Rotary Screw Trap

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The Rotary Screw Trap is used to detect presence of winter and late-fall run chinook salmon in the Delta Cross Channel (XC001M). The use of rotary screw traps by the program element began in 1992.

 

	Gear - a 2.5m diameter Archimedes screw supported by two floating pontoons; 
		minimum flow required; fish are trapped and held in a live box

	Crew - two biologists/technicians

	Sampling effort - trap is fished 5 days per week and checked once per day 
        (twice per day if high debris loads or high numbers of fish are being collected) 
        from October to January during the period when the cross channel gates are
        open