In recent years, marine ornamental fish aquaculture has been on the rise. An increase in the total number of species successfully bred in captivity, as well as the number of species being commercially produced has subsequently increased the quantity and species diversity of marine ornamental fish available to consumers. The Acanthuridae family consisting of tangs, surgeonfishes , and unicornfishes are very popular in the aquarium trade. Yet, only five species of acanthurids have been captive bred and only one species has recently become commonly available to consumers, the yellow tang Zebrasoma favenscens .
In 2015 , the yellow tang became the first acanthurid to be successfully bred in captivity at the Oceanic Institute (OI) in Hawaii. Now in 2019, four short years later, the life cycle of this species has been completed and commercialization has become a reality. Despite immense success, research focusing on addressing early bottlenecks in the yellow tang larval rearing process is still greatly needed as survival to settlement currently averages only 1% . The most severe bottleneck , coinciding with high larval mortality, occurs around seven days post hatch (DPH) with larval survival dropping to about 25%. This high mortality period early in yellow tang larval development will be investigated by focusing on improvement of lighting conditions and prey densities.
Lighting conditions have been shown to have strong effects on early larval feeding and survival in many marine fish species , and therefore are worthy of further investigation to determine its effect on early yellow tang survival. Historically, full spectrum fluorescent lighting with abrupt "on" and "off" settings was used at OI when culturing yellow tang. Lighting trials will determine the effects of light source (LED vs. fluorescent), spectrum, and intensity on yellow tang larval feeding incidence and survival. Prey density is another incredibly important factor in early larval feeding success and survival. T he effect of prey density on early yellow tang larval survival to seven DPH will be investigated. Prey type will be the c alanoid copepod Parvocalanus crassirostris , which is cultured at OI . Prey density treatments will be 5 and 8 prey items per mL. Replicates for all early larval rearing trials will consist of 200L round, black, fiberglass tanks on a flow through system with overhead lighting.
By focusing on reducing mortality to this first bottleneck , yellow tang larval survival to settlement is expected to improve and subsequent commercial production efficiency of this iconic marine aquarium trade species . The goal is to improve larval survival to seven DPH from 25% to 40% through these investigations.