The International Maritime Organization (IMO) International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) entered into force in 2017. The number of ships installing ballast water management systems (BWMS) to meet their compliance obligations has risen steeply in the last years. When BMWS are installed, “commissioning testing” occurs to determine the suitability of the installation and since June 2022 there is a requirement following the BWM Convention to include biological efficacy testing during all commissioning tests to verify that the installation allows for the ship to discharge water with organisms concentration below the “D-2 performance standard”.
We present findings from >600 tests carried out in 28 countries on more than 25 technologies. Notably, nearly all failures to meet the D-2 performance standard occurred in the largest size class (≥50 µm) of organisms. Between November 2019 and March 2022, the failure to meet the D-2 standard during commissioning as decreased from >20% failure to <7% failure. However, regular compliance monitoring from authorities during normal operations reveals that more than 1/3 of ships do not meet the convention objectives. The data set suggests that experience (spurred by mandatory, third-party testing) has allowed all stakeholders involved in the selling, design, planning, installation and operations of BWMS to correct many issues over time. As part of the Ballast Water Management Convention, the IMO has agreed to carry our regular testing (every 2.5 years) to verify ships can meet the discharge standard of the Convention. Regular testing of discharges from ship to be carried out by independent testing organisations is the only way to improve the protection of aquatic environment from the transfer of harmful aquatic organisms and pathogens.