Asian seabass Lates calcarifer is widely farmed throughout the Asia-Pacific region, including in Cambodia. A significant advantage of this species for aquaculture is its euryhaline nature, making it tolerant to a wide range of salinities from freshwater to full seawater. However, the salinity requirements for larval rearing of L. calcarifer are poorly known. This experiment evaluated the effects of different salinity regimes during the hatchery phase for Asian seabass.
In this experiment three different salinity regimes were evaluated using randomized block design. Newly hatched larvae were stocked in 600 L circular plastic tanks and reared using rotifers (3–30 DAH), brine shrimp (8–35 DAH) and compounded feed (7–38 DAH). For the first 10 DAH, the water salinities in all treatments were maintained at 30 ppt. The reference treatment (T1) was maintained at 30 ppt throughout the 38-day experiment (Table 1). The other three treatments (T2 – T4) had regular reductions in salinity as listed in Table 1.
Water in all tanks was changed daily and the tanks were cleaned to maintain water quality, remove debris and uneaten feed. Salinity, temperature, DO and pH were observed twice each day throughout the experimental period and total ammonia and nitrite were checked every three days before changing water. Total lengths of each treatment were analyzed using one-way ANOVA. Duncan’s multiple range tests were used to estimate the difference between treatment means.
At the end of the experiment (38 DAH) fish in T2 and T3 were significantly larger than fish in T1 and T4 (Table 2).
The results indicate that reducing salinity in hatchery tanks can improve growth of L. calcarifer larvae.