ABSTRACT
As fish approach fatigue at high water velocities in a critical swimming speed (Ucrit) test, their swimming mode and oxygen cascade typically move to an unsteady state because they adopt an unsteady, burst-and-glide swimming mode despite a constant, imposed workload. However, conventional rate of oxygen uptake (ṀO2) sampling intervals (5–20 min) tend to smooth any dynamic fluctuations in active ṀO2 (ṀO2active) and thus likely underestimate the peak ṀO2active. Here, we used rainbow trout (Oncorhynchus mykiss) to explore the dynamic nature of ṀO2active near Ucrit using various sampling windows and an iterative algorithm. Compared with a conventional interval regression analysis of ṀO2active over a 10-min period, our new analytical approach generated a 23% higher peak ṀO2active. Therefore, we suggest that accounting for such dynamics in ṀO2active with this new analytical approach may lead to more accurate estimates of maximum ṀO2 in fishes.
FOOTNOTES
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: Y.Z., A.P.F.; Methodology: Y.Z.; Software: Y.Z.; Validation: Y.Z., M.J.H.G., A.P.F.; Formal analysis: Y.Z.; Investigation: Y.Z., M.J.H.G.; Resources: A.P.F.; Data curation: Y.Z.; Writing - original draft: Y.Z.; Writing - review & editing: Y.Z., A.P.F.; Visualization: Y.Z.; Supervision: A.P.F.; Project administration: Y.Z., A.P.F.; Funding acquisition: A.P.F.
Funding
Y.Z. holds an Elizabeth R. Howland Fellowship and a Pei-Huang Tung and Tan-Wen Tung Graduate Fellowship. M.J.H.G. holds a Natural Sciences and Engineering Research Council of Canada (NSERC) Alexander Graham Bell Canada Graduate Scholarship. This work was funded by an NSERC Discovery Grant held by A.P.F., who also holds a Canada Research Chair Tier I.
Supplementary information
Supplementary information available online at http://jeb.biologists.org/lookup/doi/10.1242/jeb.196568.supplemental
- Received November 26, 2018.
- Accepted April 29, 2019.
- © 2019. Published by The Company of Biologists Ltd