Fish are fed fish-meal made from wild fish, PETA quote that it takes 5kg to produce 1kg of farmed salmon, WWF say 4kg of wild-caught fish is needed to produce 1kg and Farmed and Dangerous write that ‘depending on the production region, 1.5 – 8 kilograms of wild fish are needed to produce one kilogram of farmed salmon.’ The Fallacy of Farmed Fish quote 3lbs for a 1lb of Atlantic salmon. More information including an excellent Ecologist video in this link Peru’s sea lions & birds dying, locals sick, all for farmed salmon!
Last year ‘Peru cuts commercial fishing drastically on worries about stocks.‘ Peru has slashed its commercial fishing quota as warmer water temperatures and controversial practices deplete stocks of anchovy in one of the world’s richest fisheries.
Negative Environmental effects – WWF website:-
Excessive use of chemicals—such as antibiotics, anti-foulants and pesticides—or the use of banned chemicals can have unintended consequences for marine organisms and human health.
Disease and Parasites
Viruses and parasites that transfer between farmed and wild species as well as among farmed species present a risk to wild populations or other farms.
Escaped farmed species can compete with wild fish and interbreed with local wild stocks of the same population, altering the overall pool of genetic diversity.
Aquaculture must responsibly source and reduce its dependency upon fishmeal and fish oil—a primary ingredient in feed—so as not to put additional pressure on the world’s fisheries. Fish caught to make fishmeal and fish oil currently represent one-third of the global fish harvest.
Nutrient Pollution and Carrying Capacity
Excess food and fish waste increase the levels of nutrients in the water and have the potential to lead to oxygen-deprived waters that stress aquatic life.
Seafood farming often employs a large number of workers on farms and in processing plants, potentially placing labor practices and worker rights under public scrutiny. Additionally, conflicts can arise among users of the shared coastal environment.
Land Conversion and Degradation
Clearing of land for agriculture feed sources affects high conservation value areas.
This month we hear about the World’s biggest “salmon warehouse” set to be built in Scotland. Although this is good news for seals and no doubt may solve some of the problems relating to fish farms at sea, there are however unsustainable environmental impacts being caused by fish farming.