Growth and Nutrient Profile of Etroplus suratensis (Bloch) Reared at Different Salinities

Abstract- Etroplus suratensis (Bloch 1790) popularly known as pearlspot were reared in different salinities to test the hypothesis that growth and nutrient composition of the fishes varies with culture environment. Pearlspot is generally categorised as a brackish water species though it thrives well in freshwater areas. The salinity ranges tested were 0, 5, 10, 15, 20, 25, 30ppt and the experiment was conducted for 70 days with growth assessment done at every 9 days intervals. All the treatments were fed ad libitum with 40% protein and 6% lipid feed. The results showed significant difference (P≤0.05) in growth and body composition. The weight gain was found to be higher in 20ppt salinity (4.0±0.11) followed by 0ppt (3.9± 0.1) and was lower in 15ppt (3.3±0.7). The highest survival (96.0%) obtained in 0ppt and showed a lowest (85.3%) at 30ppt. The proximate composition showed significant variation between treatments, crude protein was higher in 0ppt (57.8±0.7) and lower in 20ppt (51.5±0.2) and crude lipid showed an inverse relation and was lowest in 0ppt (14.0±0.2) and higher in 30ppt (16.4±0.2). These findings suggest potential of farming pearlspot in freshwater areas. The higher survival and comparable growth obtained in freshwater condition indicates possibility of large scale culture of pearlspot in freshwater culture systems. Due to their higher salinity tolerance and ability to adapt and thrive well in freshwater makes it a better choice for aquaculture in inland water bodies.