Salmon fish are river fish; they are born in freshwater and then migrate to the oceans, returning to fresh water only when they reach adulthood to reproduce.
Salmon is an important food source for humans and many animals, such as bears, wolves, buttocks, and many mammals, birds and insects.
Females take the white Pacific salmon one time throughout their life, and die after ovulation days or weeks. It is therefore known as Semelparity, and their decaying bodies feed the micro plants and animals on which young salmon will feed after hatching for one to three months Months, while female Atlantic salmon can be ovulated more than once.
Salmon females weigh between 2500-7000 eggs, depending on the type and size of the fish. Egg color ranges from orange to red. Fertilization takes place in the water where sperm fertilize sperm for fertilization. The females then cover the eggs enriched with the pebbles to protect them.
During their development, small salmon fish acquire the ability to live in saltwater waters gradually. It takes between one to three years in freshwater, and then migrates, where its body chemistry changes to become more adaptable to salt water and spends part of its migration time in moderate waters Salinity; until you get used to regulating the body’s nitrogen pressure before reaching the ocean’s salty water.
Depending on the species, the salmon age can be determined by the number of growth rings on their scales using a microscope. These rings are similar to the growth rings that appear on tree trunks. The growth rings formed during their years of life Fresh water is close and crowded, but the growth episodes that appear during their living in saltwater are much more distant from each other.
Small salmon fish feed on insects, snails and other crustaceans, while older fish feed on other fish.
Salmon species are exposed to many life-threatening hazards such as predators and changes in their habitat due to human activity such as silt accumulation, low oxygen concentration, high water temperature, and low water flow in rivers.
Salmon fish rely on the sense of smell for their migration from the ocean to the river where they were born. At least one species of salmon, the Sukay salmon, can infer its migration path by sensing differences in the Earth’s magnetic field.