|Salmon of the West|
Why are salmon in trouble? - Poor Habitat
A salmon's world covers thousands of miles. During its four to five-year life span, an individual salmon can migrate from inland mountain streams to the Pacific Ocean, using many different habitats in between.
Common threats in streams include pollution, the destruction of stream-side plants and the lack of clean, cold water.
Pollution comes in many forms. Erosion from logging and development washes into streams, covering salmon eggs and suffocating them. Runoff from city streets, agricultural land and neighborhoods introduces harmful chemicals into streams, injuring or killing salmon and other stream inhabitants in the food chain.
Riparian (stream-side) plants shade the water, keeping the stream cooler (salmonids prefer cold water). Plants provide wood and roots that shelter young fish and provide resting places for them. Plants also filter pollution and hold soil in place to minimize erosion.
Rivers may become slow and
warm when water is withdrawn for farming and other uses, making them
unhealthy for salmon. Sometimes salmon and other fish, such as bull
trout, are stranded in small pools when sections of a river dry up
from too many withdrawals.