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Meeting Abstract
50.5 Tuesday, Jan. 5 Partition of aerobic and anaerobic swimming costs related to gait transitions in a labriform fish SVENDSEN, JC*; TUDORACHE, C; JORDAN, AD; STEFFENSEN, JF; AARESTRUP, K; DOMENICI, P; Technical University of Denmark; University of Antwerp; University of Copenhagen; University of Copenhagen; Technical University of Denmark; International Marine Centre Localita Sa Mardini jos@aqua.dtu.dk
Striped surf perch Embiotoca lateralis swim using the pectoral fins at low to moderate speeds, while the caudal fin is assisting at high swimming speeds. The gait transition from pectoral fin propulsion to pectoral and caudal fin propulsion occurs at a distinct threshold speed termed Up-c. The objective of this study was to quantify aerobic and anaerobic swimming costs at speeds below and above the Up-c in E. lateralis using swimming respirometry and video recordings to test the hypothesis that the gait transition leads to anaerobic metabolism. In this species, 1.4 body lengths per second (bl s-1) is below the Up-c, whereas both 1.9 and 2.3 bl s-1 are above the Up-c. Exercise oxygen consumption (MO2) while the fish were swimming at these speeds was determined. The presence and magnitude of excessive post exercise oxygen consumption (EPOC) was evaluated after the three swimming speeds. There was no evidence of EPOC after swimming 1.4 and 1.9 bl s-1 indicating that the gait transition from pectoral oscillation to axial undulation is not a threshold for anaerobic metabolism. In contrast, swimming at 2.3 bl s-1 resulted in EPOC being 51.7 mg O2 kg-1 suggesting that anaerobic metabolism added about 34% to the exercise MO2. E. lateralis switched to an unsteady burst and flap gait at 2.3 bl s-1. Burst activity correlated linearly and positively with the magnitude of the resulting EPOC. Collectively, these data suggest that steady axial propulsion does not lead to EPOC whereas transition to burst assisted swimming above Up-c is associated with anaerobic metabolism in this labriform fish.