Field swimming performance of bluegill sunfish, Lepomis macrochirus: implications for field activity cost estimates and laboratory measures of swimming performance

Abstract

Mobility is essential to the fitness of many animals, and the costs of locomotion can dominate daily energy budgets. Locomotor costs are determined by the physiological demands of sustaining mechanical performance, yet performance is poorly understood for most animals in the field, particularly aquatic organisms. We have used 3‐D underwater videography to quantify the swimming trajectories and propulsive modes of bluegills sunfish (Lepomis macrochirus, Rafinesque) in the field with high spatial (1–3 mm per pixel) and temporal (60 Hz frame rate) resolution. Although field swimming trajectories were variable and nonlinear in comparison to quasi steady‐state swimming in recirculating flumes, they were much less unsteady than the volitional swimming behaviors that underlie existing predictive models of field swimming cost. Performance analyses suggested that speed and path curvature data could be used to derive reasonable estimates of locomotor cost that fit within measured capacities for sustainable activity. The distinct differences between field swimming behavior and performance measures obtained under steady‐state laboratory conditions suggest that field observations are essential for informing approaches to quantifying locomotor performance in the laboratory.

Swimming from coast to coast: a novel fixed-gear swimming gait in fish

“…Most performance and energy cost data have been obtained under quasi-steady-state conditions [3,4]. The applicability of these data to understanding locomotion in the field is questionable as the routine, volitional locomotor behaviour of most animals is intrinsically unsteady [5,6]. Recently obtained data suggest that the disparity between laboratory and field performance is particularly acute in bluegill sunfish, where routine, volitional swimming is achieved via intermittent propulsion but forced swimming in flumes favours constant propulsion [5].…”

“…This stems in part from the scarcity of data for unconstrained, volitional swimming. The combined availability of large-volume calibration techniques recently applied to quantify avian flight performance in the field [11] and low-cost underwater cameras has enabled the collection of field performance data for fish [5,12] with higher temporal and spatial resolution than has previously been possible [1]. This approach has revealed the use of intermittent propulsion during routine, sustained locomotion at aerobically sustained speeds and propulsive cycle frequencies, but with insufficient detail to indicate why this swimming style is used [5].…”

Drag coefficient estimates from coasting bluegill sunfish Lepomis macrochirus

“…Coasting is an important part of the locomotor repertoire of many fish species (Gleiss et al, 2011;Tudorache et al, 2007;Videler & Weihs, 1982). It may be employed to increase energy economy if the drag and energy costs incurred during the non-propulsive phase are sufficiently low compared with those during propulsion (Videler & Weihs, 1982), to modulate average propulsive power output and speed (Cathcart et al, 2017), or to promote sensory perception without interference from propulsive movements (Kramer & McLaughlin, 2001).…”

“…We have obtained drag estimates from decelerations during coasting in bluegill sunfish Lepomis macrochirus Rafinesque 1819. Lepomis macrochirus coast frequently during volitional swimming in the field (Cathcart et al ., ) and hold their body axis straight during labriform propulsion (Drucker & Lauder, ; Kendall et al , 2007), so inertial drag on the body is functionally important in this species. Dead drag data are also available from this species (Drucker & Lauder, ; Jones et al ., ), enabling a comparison of drag coefficients estimated from alternative methodologies.…”

Red muscle function and thermal acclimation to cold in rainbow smelt, Osmerus mordax, and rainbow trout, Oncorhynchus mykiss

“…Individual fish were placed into a 180.5 L Loligo System respirometry swim tunnel maintained at 10°C (Woytanowski & Coughlin, 2012). The relatively long test section of this swim tunnel (87.5 cm) permitted a range of sustained fish swimming behaviors from intermittent to continuous, as has been reported recently for voluntary swimming by fish in nature (Cathcart, Shin, Milton, & Ellerby, 2017). A video camera recorded the length of each swim from a vantage point above the swim tunnel.…”