Low-Head Saltwater Recirculating Aquaculture Systems Utilized for Juvenile Red Drum Production

Abstract

The USDA Agricultural Research Service and the Harbor Branch Oceanographic Institute - Florida Atlantic University (HBOI-FAU) Center for Aquaculture and Stock Enhancement are collaborating to evaluate low-head recirculating aquaculture system (RAS) designs for inland low salinity aquaculture production of marine finfish. As part of this project, the systems described were utilized to intensively produce red drum (Sciaenops ocellatus) juveniles that would be part of the Florida Fish and Wildlife Conservation Commission's (FWC) Saltwater Hatchery Network Initiative. The design and performance data collected from these systems will be utilized in the engineering and determination of design costs for a statewide public-private saltwater hatchery network. The current low-head RAS design that was evaluated for the Phase I (25 mm to 60 mm standard length, SL) through Phase II (60 mm to > 100 mm SL) production of red drum juveniles included a nine-tank system and a ten-tank system. Tank diameters were 1.5 m with a water depth of approximately 1.0 m. Mechanical and biological filtration mechanisms included polygeyser filters, sand filters, moving bed torrus filters, and filter pads. For the Phase II to Phase III (100 to 180 mm SL) production, the red drum juveniles were cultured in four larger-scale replicated RAS low-head systems. Mechanical and biological filtration mechanisms in these systems included moving bed torrus filters, long-flow pathway moving media bed filters, and rotary micron screen drum filters, along with supplemental liquid oxygen addition. The systems presented indicate that intensive inland culture of marine species for commercial aquaculture production or stock enhancement purposes is possible even under the technical constraints of low-head system operation.