Fish oil is oil derived from the tissues of oily fish.Fish oil is recommended for a healthy diet because it contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), precursors to eicosanoids that reduce inflammation throughout the bodyHowever, fish do not actually produce omega-3 fatty acids, but instead accumulate them from either consuming microalgae that produce these fatty acids, as is the case with prey fish like herring and sardines, or, as is the case with fatty predatory fish, by eating prey fish that have accumulated omega-3 fatty acids from microalgae. Such fatty predatory fish like mackerel, lake trout, albacore tuna and salmon may be high in omega-3 fatty acids, but due to their position at the top of the food chain, these species can accumulate toxic substances (See biomagnification). For this reason, the FDA recommends limiting consumption of certain (predatory) fish species (e.g. albacore tuna) due to high levels of toxic contaminants such as mercury, dioxin, PCBs and chlordane. Due to this limitation, many people have turned to fish oil supplements to get adequate omega-3 fatty acids.Fish oil supplements have sometimes come under scrutiny in recent years. In early 2006, government agencies such as the Food Standards Agency in the UK and the Food Safety Authority of Ireland reported PCB levels that exceeded the strict new European maximum limits in several fish oil brands, which required temporary withdrawal of these brands. To address the growing concern over contaminated fish oil supplements, the International Fish Oil Standards program, a voluntary review process, was created at University of Guelph.Patented production purification processes do however exist in order to remove pollutants and dioxins from fish oil to levels far below the EU limits. This is called stripping technology.Most of the fish oils used for Omega purposes are originating from Peru, Chile and Morocco because the Omega 3 levels in the fish caught in these areas are higher (around 30%) than in Scandinavian and other fish oils (around 20%). Fish oils are being used in the Omega 3 industry to produce nutraceuticals and pharmaceuticals. However the largest off-takers of the Omega 3 fish oils are still the feeding buyers with the big fish feed companies such as Ewos, Skretting and Biomar in the lead.