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Arthur T Knackerbracket has processed the following story:
It has been claimed that fish farming is a sustainable source of food that will help us feed the growing global human population while protecting wild fish populations – but this isn’t true.
“Fish farming is not a substitute for catching wild fish out of the ocean,” says Matthew Hayek at New York University. “In fact, it relies on catching wild fish out of the ocean.”
Hayek and his colleagues have shown that the amount of wild fish killed in order to feed farmed fish is between 27 and 307 per cent higher than previous estimates.
Farmed carnivorous fish eat multiple times more weight in wild fish caught from the ocean than is obtained by farming them, says Hayek. For instance, producing a kilogram of salmon may require 4 or 5 kilograms of wild fish.
(Score: 5, Interesting) by zocalo on Monday October 21 2024, @02:37PM (11 children)
I wouldn't be at all surprised if they have the conclusion completely backwards. Most animals have a typical adult size at which point they stop growing (issues with obesity aside), and simple economics says that farmed fish are going to be culled right around this optimum point otherwise you're just inputting food for no additional gain. Fish caught in the wild, however, will be a random cross section of young that are too small for the market and may either be thrown back, used for chum, or die of stress in the process of sorting, and mature fish that essentially stopped growing - but not eating - some time ago. Average out the combined weight of the discarded young and whatever they've eaten, with the food eaten by mature fish that have been eating without significant further weight gain and I suspect each 1kg of wild fish for sale will have consumed quite a bit more that 4-5kg of other wild fish to get there.
UNIX? They're not even circumcised! Savages!
(Score: 3, Interesting) by JoeMerchant on Monday October 21 2024, @03:00PM
>how many wild fish would a 1kg salmon caught in the wild have eaten to grow to that 1kg weight?
Good point. Counterpoint:
Wild salmon are eating wild fish from natural food webs that evolved over billions of years to the amazingly bountiful and productive marine ecosystems we had, yes had, up until factory fishing fleets overharvested them into crisis level population collapses.
In most cases. keeping the fishing fleets docked allows those food webs to bounce back, but not always. In any event: the fish that wild salmon eat are a (mostly) sustainable source, as long as we are harvesting a sustainable amount of salmon from the wild, the system will carry on, providing the incredible volume of available high quality protein that it has for millions of years.
The fish fed to fish farms are somewhat different, they are the readily caught fish by our fishing fleets, whereas much of a salmon's diet is not. Instead of using that catch to feed people, fish farming distills it down to higher profit species for sale in global markets. I contend that while these species are more saleable, their farmed versions are lower quality than wild caught, raised in much dirtier water with a lower quality diet. In any event, those fish caught to feed the farms could, instead, be providing 5x or more food value to locals who would gladly consume them, without having to ship anything around the globe.
Counterpoint: Jane, you're an ignorant slut.
🌻🌻🌻 [google.com]
(Score: 3, Informative) by VLM on Monday October 21 2024, @03:08PM (5 children)
I'd agree with that theory. Lets test it in practice. Could independently verify the theory by looking at mercury ppb concentrations of various fish.
In tuna its "a hundred ppb" or so. In sardines its "about ten ppb" or so. In theory if mercury were perfectly conserved and never excreted (nope) then if tuna eat sardines in the wild, they eat at least ten times their body weight of sardines. At a minimum, because they do excrete a little mercury. It bioaccumultes but nothing bioaccumulates 100% efficiently, I am sure at least some sardine-mercury ends up in tuna-poop.
So, its quite plausible based on mercury data that aquaculture tuna eats at least half as much other fish as wild tuna. Probably somewhat less than half, but at least half.
(Score: 2) by JoeMerchant on Monday October 21 2024, @03:54PM (4 children)
>its quite plausible ... that aquaculture tuna eats at least half as much other fish as wild tuna. Probably somewhat less than half, but at least half.
Forget the data, just play thought experiment:
Farmed tuna don't have to hunt for food, migrate, find mates.
Farmed tuna don't have to run from predators, get eaten by predators, or fishing boats.
Farmed tuna live under the sword of Damocles - the moment they are optimal marketable size: exit stage left, directly into the freezer.
By those factors alone, farmed tuna should be expending far less calories than their wild caught counterparts. Probably much less than 50%.
Yes, farmed tuna share the same genome with wild tuna, they look similar - but do they even taste similar? That depends, early versions tasted different enough that customers complained. Even if consumers can't tell the differences, there will be significant differences in the quality of the meat. Maybe better, maybe less parasites, but certainly a lot of less desirable differences along for the ride too.
