was quantified using a magnetic flow meter (Seametrics WMP104-100) for net samples and 
built-in flow meters for the sampling skids. For each sample, between 10 and 16 L of water was 
taken for analysis of 10-50 pm organisms by collecting approximately 500 ml of the filtrate 
produced by each sampling device every minute. 
All rinse water used during sample collection (and later analyses) was prepared by 
sequentially filtering local sea water taken through the ship's scientific sea water tap system 
through a series of meshes (1000, 500, 35, and 8 pm, nominal pore sizes) followed by filtration 
through a 0.2 pm passive (gravity-fed) filter cartridge (Whatman Polycap TC150). Rinse water 
was prepared prior to the start of each trial, so that the rinse water was sourced from the same 
geographic location as the samples being tested. Table A1 in Appendix A contains detailed trial 
information including salinity, temperature, sampling time and positions, sample collection 
devices used, ballast water flow rate, and total volume of water that passed through the ship's 
ballast system during the trial. 
2.2 Sample preparation 
All sample collection and further handling, like sample splitting and sieving, was 
completed in a uniform way, so that observed variability is more likely explained by analysis 
method rather than by sample handling. Water samples containing organisms and particles > 
50 pm were concentrated during sample collection, so post-collection processing was not 
required. Individual subsamples for each analysis method were taken by mixing each 1 L 
condensed sample by inversion five times, half-filling each subsample bottle (7 bottles, total 
volume 35-300 ml depending on analysis requirements), and repeating this procedure until 
bottles were topped up to the required volume. This splitting procedure (5x inversion of the