Drama had already happened in the first of the fish farms I visited. A boat was sinking and half of the village came to shout advice, take their lunch and watch the spectacle. I was surprised that in a village where everyone would know each other, no one was offering to lend a much-needed hand. I stood by helplessly as the boat bubbled deeper into the water before being ushered by the locals. It turned out that the boat was in the down streams of the fish farm. As long as the drama was happening away from the million of US dollars worth of fish, all was casual entertainment to the farmers.
Fish have a higher food conversion efficiency than land meats. For example, it takes 1.1 kg of feed to produce a kg of salmon whereas it 2.5 kg of feed per kg of chicken range. Fish don’t have to stand up or keep warm.
Type 1: Extensive Aquaculture – is an ecosystem that relies on the good old-fashioned photosynthesis. Algae converts light into energy and passes this along the food chain until energy is delivered to the large carnivorous fish. A lot of energy, about 99%, is lost because commercial fish is higher along the trophic level. Farmers that are tempted by fertilisers to promote faster algae growth risks an algae bloom and suffocating all the fish in the pond.
Type 2: Intensive Aquaculture – relies on externally farming the fish on commercial feed. Most of the feed is mixed with vegetable protein and wheat and small fish caught from the wild that didn’t make it into the market. Large industrial purification pumps are necessary to keep the pond sufficiently oxygenated. Catfish can tolerate lower oxygen levels and are better suited to this, especially in the suffocating hot summers here.
“They used to tank cod from Alaska all the way to China. They’d keep them in vats in the ship. By the time the codfish reached China, the flesh was mush and tasteless. So this guy came up with the idea that if you put these cods in these big vats, put some catfish in with them and the catfish will keep the cod agile. And there are those people who are catfish in life. And they keep you on your toes. They keep you guessing, they keep you thinking, they keep you fresh. And I thank god for the catfish because we would be droll, boring and dull if we didn’t have somebody nipping at our fin.” -Vince Pierce, Catfish (2010)