Swimming in unsteady water flows: is turning in a changing flow an energetically expensive endeavor for fish? [RESEARCH ARTICLE]

In this study, we used a bidirectional swimming respirometer to create six oscillatory water flow regimes consisting of three frequency and amplitude combinations for both unidirectional and bidirectional oscillatory flows. Using the goldring surgeonfish, Ctenochaetus strigosus, a pectoral-fin (labriform) swimmer, we quantified the net cost of swimming (swimming metabolic rate minus standard metabolic rate) associated with station-holding under these various conditions. We determined that the swimming costs of station-holding in the bidirectional flow regime increased by 2-fold compared with costs based on swimming over the same range of speeds at steady velocities. Furthermore, as we found minimal differences in energetic costs associated with station-holding in the unidirectional, oscillating flow compared with that predicted from steady swimming costs, we conclude that the added acceleration costs are minimal, while the act of turning is an energetically expensive endeavor for this reef fish species.

Source: Journal of Experimental Biology - March 17, 2020 Category: Biology Authors: Schakmann, M., Steffensen, J. F., Bushnell, P. G., Korsmeyer, K. E. Tags: RESEARCH ARTICLE Source Type: research