Evaluating larviculture protocols for the melanurus wrasse (Halichoeres melanurus)

Abstract

Marine ornamental aquaculture provides sustainable alternatives to wild-caught fish for the aquarium trade, yet only a small fraction of the 1800 traded species are aquacultured. Wrasses (family Labridae) are the second most imported family of marine ornamental fishes imported into the USA, but none are currently produced through aquaculture. This study investigated several key larviculture parameters for the melanurus wrasse, Halicheores melanurus, such as microalgae species and density, feeding stimulants, live prey preferences, and lighting conditions. Larval survival and feeding incidence were highest when Tisochrysis lutea at a density of 300,000 cells mL⁻¹ was used as greenwater. There were no differences in larval prey preference between Parvocalanus crassirostris and Oithona colcarva copepod nauplii. Also, copeped nauplii could be offered at densities as low as 2.5 nauplii mL⁻¹ without affecting survival or feeding incidence. Feeding stimulants added to culture water did not increase larval feeding incidence and decreased larval survival. A photoperiod of 16 h light:8 h dark maximized larval performance, and microalgae-based light reduction outperformed dimmed lighting alone. These findings address early larviculture bottlenecks and further refine aquaculture protocols for H. melanurus, moving this species closer to commercial production.