A flowing fresh water stream is all business. It rushes forward. If it slows at all, it is just to create small whirlpools or eddies, and then it's back on down the mountain. It makes its bed on gravel or hard rock. Its water is cool, sometimes painfully cold, especially in the spring when the stream is brimming with newly-melted snow.
A stream is not like a river. A stream's banks follow the straight and narrow. No playful meandering curves, no muddy bottom, no sunny, quiet shores. A river is a stream without the push.
Animals that live in a stream are adapted to life in the fast lane. Brook trout have strong, streamlined bodies and powerful tail fins that can push against the current. These fish need the cold, oxygen-rich water of a flowing stream in order to thrive. Shade is very important in keeping the stream cold. When forest fires, lumbering, or road building make streams lose their shade, they also lose their trout. Atlantic salmon are famous for their ability to buck the current. They swim upstream in spring in order to lay their eggs on the gravel bottom where they were born. Where man-made dams block their route, they will dash themselves to death against the concrete walls trying to leap over them. On some rivers in Maine, fish ladders help anadromous fish continue their journey. These are fish, such as salmon, shad, and herring, which spend part of their lives in the ocean, but return to fresh water to reproduce. Fish hatcheries rear small salmon called smolts to help stock Maine streams where salmon once were plentiful.
Other animals adapt to the swift current. Black fly larvae attach their rear ends to the underside of rocks by tiny hooks. If they lose their foothold (so to speak), they can lasso another rock with silken threads. Caddis fly larvae fashion durable homes from sand grains, leaf pieces, or grasses.
Since the time of the early settlers, Mainers have been making streams and rivers work for them. Look at a map of Maine and you will find many communities were founded next to rivers. Besides being a source of food and water, streams and rivers provided transportation routes through the thickly-forested landscape. Later they carried logs to sawmills and powered machinery for other mills. Many of these activities polluted our rivers. But some of the damage can be undone. Now several of Maine's streams and rivers are cleaner than they were a generation ago, making them good for people and trout once again.
Cut the bottom off a milk carton or coffee can. Replace it with clear plastic wrap held in place with a rubber band or duct tape. Now you have an underwater viewer that can peek into streams, tidepools, or any submerged habitat.
For more information on streams, read our information on Streams.