Recirculating aquaculture systems (RAS) represent a crucial technological advancement in the aquaculture industry, with optimizing production efficiency. A key research priority remains to maximize and optimize the growth and reproduction of rearing fish species. Although environmental factors significantly influence fish growth, their systematic manipulation in RAS requires further investigation. This study examined the effects of specific environmental parameters on the growth performance of Malabar grouper (Epinephelus malabaricus), an economically important species in Asian markets. We evaluated the impacts of light wavelength, salinity, and temperature under controlled RAS conditions.
Under conditions of long-day photoperiod (light: dark = 14:10) and 21°C water temperature with red (peak at 632 nm), green (519 nm), and blue (465 nm) LED, and natural light, the specific growth rate (SGR) was significantly higher (P < 0.05) in fish exposed to blue LED light than to red LED light. In salinity trials conducted at 26°C, fish maintained at lower salinities (5 and 11 psu) demonstrated significantly higher SGR compared to those at higher salinities (22 and 34 psu) (P < 0.05). Temperature experiments revealed significantly enhanced fish SGR at 30°C compared to both 20 and 25°C ( < 0.05) under long-day photoperiodic conditions.
These findings demonstrate that the manipulation of environmental parameter can optimize fish growth in RAS operations. However, further research is needed to investigate potential interactive and synergistic effects among these environmental factors, which could provide additional insights for commercial aqua culture applications.