20 research outputs found
Influence of experimental set-up and methodology for measurements of metabolic rates and critical swimming speed in Atlantic salmon Salmo salar
In this study, swimâtunnel respirometry was performed on Atlantic salmon Salmo salar postâsmolts in a 90âl respirometer on individuals and compared with groups or individuals of similar sizes tested in a 1905âl respirometer, to determine if differences between setâups and protocols exist. Standard metabolic rate (SMR) derived from the lowest oxygen uptake rate cycles over a 20âh period was statistically similar to SMR derived from back extrapolating to zero swim speed. However, maximum metabolic rate (MMR) estimates varied significantly between swimming at maximum speed, following an exhaustive chase protocol and during confinement stress. Most notably, the mean (±SE) MMR was 511â±â15âmgâO2 kgâ1 hâ1 in the swim test which was 52% higher compared with 337â±â9 mg O2 kgâ1 in the chase protocol, showing that the latter approach causes a substantial underestimation. Performing group respirometry in the larger swim tunnel provided statistically similar estimates of SMR and MMR as for individual fish tested in the smaller tunnel. While we hypothesised a larger swim section and swimming in groups would improve swimming performance, Ucrit was statistically similar between both setâups and statistically similar between swimming alone v. swimming in groups in the larger setâup, suggesting that this species does not benefit hydrodynamically from swimming in a school in these conditions. Different methods and setâups have their own respective limitations and advantages depending on the questions being addressed, the time available, the number of replicates required and if supplementary samplings such as blood or gill tissues are needed. Hence, method choice should be carefully considered when planning experiments and when comparing previous studies.publishedVersio
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Effects of time and velocity increments in the critical swimming speeds of largemouth bass (Micropterus salmoides)
Critical swimming speed was measured for largemouth bass and found to be related tothe increments of both time and water velocity. Critical speed decreased with increase in timeinterval, and reached a peak and declined thereafter with increasing velocity incremen