Curriculum: Compare Egg Survival – Natural vs Hatchery – Tyee salmon

Compare Egg Survival Rate: Natural vs. Hatchery-Raised Chinook Salmon

For Columbia River Chinook salmon that follow Tyee’s Journey

Naturally-Produced Columbia River Spring Chinook

  • Adults enter the Columbia River in January-February, cross the Willamette Falls in April and enter the McKenzie River in May. Adults move upstream and hold in deep pools until spawning. Adults need to find suitable spawning gravel with adequate water supply, as well as a suitable mate to spawn with.
  • Fry hatch and remain in gravel.
  • Fish spend approximately one year in fresh water before migrating downstream to the ocean.
  • Estimated survival of naturally produced salmon (egg to smolt: 4-10 percent).

Chart:

Diagram - Compare Egg Rate Survival - Natural vs. Hatchery
Click to enlarge

Hatchery-Produced Columbia River Spring Chinook

  • Adults enter the Columbia River in January February, cross the Willamette Falls in April and enter the McKenzie River in May. The adults move upstream into the hatchery with controlled water supply and incubators. The adults are inoculated against bacterial diseases, treated to control fungus. and protected against predators. Salmon pairs randomly selected by hatchery personnel.
  • Eggs are treated to control fungus and placed in a protected structure.
  • Fry are placed in starter troughs (5-10% loss at this point).
  • Fingerlings are moved outside to rearing ponds and are protected from predators, given intensive feeding and provided disease control treatment. Fish reared to smolts and released.
  • Estimated survival of hatchery produced salmon (egg to smolt: 80-85 percent).