The global appetite for fish has doubles over the last thirty years. But because of depletion of the world stock, virtually all the growth in the catch today comes not from the ocean but from fish raised on farms, or aquaculture.
Farmed salmon, for example, spend the 2 – 3 years of their lives crammed into pens, where there are fed high protein fish meal. This practice of giving farmed fish the ground up bits of other marine species results in a net loss to world fish protection: according to a study, for ten types of fish commonly farmed on average of 1.9 kilograms of wild fish is required for every kilogram of farmed fish.
There is a proposing the next phase of fish farming open ocean aquaculture, or the constriction of penned farms for large carnivores fish fattened with fish meal, located more than 300 kilometers offshore.
As with livestock, farmed fish often contain a range of unexpected ingredients. They require massive doses of antibiotics and pesticides to prevent diseases that result from overcrowding , including sea lice, a parasite that can spread quickly in crowded pens.
Fish Farming of the Sea