It is more than just salmon farms. That is only part of it. Aquaculture includes the shellfish and algae as well as freshwater and marine environments – and it is growing every year. It is probably the fast growing food sector. Another fact is that fish constitutes an important source of food and animal protein for many countries in the world. It is not just the middle and upper class consumer (that is anti-fish farm rhetoric). Here are some more facts:
-Globally, fish provides about 3.0 billion people with almost 20 percent of their intake of animal protein, and 4.3 billion people with about 15 percent of such protein.
-In fact, many populations, more those in developing countries than developed ones, depend on fish as part of their daily diet.
-Approximately 16.6 million (about 30 percent of all people employed in the fisheries sector) were engaged in fish farming, and they were even more concentrated in Asia (97 percent), followed by Latin America and the Caribbean (1.5 percent), and Africa (about 1 percent).
-In the last five years for which data are available, the number of people engaged in fish farming has increased at 5.5 percent per year compared with a mere 0.8 percent per year for those engaged in capture fisheries.
-Freshwater fishes dominated world aquaculture production in 2010 with diadromous fish coming in fourth.
-Production of freshwater fishes has always been dominated by carps (71.9 percent, 24.2 million tonnes, in 2010).
-Salmonid production, particularly Atlantic salmon, increased dramatically from 299 000 tonnes in 1990 to 1.9 million tonnes in 2010, at an average annual rate exceeding 9.5 percent.
-In 2010, diadromous fish production was dominated by Atlantic Salmon at approximately 1.4 million tonnes.
-In 2010, the white leg shrimp accounted for 71.8 percent of world production of all farmed marine shrimp species, of which 77.9 percent was produced in Asia (with the rest in its native home in America)
Critics of aquaculture can deny this all they want and drag in Malthusianism, but the facts are there if you look at the Food and Agriculture Organization of the UN (FAO) website. Are there challenges to aquaculture? Absolutely, there are challenges with any agricultural sector. There are challenges for capture fisheries also, but aquaculture is not going away.
http://www.fao.org/docrep/016/i2727e/i2727e.pdf