Application of a new protocol to evaluate the benthic impacts of aquaculture: Colonization of experimental units for monitoring by polychaeta.

Graphical abstract Highlights • Experimental units could be used as a management tool for aquaculture monitoring. • AMBI and multidimensional analysis done with polychaete list showed clear results. • Total free sulphide combine with the polychaetes analysis improve the results. • Sand had a greater sensitivity for the detection of organic matter enrichment. Abstract A range of different protocols and indices have been developed in recent years for the definition of Environmental Quality Standards in aquaculture. However, it can be difficult to compare these protocols or indices between different regions or different habitats due to spatial heterogeneity at different scales. We carried out a field study to estimate the effectiveness of experimental units (sediment-filled trays) as an environmental management tool. The experimental units were filled with two different sediments - sand and mud - and placed underneath two fish farm facilities for one month. Using polychaetes to assess the ecological status, AMBI and multidimensional analysis showed clear results, and had further value when combined with sulphide concentrations measures. Sandy experimental units had a greater sensitivity for the detection of organic matter enrichment. The species with the most pronounced responses in the facilities studied were Capitella capitata , Spiochaetopterus costarum , Capitella minima , Pseudopolydora pulchra and Aricidea (Strelzovia) claudiae in the fish farm, and Gallardoneris iberica , Micronephtys stammeri , Sternaspis scutata and Ampharete lindstroemi in the reference area without organic enrichment. Experimental units provide a complete and reliable source of information about the environmental quality status of fish farms, and with further refinement they could be used as a management tool for aquaculture monitoring. Experimental units could be used as a management tool for aquaculture monitoring; data of polychaete recolonization with AMBI and multidimensional analysis showed clear results. [ABSTRACT FROM AUTHOR]