Optimizing germination and cultivation of edible halophytes using effluents from an IMTA system

BACKGROUND: Halophytes offer nature-based solutions to food insecurity and soil degradation, while their integration into integrated multi-trophic aquaculture (IMTA) systems promotes circular economy practices. This study aimed to optimize the germination and cultivation of edible halophytic species, namely Limbarda crithmoides, Suaeda vera and Mesembryanthemum nodiflorum, using effluents from an IMTA system. Germination was conducted under different substrates (perlite, vermiculite, coco peat, sand and combinations), irrigation (fresh or brackish water) and seed pre-treatments (scarification, gibberellic acid and thermal shock). Cultivation assays assessed plant responses to salinity (25.5–53.4 dS m⁻¹) and density (75–600 plants m⁻²) using IMTA-derived aquaculture effluents for irrigation. RESULTS: Salinity significantly reduced seed germination. Limbarda crithmoides had the highest germination rate (61.1%) in vermiculite under freshwater irrigation, whereas S. vera achieved optimal performance in a substrate of sand, organic peat and perlite. Thermal shock slightly improved M. nodiflorum germination. Moderate salinities (35.1–40.7 dS m⁻¹) resulted in higher survival and productivity, particularly for S. vera, which showed >86% survival and higher chlorophyll content. At high densities, L. crithmoides and S. vera maintained >75% survival, while M. nodiflorum at 75 plants m⁻² effectively reduced nitrate and ammonia concentrations in effluents. All species produced biomass with adequate nutritional and microbiological profiles suitable for human consumption, rich in protein, dietary fiber and bioactive compounds. Suaeda vera at 300 plants m⁻² exhibited the highest total content of phenolic compounds. CONCLUSION: This study outlines a sustainable approach to cultivating edible halophytes in IMTA systems, with applications in saline farming, functional foods and aquaculture wastewater treatment.