you point this discrepancy out. You have different hypotheses but consider yourselves on the same side because you're not FOR your hypothesis, you're AGAINST the theory of AGW.

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