How many organisms are in ballast water discharge? A framework for validating and selecting compliance monitoring tools

Abstract As regulations governing the discharge of living organisms in ships’ ballast water enter into force, tools to rapidly and easily measure compliance with the discharge standards will be essential. To assess, validate, and select compliance tools, a framework—consisting of three parts—is presented: proof-of-concept, validation and verification, and final selection stages. Next, a case study describing the proof-of-concept stage is discussed. Specifically, variable fluorescence was evaluated as an approach for determining compliance with the discharge standard for living organisms ⩾10 μm and