The Life Cycle of a Salmon — Passage and Quiz

Salmon have a fascinating life cycle that takes them from freshwater rivers to the ocean and back again. It all begins when female salmon lay their eggs in gravel nests called redds in rivers or streams. These eggs are fertilized by male salmon and then covered with gravel to protect them.

After a few months, the eggs hatch into tiny fish called alevin. Alevin stay in the gravel, feeding on a yolk sac attached to their bodies. Once they've used up the yolk sac, they become fry and swim up out of the gravel to find food on their own.

As the young salmon grow, they become parr. Parr have distinctive markings on their sides that help them hide from predators. They spend one to three years in the river, growing and preparing for their journey to the ocean.

When they're ready, the parr go through another change. They become smolt, and their bodies adapt to salt water. Smolt travel downstream to the ocean, where they'll spend most of their adult lives. In the ocean, salmon grow much larger, feeding on smaller fish and shrimp.

After spending one to five years in the ocean, adult salmon make an incredible journey. They swim back to the exact river where they were born. This trip is called a salmon run. The salmon stop eating and use all their energy to swim upstream, sometimes jumping up waterfalls! When they reach their spawning grounds, they lay their eggs, and the cycle begins again.

Sadly, most salmon die after spawning. But their bodies provide important nutrients for the river ecosystem, helping to support the next generation of salmon and other wildlife.