Measurement of warp loads of bongo plankton samplers

•We measured warp loads of typical bongo samplers using a flume tank.•Warp loads of bongo samplers were less than 85 kg.•There was no evidence of flow being deflected from mouth of net.•Quantitative data can be used to design winches.

We measured warp loads of a bongo sampler in a flume tank over a range of water velocities (0–1.05 m s−1) to estimate the payload on a winch during deployment. We used standard bongo setups comprising two mesh sizes: 500 μm and 333 μm. Warp load of a bongo sampler was less than 85 kg at maximum towing velocity. There was no evidence of the flow being deflected outside the net mouth for velocities above 0.5 m s−1.