Abstract

When abalones were farmed in a Recirculating Aquaculture System (RAS) with inadequate water conditioning for a long time, the salt concentration gradually increased to more than 36 psu. This study raised abalones in different salt concentrations (30, 33, 36, and 39 psu) in a RAS and examined growth (shell and weight), cumulative mortality, changes in blood components, and histological changes to explore the effect of salt concentration on these parameters. During the two-week experiment, the daily growth rate decreased and the cumulative mortality increased as the salt concentration in the water increased. Concentrations of K+, Na+, and Cl- ions in the hemolymph changed significantly, and the cell mortality of blood cells increased. In addition, histopathological alterations in gill and digestive tubule of the abalone showed more obvious with experimental condition of salinity increase. Based on the results, a salinity of 36 psu or higher is not a suitable environment for the survival of abalones.