Morphometric, Nutritional, and Blood Analyses in Hybrid Striped Bass (Morone chrysops x Morone saxatilis, Walbaum 1972) Reared in a Recirculating Aquaculture System (RAS) Implant in Sicily, Italy

Hybrid striped bass (HSB), a cross between white bass (Morone chrysops) and striped bass (Morone saxatilis), has garnered attention in aquaculture due to its adaptability, rapid growth, and high market value. This study investigates the morphometric, nutritional, and blood characteristics of HSB reared in a recirculating aquaculture system (RAS) in Sicily, Italy, over a 22-month grow-out period. The fish were managed under standardized feeding and water quality protocols, with weekly monitoring of the physicochemical parameters. A total of 21 clinically healthy fish, averaging 571.33 ± 129.32 in body weight, were randomly sampled in the spring season from a commercial RAS facility equipped with biological filtration, UV sterilization, and seasonally regulated water parameters. The results revealed strong positive correlations between the morphometric parameters and blood indices, such as red blood cell (RBC) count, hemoglobin (Hb) levels, and hematocrit (Hct), highlighting their importance as health indicators. The proximate composition revealed an average moisture content of 75.55 ± 1.49, crude protein at 20.29 ± 0.26, total lipid at 4.25 ± 0.97, and ash content at 1.69 ± 0.17. Additionally, statistical analyses, including a principal component analysis (PCA), identified relationships between body size, nutritional content, and blood parameters, emphasizing the role of body size in influencing nutritional and health outcomes. The findings of this study are crucial for optimizing farming protocols and improving the health and productivity of HSB in RAS under Mediterranean conditions.