Have you ever seen a rainbow trout or a Kokanee salmon in a Whistler stream and wondered what it would be like to trade places for a while? What kind of food would you eat if you were a fish, and where would you hide if an eagle flew overhead looking for some lunch? Fish, just like people, need various things to live a healthy life. They need food, air, and shelter just like we do, only in slightly different forms.
What do fish need? Fish need diverse conditions in the streams where they live and grow. Deep pools of slow moving water provide resting spots for fish where they don’t have to worry about fighting a current to stay in place. Riffles are places where shallow water moves over a cobble streambed, bringing dissolved oxygen to the water, which fish need to breathe. Riffles are also great places for fish to spawn, as the eggs lie hidden and protected but can still breathe the oxygen. Logs and large boulders in the stream create flow diversity, providing oxygen and resting and hiding spots for fish. Clean, clear water allows sunlight to penetrate, fostering the growth of aquatic plants, which house many insects for fish to eat.
But the stream itself is not the only important part in creating good fish habitat. Riparian, or streamside, vegetation is a critical component to healthy fish habitat. Riparian trees and shrubs shade the stream, keeping water temperatures cool and providing cover for fish to help them hide from predators. Riparian vegetation attracts insects, which supply food for fish, while fallen leaves and branches add nutrients to the stream. The roots of riparian vegetation help filter out pollution from ground water before it enters the stream and they also help stabilize stream banks, preventing erosion and sedimentation. Riparian areas also provide fallen trees, which help maintain diversity of instream habitats such as pool and riffle sequences. In light of the important role that streamside vegetation plays in creating healthy fish habitat, it might even be said that Fish Grow On Trees!
Bird Walks — Meet at the base of Lorimer Road on the first Saturday of each month to view and learn about local birds. Start time is 7 a.m.
Whistler Naturalists Speaker Series — Life on the Edge: British Columbia’s Mountain Goats by Dr. Steve Wilson on April 27th at Millenium Place. Admission is by donation and doors open at 7 p.m.
Written by: Tina Symko