Does fish farming not exist on a large scale because it isn't economic, practical or necessary, or something else

My understanding is that most fish are wild caught. Well and good. However with overfishing the world will run out of seafood in the coming decades.

Which brings up the question, why aren’t farmed fish more common? Is the process too expensive, does it require too much physical space, do we not know how to do it large scale?

Or is it a perfectly feasible alternative to wild caught fish, but its just not necessary because fish can be caught in the wild? Same way shale oil was perfectly acceptable as an alternative to other forms of oil, its just that prices had to go a little higher for them to be affordable.

I dispute your premise. Farm fishing overtook capture fishing in 2012

Thank you, hopefully I was misinformed. I thought fish farming was a tiny fraction of the seafood market.

Note that if you remove China from those numbers then for the rest of the world capture fishing is almost double fish farming (if the numbers on that site are to be believed).

Looking into it a bit more, it also depends on which kind of seafood. Apparently tuna isn’t farmed much, possibly in part because they require so much feed.

A tuna’s natural diet consists of other fish. Lots of other fish. Right now, there are tuna “ranches” that capture young tuna in the ocean and then fatten them up in big net-pens. According to Greenberg, those ranches feed their tuna about 15 pounds of fish such as sardines or mackerel for each additional pound of tuna that can be sold to consumers. That kind of tuna production is environmentally costly.

Zohar thinks that it will be possible to reduce this ratio or even create tuna feed that doesn’t rely heavily on other fish as an ingredient.

But Greenberg says the basic fact that they eat so much makes him wonder whether tuna farming is really the right way to go. It increases the population of a predator species that demands lots of food itself.

“Why would you domesticate a tiger when you could domesticate a cow,” he asks — or, even better, a chicken, which converts just 2 pounds of vegetarian feed into a pound of meat.

The canned tuna industry is entirely supplied by the wild fishery

Salmon, tilapia and (I believe) catfish by comparison, supposedly mostly come from fish farms now vs wild caught. I think tuna and cod are mostly wild caught.

Atlantic salmon is often farmed. Pacific salmon (5 species present in North America) aren’t even closely related, but are more likely to be wild caught though farming exists.

It’s not simply a case that wild caught is worse, in many situations it’s better. Farms have more potential environmental impact, plus problems like contaminating wild gene pools if not coastal.

Wild salmon and steelhead also gets a nice pink color, the farmed equivalent won’t sell in its grayish color so they use either dyes or food additives to make it look redder.

For the environmental impact and sustainability of a given fish, method of take, and country or region of origin, refer to the Monterey Aquarium’s Seafood Watch.

“Why would you domesticate a tiger when you could domesticate a cow,” he asks — or, even better, a chicken, which converts just 2 pounds of vegetarian feed into a pound of meat.

Because it tastes different/better?

Catfish or tilapia doesn’t taste like tuna.

Fish farms can have heavy parasite loads, like farming land animals there’s the problem of waste disposal, and basically it’s not as easy as it looks to do it profitably or sustainably. It can be done well, and for fish that can get by on a vegetarian diet there are some good ecological aspects. For meat-eating species, well, you have to go out and catch fish for them to eat, or farm their prey species to feed them.

Meanwhile, wild fisheries can be managed in a sustainable fashion. The Pacific salmon up near Alaska is an example. Of course, it helps that territorial claims and fishery regulations can be backed up by the US Coast Guard and/or Navy as appropriate - if you’re a small, poor country in, say, Africa you can’t keep massive fishing vessels from other nations from scooping up your fish in total disregard of your laws or any form of sustainability.

Rainbow trout are farmed in Northern Arkansas for release into the White River for sportfishing.
Catfish is farmed as food.
Tilapia are farmed, and used to clean up ponds where other fish have been raised.

the issue for me is more about sustainability. I don’t know how long wild caught seafood will be an option at the rate we are going.

The point is as a business venture. Efficiency of dollars out for dollars in. Raising fish that eat fish that you may have to raise costs lots more than raising fish closer to the bottom of the chain.

Predators are inefficient to farm.

Shrimp are grown in the Arizona desert.

Fish farming still requires a lot of wild fish to be caught and turned into fishmeal for the feed the farmed fish will be eating. And I mean A LOT of fish.

The Peruvian and Chilean anchovy meal fishery is huge, as in 9 million tons caught. I used to be the purchaser for a small fish feed manufacturer. Small as in we only used a couple million pounds of fishmeal a year. Other companies in the industry are much bigger. And it is a world wide industry.

Peru: Where have all the anchovies gone? | The World from PRX (

According to the United Nations’ Food and Agriculture Organization, the Peruvian anchovy is “the most heavily exploited fish in world history,” with annual catches in Chile and Peru sometimes totaling more than 9 million tons, two or three times the United States’ catch of all fish species.

Tangentially, Florida diver praised after spearing record lionfish.

In 2019, 25,000 lionfish were removed during the Challenge. In 2020, 21,569 lionfish were harvested and David Connerth was proclaimed Lionfish King after he removed 1,141 lionfish via recreational fishing methods.

Now, 25,000 lionfish aren’t enough to support a large industry, but I think that’s enough for a local industry. I’ve heard they’re delicious. Support local divers and fishermen? Support local restaurants? Remove an invasive species? Sounds like a win all around. (Except for the fish themselves, or course. :wink: )

And yet… we do exactly that when profits are high enough. Mink, for example. Foxes. Mostly for fur bearing animals but hey, if people are willing to pay enough for tuna to make it worthwhile…

That’s why you should check the MB Aquarium resource, it’s not as simple as “wild species X bad, wild species Y good” but also the region and such. Overfishing is sometimes an issue, but habitat issues are generally more destructive. And fishing can be controlled with less invasive methods of take - remember the trend towards “dolphin-safe” nets?

Of course some species are inherently good or bad for consumption. Orange roughy take a long time to breed so you could avoid eating them. Red snapper is getting some protections, but apparently a huge percentage of that sold in restaurants is “counterfeit” and some other species. Tilapia are very sustainable, but enjoys a poor taste reputation. Rainbow trout, arguably the most important recreational food fish in North America, has a relatively small native range but are now found everywhere and in no danger, though some steelhead (ocean-bound rainbow trout) fishers are threatened.

A recent example is menhaden which got protections last year.

It’s the fish equivalent of Gotham Greens

Here in the Midwest we need to make Asian Carp popular enough that the foodies will eat them all.

Exactly correct. Meanwhile though wild caught tuna is significantly cheaper than farmed would be while considered of higher quality, and is at a price people buy it at, so the price point consumers would pay for farm raised tuna and whether it would have any profit margin is not tested. Would they pay mink prices for a tuna steak? I doubt it personally but who knows? Consumers be strange sometimes.

FWIW though barramundi is a predator fish that IS farmed.

It tolerates crowding, does well on pelletted food, and grows fast. But it does not taste like tuna. (Okay but nothing special.)

I was in Nova Scotia several years ago and one of the towns with a harbor had what I think was a salmon farm. There was quite a bit of local opposition with yard signs all over the place. We went on a whale watching trip and the operator told us that waste (poop and uneaten food) from the farmed fish was ruining the harbor as the tides didn’t do nearly enough to flush it out. Anecdotal, but I had no reason to dis-believe him.

Yep, and that’s not limited to just Nova Scotia. It’s the same poop-disposal problem bit cattle and hog operations have, just in the water instead of on land (although cattle/hog poop can wind up in waterways, too).