Evaluation of biofloc‐based aquaculture of Pacific white shrimp (Litopenaeus vannamei) using water from a low‐salinity artificial reservoir in Korea

The Saemangeum region of Jeollabuk province, located in the central region of the western coast of the South Korea, was once a representative fishing area in Korea. However, as the fishery environment has changed significantly due to the Saemangeum development project that started in 1991, the production of aquaculture has decreased by approximately 50% (from 164,141 tons in 1989 to 82,664 tons in 2019), fishermen's income has decreased, and the local economy has stagnated. The aquaculture industry in this area is limited in part because the Saemangeum Reservoir (35°52′07.3″N, 126°30′29.8″E) became unsuitable for the use as water for aquaculture; the aquaculture industry was not activated. In order to solve this problem, an alternative to using the Saemangeum Reservoir for aquaculture was needed. In order to determine the feasibility of using water from the reservoir, a low‐salinity artificial reservoir, as water for aquaculture of Litopenaeus vannamei, a biofloc technology (BFT) system was applied. The BFT system was applied to three experimental groups; the control group using seawater (CON), the experimental group using unfiltered water from the Saemangeum Reservoir (SW) and the experimental group using Saemangeum Reservoir filtered with micro‐membrane filtration technology (FW). Shrimps averaging 0.67 ± 0.01 g (Mean ± SD) were randomly distributed into nine acrylic 50 L tanks at a density of 20 shrimps per tank. The experiment was carried out for 6 weeks without a water change. At the end of the 6 weeks, there were no significant differences in the growth performance, feed efficiency, survival rate or biochemical parameters of L. vannamei among the groups. A water quality analysis indicated that the total ammonia nitrogen, NO2− and NO3− concentrations of all groups tended to rise similarly during the experimental period, and there was no significant difference between groups. In this study, it was found that when using BFT system, the water of the Saemangeum Reservoir can be used as culturing water for L. vannamei even if the influent water is not filtered with micro‐membrane filtration technology. Therefore, our study findings suggest that the water of the Saemangeum Reservoir, a low‐salinity artificial lake, can be used for inland aquaculture of L. vannamei when a BFT system is applied.