Sockeye salmon are red, which is the usual color of females. Even small changes in wavelength, saturation, and brightness can affect preference. Both sexually naïve males and experienced males showed the same preferences, which illustrates that preference for a red hue may be innate. Some traits that lead to reproductive success, such as body size and sexual dimorphism can affect one’s survival. This leads to opposing pressures of natural selection and sexual selection. Larger males are favored, unless the risk of predation is very high. Sockeye salmon that die prematurely from predation are typically the larger ones in a population. This shows
Sockeye salmon Resources Commission in an attempt to establish the species as a forage fish for other predator fishes in the lake. This stock has remained and become a favorite target for anglers. In Japan, a landlocked variety termed black kokanee, or ""kunimasu"" in Japanese, was deemed to be extinct after 1940, when a hydroelectric project made its native lake in northern Akita Prefecture more acidic. The species seems to have been saved by transferring eggs to Saiko Lake, 500 kilometers to the south, however. This fish has been treated as a subspecies of sockeye "Oncorhynchus nerka kawamurae", or even an independent