Recommendations for representative sampling methodologies in ballast water: A case study from the land-based test.

Accurate assessment of ballast water's community composition and organism concentrations is crucial for effective management. Yet, the lack of standardized global sampling methods presents challenges to achieving this objective. Inconsistencies hinder data comparison across regions and vessels, impeding efficient ballast water treatment and discharge regulation. This study conducted land-based tests to establish suitable methodologies. For organisms ≥50 μm and ≥10 μm to <50 μm, the recommended max flow rate is 50 L/min; for <10 μm organisms, 25 L/min is advised to prevent cell damage. Sampling should cover substantial discharge durations. To ensure representation, ≥50 μm organisms require ≥1m3, while ≥10 μm to <50 μm and <10 μm organisms need 20 L. The ultimate aim is standardized methods for assessing ballast water across regions and vessel types, facilitating effective management to curb invasive species and protect aquatic ecosystems.