Propagation and culture has been accepted as an approved aquaculture method for resource managers to enhance and recover freshwater mussel populations. Although juveniles can be produced readily for many mussel species, achieving high growth and survival in the laboratory remains difficult. The goal of my project was to improve growth and survival of juvenile mussels by comparing diets, algae concentration, and culture systems. The first objective determined a suitable diet for feeding juvenile northern riffleshell, Epioblasma torulosa rangiana, a species listed as federally endangered. Three algal diets were evaluated to determine differences in growth and survival of juveniles of E. t. rangiana. After 60 d, mean survival on Phytofeast, Shellfish Diet, and WSSNFH mix were 75.1 (95% CI: 72.2 to 78.0), 78.9 (95% CI: 74.5 to 83.2), and 85.0 (95% CI: 80.6 to 89.3) percent, respectively. WSSNFH mix had the highest survival which was significantly different from Phytofeast (p=0.01).  Mean shell lengths were 2.37 mm (95% CI: 2.27 to 2.47), 2.62 mm (95% CI: 2.52 to 2.72), and 3.11 mm (95% CI: 3.01 to 3.22), respectively.  Juvenile length on all three diet treatments was significantly different from each other (p<0.0001), with the WSSNFH mix exhibiting the highest growth, and Phytofeast with the lowest growth. My second objective evaluated the effect of algal concentration (cells mL-1) on growth and survival of juveniles of E. t. rangiana and mucket, Actinonaias  ligamentina. After 60 d, mean survival of E. t. rangiana for the low (30,000 cells mL-1), medium (80,000 cells mL-1), and high (140,000 cells mL⁻¹) algal concentrations were 39.1 (95% CI: 30.7 to 47.4), 20.7 (95% CI: 12.8 to 28.6), and 12.7 (95% CI: 4.82 to 20.5) percent, respectively (p<0.01). Mean shell lengths were 1.58 mm (95% CI: 1.49 to 1.66), 1.30 mm (95% CI: 1.19 to 1.40), and 1.01 mm (95% CI: 0.936 to 1.08), respectively (p<0.0001).  Mean survival of A. ligamentina for the low, medium, and high algae concentrations were 46.8 (95% CI: 35.2 to 58.4), 24.6 (95% CI: 15.1 to 34.0), and 10.7 (95% CI: 5.45 to 15.9) percent, respectively (p<0.01). Significant differences were observed between the low feed concentration versus the medium and high feed concentrations. Mean shell lengths for the low, medium, and high concentrations were 1.15 mm (95% CI: 1.08 to 1.22), 0.994 mm (95% CI: 0.930 to 1.06), and 0.833 mm (95% CI: 0.770 to 0.896), respectively. All concentrations were significantly different, and the low concentration had the highest mean shell length (p<0.0001). The third objective compared the performance of three recirculating aquaculture systems for rearing juvenile mussels >5 mm. Mean incremental length of juveniles of E. t. rangiana at 60 d in Pans, Buckets, and Upwellers was 1.19 mm (95% CI: 0.746 to 1.62), 1.05 mm (95% CI: 0.608 to 1.49), and 2.07 mm (95% CI: 1.63 to 2.51), respectively. Incremental lengths were significantly higher in the Upwellers (p=0.03). The mean lengths for Bucket and Pan systems were not significantly different from each other (p=0.54).  Percent survival of juveniles for the Pans, Buckets, and Upwellers were 91.7 (95% CI: 87.4 to 96.0), 90.0 (95% CI: 80.6 to 99.4), and 100 (95% CI: 100 to 100), respectively. Survival in the Upwellers was significantly higher than in the Buckets (p=0.018). Survival of juveniles in the Pan system and Upwellers were not significantly different from each other (p=0.05).  Mean growth for A. ligamentina was 1.96 mm (95% CI: 1.03 to 2.9), 0.88 mm (95% CI: 0.048 to 1.80), and 2.46 mm (95% CI: 1.537 to 3.38), respectively (p=0.07). Mean percent survival of juveniles of Actinonaias ligamentina in the Pans, Buckets, and Upwellers were 100 (95% CI: 100 to 100), 86.7 (95% CI: 74.0 to 99.4), and 100 (95% CI: 100 to 100), respectively.   Survival of A. ligamentina in the Upwellers was significantly higher than in Buckets (p<0.0001).  Juvenile survival in the Pan system and Upwellers was not significantly different (p=0.998). Results indicate that the Upweller culture system supported the highest growth and survival in culturing E. t. rangiana and A. ligamentina. / Master of Science