Forever young: The successful story of a marine biotic index.

In 2000, the AZTI's Marine Biotic Index (AMBI) was published and was one of a number of marine benthic indices development to assess the ecological status of soft-bottom macroinvertebrates. This index, and its derivatives, has been very successful in its application to different geographical areas, across the world, as well as to different environments, from the intertidal to the abyssal, or from tidal freshwater to offshore habitats. In this review, we explain the story behind the AMBI development, and look for an explanation of the index's success. For doing that, we comment on the current practicalities of the index, we present the new AMBI species list, with 9251 taxa, we dismantle six myths around this index, and examine the past and the future of the index. We show that the solid ecological roots of the index make it a robust tool to assess the status of marine benthic communities, at any time and environment. Hence, we think that it will be 'forever young' helping managers in taking informed decisions to improve benthic marine systems.