🌻🌻🌻 [google.com]
(Score: 3, Interesting) by VLM on Monday October 21 2024, @04:09PM (3 children)
I would generally agree with and further extend your remarks along the lines of
In theory, with modest effort, an aquaculture farmer could grow his fish in perfectly ideal water temp and ideal water quality, so the fish don't have to either suffer or move, pretty much ever.
Sure by modest effort they might have to install some pipe, a pump, and a solar panel, or multiple ones so they can use IoT type stuff to turn on different pumps to achieve ideal water conditions based upon sensors. I'm not suggesting burying heating elements to grow tropical fish in Antarctica. Getting ideal temp for growth in a fish farm might be as simple as one pump with a warmer area of water and another pump with a cooler area of water and a thermostat selecting which one runs at any instant such that the fishies are happiest. I visited a trout farm this summer where they kind of did that, they controlled the temp of the hatchery by pulling hatchery circulation water from either a cooler or warmer pool. I would imagine this would scale up pretty well from the existing "olympic swimming pool" sized hatchery to something the size of a land-based farm.
Another idea is there's probably some location underwater that would be ideal for fish if they could live there, but there's no reef or whatever it is they require ... well... make one out of recycled concrete or sink a scrapped ship there or similar. An interesting aquaculture strategy might be to "finish feed" medium to large fish by penning them above natural sources of small fish like an artificial reef. Build the perfect environment for feeder-fish on the bottom and then station larger aquaculture fish above it, like fertilizing a pasture for sheep, kind of. Given multiple pens you could graze rotate the big fish to different areas just like they do with pastured sheep.
(Score: 2) by JoeMerchant on Monday October 21 2024, @04:19PM
In my experience, anything built in a marine environment requires more than modest effort to maintain. Salt corrosion, sun exposure, wave action, extreme storms... there are precious few locations in our vast oceans that provide year round ideal circumstances for... anything.
Along those lines, in my next lifetime - Matrix reset to 1960 - I would pursue the business of luxury submarine yachts. Go anywhere you like, but when a bad storm is closing in, submerge instead of scrambling for safe harbor. Make 'em big, out of cast concrete with non-rusting composite tension elements (instead of the traditional iron or steel rebar). Build once, cruise for centuries. Smuggle some 2030s solar panel and battery tech back to 1960 and make them self-sustaining mobile islands, producing their own fresh water and food.
Only problem is: a $1B concrete submarine yacht probably only has carrying capacity for a dozen or so people, long term, even if it could host an exclusive short term party for hundreds. Looks like Hugo Drax did have the right inevitable conclusion after all in Moonraker.
🌻🌻🌻 [google.com]
(Score: 1) by khallow on Monday October 21 2024, @11:37PM (1 child)
Fish in continual movement have better quality and health BTW. When I toured a fish hatchery [tripadvisor.com] way back when, water was continually flowing through the tanks.
(Score: 2) by VLM on Tuesday October 22 2024, @04:15PM
I think in specific you are probably correct although in general I still like my idea of improving locations. It could be as simple as multiple redundant feeder stations convincing the fish to always swim to the next feeding area, which coincidentally ALSO happens to be an ideal fish growth environment. Rather than they just eat where they want or where its convenient for humans they could always be eating where its best to live.
(Score: 1) by khallow on Monday October 21 2024, @10:20PM (3 children)
(Score: 2) by VLM on Tuesday October 22 2024, @04:36PM (2 children)
Two counterexamples to your thought experiment:
The ocean is not exactly overpopulated and at least SOME fisheries have collapsed yet the input to those fisheries is unmodified. Surely the long dead Cod from wiped out Cod fisheries don't need to be fed anymore. Something could eat what they used to eat.
A pretty big pollution problem for oceans etc is fertilizer runoff. We do NOT have a shortage of algae/krill/similar for little fish to eat. It would probably help a lot with water quality to turn megatons of algae into kilotons of itty bitty feeder fish which can then be turned into tons of canned tuna or similar giant fish.
The ocean's not a desert where there's a lack of inputs.
(Score: 0) by Anonymous Coward on Tuesday October 22 2024, @04:42PM
I am picturing a bounty of floating trash awash in untreated sewage as the engine of our economic food production miracle. Not even joking...
(Score: 1) by khallow on Wednesday October 23 2024, @01:19AM