What do you want? What do you have? These are fiberglass tanks -- about adult human height -- full of fish. Humans dump in grass clippings, and grass carp eat that. Algae grows on fish manure, and tilapia eat the algae, while mirror carp keep things stirred up. Maybe there are some bluegills to get rid of any hungry baby fish the others might pop out. Protein for crap! This 35-year old picture of ecological food production is from the New Alchemy Institute.
I'm interested in practical solutions for an empire and a world that face declining fossil-fuel wealth. Peace and justice may become more elusive as oil becomes dearer. Stability, and what E. F. Schumacher called "a becoming life," will require an economy that operates on its solar income.
At age sixty, I'm beginning to learn how.