They gather at the river's mouth to await heavy rains before moving upstream. During upstream migration, salmon do not feed. Back to Top Spawning - When salmon reach their spawning grounds males and females pair off. Females look for rippling waters and clean streambed gravel that can be swept aside with broad tail strokes. The scooped-out gravel forms a depression about the shape of the females body but twice as long.
Males compete to spawn with the female.
Sometimes smaller males called jacks are also present. Jack salmon are small because they migrate after only a year in the ocean but can spawn nevertheless. The female deposits some of her eggs in the redd and the male fertilizes them with a milky cloud of sperm called milt. Eggs are laid in batches deposited in pockets within the redd. Spawners guard the nest to protect it from intruders.