> This seems like an impossible requirement to meet for landlocked countries.
Why? There's plenty of freshwater fish that are farmed around the world. Trout, tilapia, etc.
> It's not enough just to label a country as producer/not producer for a category but rather whether that production is fully stable and internalized in case of disasters/war.
Conversely, many industrialized and wealthy countries can probably shift their production pretty easily. For example, looks like Hungary is doing well on fruit but not on vegetables. This is probably not because it's hard for them to grow vegetables, just that there's no economic incentive to.
Similarly, the two-way legumes / veggies difference between the US and Mexico probably boils down to free-market economics or government subsidies more than to any real agricultural bottlenecks on either side.
> There's plenty of freshwater fish that are farmed around the world. Trout, tilapia, etc.
Not to a level that could feed the entire country, surely.
No, but mostly for economic reasons. You can farm a whole lot of fish in aquaculture - it's just more expensive than importing wild caught fish.
The numbers look pretty insane, you can raise many tons of fish in relatively small volumes of water (several hundred kg of fish per year per cubic meter). You just gotta build the ponds/tanks/cages, and the infrastructure to filter the water, supply the oxygen and deliver the feed.
Why? If you have the money, the equipment, and the climate, what's stopping you from shifting agricultural production from one good to another on any scale you like? It's often as simple as the government saying "you know what, from now on, we're subsidizing beans instead of corn".
Barring some planetary-scale cataclysm, most of Europe and the US are at no real risk of starving. There are other countries that are at a real risk, but the map doesn't make a clear distinction between "red as a matter of convenience" and "red because they physically can't do it".
> If you have the money, the equipment, and the climate, what's stopping you from shifting agricultural production from one good to another on any scale you like?
Then we will lack whatever was produced on the place where you those new ponds with huge amount of fish.
This argument does not work, because we are not limited by available space in total agricultural output. Just consider the Netherlands: Second largest food exporter despite the US being >200 times larger.
Most of the richer countries/trade unions have a large meat surplus that could be easily shifted to something else, too.
Fish don't care about soil quality or level ground. If anything fish ponds can benefit from height differences because that allows you to flow water through multiple ponds before pumping it back up
Obviously nations do have limited surface area and creating new agricultural areas for them would be to the detriment of forests and "nature"
There is a difference between 'can produce the food with the climate' and 'should produce the food with the climate'. Comparative advantage crops up yet. Iceland can grow bananas by magma but they are grown slower and have more expensive labor than tropical banana growing countries.
What's stopping us from shifting agricultural production, is probably the same that's stopping us from fixing climate change.
If I read the study correctly the bar isn't to feed the entire population exclusively on fish, only to cover the expected ratio of fish in the diet.
> There's plenty of freshwater fish that are farmed around the world
Farmed fish are often fed on fish meal from the ocean - e.g. fish meal made from species that are not eaten by people. Between 5% and 10% of ocean fishing is used for such aquaculture.
Same same as the cattle example in Ireland being fed on imported animal feed.
That's only because that bycatch is almost free of charge in areas with significant ocean fishing fleets.
You can provide the right mix of proteins and fats from algal and insect sources, so this shouldn't be a barrier to increased adoption of fish farming.
(Scaling wastewater and disease management are perhaps greater challenges, but ought not to be intractable either)