FREQUENTLY ASKED QUESTIONS ABOUT RENEWABLES

Myth: Hydroelectric dams block the migration of anadromous fish and are the cause of species declines

The hydropower industry has taken extensive steps and spent hundreds of millions of dollars to minimize the impact dams have on aquatic life. The industry has been careful, where possible, to install systems with proven capabilities to move fish both upstream and downstream in all phases of their life cycle. Typically, turbines already successfully pass between 85 and 95 percent of fish migrating downstream on major rivers. This percentage can be further improved using advanced turbine systems. Scientific applications of spillways, fish screens and other collection and diversion techniques have greatly improved downstream migration. For upstream passage, lifts, bypass canals and ladders that simulate natural waterfalls have proven to be successful.

But dams cannot account for diminished runs prior to dam construction. Nor do they explain why undeveloped rivers experience similar trends in salmon counts as rivers with dams.

We will always be frustrated with efforts to restore fish populations to the rivers if societies efforts focus only on dams. There are a multitude of factors that contribute to the ultimate failure of species to return to their spawning grounds during their life cycle. Often ignored are the harmful effects of: legal and illegal harvesting that occurs both in-river and in the ocean; hatcheries that cause disease to native species and increased harvests; habitat degradation caused by mining, logging, agricultural run-off, road construction and urban development; not to mention the effect of climate conditions like, most recently, El Niņo which warms the ocean currents and may disrupt fish migration patterns.

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