Swimming Capacity

The energetic impact of overwinter prey assemblages on age-0 largemouth bass, Micropterus salmoides

“…We transferred 8 to 15 small age-0 largemouth bass (mean ¼ 85.7 ± 0.6 mm, TL) from each pond to temperature-controlled tanks (20 ± 1°C) with natural photoperiod. To ensure a post-absorptive state we held individual fish for 48 h prior to experimentation (Beamish 1978) and then placed them into the swimming chamber. We conducted swimming challenges in a 56-L modified Blazka type swim chamber as described by Cooke et al (2001).…”

“…A light gradient was used to encourage fish to swim. Following acclimation, we exposed fish to a series of stepwise velocity increments to determine their maximum aerobic swimming capacity (critical swimming velocity, U-crit, Beamish 1978). The velocity was increased by 0.07 m sec )1 increments every 10 min, until the test fish were fatigued.…”

“…We removed fatigued fish from the chamber and measured (TL), and weighed (g) them. Using the formula outlined in Beamish (1978) critical swimming speed was calculated and expressed both in absolute (cm sec )1 ) terms and in body lengths per second to account for variation in fish length (Hammer 1995). We used nested mixed model ANOVA to test for significant differences (p < 0.05) in untransformed absolute critical swimming speed (U-Crit) and length corrected swimming speeds (in body lengths (BL)/per second) among treatments.…”

Displacement, velocity preference, and substrate use of three native California stream fishes in simulated pulsed flows

“…Susceptibility to displacement by high flows may decrease with increasing fish size (Irvine 1986;Heggenes 1988). Swimming performance (sensu Brett 1964 in cm·s −1 ) generally increases with increasing fish length (Beamish 1978), in part due to increases in aerobic (red) muscle proportions at the caudal peduncle (Goolish 1989;McLaughin and Kramer 1991). The impinged hardhead's small size may have contributed to its inability to hold station in the flume at the fastest velocities.…”

“…In order to isolate the influence of water velocity and substrate we did not simultaneously include variables such as the presence of food items, nor the presence of conspecifics or predators. We did not vary temperature in our experiments, although temperature differences are known to affect fishes' swimming performance (Beamish 1978;Heggenes and Traaen 1988;Hammer 1995;Myrick and Cech 2000). We did not use smaller rock and sand in the flume experiments, since they would have washed into the flume sump, although movement of these substrates can occur in natural systems, and potentially affect localized velocities and refuge areas.…”