The Long Trip Home: Salmon Signal Words

The Long Trip Home

1Pacific salmon are fish with an amazing life story. They hatch in freshwater streams. However, they spend most of their adult lives in the salty ocean. At the end of their lives, most of them return to the very stream where they hatched. Many salmon swim hundreds of miles to make this round trip.

2A salmon starts out as an egg in a nest of gravel at the bottom of a cold, clear stream. After the young fish hatch, they hide among the stones and eat tiny insects. Clean, cold water is important for salmon eggs and young fish. For example, mud that washes into a stream can cover a nest and keep the eggs from getting the oxygen they need.

3When the young salmon are big enough, they migrate, or travel, downstream to the ocean. Along the way, their bodies change so that they can live in salt water. In the ocean, salmon find plenty of food, such as smaller fish and tiny shrimp-like animals. Furthermore, the open ocean gives them room to grow much larger. On the other hand, the ocean is full of predators, animals that hunt other animals for food. Seals, sea lions, and orcas all eat salmon.

4After a year or more in the ocean, the adult salmon begin the long trip home. Scientists think the fish use their sense of smell to find the stream where they hatched. The journey upstream is hard. The salmon must swim against the current, the flow of the water, and sometimes leap up small waterfalls. In addition, most of them stop eating once they leave the ocean. As a result, their bodies grow thinner and weaker as they travel.

5When the salmon finally reach their home stream, they spawn. For fish, to spawn means to release eggs that will start a new generation. Each female digs a nest in the gravel with her tail and lays her eggs there. Most Pacific salmon die soon after they spawn. Nevertheless, their long journey is not wasted. Their bodies break down and add nutrients, the materials that living things need to grow, to the stream. Therefore, plants grow well, insects have more to eat, and the young salmon that hatch there find plenty of food. In this way, each group of salmon helps the next one survive.