interreg 
Baltic Sea Region 
EAN 
JROPEAN 
EGIOMAL 
EVELOPMENT 
IHD 
- COMPLETE PLUS 
systems (MGPS). In addition, regular performance monitoring can be an important indicator for 
the necessity of inspection and in-water cleaning (IWC) of the ship’s hull and niche areas. 
Periodically, dry-docking is also essential for successful biofouling management (Watermann et 
al. 2021). 
IWC of ship hulls can facilitate the release of introduced IAS, as well as biocides and particles 
from AFS and MGPS into the surrounding environment (Department of the Environment and MPI 
2015), and therefore, poses certain environmental risks. For this reason, IWC is explicitly or 
effectively prohibited in many countries, because the environmental impact of releasing IAS, 
biocides and particles during IWC outweighs the risks that come along with biofouling growth on 
a ship’s hull with no action. This has also been shown in the COMPLETE Project (Completing 
management options in the Baltic Sea Region to reduce risk of invasive species introduction by 
shipping), where numerous administrations of the Baltic Sea countries reported that IWC in their 
coastal waters and ports is either not allowed at all or only on the basis of granted permissions. In 
the latter case, often no clear understanding exists on what prerequisites are needed for granting 
such kinds of permissions. Other information collected in the COMPLETE project showed that 
even in countries which reported that no permissions are granted, IWC takes place on a regular 
vasis without any risk assessment regarding introduction of harmful aquatic organisms and input 
of biocides and particles from antifouling paints. At IMO PPR7, several submissions dealt with the 
evaluation and review of the IMO Biofouling Guidelines according to MEPC.1/Circ.811 and their 
applicability. As one major impediment for the implementation of the Guidelines, the unavailability 
of IWC opportunities worldwide was mentioned by several member states. 
An additional problem is the current practice of performing IWC in countries with relatively weak 
environmental regulation and low costs. This is not only an ethical and environmental dilemma, it 
also provides no stimulus for the development of environmentally acceptable in-water cleaning 
methods and techniques. Therefore, in-water cleaning needs to be considered at both domestic 
and international levels (Department of the Environment and MPI 2015). 
IWC as one important aspect of biofouling management plays also an important role in the IMO 
Biofouling Guidelines. Therefore, solutions for environmentally sustainable practices require a 
common understanding on connected risks, and their assessment as background for science- 
vased decision making. As part of the COMPLETE Project, a proposal for a regional Baltic 
Diofouling management roadmap (COMPLETE 2019) has been developed that has already been 
considered by several international committees, like HELCOM Maritime 19-2019 and 20-2020 and 
the HELCOM/OSPAR Task Group on Ballast Water Management Convention (BWMC) und 
Biofouling (HELCOM/OSPAR TG BALLAST) 11-2020. Furthermore, an extract of the Roadmap 
nas been submitted to the IMO PPR 8 to directly support the work of the IMO Correspondence 
Group on the Review of the Biofouling Guidelines. As important addition to the proposed HELCOM 
Biofouling Management Roadmap, this document proposes a harmonized risk assessment 
procedure as basis for permissions of in-water cleaning (IWC) of ships in the Baltic Sea Region 
within the framework of the follow-up project COMPLETE PLUS by taking into account three 
relevant environmental aspects of IWC: