PT153 S1 P2 Q7 ExplanationFish Farming

A recent worldwide decline of ocean fishery stocks has stimulated rapid growth in cultivated production of fish and shellfish, usually known as fish farming. Between 1987 and 1997, for example, global fish production from farming doubled. Fish farming produces a quarter of all fish and shellfish eaten by humans, and, as global solution, but also a potential contributing factor, to the continued decline of ocean fishery stocks worldwide.

In the first place, the more intensive forms of fish farming, oriented toward high-volume production, threaten the sustainability of ocean fisheries through water pollution and ecological disruption. Intensive fish farming usually involves the enclosure of fish in a secure system; population densities are typically high, resulting in the generation of large amounts pathogens can all ensue, seriously damaging ocean and coastal resources and, ultimately, wild fishery stocks.

Even more important, intensive farming of many species of fish requires large inputs of fish meal and fish oil in order to supply fatty acids that vegetable matter lacks or essential amino acids that it inadequately supplies, like lysine and methionine. For the ten species of fish most commonly farmed, an average carnivorous species requires up to 5 kilograms of wild fish for every kilogram of fish produced.

Expanding farm production does have the potential to alleviate some of the pressure on wild fishery stocks. For example, increasing the farm production of fish like salmon can reduce prices, deterring investment in fishing fleets and, over time, reducing fishing efforts. Similarly, other farmed fish like tilapia and channel catfish provide alternatives catch rates to remain high even as the production of viable farmed substitutes has increased.