Effects of shrimp species and salinity in Beta maritima-based marine aquaponics

Introduction Marine aquaponics is an emerging strategy for sustainable food production in saline and water-limited environments. However, most shrimp-based systems rely on Pacific white shrimp ( Litopenaeus vannamei ), while the suitability of regionally important species such as Indian white shrimp ( Penaeus indicus ) remains insufficiently explored. Methods This study compared P. indicus and L. vannamei in a Beta maritima -based marine aquaponic system operated at 10, 15, and 20 ppt for 56 days. The experiment followed a two-factor completely randomised design with three independent aquaponic systems per treatment combination. Shrimp production, plant growth and biochemical composition, and weekly water-quality dynamics were evaluated. Results Salinity and shrimp species affected final weight, weight gain, specific growth rate, feed conversion ratio, and productivity. Shrimp species affected survival, while feed supplied showed a significant salinity × species interaction. Both species achieved greater growth and productivity at 15 and 20 ppt than at 10 ppt. Pacific white shrimp had greater growth, survival, and productivity and a lower feed conversion ratio, whereas Indian white shrimp maintained high survival and improved production at 15 and 20 ppt. In B. maritima , salinity reduced leaf width, final fresh weight, and moisture content but did not affect dry weight. Plants integrated with Pacific white shrimp had greater final fresh weight and relative growth rate. Total chlorophyll remained unchanged, whereas carotenoid, phenolic, and flavonoid contents increased with salinity. DPPH radical-scavenging activity and protein content showed salinity × species interactions. Dissolved oxygen and pH declined over time, electrical conductivity reflected the assigned salinities, ammonia and nitrate accumulated, and nitrite increased initially before declining; water-quality variables were interpreted descriptively. Discussion Pacific white shrimp provided higher production performance, whereas Indian white shrimp remained a viable regional alternative. Among the salinities tested, 15 ppt provided a practical balance between shrimp production, sea-beet fresh biomass, and selected biochemical traits.