Now, increased demand for traditional fishmeal – which is made from small species caught in the open ocean – has sent the industry scrambling for alternatives.
The stuff being used to make fish feed is a byproduct of the poultry industry – it’s what is left over after the parts of the chicken consumed by humans and the remains used for cat and dog food have been removed.
I’ve seen a documentary a while back that the fish feed from the baltic sea used for fish farms is pretty toxic.
All fish are contaminated with some kind of pollution. One of my lab mates in grad school did a study that showed there is no region of the oceans where caught fish do not have statistically significant levels of BPAs.
This is why they tell you to not eat salmon or tuna more than once a week.
Sorry I think I misunderstood the comment I replied to a little. But basically even in the EU anyone should prefer salmon that is fed chickenmeal or poultrymeal instead of fishmeal, because the contamination accumulates. And the baltic where a lot of the fishmeal came from (or at least used to come from) is especially toxic. But that is also getting better.
I think the best kind to do fish farms would be to develop systems where you grow your own protein rich algae in the ocean using sunlight and some fertilizer in big floating basins, and then feed the algae to (filter) fish. Then you can fully control it and are not dependent on waste. If we could scale up and automate that kind of aquaculture farming it would solve a lot of problems for protein food supply and overfishing. Because you could do it anywhere, and the oceans are basically lifeless deserts otherwise.
Also archive link for the OP article: https://archive.is/20261019103818/https://www.thejournal.ie/salmon-fed-chicken-7195347-Oct2026/