1. Migration: Most salmon species migrate from the ocean to their natal rivers to spawn. This journey can be hundreds or even thousands of miles, and the fish use a variety of cues, including smell, to find their way back.
2. Color Changes: During the migration, salmon undergo dramatic physical changes, including changes in color. Their skin can become bright red, orange, or green, and their scales may become darker. These changes serve to attract mates.
3. Territoriality: Male salmon establish territories in the river and defend them against other males. They often use their bodies and fins to fight and display dominance.
4. Courtship Displays: Males will use a variety of behaviors to attract females, including:
* Nesting: Males dig shallow nests, called redds, in the gravel bed of the river.
* Chasing: Males may chase females around the territory.
* Head-Shaking: Males may shake their heads back and forth, displaying their brightly colored body.
* Tail Beating: Males may beat their tails against the water to create a current that draws females towards them.
* Sounds: Some salmon species make noises to attract mates.
5. Spawning: Once a female is ready to spawn, she will select a male and deposit her eggs in the redd. The male will then release his milt (sperm) to fertilize the eggs.
6. Parental Care: After spawning, both the male and female salmon usually die. They do not provide any parental care to their young.
Some Specific Examples:
* Chinook Salmon: Males develop a prominent hump on their backs and their jaws curve into a hooked shape. They display aggression towards other males and fiercely defend their nests.
* Sockeye Salmon: The males develop a bright red body and their head becomes green. They perform a variety of courtship displays, including circling, head-shaking, and tail-beating.
Salmon mating rituals are fascinating examples of natural selection in action. These behaviors have evolved over millions of years to ensure the survival of these incredible fish.