Claim: Warmer waters from climate change will leave fish shrinking, gasping for air

From the UNIVERSITY OF BRITISH COLUMBIA and the fishy science department…

Fish are expected to shrink in size by 20 to 30 per cent if ocean temperatures continue to climb due to climate change.

A new study by researchers at the University of British Columbia provides a deeper explanation of why fish are expected to decline in size.

“Fish, as cold-blooded animals, cannot regulate their own body temperatures. When their waters get warmer, their metabolism accelerates and they need more oxygen to sustain their body functions,” said William Cheung, co-author of the study, associate professor at the Institute for the Ocean and Fisheries and director of science for the Nippon Foundation-UBC Nereus Program. “There is a point where the gills cannot supply enough oxygen for a larger body, so the fish just stops growing larger.”

This is an infographic. CREDIT Lindsay Lafreniere

Daniel Pauly, the study’s lead author and principal investigator of the Sea Around Us at the Institute for the Ocean and Fisheries, explains that as fish grow into adulthood their demand for oxygen increases because their body mass becomes larger. However, the surface area of the gills — where oxygen is obtained — does not grow at the same pace as the rest of the body. He calls this set of principles that explains why fish are expected to shrink “gill-oxygen limitation theory.”

For example, as a fish like cod increases its weight by 100 per cent, its gills only grow by 80 per cent or less. When understood in the context of climate change, this biological rule reinforces the prediction that fish will shrink and will be even smaller than thought in previous studies.

Warmer waters increase fish’s need for oxygen but climate change will result in less oxygen in the oceans. This means that gills have less oxygen to supply to a body that already grows faster than them. The researchers say this forces fish to stop growing at a smaller size to be able to fulfill their needs with the little oxygen available to them.

Some species may be more affected by this combination of factors. Tuna, which are fast moving and require more energy and oxygen, may shrink even more when temperatures increase.

Smaller fish will have an impact on fisheries production as well as the interaction between organisms in the ecosystems.

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Pauly and Cheung’s study “Sound physiological knowledge and principles in modeling shrinking fishes under climate change” was published in Global Change Biology doi: 10.1111/gcb.13831.

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139 thoughts on “Claim: Warmer waters from climate change will leave fish shrinking, gasping for air

  1. You know, it’s really weird – I live in the UK where some of the largest fish I’ve ever caught (carp) in this country live in the warmest and most oxygen-light waters. Also, I’ve just had a holiday in Tobago and caught some of the biggest fish I’ve caught in my entire life – but the sea water is considerably warmer (err, and we are not just talking about 1C here) than off the UK.
    I just must have been imaging it all. Wake me up please someone.

    • Ian

      I live on the south coast of England and our local tourist board would like to point out that there is no measurable difference between the warmth of the waters off Torquay and that of Tobago. None. Fact.

      Just off to have a dip. Hope I don’t scald myself.

      tonyb

      • Someone should tell those Whalesharks in the Caribbean that the water’s 80F and they are not allowed to grow so big

    • Couldn’t agree more – warmer waters typically produce larger fish as well as an abundance of small fish species, albeit shorter lived than very cold water fish which grow more slowly and tend to live much longer.

      Perhaps it might have been helpful if these ‘researchers’ got away from their models and theories and had a look at the real world.

      Mind you they could have spoken to a few fishermen or even checked reference books for fish sizes around the world …. but then I suppose there wouldn’t have been any AGW money for that.

      • they also dropped a bollock by using cod as an example . arctic cod are the slowest growing of the species ,mature at smaller size and don’t reach the sizes cod in warmer waters do. irish sea cod fastest growing of all cod populations . the large cod of the barents and norwegian seas do not seem to have a problem breathing or growing even when over 40 kg.

        the main thing that appears to have been overlooked is that most marine species have the ability to move to where conditions suit them best. the northward migration of the velvet swimming crab in the mid 90,s and the ongoing northward migrations of european sea bass are but two examples.

    • “When understood in the context of climate change”………..

      This is so open ended with these clowns…..what do they consider “climate change”?
      …..1 degree? or a 100 degrees?

    • “Fish, as cold-blooded animals, cannot regulate their own body temperatures. When their waters get warmer, their metabolism accelerates and they need more oxygen to sustain their body functions,”

      Dollars to donuts these poor hot fish head to deep waters to ‘cool’ down…but that’s just what my modelling reveals to me.

      • Luckily these fish are smarter than the Average UBC fishy science department members. They also went to school and learned –
        Thermocline – is a layer within a body of water or air where the temperature changes rapidly with depth. Because water is not perfectly transparent, almost all sunlight is absorbed in the surface layer, which heats up. Wind and waves circulate the water in the surface layer, distributing heat within it somewhat, and the temperature may be quite uniform for the first few hundred feet. Below this mixed layer, however, the temperature drops very rapidly—perhaps as much as 20 degrees Celsius with an additional 150 m (500 ft) of depth. This area of rapid transition is the thermocline. Below the thermocline, the temperature continues to drop with depth, but far more gradually.

        Who has the Best School, I go with the fish.

    • “However, the surface area of the gills — where oxygen is obtained — does not grow at the same pace as the rest of the body.”

      They forget that there are other metabolic functions that might not require that the gills grow as much as expected. Remember, we have “scientists” assuming that gills should be a certain size. Fish have evolved their organs together and there is not reason to think that they would short-change themselves with undersized gills. Once again, the scientists display their bias and then blame the world for it not agreeing.

  2. I wonder how big fish were in the MWP?

    Any mention of having studied fish during a known warm period in the not too distant past in this paper?

    I’m no scholar but that would have been the first test of my hypothesis.

    • I know that last time I visited a trout farm, that the farmer was complaining about the water being too warm, so they haven’t had a good yield that year.

