European legislation (i.e., Water Framework Directive 2000/60/EC or Marine Strategy Framework Directive 2008/56/EC) emphasise the importance of biological indicators to assess the status of marine systems. In order to establish the ecological quality of European coasts and estuaries, Borja et al. (2000), from AZTI, developed two indices: AMBI and multivariate-AMBI (M-AMBI), which can be calculated using the AMBI software.
These indices explore the response of soft-bottom communities to man-induced changes in water quality, integrating long-term environmental conditions. Currently AMBI and M-AMBI are used worldwide in multiple applications and officially in many countries.