Evaluation of larviculture protocols for the Pacific blue tang (Paracanthurus hepatus)

Abstract

Aquaculture of marine ornamental fish is an important tool that may help to provide sustainable alternatives to wild caught individuals. Many challenges are associated with marine ornamental aquaculture, especially during the larviculture process. Newly hatched marine larvae are often underdeveloped at hatch and require specific nutritional and environmental parameters for successful morphogenesis and ultimate metamorphosis into the juvenile stage. The Pacific blue tang (Paracanthurus hepatus) is a promising candidate for ornamental aquaculture due to its popularity in the aquarium trade and prior captive breeding success. However, improvements in culture methodologies, especially environmental and nutritional factors, is critical to viable commercial production. Seven experiments were conducted to determine appropriate green water culture conditions, photoperiod, and feeding protocols that best promoted survival, growth, and ingestion rate in early-stage P. hepatus larvae. Larval survival and feeding incidence were significantly increased when live microalgae was added to the culture system. The survival and feeding incidence of 3 days post hatch (DPH) P. hepatus larvae was greatest when the algae species Tisochrysis lutea was incorporated at a density of 300,000 cells/mL. The feeding incidence of 3 DPH larvae was not affected by prey type or prey density. When free amino acid feeding stimulants were added to the culture water, neither larval survival nor feeding incidence were improved. Lastly, the photoperiod that best promoted larval growth and survival was 16-h light: 8-h dark. Together, these results provide for improved larval survival in aquaculture and help move P. hepatus towards viable commercial production.