Survival of Migrating Salmon Smolts in Large Rivers With and Without Dams
2008

Salmon Survival With and Without Dams

publication Evidence: moderate

Author Information

Author(s): David W. Welch, Erin L. Rechisky, Michael C. Melnychuk, Aswea D. Porter, Carl J. Walters, Shaun Clements, Benjamin J. Clemens, R. Scott McKinley, Carl Schreck

Primary Institution: Kintama Research, Nanaimo, British Columbia, Canada

Hypothesis

How does the survival of salmon smolts during migration differ between dammed and undammed rivers?

Conclusion

Salmon smolt survival rates during migration are similar in both dammed and undammed rivers, challenging previous assumptions about the negative impact of dams.

Supporting Evidence

  • Survival rates of salmon smolts were similar in both dammed and undammed rivers.
  • Migration times for smolts were rapid, indicating directed movement.
  • Detection efficiencies at the Fraser River mouth were high, supporting survival estimates.

Takeaway

Scientists found that baby salmon have about the same chance of surviving their journey to the ocean whether they swim through rivers with dams or without them.

Methodology

The study used acoustic telemetry and Passive Integrated Transponder (PIT) tags to measure salmon smolt survival during migration.

Potential Biases

Potential bias due to the size of the tagged smolts and the representativeness of the populations.

Limitations

The study does not address whether survival rates in the Fraser River have changed over the last century.

Participant Demographics

The study focused on hatchery-reared spring Chinook and wild steelhead smolts.

Statistical Information

P-Value

p<0.05

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pbio.0060265

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