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A Great Stream Requires…. Clean Water. Water must be free of human waste and pollution i.e. Garbage Sewage Waste run off Ex. Industrial Agricultural . Hiding in the Gravel. Salmon require a certain amount of gravel deposit to lay their eggs
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Clean Water • Water must be free of human waste and pollution • i.e. Garbage • Sewage • Waste run off • Ex. Industrial • Agricultural
Hiding in the Gravel • Salmon require a certain amount of gravel deposit to lay their eggs • The eggs and eventually the Alevin hide in these deposits until they are big enough to emerge • These deposits must be made up of pebbles – Not dirt or sediment run off, which is made up of tiny bits of rock, soil and plant matter • This sediment • Blocks sunlight • Clogs fishes gills when they breath it in • Fills gravel spaces trapping the tiny Alevin • Carries pollution into the stream
Stream Bottom • As you just learned, Spawning salmon need clean gravel to lay their eggs. This is where the eggs and Alevin will hide and grow • Fry eat insects that live in “ Riffles” where fast shallow water flows over baseball size rocks • Fry also need larger rocks to hide from predators and sunlight • Fry also need deeper pools to rest in
Vegetation A Natural Stabilizer • Plants that grow on the banks of streams provide much needed shade for the creatures that live in these streams. A healthy stream bank has a variety of native plants of all different sizes • Plants in and around the stream also provide a food source ( leaves, twigs, and fallen insects ) • Plants along the stream bed help keep much of the soil in place and prevent it from all falling into the stream, trapping and drowning creatures in the stream
Water Flow • The speed of the water flowing down a stream is very important to salmon and trout • If the water is moving to fast the fish get tired • If the water is moving to slow, the fish don’t get enough fresh water passing over their gills to breathe • Slow water warms up faster and loses oxygen • Fish diseases grow faster in warm water • Salmon eggs need water slowly trickling through the gravel spaces
Water Flow That Is Just Right • A stream that has changing water flow is a stream that is just right • Large rocks or logs slow down flowing water • Deep pools also slow the flow down and give a fish a place to rest • Shallow blockage free areas get water moving fast again
Livestock using a stream as a drinking source can cause soil and other contaminants to fall into the stream • Can eat many of the important plant life on the stream banks • Too much livestock manure can seep into a stream and pollute it