The Impact of Hydropower Dams on California's Populations of Anadromous Fish: What Can Be Done to Mitigate the Dams Effects and Restore California's Watersheds.

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  • Published : February 18, 2008
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The Impact of Hydropower Dams on California's Populations of Anadromous Fish: What Can be done to mitigate the Dams Effects and Restore California's Watersheds. Russell Cole
Western Governors University

The Impact of Hydropower Dams on California's Populations of Anadromous Fish: What can be done to mitigate the Dams Effects and Restore California's Watersheds.

The indigenous people of California were completely dependent on the seemingly infinite quantities of salmon and steelhead that annually returned to their coastal rivers. Upon their arrival, European settlers soon developed a commercial fishing industry, which supported them very well. Today, however, that never-ending supply of fish is ending. The effects of hydraulic mining, clear-cut logging, water diversion and most of all, the building of hydropower dams has decimated populations of anadromous fish, by cutting them off from their natural breeding and rearing habitat (i.e. critical habitat). California's populations of anadromous fish (steelhead and salmon) are quickly headed for extinction unless government agencies join with hydropower dam operators to initiate policy changes essential to restore the state's watersheds (Spain, 2007) Anadromous fish spawn in fresh water (rivers, streams and tributaries); their young (fry) are born and reared in coastal rivers and streams. Then as juveniles they migrate to the ocean where they spend the next two to three years maturing into adults. When the fish become sexually mature they return to their home rivers to continue their breeding cycle. Some even follow their instincts to the same pool of their birth (M. Podlech, personal communication, January 15 2008). There are many different species of anadromous fish found in California's watersheds, however this paper will focus on the most revered andromous fish of the California coast: salmon and steelhead trout. Fisheries biologists monitoring the health of California's watersheds view salmon and steelhead (salmonids) as invaluable. Because salmonids utilize all the habitats of a watershed, including the estuaries, main river channels and natal tributary streams, they are seen as the "canary in a coal mine" of the river ecosystem (California Trout, 2005). Salmonids are referred to as an indicator fish, biologists know that when wild trout do poorly it is seen as a strong indicator that the watershed itself is suffering (CalTrout, 2005). Trout have a very limited tolerance for changes in their habitat and when they are suffering, the cause can almost always be traced to some degradation to the watershed. "Healthy rivers have healthy trout" (M. Podlech, personal communication, January 15 2008). Historically, California was home to vast populations of steelhead and also a large variety of salmon (West Coast salmonids). However, with the introduction of hydropower dams in the early 1900's, the fish no longer have access to a majority of their breeding habitat. As a result the populations have dwindled to a small fraction of those seen in the past (National Marine Fisheries Service, 2001). In 1991 the American Fisheries Society conducted a comprehensive status assessment of West Coast salmonids and found 106 major populations of salmon and steelhead already extinct, with 214 more salmon runs in danger of becoming extinct in the not so distant future (Spain, 2007). The ramifications of this population decline are far reaching. Gone is the once thriving California coast fishing economy. With a reduction in take of more than 80% it has been estimated that more than 72,000 jobs have been lost (Buck, 1999). This has been a devastating blow not only to families, but also to whole communities with economies based solely on salmon fishing for decades. Gone is one of California's largest export items and also a primary food source. California, known for decades as a prized destination for sport fishing, has seen a...
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