# Lessons for Coastal Applications of IMTA as a Way towards Sustainable Development: A Review
## 3 Sustainability Potentials of IMTA
### Environmental Sustainability  
Population growth increases demand for food, but global resources cannot indefinitely satisfy this demand [38]. Environmental sustainability is concerned with pollution control, the wise and effective use of natural resources, ecosystem integrity and the carrying capacity of the natural environment [39]. One of the most harmful environmental effects of coastal aquaculture is the release of polluted effluents containing uneaten feed and faeces. By increasing nutrients in the water, particularly nitrogen and phosphorus, a phenomenon also denominated as \"organic enrichment\", it degrades receiving water bodies and sediments [40]. IMTA may turn aquaculture more sustainable by removing nitrogen and phosphorus from the water column, thus mitigating eutrophication and lowering biological degradation risks [41]. Improved coastal aquaculture waste management also reduces the risk of disease transmission and allows for higher quality production by improving water quality. The treatment of wastes from aquaculture requires the development of sustainable coastal aquaculture. The utilization of IMTA systems and the microbial nitrification and denitrification that occurs in sediments play an important role here [40; 41].  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Region/Countries** & **Aquaculture Ecosystems** & **References** \\ \hline Asia (China, Thailand. Cambodia, Vietnam, Indonesia) & Integrated aquaculture benefits millions of rural people. & [35] \\ \hline Asia (China) & Bioremediation and an increase in total yields of up to fifty percent can be achieved with IMTA, which combines fish, shellfish, and seaweed. & [36] \\ \hline Canada & Cooke Aquaculture, the largest salmon aquaculture company in eastern Canada, embraced integrated multi-trophic aquaculture. & [20; 30; 37] \\ \hline South Africa & Numerous abalone farms using seaweed to filter effluent water and substitute commercial feed. & [33] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Examples of integrated or other ecosystem-based aquaculture developments (Source: [33; 34]).  
Figure 2: Sustainability in the context of IMTA (Adopted from [28]).  
Assimilative biofililtration by algae increases the environmental capacity for nutrient assimilation. Macroalgae are an efficient instrument for bioremediation because they can absorb anthropogenic nutrients [40]. Seaweeds are best suited for biofililtration since they have the highest productivity of all plants, as well as high economic potential [21]. An Atlantic Coast IMTA study that focuses on algae (Rhodophyta) with fish (turbot _Scophthalnus maximus_, and sea bass _Dicentrarchus labrax_), also identified algae as great candidates for biofintering and wastewater reduction [24]. Research has also been conducted on _Gracilaria bursa-pastoris_, _Gracilaria gracilis_, _Chondrus crispus_, _Palmaria palmata_, _Porphyna dioica_, _Asparagopsis armata_, _Gracilariopsis longissima_, _Ulva rotundata_ (Rhodophyta), and _Ulva intestinalis_ (Chlorophyta) as biofiltration in IMTA approaches. Experimental studies have continued on the integration of algae with sea bass and turbot [42; 43]. _Gracilaria bursa pastoris_ had the best yields and nitrogen absorption efficiency of the three species examined (_Gracilaria bursa pastoris_, _Chondrus crispus_, and _Palmaria palmata_), and was thus recommended as the best choice for integration with sea bass or turbot [43]. _Ulva rotundata_, _Ulva intestinalis_, _and Gracilaria gracilis_ were co-cultivated with sea bass and found to be effective biofilters of phosphate (PO\({}_{4}\)\({}^{3-}\)) and ammonium (NH\({}_{4}\)\({}^{+}\)) from waste waters [44].