OVER A DECADE PROMOTING SEAWEEDS AS EFFICIENT INORGANIC NUTRIENT SINKS IN INTEGRATED MULTI-TROPHIC AQUACULTURE (IMTA): NOW WHAT?
In the beginning of the 21st century as the aquaculture production started to raise researchers started to advocate alternative methods to the industrialized monoculture system. The booming industry was showing signs of environmental, social and economic difficulties. In 2004 researchers introduced the concept of Integrated Multi-Trophic Aquaculture (IMTA) hoping to make aquaculture more sustainable and resilient to environmental and economic change. IMTA is the farming of several species in close proximity occupying different positions in the food chain that is feeder species such as fish, sharing space with extractive species such as seaweeds, or bivalves. Since then more than 150 papers have been published showing that seaweeds are efficient inorganic nutrient extractors (bio-filters) which can be used in IMTA. But after 11 years and despite the potential of this method the industry has not adopted it yet and research seems to be stuck asking the same questions over and over again. Where did we go wrong and where does all this science leave us now in 2015 and beyond?
To answer this question we used a descriptive statistics based approach to characterize all published papers since 2004. The 150 papers were classified based on 3 criteria: a) publication (journal, year, citation numbers, country); b) publication type (review, model, or experimental studies); c) main theme/aim. To describe the theme/aim of the paper we listed the main title keywords (Table 1) and defined 3 broad themes: biomitigation, feed and socio-
economics.
Experimental studies were further classified according to broad categories describing which variables were controlled (system type, temperature, light); combination of species studied, the measurable variables (nutrients, growth, nutrient efficiency).
We conclude that with time research is getting less significant, focused on small scale (flasks or aquariums) with limited experiment time (hours to less than a month) or more general based on models. In between these two options we discuss alternatives. We also identified several external factors that affect the scientific approaches, namely stakeholder's agendas, funding opportunities, consumer's trend and social media impact.