What size of swim tunnel respirometer should I choose?
Active fish swimming in a tunnel respirometer have high mass-specific oxygen consumption rates (MO2), allowing reliable oxygen consumption estimates in relative higher respirometer volume than for static respirometry. Tunnel respirometers are difficult to build with a fish volume to respirometer volume of less than 1:100. We recommend a maximum ratio between the wet weigth (or volume) of the fish and the volume of the swim respirometer of 1: 200, e.g. a 90 liter swim respirometer fits fish down to app. kg. If the volume is too large the resulting oxygen curve will be too flat for reliable estimates of the slope that is used in the calculation of oxygen consumption rate (MO2). Another restraint is the dimensions of the test section, which should allow the experimental fish to perform unrestricted swimming. This will largely depend on the species and mode of swimming. Please find our recommendations for fish shaped like salmonids under swim tunnel specifications.