      According to one site:
      “Brown Trout find very comfortable temperatures between 12 and 20 Degrees Celsius and often feed best at the top end of this range for brook and rainbow trout is several degrees less. Trout can live for only limited periods in water temperature of 28 degrees. They can tolerate without problems temperatures just above freezing to lengthy periods up to 24 degrees, so long as temperature changes slowly.”

      So for some species of fish (even different among Trout varieties), the heat/oxygen effect is a big deal (eg, Trout farms oxygenate the water by churning it, or pumping air into it… fish tanks have air pumps, etc).

      I don’t know if climate change will be big enough to make enough of a difference to the fish – and I can’t read the study to see if they proved anything either… But to some degree the effect is plausible.

      • I worked on a very large trout farm for a number of years. We did daily recording of O2, CO2 and temp and believe me, warm days were killers for rainbow trout as oxygen levels plummeted. But this was in South West, Western Australia with a vast series of tanks fed from a still water dam. Summer temperatures got into the 40C range, water temps went up fast and to be honest, trout was a stupid choice of fish for the conditions they were expected to face.. these are cold water fish who are notorious for suffering in warm water – the feeder dam (brown water) lay in the sun, the pipework lay in the sun and there was nothing stabilizing the temperatures at all. I suspected if we’d been able to maintain a close temperature range (even a warmer one) the fish could have adapted to the warmer temps by possibly growing more branched gills to gather more O2 but I never got to test that theory.

        But we got around it nonetheless, by cascading the flow of water into the tanks and on really hot days, by firing up 3 phase floating impeller pumps which blew the water into the air force aerating it.

        We had to do this because it was a closed system. Like any pond prone to drying up, like any shallow lake – if the fish cannot move they risk the environment changing and becoming hostile.

        These same fish thrived in local waterways and grew far larger, far quicker than in our tanks as they were free to move up and down the river to deeper more oxygenated water and we never even heard of wild swimming fish dying from heat stress – that only happened in billabongs or in restricted fish farms.

        However I am reminded of a massive fish kill event in WA that affected almost all the waterways – the one that occurred when green groups pushed through a ban on duck shooting against the advice of shooters who’d been force stocking lakes and streams for decades – they warned that without a population reduction the artificially heightened populations would remain on the waters through the hot summer ahead and would pollute the water with their crap and it would be a disaster. Guess what happened? Yup.. and entire populations of the rare native fish species were wiped out, rare tortoises were locally taken to extinction and hundreds of thousands of birds and fish died to botulism. Force aerators were installed that ran for over a decade in the aftermath of that to try to resurrect the destroyed waters. It was not a particularly hot summer, there was nothing out of the ordinary – it was just know-all green tampering and the law of unintended consequences that led to the most appalling destruction of the local ecosystem we’ve ever witnessed. the upside was it turned me from the greens, more so when the whole event was written from the record and the duck shoot ban declared a success.

        I have no doubt in a warming world (should that ever come to pass) that the fish will display intelligence beyond that of researchers and they’ll merely alter their range and habits to adapt.

      • Quoting the study verbiage:

        Fish, as cold-blooded animals, cannot regulate their own body temperatures. When their waters get warmer, their metabolism accelerates and they need more oxygen

        WOW, someone explain to me why warmer water causes one’s metabolism to accelerate, ……. biologically speaking that is.

        Me thinks the actual problem is, ……. the warmer the water, the less dissolved oxygen there is.

        Warmer water is usually “slower” moving and thus less likely of being oxygenated.

      • There are warm are fish and cold water fish. For example trout and salmon are cold water fish; catfish and crappie are warm water fish (these are freshwater examples). I don’t see any examples of temperature change in the article. How long before an expected 2 degree change in water temp? Typically fish respond to temperature change in the water by altering the depth they spend time at. They also shift their spawning/feeding grounds.

        The paper isn’t suggesting that threw are no large fish in tropical waters is it?

        Once again some scientist is claiming that there will be no shift in the behavior of species due to a shift in natural conditions. Ludicrous..

      • “Karl August 22, 2017 at 1:19 am
        …and to be honest, trout was a stupid choice of fish for the conditions they were expected to face.. these are cold water fish who are notorious for suffering in warm water”

        That says it all.
        Raising creatures adapted to moving cold oxygenated water in low water movement warm low oxygen conditions takes the kind of brains that produced the alleged research.
        As Ron White love to say, “You can’t fix stupid”.

        Early this summer, I watched a large rainbow trout idly swimming in what is considered a warm water river, The Rappahannock River in Virginia. beautiful fish, beautiful day, beautiful location; and me without my fly rod.
        That trout was feeding in a slow river eddy located very close to a shady cold water inlet. Fish, including trout or the study’s codfish, easily move to preferred water temperatures. Often just by moving from sunny spots to shady stream banks.

        I’ve caught trout in other “too warm for trout” streams and rivers by fishing deep pools or smack up against and under river banks during hot weather.

        Why didn’t the fish farm raise a warm water species? Carp, Largemouth bass, snakeheads or perhaps a native warm water Australian fish?

      • ATheoK sensibly asked “Why didn’t the fish farm raise a warm water species? Carp, Largemouth bass, snakeheads or perhaps a native warm water Australian fish?”

        The guy who owned it wanted trout. He also wanted to run Angora goats in sheep-fenced paddocks so it was no surprise his stock dropped to zero day one when they discovered the State Forest next door. He was a nice guy but both wealthy and stubborn so trout it was.. I kind of admired him but yes, trout was a less than brilliant idea. Even more amusing was that the tanks were designed for catfish – you know, you open a sluice and all the water and catfish spill out. Kinda difficult with trout – opening a sluice was guaranteed to ensure all the fish swam like mad into emptying tanks, leaving them flapping about on the floor. I didn’t last there too long, my big mouth and I were invited to leave within the year.

