GROWTH PERFORMANCE, FEED CONVERSION RATIO (FCR) AND TEMPERATURE TOLERANCE OF SELECTED MARINE FISH SPECIES WITH AQUACULTURE POTENTIAL FOR THE RED SEA

With the scarcity of freshwater in Saudi Arabia, mariculture production in the Red sea is considered an integral strategy to achieve the country's future fish-food demand. In this research, we tested the culture of Asian seabass Lates calcarifer, Sobaity seabream Sparidentex hasta and Gilthead seabream Sparus aurata using the hypersaline seawater from the Red sea to determine their growth performance, baseline FCR, and nutrient retention efficiency. For each experiment, fish (initial avg. body weight).: A. seabass (455 g); G. seabream (310 g); sobaity (331 g) were cultured for 10 weeks in 1-ton capacity tanks with flow-through set-up (Avg. temp.: 27-28°C). The fish were cultured at an initial stocking density of 10 kg ton^-1 to follow the stocking in commercial fish farms. The fish were fed to satiation with different commercial diets to determine baseline FCR: (diet A) 42.1% protein, 11.7% lipid; (diet B) 44.2% protein, 12.5% lipid; (diet C) 43.5% protein, 11.9% lipid. Our results showed that A. seabass has an average FCR of 1.51 and an average daily growth rate (DGR) of 6.67 g day^-1. For G. seabream, the average FCR was 2.04 while the average DGR was 2.21 g day^-1. For sobaity, the average FCR was 1.53 while the average DGR was 3.29 g day^-1. Our results suggest that the three fish species are suitable for culture in the hypersaline Red sea conditions with sobaity and A. seabass showing FCR levels that indicate potential economic feasibility at a commercial scale. Additionally, the growth performance of these fish species cultured at three different temperatures (24, 28 and 32°C) corresponding to low, average, and high levels encountered in the Red Sea are also being studied. In the case of sobaity (initial ABW 100g) , a significantly lower FCR (1.63) was observed at 32°C as compared to 24°C (FCR: 1.86) and 28°C (FCR: 2.02). The DGR was also significantly higher at 32°C (1.76 g day^-1) as compared to 24 (1.3 g day^-1) and 28°C (1.54 g day^-1). With the remaining species being currently under study, the full results will be presented during the conference, including the data on nutrient retention efficiency in the fish.