Integrated pond co-culture of Penaeus vannamei with red seaweeds: Implications for nutrient uptake and dual production performance

Abstract

The integration of seaweeds into shrimp aquaculture offers a sustainable strategy for nutrient bioremediation and productivity enhancement. Despite its potential, comparative nutrient dynamics, shrimp performance, and seaweed bioactive responses in semi-intensive pond co-culture systems along the Maharashtra coast remain insufficiently explored. A 56-day pond experiment was conducted in a completely randomized design with three treatments: shrimp monoculture (C), shrimp co-cultured with K. alvarezii (T1), and with G. foliifera (T2), with seaweed monolines stocked at 1 g L⁻¹ introduced on day 45 of shrimp culture. Compared to the control, co-culture treatments, especially with Gracilaria foliifera (T2) significantly improved water quality by reducing nitrate, nitrite, total ammonia nitrogen, and phosphate by 90.1%, 72.1%, 57%, and 75.1%, respectively. Co-cultured shrimp, particularly in T2, showed enhanced growth performance, with higher final weight (19.13 g), weight gain (812.74%), specific growth rate (3.94% day⁻¹), and yield (0.12 kg m⁻³) compared to monoculture. Physiological assessments revealed reduced oxidative stress, improved immune status, healthier tissue histology, and increased protein content in co-cultured shrimp. While K. alvarezii achieved higher biomass increment, G. foliifera contributed more effectively to nutrient removal and shrimp performance. Co-cultured seaweeds also exhibited elevated protein, lipid content, enhanced elemental profile, with co-cultured seaweeds also exhibiting improved protein, lipid content, and elemental composition compared to pre-co-culture biomass. Bioactive properties were influenced by co-culture conditions and solvent polarity, with aqueous solvents enhancing phenolic content and organic solvents improving antioxidant activity. Shrimp–seaweed co-culture, particularly with G. foliifera, offers farmers a practical and scalable approach to improve water quality, enhance shrimp yield, and generate additional income from value-added seaweed biomass.