    • hotscot

      there are landed fish records for Plymouth that go back to the 12th century. We know that the distribution of fish species then was similar to today. Weights are recorded but I have never studied them.
      tonyb

      • uk saltwater species movements alter in line with the amo tony. species like atlantic cod and bass are near the extremes of their range ,currently bass as are far north as most anglers and commercials can remember and the english channel cod population appears to be at a low for the last 60 years or so.

        as the amo continues the decline into the cool phase these will reverse. the signs are there already with a huge increase in recruitment for many species the last few years. i have been trying to find recent data from the continuous plankton recorder but it appears i would have to purchase it. the key species of plankton for gadoid species recruitment is calanus finmarchicus and the last two years would suggest this species is reappearing in large numbers over much of the spring as recruitment is high over the batch sizes from individual spawnings. this can only happen with sustained levels of the correct plankton as the larva need to switch on to them within hours of the egg sack being consumed.

        this species of plankton saw a huge drop in the climb to the peak of the amo and is largely responsible for the decline in recruitment of the major species around the uk at the end of the gadoid outburst. sustained levels of commercial fishing coupled with the disaster that is the common fisheries policy during this period resulted in major stock declines.

        thankfully all is heading in the right direction now. the prey fish species like herring, sprat etc are the key indicators and currently numbers are sky rocketing , so much so we have a humpback whale in montrose bay feeding on sprat and a commercial boat had to be towed in after the water intake for the cooling system became blocked by sprats and the engine overheated. all up and down the coast along the shoreline the water is also thick with herring fry. fantastic to watch this happening from the point of view of a recreational angler that has fished through the bad times .

    • @ CommonA & Karl

      Good points – and particularly Karl’s about the trout in the rivers next to the trout farm growing faster and larger than those in the ‘stew ponds’.

      Trout are native to fast flowing, cold and highly oxygenated water – they are out of their element in trout farms and trout fishing lakes where the still, and often shallow waters, mean that oxygen levels are much lower than their natural environment.

      That is compounded by the fact that the shallower, still water heats up considerably in summer meaning oxygen levels are far lower as cold water alllows far more O2 (and CO2) to dissolve in it than warm water does.

      Rainbows seem farm more able to cope with being kept in trout lakes than Brownies which do badly in the absence of fast flowing cold water.

      • That’s a possibility, but what was the average size of humans back then? You have to take the reduced size of humans into account for depictions in mosaics.

  3. This makes sense as warmer water contains less oxygen than cold water. That’s why all the giant marlin and swordfish and great white sharks are caught in the arctic.

    Oh wait…

    • Great White sharks do quite well in cool waters — e.g. off the coast of California. But lamnid sharks (Great Whie, Mako, “Salmon sharks”) aren’t actually cold blooded. Neither are Tuna.incidentally.

      I should think that as waters warm, fish populations will migrate poleward a bit. But marine water temperatures seem to be as much controlled by currents as by air temps. Miocene and Eocene marine faunal mixes along the US East and West coasts don’t seem dramatically different from the current faunas. Perhaps a bit more tropical, but nothing all that dramatic. Based on fossil teeth, the sharks back then seem to have been — if anything — larger than today. But that could be sampling bias of one sort or another.

      • I should think that as waters warm, fish populations will migrate poleward a bit.

        Most every fish species are predators …. and being mobile predators, they will migrate to wherever their prey animals are the most plentiful. Be it northward to the cold Arctic waters, ……. or southward to the cold Southern Ocean, …….. or up the warm Amazon River basin during its yearly “flooding”.

        The larger predator fish will follow the smaller “spawning” prey fish to just about anywhere they congregate in sufficient numbers.

        And that is why this predator is named …… “The salmon shark (Lamna ditropis) is a species of mackerel shark found in the northern Pacific ocean. As an apex predator, the salmon shark feeds on salmon,

  4. But then, in recent years, global seas have actually been getting cooler. Perhaps we will have bigger fish soon?

  5. As I noted in another thread some of the biggest fish, Marlin, swin, eat, spawn in tropical waters, ie, warm! Fish have managed quite nicely for millions of years with fluctuating CO2 levels and warm waters. More fake news. I hope Trump follows through. The lame stream media here in Aus continually slates him and his admin, accoring to them he’s out the door. Please Prs. Trump keep it up. Drain the swamp, set an example for the other countries to follow.

    • Smaller fish will have an impact

      Above is missing the weasel word. But it is also BS. There will be no smaller fish due to AGW. And I’m quite sure people will laugh at these papers later on, and wonder why they got published in the first place.

      • The word ‘impact’ is also a weasel word. As it’s not definitely quantified, an impact can have a low energy photon on a surface, or a supernova close to a planet. The same word for both… as for the small fish (compared with the big ones), they already have an impact. Anything in the system can be said to have an ‘impact’. Stupid weasel pseudo science.

  6. How to thrive as an academic in the 21st century:
    1. Decide upon the desired politically correct conclusion for your thesis
    2. Make the story fit the agreed conclusion.
    Scientific method entirely optional.

    • Exactly Asp!

      This alleged research is another climastrologist aided and abetted example of “confirmation bias”, cherry pick subjects, gross assumptions and as you point out; preconceived results.

      Bafflegab and sciencey phrases while hoping no one notices incorrect assumptions, obvious conflation and then claiming a “model” produced the results.

  7. Models again.
    When I was younger, I was an advisor to what was then the biggest LNG plant in the world. The big refrigeration compressors produce a LOT of heat, and it was dumped in the harbour. I understand that temperatures went up a couple of degrees. The result was more fish, bigger fish and lots of coral etc.
    As an aside, the local fishermen were indentured labor. The multinational I worked for wanted to buy them out of there slavery. The Left in the USA fought very hard to stop this, going straight to the (Republican) President. The fishermen then overfished the waters with consequences, and the multinational was forced to compensate the fisherman’s owner.
    I now live next to a new LNG plant in my home country. Fish numbers are exploding. There is coral growing the the harbour’s muddy estuary! Bird numbers are exploding. And the Left are telling everyone it’s a disaster again.

    • As a young lad in the 70’s I was taken to visit Hunterston nuclear power station on the west coast of Scotland.

