The intercalibration (IC) exercise is a basic requirement established in the WFD (Annex V section 1.4.1) for the harmonisation of the ecological status assessments carried out along Europe. It aims to ensure the comparability of the methods developed by different Member States for each of the biological quality elements. The IC process is led by the Ecological Status Working Group (ECOSTAT) and coordinated by the European Commission’s Joint Research Centre (JRC). (See more about IC)

The intercalibration of intertidal macroalgae assessment methods in the NE Atlantic region has been carried out between 8 National methods from 6 European Member States. In the southern NEA region, the CFR index has been used as Intercalibration Common Metric (ICM) due to its wide application in Spain, France and Portugal. The details concerning the IC exercise at the NEA region can be found in the Intercalibration technical report developed by the JRC (2013).