There are 7 different indigenous salmon in Washington State and Oregon. They are the Coho, Chinook, Chum, Sockeye, Pink Salmon, Cutthroat, and Steelhead. When Lewis and Clark came to the Pacific Northwest in 1805 there were nearly 5 million fish in the Pacific Northwest area. Now many salmon stocks in Washington and Oregon are listed as either threatened or endangered under the Federal Endangered Species Act. The salmon that we have chosen to study is the Coho Salmon (Oncorhynchus kisutch). We have studied these fish at Eagle Creek Springs near the Sol Duc River.

The Coho Salmon is an anadromous fish. This means a fish that spends most of its life feeding in the ocean but returns to fresh water to breed. 

There are 2 kinds of Coho salmon. One is a wild salmon. A wild salmon is a fish that is born in a stream, migrates to the ocean and returns to the same stream it was born in to spawn. A hatchery salmon is a salmon that is born in a hatchery, migrates to the ocean, and returns to the hatchery to spawn. Hatcheries have been making the Coho salmon but they can’t become wild because they always return to the hatcheries to spawn. 

Salmon always return to where they were born. Scientists aren’t sure why they do this. Some scientists think that the soil and plants give off a smell. Salmon pick up this smell before they leave the stream. When the salmon return to the stream from the ocean it will remember the smell and follow that smell back to the stream it was born in.

A salmon’s life history has five different stages. These are the alevin, fry, smolt, ocean salmon, and spawning salmon. 

A salmon egg takes 2 to 4 months to develop before they hatch. When the salmon hatch it is called an alevin. Alevin live under the rocks where they were born. The alevin are born with egg sacks and they feed from these egg sacks for up to 40 days. They then swim out of the rocks. When they emerge from the rocks they are then called fry.

Fry come out of the rocks about April or May. The fry stay close to where they were born. They feed off on aquatic bugs (water bugs) and dead salmon. A fry will start moving down stream around November.

Around April or May of the next year the salmon are very close to the ocean. The salmon now are called smolts. Smolts live in an estuary. An estuary is a pool near the ocean that has a mix of fresh and salt water. They stay here for smoltification.

Smoltifications is how a fish goes through changes to be able to live in salt water. A fry can live only in fresh water. The fry have gills to breathe. The gills separate the oxygen from the water. A fry is an orange color with spots. This helps from being seen from predators that would like to eat them. When a fry becomes a smolt its colors change to silver. They live in the estuary with fresh and salt water until their gills change. When their gills are able to filter out the salt, the salmon is ready to go to the ocean. The ocean salmon will live and feed in the ocean for about one year. A jack is a salmon who stays less than 6 months at sea before trying to return to fresh water.

The adult Coho will leave the ocean and go back to fresh water. Salmon like to swim upstream during the daytime. Most of the salmon migrate between 8 a.m. and 6:30 p.m. The peak hours for migrating are 2 p.m. to 4 p.m.