      Warm water from the station was pumped into the Firth of Clyde and the immediate area surrounding the exhaust was teeming with enormous fish. So much so that the station had observation tanks the fish could freely traverse.

      Fish will travel to areas best for them. With warming seas I would expect the type of fish seen in a given area to change over time, but expecting fish to hang around whilst they shrink is just idiotic.

      • The warm waters surrounding the cooling water outlets at the Sizewell power stations on the Suffolk coast are a big draw for the local fish and thus for the local fishermen.

        Many years ago I remember visiting Barrow docks where nuclear submarines tied up and continued to dump excess heat into the water. The docks were teeming with massive fish. It was just like a fish farm.

    • Question: Doesn’t cooling involve drawing in fresh water to cool the exhaust & a subsequent discharge back relatively lower in CO2? If this (simplified) dynamic occurs then the exposed fish would be in an oxygen enriched environment & this over comes physiological growth limitations otherwise driven by temperature (ie: synthesis & degradation rate of mitochondrial proteins as relates to aerobic ATP production, composition of membranes, status of phosphorylations, etc.).

      • The level of CO2 in the water is not an issue and neither the article nor any of the responses address CO2 levels directly. CO2 levels also do not effect O2 levels.

        The issue under discussion is that warmer water is less able to dissolve O2, so O2 levels are lower in warmer waters. However, WRT warm water discharges from power plants, etc., the intake water was already oxygenated. Now the question becomes: How quickly is the oxygen outgassed? Perhaps the discharge water is in a supersaturated state, making O2 uptake by fish gills more efficient than normal.

        SR

  8. Somewhere there’s a website – numberwatch/climate? – with 833 silly scare stories. Now we have 834. The best is the increase in UFO sightings – aliens are concerned about our planet

  9. If they don’t like the temperature won’t they just either shift towards the equator or swim slightly closer to the surface?

    • That wasn’t mentioned as being part of the model. The researchers modelled two factors—water temperature and gill size, then drew a conclusion. If one ignores all but a couple of factors, the result is really quite useless.

  10. When big J were a lad the fish were so big you could feed 5,000 with just a couple of them.

    And t’sea of Galilee were so cold you could walk on’t.

    Miracles ain’t what they useter be…

  11. “When their waters get warmer, their metabolism accelerates” – could someone explain this?

    • Metabolism is a series of chemical reactions, which are accelerated by increases in temperature and slowed by decreases in temperature. As a general rule, an increase of 10 C will double the reaction rate and vice versa.

      • Nonsense. Metabolism in living creatures is controlled by different enzymes. Enzymes have a peak efficiency temperature. It’s isn’t a strictly linear relationship, so there is no reason to assume that metabolism speed will increase steadily with increasing temperature.

      • en·do·ther·mic – adjective

        1. Chemistry – (of a reaction or process) accompanied by or requiring the absorption of heat.

        2. Zoology – (of an animal) dependent on or capable of the internal generation of heat

  12. Given that:
    * the top few meters of the ocean hold more energy than the entire atmosphere, and that:
    * a warm wind blowing over the surface of the ocean cools it by evaporation (it is why you blow on your coffee to cool it), and that:
    * infrared cannot penetrate more than a micron or two into water and increases evaporation again cooling the surface, and that:
    * solar heating of the ocean leads to clouds that increase albedo reducing the incoming heat

    Can someone describe the mechanism that allows a very slightly warmer atmosphere to heat the ocean noticeably to the level that fish species are affected?

    • The evidence is that Mars once had liquid water. link It is explained that Mars no longer has water because it has lost most of its atmosphere.

      We have measured the subsurface temperature of the moon. link It’s quite a bit cooler than it would be at the same latitude on Earth.

      We have actual evidence, as opposed to theory, that the Earth’s atmosphere results in a warmer surface.

      • The sea has a much lower albedo than land. A vast majority of all solar energy is absorbed by the ocean and then all ultimately given off to the atmosphere, either as heat or latent heat of evaporation. So, yes the ocean heats the atmosphere and the atmosphere is therefore warmer than it would be on a dry planet.

    • Ian W – August 22, 2017 at 2:20 am

      * a warm wind blowing over the surface of the ocean cools it by evaporation (it is why you blow on your coffee to cool it), and that:

      Try again, Ian W, ……. your confusion might be catching ….. which is not a good thing for science literacy.

      A warm wind blowing across the cooler surface of a body of water will result in a “conductive” transfer of thermal “heat” energy into the cooler water.

      And given the fact that the temperature of your breath is 98.6°F (37°C), …… which is considerably cooler than the surface of your cup of coffee, ….. then it is reasonable to assume that there will be a “conductive” transfer of thermal “heat” energy from the surface of the hot coffee into the stream of air molecules of your cooler breath.

      Three (3) methods of transferring thermal “heat” energy, take your pick: conduction, convection and radiation

      • You mean like lake effect snow perhaps?
        Have you ever held your wet hands under a hot air drier Samuel? Your hands will feel cold while the water evaporates then get hot when there is no water left to evaporate.
        As your hands become dry as they get cold – then the reason is not thermal conductivity but evaporation and loss of latent heat.
        Convection of the moist air is correct but the air did not get moist through conduction it got cold through evaporation and loss of latent heat of evaporation.

        So perhaps you should worry less about lack of scientific literacy. Instead you could do an experiment to falsify what I state. It should show how blowing air over water warms the water and that no water evaporates.

      • Ian W responds:

        Have you ever held your wet hands under a hot air drier Samuel? Your hands will feel cold while the water evaporates then get hot when there is no water left to evaporate.

        Ian, please educate me on the science that explains the actual source of the thermal “heat” energy …….. that caused my cold hands to get hot after all the liquid water (H2O) had evaporated off of their surface?

        I anxiously await your scientific explanation.

