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
Fish meal be made from almost any type of seafood, but is generally manufactured from wild-caught, small marine fish that contain a high percentage of bones and oil, and are usually deemed not suitable for direct human consumption. The fish caught for fishmeal purposes solely are termed "industrial". Other sources of fishmeal are from bycatch and byproducts of trimmings made during processing (fish waste or offal) of various seafood products destined for direct human consumption. The main fish sources by country are: It takes 4 to 5 tons of fish to produce one ton of fish meal; about 6 million tons of