RECENT ADVANCES IN THE CULTURE OF THE PACIFIC BLUE TANG Paracanthurus hepatus

Matthew A. DiMaggio*, Eric J. Cassiano, Kevin P. Barden, Shane W. Ramee, Cortney L. Ohs, and Craig A. Watson
 
University of Florida
Tropical Aquaculture Laboratory
School of Forest Resources and Conservation
Ruskin, FL 33570
mdimaggi@ufl.edu

It is estimated that over 11 million marine ornamental fishes, representing approximately 1,800 unique species, are sold annually; with the preponderance of specimens resulting from wild capture. Growing interest in marine ornamental aquaculture has served as an impetus for efforts to commercialize new species for the industry and develop novel culture protocols. The Pacific blue tang, Paracanthurus hepatus, is consistently among the top twenty species imported into the United States by volume, with all specimens sourced from wild stocks. Captive culture of this species through metamorphosis has not been previously documented and fundamental information regarding reproduction, larval culture, and production techniques is scarce. This study aimed to elucidate methods that would advance our understanding and success with captive propagation of this species.

A total of 50,000 eggs were collected from a single broodstock population (1 male, 2 females) over a three day period in May 2016. The eggs were successively stocked in a 1000 L larval tank for a final density of 50 eggs/L. Beginning at 3 days post hatch (DPH) larvae were fed 3 times daily a diet comprised exclusively of the copepod nauplii (<75 μm, mean ± SD = 5.1 ± 2.3 mL-1 day-1) of Parvocalanus crassirostris. At 12 DPH, enriched rotifers Brachionus plicatilis (6.8 ± 3.2 mL-1 day-1) were first fed to the tank. At 20 - 21 DPH, powdered feed and first instar Artemia nauplii (1.1 ± 0.7 mL-1 day-1) were also added to the diet. Live microalgae (~3:1 of Tetraselmis chuii and Symbiodinium microadriaticum) were added daily to the culture tank throughout the rearing trial. Large mortality events were observed at 7 and 20 DPH corresponding with starvation and flexion, respectively. By 41 DPH, a behavioral change was noted with the majority of the remaining larvae associating with the bottom of the tank. On day 50, the first signs of blue pigmentation marked the beginning of metamorphosis. A total of 27 juvenile blue tangs were cultured during this trial. This effort represents the first successful rearing of this species in captivity and provides important information for future production studies.