Gunter Pauli suggests a different model for the 21st century and beyond based on the notion of “economies of scope”:
Fish is healthy and proteine rich, but human appetite can hardly be satisfied only with fish caught from the oceans. On the other hand, the many fishes squeezed together in aquaculture lead to eutrophication of the ponds and surroundings due to the high amounts of fish feed and feces.
China has a long tradition of sustainable aquaculture. Professor George Chan has studied the production methods in the rural areas of his homeland and learned how to combine fish ponds and piggery in an intelligent manner. The pig maure is lead through algae ponds where benthos and plancton is raised which serves as feed for the fishes. The grass on the dikes is used as animal feed as well.
The result is a cycle of nutrients which involves all five kingdoms of nature. Without any additional fishfeed, the productivity achieved is lower if you only account for fish, but as there is also pork and vegetables, the business is competitive and economically sustainable. A new aquaculture model which uses economies of scope: This is how Blue Economy works.
More at http://www.blueeconomy.de/