In 2022, aquaculture supplied a majority of seafood consumed by humans for the first time. But there are many gray areas – fish are hatched in tanks, released to the wild or pens located in natural water bodies, then caught again later. Farmed fish are fed wild-caught fish. And regardless, fish farming generates nutrient loads to natural waters.

I’ve fantasized about a system where earthworms are produced using compost from food scraps and other sustainable sources, then fed to fish and shellfish in tanks, then the nutrient-enriched water is used in fertilizer-free hydroponic agriculture, and finally the water is cycled through a wetland treatment system and used repeatedly. So the only input to this hypothetical system would be garbage (okay, and air and energy), and the outputs would be compost, fish, shellfish, and vegetables. I’m sure there are may practical challenges to this system, but in principle it should work. AI might be able to constantly monitor and make small adjustments to a system like this to keep it running efficiently.