        Sam C

  13. The ocean water temperatures and oxygen content are not consistent across various depths
    and locales. Fish can swim , you know. They are mobile and can move to locales or depths where they are most comfortable, assuming their prey/food can also be found at that locale/depth. I don’t know exactly what this study is claiming, but if they haven’t answered the question about movement to better conditions, they haven’t proven anything. But that would have required some effort to determine and therefore wasn’t done – they already had their anti-warming pronouncements in hand, and that was their goal in the first place.
    This seems to be a recurring fault with all of these types of studies – they never answer the question of how animals will react if the areas where they currently reside were to become warmer
    and more importantly, how much warmer.
    But THAT is the question that is relevant.

  14. Perfectly good science and known since at least the 1940s (see any textbook of animal physiology) – I’m surprised it got published. The “theory” does not consider fish behaviour.

  15. This is why the immediate surrounds of hottest water on earth, hydrothermal vents, are void of life. /sarc

  16. “Warmer waters increase fish’s need for oxygen but climate change will result in less oxygen in the oceans. This means that gills have less oxygen to supply to a body that already grows faster than them.” — climate has been changing in the past, present and will change in future. Ocean water temperature follow the natural cyclic pattern. That means sea creatures including fish has been adopted to those changes in temperature and climate. Has any researcher observed changes in fish size in those circumstances?

    Dr. S. Jeevananda Reddy

    • Weren’t there some really big fish in prehistoric times? Seems to me it was pretty warm back then.

  17. One would of course expect greater photosynthetic activity with a warmer and more CO2 rich world with the upper levels of the ocean positively fizzing with oxygen.

    Q. Are the upper layers of the ocean saturated with oxygen already?
    Q. What about deeper layers where its much much colder?

  18. “…but climate change will result in less oxygen in the oceans….” How does this Carp get Oxygen???

    What so suddenly all the fish will head North and South to avoid the warming waters???
    Hey what if the waters cool? will the fish get 20-30% larger??

    Absolute BS. Some of the best fish in the world are warm water fish eg the great Barramundi. Even if it did happen – how long?

  19. On the Great Lakes, warmer winters make for much bigger salmon the following year. During cold winters their metabolism apparently slows down and they dont feed as much.

    During a hot summer sometimes they just go little deeper to find the water temperature they prefer. Sometimes they don’t have to go deeper if winds are from the right direction. Temperatures change drastically from day to day, and they will move miles in a day to find the temperaure they like.

  20. When I heard this garbage on the radio I instantly thought of the Barramundi and thought no way it could be all gilled fish , must just be the cold loving species but we’ve had ice ages that came and went and warmer periods but still have big fish in cold and warm waters .

  21. This is just so true.
    Every time I have sailed across the equator, the sea is just boiling with gasping, shrinking fish.

  22. Also supposed to affect sharks more but again there are species that prefer the warmer water .

  23. I guess the reports of Megalodon are false it went extinct 2.6 million years ago at the start of the current ice age

  24. So sayeth the Wizard of CO2: “Shrinking and gasping for air — oh my! Shrinking and gasping for air — oh my!”

    • It might be instructive if you googled the number of installed turbines world wide, then searched for all turbine fires in a year

      • I get about one report a week. There is a media blackout in Canada according to a good source there. A partial blackout in regions in the US, EU and AU/NZ.

        I worked in the industry and also served as a volunteer fire chief/ foredt fire warden with a service area of 2,500 + sq miles.

        There is a big problem here and I intend to adress it with facts.

      • Please excuse my spelling errors.

        Address and Forest Fire Warden were mispelled. My apologies for being a bit pissed, old and using an iphone.

      • On that note, how many Hoverboards were made and how many of them caught fire before a recall was issued? What about the batteries Boeing was using?

      • Neighbours Sue Wind Power Operator – Infigen – for $20m Damages Caused by Devastating Wind Farm Fire

        On 17 January 2017, wind farm operator Infigen sparked a blaze that ripped across the southern Tablelands of NSW and destroyed 3,400 hectares (8,400 acres), hundreds of sheep and cattle, sheds and at least one home. STT first reported on it on 25 January: Wind Power Setting the World on Fire: Infigen Sparks Devastating NSW Bushfire
        The losses suffered by neighbours are in the tens of $millions. A class-action just launched by some of those neighbours is chasing Australia’s most notorious wind power outfit for $20 million in loss and damage, with more neighbours set to join the action and add many $millions more to that number.

        https://stopthesethings.com/2017/05/15/neighbours-sue-wind-power-operator-infigen-for-20m-damages-caused-by-devastating-wind-farm-fire/comment-page-1/

  25. They say bumble bees shouldn’t be able to fly …. but they do. I’m betting fish will also defy these wizards of smart.

    • According to my calculations, old doomsayers ought to be able to learn new tricks. So far, no luck.

    • Stupidity is legal. Slapping isn’t — it’s a form of assault. Hence the need for free speech leavened by ridicule. Both are still legal. . . so far.

  26. The point here seems to be that gills limit the size of fish, dependent on the available oxygen in water. So the current upper limit on fish size would be represented by the largest gilled fish extant today. That would be the the whale shark – typically nearly 10 meters and 9 tonnes for an adult. This would not seem to be a problem for other species, which would presumably have their size limited by other factors.

  27. The tropics have some of the largest bony fish species in the world… Giant Groupers, Giant Wrasse, Marlin, etc… I’m not sure where these so called Marine Biologists are coming from?

    The only species of marine life that I have found to be smaller in the tropical warm waters than in colder southern waters is the Blue Swimmer crab, Portunus pelagicus. These crabs are definitely larger in the southern colder waters of the Peel Inlet of Mandurah or the Swan River in Western Australia than they are in the tropical waters of Nth Queensland’s Princess Charlotte Bay.

    But crabs aren’t bony fishes….

  28. Or they could swim off where its best for them, as we have migrtaed over 10,000 years of continual climate change. But no one seems to think beyond their tiny little bubble of expectation that nothing must change, a perception because they don’t live long enough to notice it. Everything changes, all the time, some slower than others. The only correct evolutionary response is to adapt. Moving is easier than evolving.

