Long-term assessment of benthic ecological status in sediments affected by offshore aquaculture: The case of the Republic of Cyprus.

Fish farming in the Republic of Cyprus is carried out at offshore locations with mandatory, annual environmental impact monitoring conducted consistently in each fish farm, according to the national aquaculture legislative framework and following a state-mandated National Environmental Monitoring Protocol. This study aims to assess the findings of the implementation of the monitoring program over a 12-year period, by examining the variability of the benthic macrofaunal community and ecological quality status assessment through benthic indices across different factors. The results indicated that the classification by all indices was independent of the taxonomic variability from sample analysis, even if the community structure patterns varied significantly between the consultancies implementing the monitoring programs. The analysis from the combined benthic data showed that, unless specified by the presence of sensitive habitats, the effects were found to be at 50 m distance from the edge of the cages, since most indices revealed acceptable ecological quality at this distance. The BENTIX index, which is established under the Water Framework Directive and implemented within the context of the National Environmental Monitoring Protocol, highly correlated with all other indices. A cost-effective and taxonomic sufficient alternative is the BQI-Family index, since its thresholds are also calibrated for Eastern Mediterranean Sea.