Paula Senff

Integrated multi-trophic aquaculture (IMTA) systems integrate the cultivation of species from different trophic levels. Uneaten feed, solid wastes, and dissolved nutrients are turned into harvestable and healthy food, making IMTA a driver for ecologically sustainable aquaculture. Its wider sustainability potentials arise from social, environmental, and economic sustainability enhancement options. Biological and economic outcomes are promising, while social equity and acceptance remain to be further investigated in the context of the long-term viability of aquaculture. Sustainable coastal and marine aquaculture development requires a holistic approach that involves social/cultural, economic, as well as environmental sustainability. This article examines IMTA as a pathway to socially, environmentally, and economically sustainable development. We collate evidence that shows that IMTA can minimize the negative environmental effects of aquaculture, assist local economies, and boost competitiveness and long-term economic viability. Available analyses of socio-economic and cost-effectiveness reveal positive prospects for IMTA systems, through product diversification, faster production cycles, and IMTA product prices and show a divergence between financial returns at the level of the entrepreneurial unit and economic returns at the macro level, which inhibits the uptake of IMTA. We conclude that the lack of governance analysis or inappropriateness of institutional development, in terms of aquaculture governance and management laws and regulations, is at the core of the hitherto weak engagement with IMTA. Unsuitable policies, regulations, and public and private sector decision policies and implementation, underlined by the scarcity of analyses of aquaculture governance institutions, are part of the reason for this. The evidence we have aggregated indicates that the relative scarcity of commercially successful coastal IMTA undertakings is not so much an intrinsic feature of the IMTA approach but is likely to have been generated by missing or inappropriate governance structures and procedures in the coastal realm.