  29. Climate Change Corollary 101: Climate change harms polar bears, butterflies, honey bees, bunny rabbits, fish, crops, humans and all good forms of life.

    Climate Change Corollary 102: Climate Change is beneficial to ticks, fleas, rats, mosquitoes, bacteria, virus’s, weeds and all bad forms of life.

    Climate Change Corollary 103: Research funding and peer review standards for the study of Climate Change will be applied based on accepted assumptions and standards consistent with Corollary’s 101 and 102.

    • Climate Change Corollary 104: Global warming since the advent of the Industrial Revolution is assumed to be caused by humans.

      Climate Change Corollary 105: The optimal level of temperature for the planet, was the global temperature measured at the advent of the Industrial Revolution.

      Climate Change Corollary 106: The optimal level of carbon dioxide for the planet, was the level of atmospheric carbon dioxide at the time of the advent of the Industrial Revolution.

      Climate Change Corollary 107: Processes that led to natural Climate Change in the past are assumed to be negligible.

      Climate Change Corollary 108: Carbon dioxide is pollution when defined in terms of it’s role in Climate Change.

      Climate Change Corollary 109: Photosynthesis plays only a minor role in assessing the effects of carbon dioxide on life.

      • Caused by humans — land use change, land cover change contribute to the change in temperature at local and regional level. This is not part of global warming. So 104 is invalid statement.

        The natural variability in climate is the major contributor for agriculture and water resources and as well health related problems. Temperature is modified by rainfall and thus humidity and thus wind speed and direction. So 107 is invalid statement.

        Dr. S. Jeevananda Reddy

    • WRT#102, Until 5-6 years ago, I found 3-5 ticks per week during the summer on my clothing. Since then there have been literally zero for years now. WUWT? I don’t miss the critters a bit.

      • No ticks? Did you have a spell of extremely hot weather during that time? Extreme heat dries out ticks and reduces their populations.

        During the very hot summer of 2011, I walked through the woods around my house watering trees (a bad drought was occurring at the same time as the high heat), and did this for several months and never got one tick on me. Normally, ticks are plentiful in the areas I walked.

        So the high heat definitely affected the ticks at that time, but they are back in business today, six years later, so it wasn’t a knockout blow. Of course, we have had fairly mild, wet summers most every year since 2011, which is good for ticks (and all living creatures:).

  30. As a former alumnus of the University of British Columbia, I must state how proud I am to know that when cattle are extinct we will not lack for a source of their most aromatic leavings because my old univeristy has found a way to synthesize the material in massive quantities from taxpayer funding.

  31. Here is another example of a case where “scientists” need to do some actual science.

    They propose a theory that on the face of it, gills grow slower than body and warmer water holds less gases (oxygen), seems to have some logic. So they make a prediction based on their theory.

    Up to here I don’t see any problem. But them stop. And so stops any resemblance they have to scientists. The last, and most important step, is missing. TEST THE THEORY.

    Set up a number of separate tanks at different temperatures and dissolved oxygen content. Then actually raise fish of a number of species in the tanks for a few years, Finally measure the fish and see if the fish from warmer tanks with less oxygen smaller than those from colder tanks with more oxygen.

  32. Meanwhile, dwindling belief in CAGW is leaving Climatists budgets and jobs shrinking, and the remaining holdouts grasping at straws.

  33. Pauly and Cheung have just laid to waste the fear of sea level rise. All those shrinking fish should displace less water and thus adequately compensate for the heat expansion of the water in which they swim.

  34. From the alleged research.

    “Daniel Pauly, the study’s lead author and principal investigator of the Sea Around Us at the Institute for the Ocean and Fisheries, explains that as fish grow into adulthood their demand for oxygen increases because their body mass becomes larger. However, the surface area of the gills — where oxygen is obtained — does not grow at the same pace as the rest of the body. He calls this set of principles that explains why fish are expected to shrink “gill-oxygen limitation theory.”

    The author ‘names’ his theory? With such a self explanatory name too; not!
    • Larger body mass = greater oxygen demand. Profound!
    • “the surface area of the gills — where oxygen is obtained — does not grow at the same pace as the rest of the body”
    Amazing claim!?
    Did the research authors actually raise fish under the specified environment parameters? No.
    Apparently this “set of principles” is only predefined model programming.

    “Daniel Pauly, For example, as a fish like cod increases its weight by 100 per cent, its gills only grow by 80 per cent or less. When understood in the context of climate change, this biological rule reinforces the prediction that fish will shrink and will be even smaller than thought in previous studies.”

    Amazing!
    Meaning, the research authors are unaware or perhaps just ignore normal biology.

    From a human perspective then, humans are already suffering from “climate change”. Where a human’s body grows many times larger from infant to adult; a human’s head only grow 30% larger.
    Gasp!

    And these characters are:
    • Associate professor at the Institute for the Ocean and Fisheries
    • Director of science for the Nippon Foundation-UBC Nereus Program
    • Principal investigator of the Sea Around Us at the Institute for the Ocean and Fisheries

    Perhaps they’re over qualified?

    “Daniel Pauly, Warmer waters increase fish’s need for oxygen but climate change will result in less oxygen in the oceans. This means that gills have less oxygen to supply to a body that already grows faster than them. The researchers say this forces fish to stop growing at a smaller size to be able to fulfill their needs with the little oxygen available to them.”

    Gross assumptions:
    • “Warmer waters increase fish’s need for oxygen
    • “climate change will result in less oxygen in the oceans
    • “This means that gills have less oxygen to supply to a body that already grows faster than them

    Absurd leap to conclusion based on zero evidence:
    The researchers say this forces fish to stop growing at a smaller size to be able to fulfill their needs with the little oxygen available to them

    Reading this drivel causes one to wonder if the alleged research paper is simply psychological testing on unsuspecting subjects testing truly bad research science acceptance.

