Assessment of AquaMats for removing ammonia in intensive commercial Pacific white shrimp Litopenaeus vannamei aquaculture systems

Abstract

AquaMats are high surface–area polymer filters whose use produces higher yields with reduced health risks for the aquaculture product. We used AquaMats in pilot-scale systems and in intensive commercial Pacific white shrimp Litopenaeus vannamei production systems to stabilize and improve water quality by removing ammonia. In the pilot-scale systems, evaluation of the effects of temperature and hydraulic retention time (HRT) on ammonia removal rate indicated that the surface total ammonia nitrogen (TAN) conversion rate (STR, mg TAN/m2-day) increased with increasing temperature and decreasing HRT. The highest STR of 319.8 mg TAN/m2-day was observed at a temperature of 30 °C and a HRT of 5 min. In the commercial shrimp production systems, ammonia levels were significantly greater in the control systems (without AquaMats) than in the treatment systems (with AquaMats) after 6 days (P < 0.05). Results suggested that eight 150 cm × 90 cm pieces of AquaMats (0.057 m2 surface area per m3 culture volume) were sufficient for promoting nitrification in this system. The growth rate of juvenile shrimp was most enhanced in treatment C (with 12 pieces of AquaMats, 0.085 m2/m3), which exhibited a significant decrease in ammonia.