Ecosystem model of Tasmanian waters explores impacts of climate-change induced changes in primary productivity

An Ecopath with Ecosim (EwE) model was developed that represents the marine shelf environment surrounding the island state of Tasmania (south of mainland Australia). Climate change scenarios representing a range of potential impacts (30% increase or decrease over a century) on marine primary productivity were investigated. Temperature changes and other impacts were not investigated. This analysis uncovered an asymmetric set of system responses. Modeled increases in primary productivity predict increases in the biomass of most groups, especially shallow filter-feeders (which includes oysters), fished macrozoobenthos which includes rock lobsters (Jasus edwardsii) and octopus. In contrast the group of unfished macrozoobenthos (sea stars, whelks) decreased their relative biomass as primary productivity increased. All modeled fisheries responded to varying primary production levels. The most responsive modeled fisheries were for flathead (Platycephalidae) and for those offshore. Of the groups of special conservation interest (marine mammals and seabirds) the most responsive was the dolphin group – though all responded.