Comparative study of blood biochemistry in clinically healthy farmed barramundi ( <i>Lates calcarifer</i> ) and rainbow trout ( <i>Oncorhynchus mykiss</i> ) from freshwater recirculating aquaculture systems

Barramundi (Lates calcarifer) is an economically significant aquaculture species and ranks among Australia's top five farmed finfish. As global production intensifies, understanding the physiology and health of barramundi is essential to support animal welfare and industry profitability. Blood biochemistry is a valuable diagnostic tool in veterinary medicine, yet its application in aquaculture is limited by the absence of established reference intervals (RIs) for many species, including barramundi. Establishing RI enables early detection of altered physiological states and disease processes by comparing measured analyte concentrations against defined healthy ranges. This study generated blood biochemistry RI for barramundi for the first time. Forty-seven blood samples were collected from clinically healthy farmed barramundi to establish RI for 16 biomarkers, including plasma metabolites, enzymes and electrolytes. To validate our methodology, 41 rainbow trout (Oncorhynchus mykiss) samples were analysed concurrently, with results compared against published RI as a quality control. Our findings provide baseline blood biochemistry values for barramundi, filling a gap for this emerging aquaculture species and supporting the future application of aquamedicine in diagnostics, health monitoring and welfare management.