Turkish Journal of Fisheries and Aquatic Sciences
2013, Vol 13, Num, 1 (Pages: 101-110)
The Usage of Aquatic Floating Macrophytes (Lemna And Wolffia) as Biofilter in Recirculation Aquaculture System (RAS)
Katia Naneva Velichkova 1 ,Ivaylo Nikolaev Sirakov 1
1 Trakia University, Faculty of Agriculture, Department of Biology and aquaculture, Students Campus, 6000 Stara Zagora, Bulgaria
DOI :
10.4194/1303-2712-v13_1_13
Viewed :
5356
-
Downloaded :
5642
Conventional water treatment in recirculation aquaculture systems (RAS) is a limited technology to answer the
challenges of so called “sustainable aquaculture”. This is why new and innovative technologies need to be invented and
introduced in RAS. The aim of the conducted study was to determine the possible advantages of using two macrophytic plants
– Lemna minor and Wolffia arrhiza and their quality as biological filter in a RAS for the cultivation of fingerlings from
common carp. The temperature, dissolved oxygen, pH and conductivity were measured daily with a portable combined meter
and with a probe appropriate for the parameters in the newly constructed control and experimental RAS (with floating
macrophytes as a biological filter). Ammonium, nitrite, nitrate, total nitrogen and phosphorus were measured
spectrophotometrically. At the end of the trial the fish were weighed and individual weight gain, specific growth rate and FCR
(feed conversion ratio) were calculated. The utilization of two macrophytes (Lemna and Wolffia) in their quality as a biofilter
in RAS increased dissolved oxygen in the water, significantly decreased the quantity of total dissolved solids, ammonia,
nitrite, orthophosphate as well as total phosphorus in water, and significantly increased the growth of the cultivated carp’s
fingerlings.
Keywords :
Lemna, Wolffia, biofilter, RAS, water quality, carp’s fingerlings