Rethinking Dams: Pacific Salmon Recovery May Rest on Other Factors

Liza Gross

doi:10.1371/journal.pbio.0060279

Abstract

Rethinking Dams: Pacific Salmon Recovery May Rest on Other Factors

Highlights

Approaching the confluence of the Snake and Columbia Rivers in 1805, Lewis and Clark marveled at the “almost inconceivable multitudes” of salmon hurling themselves through the roiling waters, but worried at the “emence numbers” of bruised, battered, and dead fish farther upriver
Most researchers and environmentalists believe that the extensive network of dams poses the biggest threat to salmon recovery
Because salmon declines continued after 1938, when the first dam was built, and were sharp after 1977, when the last Snake River dams were built, recovery efforts have focused on mitigating threats posed by the hydropower system

Summary

Introduction

Approaching the confluence of the Snake and Columbia Rivers in 1805, Lewis and Clark marveled at the “almost inconceivable multitudes” of salmon hurling themselves through the roiling waters, but worried at the “emence numbers” of bruised, battered, and dead fish farther upriver. Most researchers and environmentalists believe that the extensive network of dams poses the biggest threat to salmon recovery. Because salmon declines continued after 1938, when the first dam was built, and were sharp after 1977, when the last Snake River dams were built, recovery efforts have focused on mitigating threats posed by the hydropower system (including warmer waters, fish-grinding turbines, and new predators).

Results

Conclusion