Application of signal detection theory approach for setting thresholds in benthic quality assessments

•Signal detection theory (SDT) was used to assess the BQI (Benthos Quality Index) performance.•BQI (Benthos Quality Index) was found to respond acceptably to eutrophication parameters at the exposed coastal areas.•BQI (Benthos Quality Index) response was affected by estuarine water outflow.•SDT provide a method to assess the accuracy of indicators.•SDT can be helpful for management decisions when planning environment monitoring intensity.