The effect of recirculating aquaculture system on blue swimming crab (Portunus pelagicus Linnaeus, 1758) instar crablet growth and survival rate

The purpose of this study was to investigate the effect of Recirculating Aquaculture Systems (RAS) on the growth and survival of blue swimming crab (Portunus pelagicus) seed (instar crablets). The study was carried out at the Universitas Hasanuddin Crab Hatchery in Bojo Village, Barru Regency, South Sulawesi, Indonesia from March to July 2020. Two nursery systems were tested, namely RAS and NON RAS installations. Five day old crablets (N = 400) were stocked at a density of 100 crablets per tub. Crablets were maintained for 1 month. The results showed that maintenance using RAS installations resulted in significantly faster crablet growth (weight gain, increase in carapace width and carapace length) than NON RAS (p < 0.05). However, crablet survival rate did not differ significantly between the two installations. Crablet growth was strongly influenced by water quality. Although the measured values of water quality parameters such as temperature, salinity, and pH did not differ between the two maintenance installations, the ammonia and nitrite content in the NON RAS installation were higher than in the RAS installation.