Aquaculture Recirculation Systems

Bes­i­des tra­di­tio­nal aquacul­tu­ral cul­ti­va­ti­on methods like pond cul­tu­re, net cages and race­ways, the clo­sed sys­tem cal­led recir­cu­la­ting aquacul­tu­re sys­tem (abbr. RAS) has been estab­lis­hed more and more during the last deca­des. This is the most modern and abo­ve all the most effi­ci­ent opti­on of all fish farms. Recir­cu­la­ti­on sys­tems by defi­ni­ti­on have a dai­ly water exchan­ge rate below 10% of the who­le water volu­me of the faci­li­ty (EIFAC, 1986). Sus­tainab­le and ele­va­ted tech­no­lo­gi­cal cir­cu­la­ti­on sys­tems, like­wi­se the SEAWATER Cube, can even achie­ve a dai­ly water exchan­ge rate below 1% and are the­re­fo­re espe­cial­ly resour­ce-con­ser­ving. Uni­que fea­tures of this cul­ti­va­ti­on form are the com­ple­te inde­pen­dence of loca­ti­on, becau­se the­re is no natu­ral water­bo­dy nee­ded, as well as the sepa­ra­ti­on from the envi­ron­ment. Through a con­ti­nuous water tre­at­ment using phy­si­cal and bio­lo­gi­cal fil­ter sys­tems wit­hin the recir­cu­la­ti­on, a gre­at water qua­li­ty is achie­ved. Fur­ther­mo­re, the sepa­ra­ti­on per­mits to avoid inter­ac­tions with the envi­ron­ment and to save resour­ces. Such extre­me meteo­ro­lo­gi­cal and hydro­lo­gi­cal occur­ren­ces (e. g. storms, waves or brea­kers), indus­tri­al risks (oil pol­lu­ti­on, nuclear acci­dents) or bio­ge­nic hazards (toxic algal bloo­ms) are con­si­de­red no direct dan­gers for a RAS.

Other advan­ta­ges are:

  • con­su­mer protection
  • food safe­ty
  • relia­bi­li­ty of the pro­duc­tion process
  • expan­ded portfolio
  • sus­taina­bi­li­ty

Due the on the ani­mal wel­fa­re adap­ted water para­me­ters as well as their con­stant con­trol, hig­her sto­cking den­si­ties than in e. g. the con­ven­tio­nal pond cul­tu­re are attainab­le, without expo­sing the ani­mals to unne­cessa­ry stress. The result is a con­si­der­ab­ly grea­ter space effi­ci­en­cy and that is why a modern recir­cu­la­ti­on sys­tem only takes up around 1% of the area of a pond sys­tem, while pro­du­cing the same annu­al amount.

A spe­cial kind of aquacul­tu­re in recir­cu­la­ting sys­tems is aqua­po­nics. It is a com­bi­na­ti­on of aquacul­tu­re and hydro­po­nics (crop gro­wing without soil). With this inte­gra­ti­on, not only the water cycle is clo­sed but also the nut­ri­ent cycle, becau­se the water out­let of the fish farm is led into the plant patches. Crops like tomatoes, basil or egg­plants are stan­ding in an inor­ga­nic bed­rock such as gra­vel or clay gra­nu­la­te and are extrac­ting the nut­ri­ents from the freshwa­ter. Under the­se con­di­ti­ons, the growth of plants is excel­lent, and they can fil­tra­te the water up to this point, whe­re the water can be led back into the fish tank without having to tre­at it any further.

Further informationen about the SEAWATER Cube

Check out more facts about our sys­tem and the technology.

Refe­ren­ces

Wal­ler, 2012. Aqua­kul­tur im Fokus. Hoch­schu­le für Tech­nik und Wirt­schaft des Saar­lan­des. Saar­brü­cken
FAO (Food And Agri­cul­tu­re Orga­ni­sa­ti­on Of The United Nati­ons), 2016. The Sta­te Of World Fishe­ries and Aquacul­tu­re. Rome
Green­peace: https://www.greenpeace.de/themen/meere/welche-aquakulturmethoden-gibt-es (Stand 21.02.2018)
Tim­mons, M.B. & Ebe­ling, J.M., 2010. Recir­cu­la­ting Aquacul­tu­re. 2nd ed. New York: Caya­gua Aqua Ventures