Refining selection criteria and updating the Baltic Sea Target Species list for exemptions from ballast water management

The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) of the International Maritime Organization was adopted to reduce the spread of harmful aquatic organisms and pathogens via ballast water and sediments. Regulation A-4 of the BWM Convention allows ship operators to apply for exemptions from ballast water management on specified routes. An exemption requires conducting a scientifically robust risk assessment (RA) according to the Guidelines for risk assessment under Regulation A-4 of the convention (G7 Guidelines). One of the proposed RA approaches in the G7 Guidelines, species-specific RA, relies on the identification and selection of target species (TS). The approach has been applied to the Joint Harmonized Procedure (JHP), a regional RA scheme developed jointly by the coastal States of the Baltic Sea and North-East Atlantic Ocean through the two regional commissions - HELCOM and OSPAR.

The relevant activity in COMPLETE PLUS was aimed at further specifying and refining the previously proposed selection criteria for the process of identifying TS, and ultimately updating the TS list for the Baltic Sea. The suggested refinements are intended to further improve the transparency and robustness of the TS selection process to be also applied beyond the Baltic Sea.

• Primary criteria assessed and used in TS selection:
  • Relationship with ballast water as the vector of transport;
  • Impact and its severity.
• Supporting criteria assessed, but not used in TS selection:
  • Evidence of prior introduction(s) elsewhere (documentation of the species’ ability to spread outside its native area);
  • Current distribution in its native biogeographic and in other biogeographic regions (Species with a wide biogeographical or habitat distribution are categorized as potential TS).
• In addition, refining the definition on the widespread status of a non-indigenous species in the Baltic Sea deemed necessary to exclude widespread NIS from the TS list: ‘Species is already widespread in the Baltic Sea if present in all level 2 HELCOM sub-basins, where suitable habitats and environmental conditions occur’. Therefore, shipping cannot contribute to further spread of the species within the Baltic Sea.

The adjusted TS selection criteria were used to identify ballast water-related TS for the Baltic Sea. The process included a pre-screening procedure, where 101 species were tested against the updated TS criteria. The activity was led by Finnish Environment Institute and University of Tartu, with involvement of Klaipeda University, Latvian Institute of Aquatic Ecology, and HELCOM.

Text: Henn Ojaveer (University of Tartu), Maiju Lehtiniemi and Okko Outinen (Finnish Environment Institute).

Mnemiopsis leidyi is one of the species which fulfils the adjusted target species selection criteria. Photo: Maiju Lehtiniemi, Finnish Environment Institute.

Ballast water of ships can transport non-indigenous species. Photo: Maiju Lehtiniemi, Finnish Environment Institute.