A Variable‐Speed Swim Tunnel for Testing the Swimming Ability of Age‐0 Fish

Laboratory swim tunnels are a valuable tool for studying fish physiology and the responses of fish to controlled environmental conditions. We combined aspects of large and small swim tunnels to construct an apparatus that can confine age‐0 fish to a specific area while producing a wide range of velocities. We used low‐cost plumbing supplies and a centrifugal pump to create a swim tunnel capable of producing velocities from 1 to 66 cm/s. A DC electric barrier and screened knife gate valves prevented fish from leaving the test section. A flowmeter incorporated into the swim tunnel measured water velocity within the apparatus.