Breeding events lasted only one night, the sex ratio was male-biased, and male mating behavior changed from acoustic competition to scramble searching over the breeding event. Most of the males had similar opportunities to mate with a large or small female. Males did not defend territories and did not exhibit parental care. A female digs a nesting hole (called a redd), where she deposits thousands of eggs before the male releases his sperm. After mating, the male and female stand guard over the eggs to protect them from predators. Chinook salmon burn a lot of energy migrating to the nesting grounds, breeding and protecting the eggs.
These eggs usually measure around 30 by 23 millimetres ( by in). The male incubates the eggs for 28 days. A female may sometimes shade and squat over the eggs but rarely incubate them. A female may reluctantly incubate the eggs if a male doesn't have sufficient time to forage throughout the day due to rain and cool temperatures. Dec 15, · Encourage the male to mate by introducing him to competing males. Males compete for females in the wild, so this will encourage him to mate. Do not disturb them while coupling to allow them time to mate. The female will soon become gravid (pregnant). About 6 weeks later, when the female lays her eggs, put them in an incubator.
Males set up territories under submerged objects and defend these breeding sites from other males. Females are attracted to the males and lay eggs on the undersides of hard surfaces in the water. Spawning substrates provided by farmers include boards, pallets, plastic tarps and irrigation tubing. The female lays up to seven eggs between late April and early May. Both sexes incubate the eggs, which hatch after days. The young birds, or cygnets, sometimes ride on their parents' backs and remain with the adult birds for four or five months. Cygnets are .