Testing the applicability of marine biotic indices for ecological quality in the northern East China Sea

The northern East China Sea is currently subjected to anthropogenic disturbances during the past few decades. Using data collected in July 2019 and July 2020, the AZTI's Marine Biotic Index (AMBI), multivariate-AMBI (M-AMBI), Shannon–Wiener diversity index (H′), and BENTIX index were adopted to assess their applicability and evaluate the benthic ecological quality of the northern East China Sea. The results of the Pearson correlation between biotic indices and eutrophication environmental factors showed that H′ and M-AMBI were suitable biotic indices for evaluating the benthic ecological quality in the northern East China Sea rather than AMBI and BENTIX. The overall benthic ecological quality in the northern East China Sea was moderate to good during 2019–2020. Ecological quality showed a positive correlation with distance to mainland. However, a slow declining trend was detected for the benthic ecological quality of the northern East China Sea, especially the nearshore areas. •The H′ and M-AMBI were suitable biotic indices in the northern East China Sea.•The benthic ecological quality was negatively correlated with offshore distance.•The benthic ecological quality in the study area was at a moderate to good level.•Macrobenthic assemblages were affected by eutrophication stress.•The effects of human activities had spread beyond 122.5° E.