depressed populations. The commercial salmon fisheries in California have been either severely curtailed or closed completely in recent years, due to critically low returns on the Klamath and or Sacramento rivers, causing millions of dollars in losses to commercial fishermen. Both Atlantic and Pacific salmon are popular sportfish. Salmon populations have been established in all the Great Lakes. Coho stocks were planted by the state of Michigan in the late 1960s to control the growing population of non-native alewife. Now Chinook (king), Atlantic, and coho (silver) salmon are annually stocked in all Great Lakes by most bordering states and provinces. These populations are not self-sustaining and do not provide much in the way of a commercial fishery, but have led to the development of a thriving sport fishery. Wild, self sustaining Pacific salmon populations have been established in New Zealand, Chile, and Argentina. They are highly prized by sport fishers, but others worry about displacing native fish species. Also, and especially in Chile (Aquaculture in Chile), both Atlantic and Pacific salmon are used in net pen farming. In 2020 researchers reported widespread declines in the sizes of four species of wild Pacific salmon: Chinook, chum, coho, and sockeye. These declines have been occurring for 30 years, and are thought to be associated with climate change and competition with growing numbers of pink and hatchery salmon. As food Salmon is a popular food fish. Classified as an oily fish, salmon is considered to be healthy due to the fish's high protein, high omega-3 fatty acids, and high vitamin D content. Salmon is also a source of cholesterol, with a range of depending on the species. According to reports in the journal Science, farmed salmon may contain high levels of dioxins. PCB (polychlorinated biphenyl) levels may be up to eight times higher in farmed salmon than in wild salmon, but still well below levels considered dangerous. Nonetheless, according to a 2006 study published in the Journal of the American Medical Association, the benefits of eating even farmed salmon still outweigh any risks imposed by contaminants. Farmed salmon has a high omega-3 fatty acid content comparable to wild salmon. The type of omega-3 present may not be a factor for other important health functions. Salmon flesh is generally orange to red, although white-fleshed wild salmon with white-black skin colour occurs. The natural colour of salmon results from carotenoid pigments, largely astaxanthin, but also