1.0 Introduction 
The International Maritime Organization adopted the International Convention for the 
Control and Management of Ships' Ballast Water and Sediments in 2004 to minimize the 
transfer of harmful aquatic organisms and pathogens in ships' ballast water (IMO 2004). 
Regulation D-2 restricts the concentration of viable organisms > 50 micrometers in minimum 
dimension at discharge to < 10 viable organisms per cubic meter, and organisms < 50 
micrometers and > 10 micrometers in minimum dimension (hereafter, 10-50 pm) to < 10 per 
millilitre (IMO 2004). Now that the International Ballast Water Management Convention has 
been fully ratified, and will enter into force on September 8, 2017, there is a pressing need for 
ships to plan installations of ballast water treatment systems, and for regulators to plan the 
implementation of the Ballast Water Management Convention into their national legislation 
and Port State Control inspection programs. 
Compliance monitoring and enforcement must be consistent, rigorous, and efficient 
(IMO, 2008); it can be divided into two main parts: ballast water sample collection and sample 
analysis, each of which is challenged by several difficulties (Gollasch & David, 2003; Gollasch & 
David, 2013; IMO 2013; Gollasch & David, 2015;). A number of tools and technologies are in 
development for both sampling and analysis, and recent studies have shown promising results 
for sampling devices (First et al., 2012; Bradie, 2016). For sample analysis, two types of methods 
may be employed: 'indicative' or 'detailed' analyses. 'Detailed' analyses, such as microscopy, 
provide a direct and precise measurement of the number of viable organisms in a sample that 
typically requires extensive scientific expertise, costly equipment, and a timeframe generally 
too long for a compliance enforcement scenario. In contrast, 'indicative' analysis methods