Abstract
As a pilot study for ecosystem-based fishery management in Japan, we constructed an Ecopath model based on demersal fish stock survey data and regional catch statistics in the northern area off the Pacific coast of northeastern Japan. Ecopath is a massbalance model parametrized to have high affinity to fishery-related data, and can build up available data and supplementary literature information into a trophic flow system. Once an Ecopath model is constructed and mass-balanced, it can provide system properties such as food web structure, niche overlap, mixed trophic impacts and keystone indices. We further compared our model with the global models published in the scientific literature. Impacts of fisheries on lower and higher trophic levels
were calculated and evaluated through trophic level fractionation of biomass, production and commercial harvest. Further promotion of Ecopath modeling for other waters around Japan would delineate gaps in the data and modeling and improve our knowledge and experience of ecosystem modeling and its practical application.