  35. Ian W and tty:A typical tropical ocean surface energy balance gives the evaporative heat flux as 80 W/m^2,the back I.R.radiation as 350 W/m^2, and the I.R. emission as 415 W/m^2.How do these values support your ideas about the role played by evaporation?

    • Granted, I am neither Ian nor tty. However, if you can ask them a question uninvited, so I can ask you a question uninvited:
      Consider that SST is lowered by a hurricane’s passage. While the hurricane passes over a patch of sea, cloud cover is much greater than the norm. Since cloud cover increases back radiation, while I.R. emission would be unchanged, what do you conclude about the role played by increased cooling due to evaporation affected by stronger wind?

      SR

  36. I call the practice of producing not-ready-for-prime-time climate reports and always predicting dire consequences in the future “What if” research or the “cart before the horse syndrome.” It works like this. Someone hypothesizes a future climate anomaly. Taking that hypothesis as a given, other researchers churn out reams of reports that describe the disastrous effects on people, plants, water supplies, air, fish, insects, etc. that will occur because of the anomaly. The “If such and such happens…” is dropped from the discussion.

    Focusing research on untested hypotheses to prepare for an event with little or no likelihood of occurring is the wrong research, and policies stemming from that research are the wrong policies. The “results” from such research stimulate baseless scare-mongering. Get the science right first, and the right policies will follow. Research on an untested hypothesis is based on a fairy tale.

  37. “Gasping Fish and Panting Squids: Oxygen, Temperature and the Growth of Water-Breathing Animals” I never saw a panting squid or anything breathing water, but I suspect I have seen more gasping fish than Pauly. He is a well-known crisis type, and as many still are, long doing exceptionally well, in one sense, anyway. The fisheries situation, models again, is not simple and Pauly has been part of the oceans dying crowd for decades. Without much trouble I found these quick examples, as Hilborn’s work that I know about is solid and has not gotten along well with the crisis crowd. Each paper has to be judged on its own, however, but I have a bias against papers with too many authors.

    Pikitch, E., P.D. Boersma, I.L. Boyd, D.O. Conover, P. Cury, T. Essington, S.S. Heppell, E.D. Houde, M. Mangel, D. Pauly, É. Plagányi, K. Sainsbury and R.S. Steneck. 2017. The strong connection between forage fish and their predators: response to Hilborn et al. (2017). Fisheries Research [in press]
    Hilborn, R. and C. V. Minte-Vera. 2008. Fisheries-Induced changes in growth rates in marine fisheries: Are they significant? Bulletin of Marine Science. 83(1): 95–105.
    de Mutsert, K., J. H. Cowan, Jr., T. E. Essington, & R. Hilborn. 2008. Reanalyses of Gulf of Mexico fisheries data: Landings can be misleading in assessments of fisheries and fisheries ecosystems. Proceedings of the National Academy of Sciences. 105(7):2740-2744.

    The same species occupying a temperature gradient (compare Florida with Virginia) will be larger with lower temperature. Oxygen is a problem with aquatic organisms and may be one reason why they came out on land to increase it some roughly 30X. Some very active fish are somewhat warm-blooded, including large sharks (mako) and oceanic fishes(tuna).

    I recall a seminar on this over two decades ago where the “superior” (trouts, etc.) were going to be replaced by the “inferior” southern species. There are many more species of fishes in warm water than cold, many quite large. Maybe they will.

    • Oxygen does seem to be more of the driving factor than temperature; wherein warm water holds less oxygen than cooler. Fish adapted to a range respond to reduced oxygen with increased resting heart rate & there is subsequently reduced aerobic ATP production in other tissues (demonstrated as more phosphorus found in it’s inorganic molecular form than compounded as phospho-creatine). See free full text available on-line: “Oxygen limited thermal tolerance in fish? Answers obtained by nuclear resonance techniques”.

  38. ‘“Fish, as cold-blooded animals, cannot regulate their own body temperatures. When their waters get warmer, their metabolism accelerates and they need more oxygen to sustain their body functions,” said William Cheung, …’

    ‘Tuna, which are fast moving and require more energy and oxygen, may shrink even more when temperatures increase.’

    Um, some Tunas are actually warm blooded, and they are among the race horses of the sea. While it’s a much more primitive animal some Sharks are warm blooded as well; notably the Great White and the Bull sharks. Interestingly, Bull sharks, which range the oceans throughout the world, can swim upriver, one example being from the Gulf as far north up the Mississippi River as Dubuque, Iowa.

    Me thinks Cheung and Pauly need to get out more. I’m guessing that the size of fish, just like most animals, tends to relate to the size of the area they inhabit, what they eat, and how much of it they eat.

    • Whoops. Bull sharks are not warm blooded. But, they can adapt for periods of time to freshwater and can swim upriver.

      In addition to the Great White it’s the Mako shark that’s warm blooded. And, like the Tuna they’re speed demons as well.

  39. The authors forget that the oceans are a three-dimensional universe with various thermohaline layers throughout the entire water column. If it’s too warm for a specific fish species at depth n then they’ll move lower to depth p where the oxygen level is higher and likely the richness of the food chain as well.

    “There is a point where the gills cannot supply enough oxygen for a larger body, so the fish just stops growing larger.”

    How, then, do they explain the great masses of paleolithic fish species that were many times larger than current fish species and existed in far warmer oceanic temperatures? Did they forget to include them into their analysis?

    Yes, yes I believe they did.
    /smh

  40. The only thing that makes African Cichlids grow smaller is an enzyme in the water that inhibits growth. This allows more fish to occupy smaller water bodies.

    Their size is not even remotely temperature dependent.

    This study was done by “scientists” who don’t know anything about fish it seems

    • or O2 dependent, Cichlids thrive in low oxygen waters too. Growing in small pockets of water in African summers, you can bet the water is warm and the O2 low

      • Good point. Bettas like warm, still water.
        I saw South American Killifish in tanks with only chlorophyllic oxygenation at 85F during my career as a university “building engineer”.

