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What's New! Ocean Matters Salmon Habitat Restoration of Salmon Habitat Salmon are one of the most vitally important fish to the British Columbia economy. Dependent on good habitat areas for spawning, salmon have adapted to live both in oceans and freshwater. The spawning process involves mature male and female salmon leaving the ocean to swim upstream against river currents, waterfalls and other obstacles to rivers and creeks where they will spawn just before passing away. Salmon will usually spawn in the creek they were born in and can find this creek through a remarkable sense of smell. During spawning, the female releases her eggs and the male fertilizes them. After spawning occurs, the adult salmon die. Salmon spawning areas usually have high quality sands and gravels, which the females will use to bury their fertilized eggs in.
There are many ways to lessen damage to spawning grounds caused by logging. One potential solution is to leave an area of trees known as a buffer zone surrounding all creeks, rivers, lakes and other bodies of water to reduce potential erosion and minimize destruction of the spawning grounds. The above picture illustrates this concept well as the Pachena River has very little erosion where the trees are growing. Habitat Restoration Once some damage has occurred, there are still many ways to fix and repair the spawning grounds. Mechanically repairing salmon spawning grounds is one option available, although this can be quite expensive, costing tens of thousands (and often more) of dollars per kilometre of stream in need of repair. Despite the cost, this option does have its benefits. Mechanically repairing streams allows managers to reintroduce Large Woody Debris (LWD) into the streambeds. Large Woody Debris serves two important functions: Firstly, the debris slows the river speed down, which is better for spawning salmon; Secondly, this technique allows stream managers to provide shade for baby salmon so they do not die from overheating. If you have ever felt sick on a hot sunny day imagine what a salmon feels like when it gets hot! Other stream restoration methods include building small natural stream flow impediments such as boulder dams, back-water channels and bank stabilizers. These methods serve to reduce water flow and erosion of spawning gravels, aiding salmon to reproduce. The two pictures below show examples of LWD and stream flow impediments designed to reduce stream velocity. Notice in both pictures that the debris and gravel bars reduce erosion, allowing for enhanced salmon spawning habitat.Habitat Loss One of the concerns with salmon reproduction is destruction and damage to the spawning grounds. For salmon this is deadly because they can swim thousands of miles to spawn only to find their spawning grounds ruined. If the home spawning grounds are ruined it is unlikely that the salmon will reproduce successfully.
If total destruction of salmon spawning grounds were to occur, it would mean that the salmon would not be able to reproduce. Ensuring that salmon have adequate spawning grounds will guarantee that this magnificent fish will continue to survive.
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