If you read this site regularly you will know that I am no fan of farmed fish as industrial fish farming raises many of the same concerns about chemicals and pollutants that are associated with feedlot cattle and factory chicken farms. Today, farms typically put 50,000 to 90,000 fish in a pen 100 feet by 100 feet. A single farm can grow 400,000 fish. Others raise a million or more. Unfortunately, a farm of 400,000 salmon flushes nitrogen and phosphorus into the water at levels equivalent to the sewage from 40,000 people and since most farms are near the shore where currents don't disperse these wastes they become an ecological disaster.
Now we learn that technology will allow these farmers to deploy open-ocean aquaculture. These deep-sea farms will spew as much waste into the water as the near-shore facilities opposed by environmentalists, but they'll be operating in the open ocean--an area so devoid of life that it's routinely called a wasteland.
However, even if the waste issue isn't a problem, the major issue will be releasing genetically modified mutants into the sea that invariably escape from these pens. This year the FDA will likely approve the first genetically modified AquAdvantage salmon for human consumption. What policing body is going to go into the middle of the ocean to make sure this isn't happening? Preventing the farmed and the wild from interbreeding is surprisingly difficult. Fish leap from pools and tanks into nearby streams and wriggle through holes in near-shore pens gnawed by seals and sea lions. Such escapes are potential genetic catastrophes.
Wired May 2004