EU standardised methods
The problem of NIS is a trans-regional one, and therefore needs common standards for assessing, monitoring, prevention and management of targeted species. However, some specific standards need to reflect specific regional risks associated to exposure to vectors, pathways and sensitivity of ecosystems to the species introductions, and the ecosystem characteristics. 

There are several monitoring and recording systems in place and efforts should be made to collate and co-ordinate this information so that it can be used effectively for the GES assessment. Habitats exposed to a high risk of receiving IAS also should be prioritised. Standard marine biological survey methods are recommended for monitoring of NIS; which may have to be adapted to obtain the level of taxonomic identification required.
A broader understanding and commonly agreed methodological standards are needed to implement monitoring of D2 criteria. D2 monitoring parameters have been inventoried by Zampoukas et al. (2012):
EU guidance is available in the following links:
Regional Seas Conventions standardised methods
Parallel work towards selecting and developing environmental status indicators under the different Regional Sea Conventions covering the EU waters is relevant for this process.
HELCOM:
OSPAR
HELCOM & OSPAR
UNEP MAP
Black Sea Commission