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Research Methods for Salmon Abundance Estimation

Juvenile Trap Design: Screw Traps

  • Cone rotation locks in fish and actively traps outmigrants
  • Most effective at trapping fry, parr, and yearling outmigrants: pink, sockeye, coho, Chinook, chum, steelhead, bull trout and cutthroat
  • Customizable to fish small creeks to large rivers


  • Self-cleaning debris drum minimizes direct maintenance
  • Cone design minimizes fish escapees: less size selective than scoop traps
  • Smaller traps may be packed into relatively remote locations


  • Limited cone sizes (1.5M and 2.5M)
  • Trap noise may contribute to trap avoidance