Salmon
Fall heralds the annual return Stella Wenstob | contributor As the weather chills, local streams and rivers are festooned with shades of orange and red of the turning leaves. Fall also marks the last weeks in the life cycle of many salmon species who return upstream to spawn. Using a sense not completely understood by biologists, millions of migratory salmon return to their home streams to lay eggs. After swimming upstream to their spawning ground the female chooses a spot in the shallow, but swift flowing part of the river that is ensured to be highly oxygenated, called the riffle. In some of the inland streams that location can be many hundreds of miles up rapids and past many impediments. Here she digs a depression in the gravel that will serve as her nest or redd. The males will put on an impressive show biting and jumping to show their dominance and protect their chosen female from other males. After the eggs are laid in the redd, the male will deposit sperm over them, and the female will cover the eggs with gravel to protect them. A female may create as many as seven redds before she is FJORD
finished spawning and each redd may hold as many as 5,000 eggs. As soon as the salmon enter the fresh water their skins begin to change color, their sexual dimorphism enhances, they stop eating and they begin their decaying process. A migrating salmon typically lives for about two weeks after entering the freshwater. The carcasses provide an important food source to other animals and small invertebrates who in turn provide food for the salmon fry (baby salmon) as they get older. Additionally, the nutrients given off by the rotting carcass are important fertilizers to the plants and trees growing on the banks, which in turn provide essential root systems that prevent erosion and protects the streams for further generations of salmon. 3636
There are seven species of salmon in the Pacific Northwest: Pink (Oncorhynchus gorbuscha), Sockeye (Oncorhynchus nerka), Coho (Oncorhynchus kisutch), Chum (Oncorhynchus keta), Chinook (Oncorhynchus tshawytscha), Steelhead (Oncorhynchus mykiss), and Cutthroat (Oncorhynchus clarki clarki). All of these species have very different life-cycles – some spend several years before they migrate up streams; some can run and spawn several times before dying; some only spawn at the mouth of streams, where others need to spawn in lakes at the head of rivers. This unique phenomenon of the salmon running can be viewed in streams and rivers all across the Hood Canal and South Puget Sound.
