Estuary Rearing Estuary Rearing Estuaries are very important in the life cycle of salmon.
Estuaries are areas where fresh and salt water mix to form brackish water.
When fry enter the brackish water, the smoltification process begins. Smolts must undergo many physiological changes to live in salt water, and estuaries allow salmon to undergo these changes gradually. This gradual change increases survival of the smolts. If a flood occurs on a river or stream, parr or smolts may be washed out to sea before most of the physiological changes occur. This can cause high mortality of juveniles.