Assessing the benthic ecological status in the stressed coastal waters of Yantai, Yellow Sea, using AMBI and M-AMBI

•We firstly applied AMBI & M-AMBI to assess the ecological status in the research area.•The ecological status of coastal waters around Yantai was “moderate” to “good”.•The AMBI & M-AMBI is suitable to assess the ecological status in the Yantai coastal waters.•Some local species assignation could provide reference for further research in China waters.•This study will provides an criterion for assessing the ecological status of China waters. The coastal waters around Yantai have been subjected to a variety of anthropogenic pressures over the last two decades. To assess the current benthic ecological health and the recovery process of the benthic ecosystem, four surveys were conducted in 2010 and 2011. The AMBI and M-AMBI were applied to assess the benthic ecological status. The ecological status of the Sishili Bay and Taozi Bay was “moderate” to “good” at most sampling stations during four surveys, but some stations were degraded due to pollution and eutrophication induced by human activities. The ecological status improved after removal of the marine raft culture and minimizing the amount of waste water discharged into the coastal waters of Yantai. The AMBI and M-AMBI could be used as suitable bio-indicator indices to assess the benthic ecological status of coastal waters in Yantai, Shandong Province.