Tag RAS

The ability to maintain adequate oxygen levels can be a limiting factor in carrying capacities for RAS. The amount of oxygen required is largely dictated by the feed rate and length of time waste solids remain within the systems. 

A unique pilot project supported by northern Chile’s biggest power-generating company and the Undersecretary of Fisheries and Aquaculture is raising cobia in a recirculating aquaculture system in the desert. 

Today’s aquaculture industry is rapidly adopting recirculating aquaculture systems (RAS) for hatchery and nursery applications. Recently, there has been a move to combine RAS technology with the floating raft aquaponics. 

The presence of compounds such as geosmin and 2-methylisoborneol (MIB) in recirculating aquaculture systems (RAS) can result in earthy or musty off-flavors in salmonids raised in the systems. 

Studies on improving water quality in recirculating aquaculture systems has identified ozone as an excellent solution for an optimal water environment. 

One promising new technology for dewatering aquaculture solid waste is the use of geotextile bags: porous, sealed tubular containers constructed of high-strength, woven polyethylene material. 

Floating closed-containment systems incorporate low-pressure pumping, oxygen supplementation, solid-waste separation and efficient feed management. 

Healthy populations of both ammonia- and nitrite-oxidizing bacteria must be present in aquaculture systems to support the nitrification of potentially toxic ammonia to nitrite, with further oxidation to less problematic nitrate. 

Smolt production in Norwegian hatcheries will likely increase during the next decade to answer salmon grow-out needs. Farmers are converting existing flow-through systems to partially or fully incorporate recirculation technologies. 

Nitrifying bacteria readily form biofilms on surfaces, and colonization by these important bacteria on the interior walls of RAS production units likely provides an additional source of nitrification. 

Circular tank-based recirculating aquaculture systems can be used to effectively culture rainbow trout and other salmonids in a bio-secure and environmentally friendly manner that imposes a much lower water and wastewater footprint than traditional flow-through culture technologies. 

Hydrogen peroxide is a candidate for water treatment in aquaculture systems for it has antimicrobial effects and easily degrades to harmless byproducts. 

The Fjordsmolt RAS farm applies a relatively simple, low-cost design to produce millions of salmon smolts per year in fiberglass tanks. 

U.S. institutions are collaborating to evaluate low-energy recirculating aquaculture system designs to produce marine finfish in a low-salinity environment. 

A boutique design project validated a land-based, recirculating production system capable of producing 50 metric tons of spotted sea trout per year.