Effect of water velocity on the growth of California halibut (Paralichthys californicus) juveniles

The rate of water renewal in fish tanks is biologically important in land-based aquaculture systems as it affects many of the water quality limiting factors for fish production. Current water velocity, a factor closely related to water flow rate, can significantly affect fish performance in culture tanks. A study was carried out to test the effect of three relative water velocities of 0.5, 1.0, and 1.5 body lengths per second (bl/s) on the growth of California halibut (Paralichthys californicus) juveniles over 10 weeks of culture. Nine rectangular tanks were used in this experiment to provide the velocities to be tested, which were stocked with 15 fish each. Weaned California halibut 90 days post hatch (dph), 5.4 cm average total length, and 1.53 g average wet weight were used for this study. All fish were sampled every other week to record their biomass and morphometric data. This research has shown that California halibut juveniles can be raised between 0.5 and 1.5 bl/s without affecting their survival. However, California halibut juveniles grew faster and made more efficient use of the feed provided at 0.5 and 1.0 bl/s than at 1.5 bl/s. Moreover, it was determined that maximum fish growth was achieved for velocities up to 1.0 bl/s.