Bull. Jpn. Soc. Fish. Oceanogr. 79(4), Page 255-265, 2015   Fish stock assessment targeting on multi-species and multi-fisheries based on Ecopath with Ecosim approach in Suo- nada, Seto Inland Sea, Japan Shingo Watari1 † 1 National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan † E-mail: swatari@affrc.go.jp Fish stock assessment targeting on multi-species and multi-fisheries based on Ecopath with Ecosim approach was conducted in Suo-nada, Seto Inland Sea, Japan. Ecopath was constructed using diet composition data and archive data. Ecosim was used for evaluation of effective fisheries management strategy. Landing and discarding of trawl nets, and landing of gill nets, set nets and others were incorporated in this model. Reduction of fishing mortality of each type of fishing gear and reduction of discard mortality of trawl nets were considered. The simulation result of Ecosim indicated that reduction of discard mortality of trawl nets was the only way to increase landing with all fishing gear compared to current landing level. This approach was considered to be an effective method for illustrating the effects of management strategies for multi-species and multi-fisheries, and providing material for discussion and examination. Key words: Ecopath with Ecosim, ecosystem model, Seto Inland Sea, fisheries management, discard