User-friendly guide for using benthic ecological indicators in coastal and marine quality assessment

Experience demonstrates that none of the available measures on biological effects of pollution
should be considered ideal. The use of a single approach does not seem appropriate due to the
complexity inherent in assessing the environmental quality of a system. Rather, this should be
evaluated by combining a suite of indices providing complementary information.
Having this in mind, a key table is proposed in this work with the aim of helping managers and
authorities of coastal areas in selecting the most suitable ecological indicators taking into account the
type of disturbance and the data available. Such key includes numerous indices based on benthic
invertebrate fauna information, because in the case of coastal and transitional waters ecosystems
there is a clear preference for benthic communities, which integrate environmental conditions and
changes in an a very effective way if we want to monitor long-term responses and site-specific
impacts.
The development of this key was based not only on theoretical approaches, but also on results
from its application using data bases corresponding to different geographical areas (the Mondego
estuary, in the North-Western Coast of Portugal, and Mar Menor coastal lagoon, Escombreras
basin, and Cabo Tin˜ oso in the South-Eastern coast of Spain).
Some recommendations are provided with regard to the most adequate application of the indices,
as for example, in what situations it is not advisable the use of some of them, depending on the type
of disturbance or the level of taxonomic identification of the organisms.