  41. I would trust experienced aquarists over scientists on these matters any day. The corals debacle made that very clear to me

  42. Some of my projects when I was recording them. Not possible without precision, chemical and biological science.
    https://youtu.be/UROlqJNLw6s
    https://youtu.be/YA0lpPnm-_E
    Recreation of Bolivian river Abuna water chemistry to breed wild caught Ancistrus Rio Abuna genus. Took me a year and a half to get these babies where most other ancistrus breed in toilet water 😀
    8 weeks old
    https://youtu.be/9jKbjKzq6gI
    https://youtu.be/K7EOwnztInY
    Dad, mom very shy.
    https://youtu.be/HIDGNpP__LQ
    Blackwater Amazon chemistry, and a taken in Bala shark, not really suited to this environment but he thrived nonetheless. Upsidedown catfish I had since fry size, had them for 4 years until I moved from Ireland to Finland. They start swimming upside down soon after birth and do so for the rest of their lives
    https://youtu.be/cWWuaNIeNVs
    Amazon, tetra mania. 120 fish in 180 liters, 2 filters, CO2 injection, pristine waters.
    https://youtu.be/YYWcWlz25SE
    I could post many more but spamfest 😀

  43. William Cheung, co-author of the study, associate professor at the Institute for the Ocean and Fisheries and director of science for the Nippon Foundation-UBC Nereus Program. said “There is a point where the gills cannot supply enough oxygen for a larger body, so the fish just stops growing larger.”

    Not sure where he gets that nonsensical idea from, in some 60 years of fishing i have always found that the larger the fish the larger the gills …… never heard of fishes gills stopping growing …. as the body size increases so do the gills.

    The warmer the water, the bigger the fish, they need to look at the fish around warm water outlets from cooling towers and cooling systems which feed into rivers. That is always where the largest fish are.

  44. ” published in Global Change Biology ”

    So a magazine dedicated to biological adaptation to climate change? Well THAT’S quite convenient for those who adhere to the AGW myth! An entire magazine dedicated to biological papers related to climate change!

    • IMO it’s a legitimate field of study which has become agenda driven because of its funding sources. Naturally climate does change and we should study the effects on flora and fauna as we ourselves adapt, mindful that the present lush greening of the planet is due to warming+CO2.

  45. For example, as a fish like cod increases its weight by 100 per cent, its gills only grow by 80 per cent or less.

    What if? The young fish has more gill than they need, and as they grow into adulthood, the gill size more closely matches what the fish need? Kinda like a puppy having huge feet, but they grow into them.

  46. “Fish are expected to shrink in size by 20 to 30 percent if ocean temperatures continue to climb due to climate change.”
    I need to see some proof that the atmosphere can warm the ocean, instead of the reverse being the obvious case. When the SSTs cycle to a 1970s like condition they will once again cry ice age.

    • There’s another common pressure towards smaller average fish sizes — overfishing. The more fishing pressure, the fewer fish reach the biggest possible size, across many species. Atlantic halibut used to reach several hundred pounds, but they are a slow-growing fish that was, in effect, mined. It’s the same dynamic as logging forests full of 600 year old trees, and letting them regrow for only 90 years.

      Catching fish as soon as possible has a dysgenic tendency to eliminate the monsters, and work in favor of fish that mature early and lay eggs before they get caught.

      That factor can’t be separated from other factors. The latest doomsday scenario about water temperatures is popular now, but if it’s disproven, pessimists will come up with something new.

  47. ‘Fish, as cold-blooded animals’

    How scientific of them.

    If the water is warmer, won’t they be warm-blooded animals?

    Note that the poikilothermic generally don’t care what the temperature is. It is us homeotherms that care.

  48. Stefan Reddish:I am not sure what you are questioning, but let me try to reply.For the same ocean surface energy balance I cited to Ian.W,consider a perturbation of 1 W/m^2 increase in the back radiation.The new balance shows an increase in surface temperature of 0.00227 K, and of the 1W/m^2 in back radiation,95.3% goes to reduce the convective heat loss from the near surface water,2.57% goes to increased evaporation,1.25% to increased emission, and 0.91% to sensible convection into the air.The ocean surface temperature plays a critical role in determining the various fluxes.Also, it is the very large convective heat transfer coefficient on the water side of the interface that dominates the response of the balance to perturbations.

  49. The size-dependent estimate on weight is 24.9% per degree Celsius (assuming the fish in question don’t change their range as ocean temperatures change, which seems an unlikely assumption). This is the temperature of the *water*, not the sea surface. The heat capacity of the ocean is much, much larger than the atmosphere, it isn’t going to go up by 1C anytime soon.

  50. Why does it seem like everyone constantly forgets that overall ocean temperature change is almost too small to measure since 1950?

    • If that’s a real question, rather than a rhetorical question, the answer might be: Anything that doesn’t conform to a doomsday scenario gets ignored. “Settled science,” and such. Everything is bad and getting worse. That’s my story and I’m sticking to it.

  51. Here is the state of marine life in the UK from 1970-2013, when CO2 emissions went up dramatically:

    Of all 104 Marine Species surveyed:
    47% increased
    28% little change
    25% decreased
    (62%-38% when little change excluded)

    “Marine fish have been influenced by commercial fishing and climate change altering the composition of marine communities, the abundance of species and the body sizes of individual fish. Over our long-term period, the populations of a large proportion of smaller-bodied fish species have increased due to warming sea temperatures, while the populations of a smaller number of larger-bodied species have declined due to fishing” (emphasis added)

    Source: State of Nature 2016 report (produced in partnership with 50 conservation organisations) – https://ww2.rspb.org.uk/our-work/conservation/projects/state-of-nature-reporting (Main Report p.45, plus Supplemental Data Tables, Table 1a).

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