APRIL RALSTON LAYHER, Arkansas Game and Fish Commission, #2 Natural Resources Drive, Little Rock, Arkansas 72205, USA

WILLIAM G. LAYHER, U.S. Geological Survey, Biological Resources Division, University of Arkansas at Pine Bluff, 1200 North University, Box 4912, Pine Bluff, Arkansas 71611, USA

An inexpensive ichthyonatometer was used to assess swimming endurance of longear sunfish and bigeye shiners at various flow velocities for varying length of times. Percent success of fishes that could endure such flows was recorded. Longear sunfish could successfully traverse low flows less than 19 cm/sec for up to 14 minute intervals. However success swindled rapidly for increased flows with no fish being able to swim or maintain position for over ten minutes at 33 cm/sec. Bigeye shiners could negotiate against currents of up to 33 cm/sec while success rapidly failed at velocities of 39 cm/sec at times exceeding four minutes with no fish being able to maintain position for any time period at 53 cm/sec velocities. Presumably body shape may have a great deal to do with endurance at higher velocities.