Anadromous salmonids spend part of their lives in salt water. Chinook salmon, coho salmon, steelhead trout and coastal cutthroat trout are all anadromous. These fish leave their streams and migrate out to the ocean, where they grow much larger than salmonids that stay in the stream all the time. Chinook usually move into the estuary when they are several months old. The other anadromous fish all spend at least one year in the stream before migrating to sea. At the river's mouth, fresh water flows into the sea. The sea also surges into the river, and salt water mixes with fresh water. This area of brackish water is the estuary. Migrating fish stay in the estuary for a while before entering the ocean. They find new types of food to eat and grow larger, which helps them survive in the ocean. Their bodies also adjust to the salt water.
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The ocean
is a vast resource for the fish. They find much to eat, and they grow very
large. Cutthroat trout usually keep close to the river's mouth, and stay
for only a few months, so they remain fairly small. But salmon and steelhead
stay in the ocean for several years and grow very large. They may swim many
miles up and down the coast line. California's north coast is one of the
places richest in food in the Pacific Ocean. |
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Salmon and steelhead spend from two to five years in the ocean, depending on the species. The waters just off the coast of northern California and Oregon experience an upwelling of nutrients, which supports a rich ecosystem. Food is plentiful and the salmon grow large quickly. Schools of smelt, like the ones pictured above, are just one source of food.ts. | |
Salmon and Steelhead Life Cycle: | Early Stages | Adult | Spawning |
Salmon and Steelhead Habitats: | Freshwater | Ocean |
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