Fischerei und Viehzucht

Abstrakt

Flow Patterns in Circular Rearing Tanks Containing Vertical Structure

Moine J, Barnes ME*, Kientz J, and Simpson G

Circular tanks are widely used in aquaculture, and the addition of vertically‑suspended rod arrays can provide structural complexity during fish rearing. This study assessed the effects of such an array on water velocities at two flow rates in 1.8-m diameter circular tanks. At inflows of 62 L/min and 113 L/min, the presence of the rod array significantly reduced in-tank velocities. The largest decrease in velocity was observed on the water surface midway between the center and edge of the tank. The presence of vertically-suspended rods significantly reduced velocities at each sampling depth (surface, mid-tank, bottom), at each radius (30, 60, or 90 cm from the center of the tank), and at each position (prior to, immediately after, and directly opposite the rod array). At both of the flow rates, velocities with the rods present were still sufficient to create a vortex capable of keeping the tank self-cleaning. The decrease in velocities may explain part of the reason for the positive effects of vertically-suspended rods on fish rearing performance.