Effects of Stocking Density on Shrimp Survival, Growth Performance, Product Quality, and Halophyte Biomass in a Coupled Aquaponic System Integrating Penaeus vannamei and Salicornia

Aquaponics is recognized as a sustainable and eco-friendly farming system, as it enables the simultaneous production of aquatic animals and plants, thereby maintaining ecological balance and minimizing environmental impact. While aquaponics has been widely studied as a sustainable food production system, in the case of shrimp production, research addressing the role of stocking density in both shrimp culture and halophyte outcomes remains scarce. Specifically, limited data exist on how stocking density influences shrimp growth, survival, and product quality when reared under aquaponic conditions. This study evaluated the effects of stocking density on the survival, growth performance, product quality of whiteleg shrimp (Penaeus vannamei), and biomass production of Salicornia in a coupled aquaponic system. In this intensive aquaponic system, shrimps were reared under three stocking densities: LD with 65 shrimps/m2, MD with 123 shrimps/m2, and HD with 182 shrimps/m2. Across all treatments, water quality parameters such as ammonium, nitrite, nitrate, pH, turbidity, and chlorophyll remained within safe limits for both shrimp and plants, demonstrating the resilience of the integrated system in maintaining environmental stability. Shrimp survival was uniformly high, even at the highest density, likely supported by aeration, system design, and the use of artificial substrates that reduced crowding stress and aggression. However, growth performance and morphometric traits such as body weight, length, and antennae ratio declined progressively with increasing density. Yet, as stocking density increased, total biomass gain also increased, reaching 465.4 g in LD, 611.8 g in MD, and 701.5 g in HD. Lesion incidence was more strongly linked to body size than to density, suggesting behavioral causes rather than feed limitation. Meat quality attributes, including pH, color, and texture remained stable across treatments, although shrimp from low-density tanks exhibited slightly firmer texture and more intense redness after cooking, traits generally associated with higher consumer appeal. In contrast, Salicornia yields were highest under high-density shrimp culture, reaching 12.0 kg/m² compared to 9.87 kg/m² at low density, indicating enhanced nutrient recycling and plant growth under higher nutrient loads. These findings highlight trade-offs linked to stocking density: low stocking density promoted superior shrimp growth and product quality, whereas high density optimized halophyte yields. Medium density provided a balance between animal and plant performance. Overall, the integration of P. vannamei and Salicornia in aquaponics demonstrates a sustainable pathway to produce two high-value products with reduced water and land use, while mitigating the environmental impacts of intensive aquaculture.