1a. Objectives (from AD-416)
The objectives of this cooperative research project are to: 1) develop feeding management strategies and diets for optimal growth, efficiency, and reproductive success of high-value marine finfish reared in low salinity recirculating systems; 2) develop year-round spawning strategies for captive broodstock and larviculture methods for sustainable seed production of high-value marine finfish species; and 3) develop engineering processes and sustainable effluent technologies to enhance water and energy utilization and reduce environmental impacts within, and discharged from, low-salinity recirculating aquaculture systems.
1b. Approach (from AD-416)
ARS will conduct cooperative research with Florida Atlantic University at Harbor Branch Oceanographic Institute (HBOI). In consultation with the ADODR, cooperative research will be conducted in efforts to design and evaluate cost-effective recirculating nursery and growout production systems for marine finfish cultured in low-salinity water. Cooperative research will primarily focus on four companion areas of study. Area one will focus on determining nutrient requirements and development of feeding strategies and diets for optimal growth, efficiency, and reproductive success of marine fish reared in low-salinity recirculating systems. Area two will focus on developing year-round spawning strategies for captive broodstock and development of early juvenile rearing methods for sustainable seed production of selected marine finfish species. Area three will focus on developing engineering processes and sustainable effluent technologies that enhance water and energy utilization and reduce environmental impacts in low-salinity environments. Area four will focus on disease management strategies for recirculating aquaculture production systems.
3. Progress Report
The ADODR is in regular contact with the cooperator via e-mail, phone, and face to face contact. Studies were initiated to evaluate low-head recirculating aquaculture systems for potential to produce marine fish in low-salinity environments. Red fish were chosen as the test species. Studies were conducted to evaluate three types of filters (swirl separators, TORUS filters, and static-bed filters) for solids removal efficiency. Technology was transferred via two scientific presentations, two trade journal articles and two newspaper reports. (NP 106, Components 6b and 6f)
1. LARGE SCALE LOW-HEAD RECIRCULATING AQUACULTURE SYSTEMS DESIGNED AND CONSTRUCTED: Four replicated 43,000-Liter low-head recirculating aquaculture systems (RAS) were redesigned and retrofitted in the Sustainable Tank Aquaculture Recirculating Research (STARR) facility by scientists at Harbor Branch Oceanographic Institute at Florida Atlantic University (HBOI-FAU) and ARS Sustainable Marine Aquaculture Project in Fort Pierce, FL. Low-head RAS are less expensive and use less energy to operate than high-pressure systems due to the lower horsepower required for pumping water. Individual system components of the low-head RAS were evaluated under low salinity conditions to provide design criteria and performance characteristics for low salinity production scale systems. The outcome is a state of the art research and demonstration facility to provide design criteria and technology transfer to existing and potential farmers to expand the low-salinity marine aquaculture industry. (NP106, Components 6f and 8b)
2. SOLIDS REMOVAL IN LOW-HEAD RECIRCULATING AQUACULTURE SYSTEMS: Solids removing filters (water clarifiers) installed on three 43,000 liter low-head recirculating aquaculture systems (RAS) were evaluated by scientists from Harbor Branch Oceanographic Institute at Florida Atlantic University (HBOI-FAU) and the ARS Sustainable Marine Aquaculture Project in Fort Pierce, FL. Efficient removal of particulate solids is critical to maximizing production of fish in large-scale RAS. Swirl separators, TORUS filters, and static-bed filters were evaluated for removal efficiency. Static-bed filters were found best for removing solids with a single pass by removing the smallest particulates that represent 90% of total system solids. This accomplishment provides design criteria for the inexpensive removal of solid particulates from energy efficient low-head systems and provides fish farmers a low cost alternative technology for rearing fish in RAS. (NP106, Component 8b)
3. RED DRUM PRODUCED IN LOW-SALINITY LOW-HEAD RECIRCULATING AQUACULTURE SYSTEMS: Red drum were grown from 8 grams to 200 grams in low-head recirculating aquaculture systems (RAS) at 11 ppt salinity by scientists from Harbor Branch Oceanographic Institute at Florida Atlantic University (HBOI-FAU) and ARS Sustainable Marine Aquaculture Project in Fort Pierce, FL, in partnership with the Florida Wildlife Conservation Commission's (FWC) Hatchery Network Initiative. Red drum are an important marine fish that can be reared in nearly fresh water (< 1 ppt) in recirculating aquaculture systems as food fish or for stock enhancement. Low-head RAS were tested under production conditions, and results indicated red drum could be produced at up to 41 kilograms per cubic meter of rearing space in low-salinity conditions. This accomplishment provides information for economic and performance evaluations of low-head systems for the production of red drum under low-salinity recirculating aquaculture conditions, significantly increasing opportunities and crop diversity for inland fish farmers. (NP106, Components 6b and 6f)