Temperature, DO, pH and Salinity of Seawater in a Fish Hatchery System

Quality of water is a major factor in management of a hatchery. Seawater of sub-optimum quality is known to affect spawning and cause high larval mortality. This study was undertaken to assess the water quality in the hatchery at Universiti Malaysia Sabah. Attention was given to parameters including temperature, DO, pH and salinity. Samplings were done at six stations from March to December 2006. Results showed that the maximum seawater DO at the seawater intake point (Sepanggar Bay) was 12.2 mg/L, which is higher than what is generally seen in marine hatcheries. Solubility of oxygen in the water at 30oC and 30 ppt was 6.39 mg/L. Minimum seawater DO, pH and salinity recorded in the settling tank were 0.5 mg/L, 5.5 and 6.4 ppt, respectively, which was beyond the optimal values for marine fish culture. Although the maximum seawater DO at the intake point and minimum seawater DO, pH and salinity in the settling tank were detected out of the optimal ranges but it did not affect water quality at other stations, particularly the culture tanks. This study suggested that the seawater temperature, DO, pH and salinity in the hatchery were still suitable for the on-going aquaculture activity, but at certain stages along the water supply route, quality improvement may be necessary to conform to optimum requirements for still better results from the hatchery operation.


This paper was presented in the Seminar on Marine Science and Aquaculture, Sabah. March 2008