In three separate experiments, the effects of salinity on growth, survival rate, and feed efficiency of the puffer fish Takifugu rubripes were studied under laboratory conditions.
Juveniles of 10.5±1.0mm (Exp. I), young of 37±3.5mm (Exp. II), and immature fish of 97±3.8mm (Exp. III) were reared at salinity levels of 12.8-32.0‰, 10.0-35.0‰, and 5.0-30.0‰, respectively.
In Exp. I, the maximal growth performance, survival rate, and feed efficiency were observed among the groups of fish reared at higher levels of salinity (25.6-32.0‰).
A significant high (p<0.05) in young fish (Exp. II) was obtained at the lower salinity level of 10.0‰. Poor growth was seen among the groups of fish reared at higher levels indicating a converse relation between growth and salinity.
In Exp. III, the optimum salinity for growth was estimated to be 15.0‰. A gradual decrease of growth were observed at lower salinities below this level.
These results indicate that the optimum salinity changes drastically through the early stages, and clearly reflects the habitat transits of this species under a natural environment.