Fish Rearing Experiment in a Combined Intensive-extensive System (I.E.S.) for Complex Recovery of the Fishery Potential from Water Basins

In 2015, the researchers of the Fish Culture Research and DevelopmentStation of Nucet have experienced a combined intensive-extensive system (I.E.S.) for fish growing, that aimed a complex recovery of the fishery potential from water basins. Fish population in the extensive system (EC3 Nucet pond - 3.8 ha) was constituted from: carp (Cyprinus carpio) - 300 ex.; North American sturgeon - paddlefish (Polyodon spathula) - 125 ex.; Asian Ciprinidae: silver carp (Hypophthalmichthys molitrix) - 530 ex. and grass carp (Ctenopharyngodon idella) - 185 ex. The combined intensive-extensive system (I.E.S.) was located in the fish growing pond. The module is composed from 8 floating cages (6 x 6 x 2 m each one), module surface was 288 square meters and total volume / module was 576 cubic meters. Stocking density in the intensive system was 500 ex. carps 1 year old / floating cage (4000 ex./module). In the moment when the floating cages were stocked, the average weight of carps was 150 g/ex., resulting in a total quantity of 600 kg/module. Total production obtained was 3267 kg/module (3.803 ex.; 95% survival rate) on average 408 kg carp / floating cage, without any additional technological interventions. The fish were fed with floating feed (32% protein) and conversion rate (FCR) was 1.37%. The fish were clinically healthy,on the length of the entire experiment, and the quality of aquatic environment was within the rules of good practice for aquaculture.