Fish farming is gaining popularity as a way to save endangered species of fish, particularly the blue fin tuna. Farming carnivorous fish such as salmon and tuna is less efficient than raising omnivorous fish such as tilapia. The increasing demand for the more popular carnivorous species has made farming them profitable in spite of the fact that they create a demand for feed that wild fisheries struggle to fill. A single blue fin tuna, endangered in the wild, sells in the Japanese sushi market for many thousands of dollars.
Things You'll Need
- Containment facilities
Decide which sort of containment facility to use. These include open net pens or cages, ponds, raceways and recirculating system. Tuna are typically farmed in open net pens, which are offshore enclosures of nets suspended from surface catwalks. However, they can also be raised in a recirculating system. In recirculation, the environment is enclosed, and the fish cannot escape or pollute the wild population with waste, parasites or less hardy breeding. One drawback of the recirculating system is that it requires electricity and is less profitable.
Catch your stock. Most tuna is caught in the wild and raised in a facility for the sake of increasing the fatty content (called “toro” in Japan) to make it tastier. Only recently has blue fin tuna been raised from parents in captivity. There has been much progress in developing fully farmed blue fins, but they are still very expensive to raise.
Feed your stock. A viable tuna farm requires approximately 2,000 fish at any time, and they consume tons of feed. Tuna are carnivorous and eat other fish, commonly pilchards, sardines, herrings and anchovies. These fish are high in oil content.
Harvest your stock. Typically, divers enter the pen and toss the fish into small boats until the numbers have thinned and the fish become hard to grab. Stragglers are then caught conventionally with hook and line.