To eat or not to eat? Two systems analytic approaches to evaluate the sustainable use of dioxin-rich Baltic herring and salmon

Ecosystem-based fisheries management aims to achieve sustainable use of the fish stocks in a socioecologically balanced manner, paying attention to human-environment interconnections. This requires systemic perspective to management: the interactions between species, environmental conditions and human pressures determine the productivity and health of the ecosystem. These further on define the limits of the sustainable use, where both environmental, social, and economic aspects are considered. We examine dioxin flux in different basins of the Baltic Sea and analyze alternative ways to reduce the dioxins accumulating to humans via eating Baltic herring and salmon. Dioxin compounds accumulate to fatty tissues, thus the concentrations in the organisms increase cumulatively when shifting upwards along the food chain. On the other hand, fatty fish as part of human diet form an excellent source of healthy Omega-3 fatty acids and vitamin-D. We study the impact of different fishing regulations and fish eating recommendations to find ecologically and socially sustainable ways to use Baltic herring and salmon, acknowledging the risks and utilities to different sectors. Two systems analytic approaches are presented: 1) a qualitative study to conceptualize the causalities of key biotic and abiotic factors in different basins, including mapping of the prevailing levels of uncertainties and 2) a probabilistic influence diagram for the Bothnian Sea area, based on modular model coupling, where the output of an ecosystem model serves as an input to a human health risk–benefit model. The management options are evaluated from the multi-criteria perspective, acknowledging all the three aspects of sustainability.