The health benefits of eating fish have been increasingly promoted over the past few years. Fish are low in fat and high in omega-3 fatty acids making them an excellent alternative to artery clogging red meat. However, the increased popularity in fish has taken its toll on wild fish stocks throughout the world leading to an increased dependence on fish farms. Yet, aquaculture poses problems of its own and may not provide the needed relief for wild fish populations.
The Popularity of Fish Farms
There are a variety of ways to farm fish including using human made tanks on land and net enclosures at sea. According to the NOAA Aquaculture Program website, as of September 2009 roughly half of the world’s seafood came from aquaculture resulting in a $70 billion industry. China currently exports the most aquaculture products in the world. However, countries such as the US strive to be more self-reliant. On September 3, 2009 the Associated Press reported plans for new fish farms in the US controlled waters of the Gulf of Mexico in “Federal agency approves plan for Gulf fish farming”.
Aquaculture Creates Pollution
The US plans to open new fish farms met with opposition from fishermen and environmentalists who argued that pollution from the farms could threaten marine life. This is a point elaborated upon by the WWF in their web page “Problems: Aquaculture”. Fish farms at sea typically use an open net cage system which allows waste water to leak into the surrounding environment. The high concentration of fish in an aquaculture system means a large load of fish feces in a small area. This can cause algal blooms which reduce oxygen in the area as well as produce ammonia, methane, and hydrogen sulphide. In excess, these compounds can kill marine life.
Fish Farm Escapees Endanger Marine Life
Fish farms are not high security prisons. Although farmers do their best to keep fish in their nets, these creatures often slip out. This is illustrated in the September 3, 2009 BBC article “Fish fears after sea farm escape” where 37,000 juvenile salmon escaped their Scottish nets to swim out to sea. The main problem cited in the article was the “genetic integrity” of wild salmon. Farmed fish are bred for certain traits and having them breed in the wild could cause havoc to the ecosystem. Another health issue, posed by the WWF in “Problems: Aquaculture” is the higher incidence of disease and parasites on fish farms. In particular, farmed salmon have a higher incidence of sea lice – which can be deadly to a fish.
Farmed Fish Eat Wild Fish
Perhaps the worst problem posed by aquaculture is that it puts pressure on fish populations. As Ken Stier’s September 2007 Time Magazine article “Fish Farming’s Growing Dangers” points out, humans tend to eat carnivorous fish such as tuna, bass, and cod. These fish must be fed smaller fish which are typically caught from the wild and ground into fish meal. Roughly 37% of all seafood in the world is ground into feed. It takes 20 kilograms of fish feed to create 1 kilogram of tuna, making for a highly inefficient system.
Also related to fish farming: Tuna Farms Are More Like Ranches
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