Target species selection criteria for risk assessment based exemptions of ballast water management requirements

Abstract The Ballast Water Management Convention adopted at the International Maritime Organization (IMO) allows exemptions from ballast water management requirements. These exemptions may be granted when a risk assessment results in an acceptable low risk scenario. IMO has adopted a guideline describing different risk assessment approaches (G7 Guidelines, 2017). One approach is a species-specific risk assessment in which so called target species (TS) become important. TS are species that meet specific criteria indicating that they may impair or damage the environment, human health, property or resources and they are defined for a specific port, State or biogeographic region. The guidelines continue to describe general TS selection criteria, which include the species relationship with ballast water as a transport vector, their impact type and severeness, evidence of prior introduction(s), and its current distribution. However, the G7 Guidelines lack details how these criteria are to be defined. This paper presents the TS selection criteria developed during the EU-Interreg Baltic Sea Region COMPLETE project (Completing Management Options in the Baltic Sea Region to Reduce Risk of Invasive Species Introduction by Shipping), including explanations on what ballast water relationship means, which impact threshold is eligible to identify a TS, as well as why prior introductions and the current species distribution are relevant in that context. It was concluded that TS lists need to be regularly reviewed and that the described TS selection criteria may be also adopted elsewhere when planning species-specific risk assessments for exemptions from ballast water management requirements.