What are impacts of dams?

• Negative: fish unable to return to spawn in their natal tributary if they cross the dam

• • Lose genetic diversity?
  • • Lower allelic richness than bull trout in Columbia and Snake
  • Alter genetic relationships?
  • • Some of these fish go to nearby tributaries
    • • SF Tieton fish in Rattlesnake
      • NF Tieton fish in Rattlesnake
      • One-way gene flow out of Tieton basin

• Positive: opportunity for bull trout in Tieton tributaries to become adfluvial

• • Grow larger – have more offspring