Decadal‐scale variations of ecosystem productivity in the Bohai Sea are described by using the survey data of 1959–60, 1982–83, 1992–93 and 1998–99. Indices including chlorophyll a concentration, primary production, phytoplankton abundance, zooplankton biomass and fishery biomass were used to describe the ecosystem productivity at different trophic levels. During the past four decades, the productivity and community structure...