COMPARISON OF SHRIMP PERFORMANCE IN A RECIRCULATING RACEWAY VERSUS A FLOW-THROUGH ROUND POND

With the emergence of virulent shrimp viruses and concerns about environmental pollution from pond effluent, there are strong incentives for the shrimp aquaculture industry to consider alternative approaches to traditional shrimp farming. These approaches may include the stocking of high-health, genetically improved shrimp in biosecure production systems designed for pathogen exclusion. We have developed a prototype biosecure system for intensive shrimp culture that consists of a covered, 58-m2 raceway. Water in the raceway is recirculated through a 25-ft3 bead filter designed for clarification and biofiltration. In two separate trials, we compared shrimp performance in the covered, recirculating raceway with performance in an uncovered, 337-m2 round pond that relies on flow-through water at an exchange rate of about 50% per day.

In trial #1, both the raceway and round pond were stocked with juvenile Pacific white shrimp, Litopenaeus vannamei, from 44 full-sib families at a density of 100 shrimp/m2. Shrimp in both systems received a commercial, 30%-protein feed ad libitum. After 22 weeks, shrimp in the round pond grew 20.9 g, shrimp harvest weight was 22.2 g, survival was 90%, and production was 2.0 kg/m2. After 16 weeks, shrimp in the raceway grew 21.1 g, harvest weight was 22.9 g, survival was 88%, and production was 2.0 kg/m2. In trial #2, both the raceway and round pond were stocked with shrimp from 80 full-sib families at a density of 200 shrimp/m2. Shrimp in both systems received a commercial, 35%-protein feed ad libitum. After 14.5 weeks, shrimp in the round pond grew 17.0 g, harvest weight was 19.1 g, survival was 84%, and production was 3.3 kg/m2. After 16 weeks, shrimp in the raceway grew 21.1 g, harvest weight was 23.3 g, survival was 85%, and production was 4.0 kg/m2. 

The raceway cover acted as an effective thermal insulator, resulting in warmer water temperatures, and this may have contributed to the higher growth rates of raceway-reared shrimp, especially in trial #1. Importantly, the amount of water used to produce one kg of shrimp in the round pond was two orders of magnitude greater than in the raceway. Results from this work indicate that high levels of shrimp production can be achieved under biosecure conditions with minimal water use.