Regional Integrated Multi-Trophic Aquaculture (RIMTA): Spatially separated, ecologically linked

Abstract

Aquaculture sustainability is restricted by environmental drawbacks such as the pollution derived from the released organic waste. Integrated multi-trophic aquaculture (IMTA) aims to lower the input of this waste by culturing other species of low trophic level which feed on them. Despite the appealing idea of IMTA, its implementation is very limited in marine ecosystems. Focusing on marine fish farming, in general terms, fish farm waste is not expected to constitute a relevant food source for low-trophic level organisms cultured in the water column. We propose Regional Integrated Multitrophic Aquaculture (RIMTA) as a shift of paradigm in the way IMTA is used to sequester the dissolved exported waste and derived primary production generated by high trophic level cultures. RIMTA advocates for independent allocation of cultures of low and high trophic level species within the same water body. RIMTA implementation should be economically supported through tax benefits or nutrient quota trading schemes. Moving from IMTA to RIMTA should not only foster aquaculture sustainability but also the circular economy and the ecosystem services that the low trophic level cultures provide.

Keywords: Ecosystem-based approach; Eutrophication; Integrated coastal zone management; Integrated multitrophic aquaculture (IMTA); Macroalgae and bivalve aquaculture; Organic matter pollution.