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.”
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.
###
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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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?
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.
A fishy tale.
Smaller,
hotter,
short of
breath…
we
can
foretell
this
because
WE
are
modellers.
In my experience, anatomy grows in the warm & shrinks in the cold (:-))
+10000000
+10000001
turn up the shower water temp then:-)))
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:
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..
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 .
@ur momisugly 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.
https://www.seeker.com/ancient-mosaics-reveal-changing-fish-size-1765421259.html
The Roman Warm Period was during the 1st through 3rd centuries. The Migration Cooling Period occurred in the 4th and 5th centuries.
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.
It was probably all some inside joke that only contemporary mosaic artists understood.
I suppose it could have been their version of the SyFy channel… 😉
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.
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,”
But then, in recent years, global seas have actually been getting cooler. Perhaps we will have bigger fish soon?
No, the current temp is optimal and no adaptation is possible.
Indeed. The global average temperature is so perfect that we must not allow it to change, at any cost.
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.
When the swamp is drained many big fish will be gasping for air.
Mostly suckers …GRIN !
Unsuccessful science fiction writers get more money in climate research.
“may”, “are expected” Weasel words are expected in climastrology and they may fill the pseudo scientific articles.
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.
With the World’s oceans cooling off recently, we should soon be able to see some really big fish swimming in the seas.
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.
Touché!
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.
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
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
I hope there’s intelligent life out there because there’s bugger all down here .
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.
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…
“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.
When you feed captive fish pelletized, high-protein meal, their meatballism increases.
A philosophical “paper”. Not science.
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
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:
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
And by the way, …… Ian W, …… what is your reason for NOT responding to this posted comment of mine, …… which is accessible at the following url, ……to wit:
https://wattsupwiththat.com/2017/08/20/paper-examines-unconscious-assumptions-that-have-impeded-scientific-progress-in-the-past/comment-page-1/#comment-2586875
I posted it especially for you.
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.
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.
This is why the immediate surrounds of hottest water on earth, hydrothermal vents, are void of life. /sarc
Tell me why do goldfish increase their size depending on their environment.
I can’t believe they are serious – did they write it on April 1st?
“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.
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?
photosynthetic activity in oceans is limited by nutrients, not by temperature or CO2. Nutrients are normally low in warm seas. There is a reason fishermen mostly work in areas with cold water, despite the danger and discomfort.
https://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MY1DMM_CHLORA