Figure 2; most data points fall below 1:1 line) and flow cytometry overestimated organism 
concentrations as compared to microscopy (see Figure 3a,3b; most data points fall above the 
1:1 line). Variation between replicates generally increased with abundance (Figure C.2). 
The CFA measurements had the strongest correlation with microscope results, both 
when comparing F v values (r=0.84-0.94; Figure 3) and data converted to concentrations (Figure 
2; Pearson correlation coefficient= 0.82-0.94; note concentrations could not be calculated for 
Walz WATER-PAM). The F v values for devices measuring chlorophyll fluorescence were highly 
correlated with each other (range 0.96-0.97; TD BallastCheck-2™ vs. Hach BW680 excepted; 
Figure 3), with TD BallastCheck-2™ and bbe lOcells showing the highest similarity. 
4.0 Discussion 
Our study considered several types of 'indicative' analytic tools, including methods 
based on CFA, ATP, and FDA, and two detailed methods, flow cytometry and microscopy. 
Results indicate that measurements for all types of indicative methods showed concordance 
with microscopy results, whether those results were analyzed as raw biomass measurements or 
when converted to concentrations (where possible). There was variability between indicative 
methods in the strength of the relationship (which varied with numerical abundance of the 
organisms), and also differences in the sensitivity (i.e. minimum detection limit) of methods. It 
should be noted that some of the indicative methods are designed for ballast water monitoring 
where low organism concentrations are expected and therefore are not necessarily expected to 
give accurate results at high concentrations, but rather simply recognize non-compliance; in 
other words, unlike methods developed for standard marine research, the focus here is on