Kentucky State University
Evaluation of Stocking Density During Second Year Growth of Largemouth Bass, Micropterus salmoides, Raised Indoors in a Recirculating Aquaculture System
Institution
Kentucky State University
Faculty Advisor/ Mentor
Shawn Coyle; Leigh Anne Bright; James Tidwell
Abstract
Largemouth bass, Micropterus salmoides, (LMB) are a highly desirable food fish among ethnic Asian populations in large cities throughout North America. The primary production method for LMB has been in outdoor ponds, requiring two growing seasons (18-24 months). Indoor controlled environment production using recirculating aquaculture system (RAS) technologies could potentially reduce the growout period to 12 months by maintaining ideal temperatures year around. We conducted a 26 week study with second-year LMB in indoor recirculating tanks to evaluate optimal stocking densities for growout to food-fish size. Largemouth bass fingerlings (101 ± 10 g average weight) were randomly stocked into nine 900-L tanks to achieve densities of 30, 60, or 120 fish/m3 , with three replicate tanks per density treatment. A shared recirculating system consisted of a 3,000-L sump, a ¼ hp pump, a bead filter for solids removal, a mixedmoving-bed biofilter for nitrification and 400 watt ultraviolet light for sterilization. All fish were fed a commercially available floating diet (45% protein and 16% lipid) once daily to apparent satiation. At harvest all fish were counted, individually weighed, and measured (total length). Total biomass densities significantly increased (P < 0.05) with stocking rate achieving 6.2 kg/m3 at 20 fish/m3 , 13.2 kg/m3 at 60 fish/m3 , and 22.9 kg/m3 at 120 fish/m3 . However, the stocking densities evaluated here had no significant impact (P > 0.05) on survival, average harvest weight, or feed conversion ratio (FCR) which averaged 93%, 29 4g, and 1.8, respectively.
Evaluation of Stocking Density During Second Year Growth of Largemouth Bass, Micropterus salmoides, Raised Indoors in a Recirculating Aquaculture System
Largemouth bass, Micropterus salmoides, (LMB) are a highly desirable food fish among ethnic Asian populations in large cities throughout North America. The primary production method for LMB has been in outdoor ponds, requiring two growing seasons (18-24 months). Indoor controlled environment production using recirculating aquaculture system (RAS) technologies could potentially reduce the growout period to 12 months by maintaining ideal temperatures year around. We conducted a 26 week study with second-year LMB in indoor recirculating tanks to evaluate optimal stocking densities for growout to food-fish size. Largemouth bass fingerlings (101 ± 10 g average weight) were randomly stocked into nine 900-L tanks to achieve densities of 30, 60, or 120 fish/m3 , with three replicate tanks per density treatment. A shared recirculating system consisted of a 3,000-L sump, a ¼ hp pump, a bead filter for solids removal, a mixedmoving-bed biofilter for nitrification and 400 watt ultraviolet light for sterilization. All fish were fed a commercially available floating diet (45% protein and 16% lipid) once daily to apparent satiation. At harvest all fish were counted, individually weighed, and measured (total length). Total biomass densities significantly increased (P < 0.05) with stocking rate achieving 6.2 kg/m3 at 20 fish/m3 , 13.2 kg/m3 at 60 fish/m3 , and 22.9 kg/m3 at 120 fish/m3 . However, the stocking densities evaluated here had no significant impact (P > 0.05) on survival, average harvest weight, or feed conversion ratio (FCR) which averaged 93%, 29 4g, and 1.8, respectively.