9703

• UCREFRP Catalog Number: 9703
• Author: Mueller, G.A., J. Carpenter, R. Krafel and C. Figiel.
• Title: Preliminary testing of the role of exercise and predator recognition for bonytail and razorback sucker.
• USFW Year: 2007.
• USFW - Doc Type: U.S. Geological Survey
• Copyright Material: NO

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Figure 6. Distribution of razorback suckers observed in predator vs. safe (sanctuaryl zone in a circular
tank. Trials 1 and 2 (pre-predation) represent prey distribution prior to a predation event. Trial 2 (post-
predation) and trial 3 illustrate prey distribution following a predation event. The size of the sanctuary in
trial 3 was reduced from one-half to one-fourth of the tank's area. Observations were made periodically
throughout daylight hours. Trial 1 occurred May 14-18, 2006 (n = 20); trial 2 occurred May 21-27,2006 (11 =
16); trial 2 post-predation occurred May 28-June 13 (n = 50); and trial 3 occurred June 14-16 (11 = 121.

No predation occurred the first seven days of trial 2. Distribution of razorback suckers was
similar to observations from triall: fish frequented both sizes of the tank equally (52 percent. 11 = 16).
However, following the predation event, prey distribution shifted immediately toward the sanctuary side
(trial 2, post-predation; fig. 6) with twice as many razorback suckers frequenting the sanctuary zone
compared to the area occupied by the predators. Predation occurred the first night in trial 3 and as with
trial 2, prey were found twice as often (63 percent versus 37 percent, n = 12) in the sancwary zone.
When considered in terms of available area, razorback suckers used the sanctuary zone six times more
often than the predator zone.

Razorback Suckers-2007 Efforts
Moving the prey into the predator tanks worked well. We established a 4-rn tank with (Hll'
flathead catfish we affectionately named "Oscar." Oscar had a feeding rate of less than one rawrback
per night. He generally ate one or two of the treatment fish then fasted for a night. However, on several
occasions more were eaten and/or mortally wounded, which caused quite a bit of variability (2- J 0) in
the size of some test groups.

Bonytail
Largemouth bass generally feed during the day, but feeding rates varied from prey taken every
few minutes to one in two days. Survivors of both species were removed as soon as predation occurred.

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