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 Tiñoso 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.