Well, it's not like "harðfiskur" is cheap. 100 grams go for about $8. Icelanders don't eat a lot of fish any more. Almost all of it is exported.

Is the fishing sustainable? I don't know. Probably not.

There are about 340,000 Icelanders, and Iceland has a 200 mile exclusive fishing zone around its coast.

Such a zone around a single point already is over 120,000 square miles.

So, at less than 3 Icelanders per square mile of ocean, I doubt they could eat all the fish in ‘their’ ocean.

Drying fish is highly sustainable, as it is done on low-tech solar power.

The only concern could be the method of catching fish. I doubt that makes much impact, though, and if it does, there’s bigger fish to fry elsewhere (pun intended)