Abstract

The implementation of marine IMTA at commercial farm scales has not occurred in the Los Lagos region (Chile), where intensive salmon farming and mussel farming share common bays and channels. However, the co-occurrence of both farming systems makes possible to evaluate the IMTA potential at a landscape scale. As a first approach, we explored the relationship between the production of mussels and salmon to identify the potential area of influence of the nutrients provided by salmon farming and potentially used by mussel farming, then we estimated the theoretical aquaculture nitrogen balance for relevant water bodies containing both activities. We observed that mussel production was higher when closer to salmon farms (1000 m) and we propose that this was related to the shorter distance for nutrients dispersion from salmon farming. Between 2009 and 2019 salmon farming has contributed 12 to 22 thousand t of nitrogen (N) annual, while mussel farming has extracted 1 to 2 thousand t of N annual to the inner seas of Los Lagos. However, inputs and outputs differ among the different Salmon Farming Concessions Groupings (ACS, as the Spanish acronym). ACSs 10(a), 3(a) and 9(a) presented the largest proportion of salmon farming-generated nutrients potentially going out with farmed mussel biomass, being up to 40% in ACS 10(a); therefore, we suggest focusing research efforts leading to the integrated management of aquaculture on these areas. Our results show that implementation of multitrophic integrated aquaculture involving commercial farms is possible, it is likely happening already, and we discuss implication for the current regulations in Chile and suggest implementation changes within the framework of an ecosystem approach to aquaculture.