Key food web technique and evaluation of nearshore marine ecological restoration of Bohai Bay

•An ecological restoration technique based on construction of the local key food web was proposed.•The implementary effect was forecasted by applying Ecopath model and ocean health index.•The results of Ecopath model showed that the restored ecosystem is more mature.•The results of ocean health index assessment showed restored ecosystem is more healthier.•The key food web ecological restoration was shown to be effective and safe restoration technique.

An ecological key food web restoration technique is proposed to restore the degraded nearshore marine ecosystem near the Bohai Bay, in which the key species are screened and the local key food web is built according to the trophic relationships of screening species to reference ecosystem. The trophic relationships of the key food web are quantified by the biomass of the screening species of each trophic level and the restoration input biomass is fixed. The restoration effect of the proposed technique on the restored ecosystem is predicted by the maturity and health with the Ecopath model and the ocean health index. The proposed technique is applied to the First Harbor of Tianjin Lin Gang Economic Zone. The calculated restoration effect shows that the restored (target) ecosystem is more mature, faster ecological balanced and healthier than the existing ecosystem. The ocean health index of the target ecosystem is 86.3, which is much higher than 51.8 of the existing ecosystem. It is concluded that the proposed technique is effective and applicable in the nearshore marine ecosystem restoration.