Halopteris scoparia: a promising seaweed candidate for integrated multi-trophic aquaculture

Abstract This study evaluated the cultivation parameters and growth dynamics of Halopteris scoparia under controlled laboratory conditions to optimise its production for integration into integrated multi-trophic aquaculture (IMTA) systems with marine finfish. Five independent, sequential trials tested culture medium, light (wavelengths), salinity, stocking density, and meagre ( Argyrosomus regius ) recirculating aquaculture system (RAS) wastewater. Growth proxies were relative growth rate (RGR) and productivity; compositional changes (moisture, ash) were also assessed. Growth performance and productivity varied significantly across treatments. The best growth conditions included Nutribloom® as the nutrient medium, salinity near 30 psu, and a stocking density of 1 g L −1 fresh weight. White LED light at ~ 60 µmol photons m −2 s −1 yielded the highest growth rates. Wastewater from a meagre RAS, both full-strength and diluted, supported seaweed growth, highlighting its suitability for bioremediation. Cultivated biomass exhibited notable changes in moisture and ash compared to wild samples, underscoring the influence of culture conditions on composition. These findings confirm the species’ capacity for rapid growth and its potential role in sustainable aquaculture.