Each year millions of salmon navigate their way from open ocean to freshwater spawning grounds in a journey to reproduce. These runs are vital to the survival of the many species influenced by wild salmon populations.
In addition to being a food source for predators like sea lions, sea gulls, bears, and orcas, salmon have influence on bacteria and algae communities by bringing nutrients from a rich marine environment to nutrient poor freshwater watersheds. Even the large trees that make up the temperate rainforest in the Pacific North West benefit from the nitrogen carried within salmon carcasses left by predators!
With more than 40 vertebrate species affected by each stage of the salmon life cycle, the influence of salmon is prolific through all levels of the food chain. As such they are classified as a ‘keystone species’, much like bees; without these animals our ecosystems will suffer drastically.
Food chains have been suffering from a decline in wild salmon populations partly due to the construction of dams in vital river systems. Here in Victoria we see the affects on the salmon eating orca. Whose numbers have been decreasing over the years due to a lack of sufficient food. This begs the questions “How do we fix this?’
One solution that has been advocated for, researched, and implemented, has been the removal of dams from large freshwater rivers. The Elwha River, located just outside of Port Angeles in the beautiful Olympic National Park, was the fortunate benefactor of the largest dam removal in U.S history.
In a four-year span starting in 2011 the Elwha Dam and Glines Canyon Dam were removed leaving the river to run freely and change with surprising speed. A hundred years of accumulated sediments, roughly 22 million tons, were released from the river into the ocean, altering the oceanic landscape.
The formerly choked-up river started recovering rapidly with an explosion of flora and the return of many fauna species including salmon. While the past five years have been an ecological success many of the salmon have been introduced through hatcheries and we have yet to learn if this will facilitate a full recovery of the ecosystem. Only time will tell if this sort of extreme action can create and stabilize a successful wild population and further rehabilitate the species dependent on salmon runs.
This restoration project is quite possibly related to the surge of Northern Pacific Humpback Whales coming back to the Salish Sea as nutrients flow between the saltwater and freshwater systems and food sources flourish.
What’s next? There has been some speculation and controversy in Idaho and Washington regarding the removal of the four dams along the Snake River. The removal of these dams could very well reap the same benefits seen with the Elwha River project; increased salmon migration, flooding reduced in high risk areas, and restoration of flora suffering from the accumulated silt and sediment.
According to some experts, the removal of the Lower Granite Dam alone could restore 1 million Chinook salmon providing a significant food source for orca’s and all the other species dependent on these incredibly important fish. Large projects like this often get politicized and many elements are taken into account including economics, energy sources, and employment. This means these decisions are slow in the making.
Many believe that removing dams which are at the end of their useful economic lifespan is a necessity. They believe that the time to do it has arrived and that with time there will be huge environmental and economic benefits.
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