WWW.WAS.ORG • WORLD AQUACULTURE • SEPTEMBER 2014 33 and began hatching at 14.25 hr post-fertilization, with all viable eggs hatching after 16 hr. We expected to see increased spawning performance in the July spawn because three females were mature and implanted (versus two mature females in June); however, fish were handled twice during this sampling event because some fish escaped the confined sampling space, which may have resulted in a decrease in spawning success from handling stress. Egg Hatching and Larval Development Eggs were stocked directly into hatching cones and newly hatched larvae were transferred to larval-rearing tanks. Hatching tanks were stocked with enough eggs to meet the required larval tank stocking density (see below), assuming a 75 percent hatch rate. To assess hatch rate, larvae and unhatched eggs were homogenized in the hatching tank and three, 10-mL aliquots were collected. When all larvae had hatched, water from hatching cones was decanted into larval rearing tanks and unfertilized eggs and egg casings remained in the bottom of hatching cones. Because there is no information in the literature on rearing black snook larvae, we adapted the protocols developed at Mote for common snook (Yanes-Roca and Main 2012, Neidig et al. 2014). Initial larval stocking densities were 50, 100 and 200 larvae/L in 0.9-m³ (1.52-m diameter) larval rearing tanks. Fish were sampled at 0, 3, 6, 9 and 15 days post-hatch (DPH) to assess larval growth and development (Figs. 10-12). Black snook larvae appear to grow and develop at similar rates to those of common snook (Yanes-Roca et al. 2012). Larvae from the June spawn were reared to 16 DPH and larvae from the July spawn continue to grow from the time this article was written (13 DPH). Future Goals for Black Snook at Mote A second black snook broodstock population is being established at Mote to more rapidly develop optimal spawning parameters. We are also working to explore DNA profiling to monitor mating outcomes for the Mote black snook population. This will provide the opportunity to identify parentage of larvae and improve husbandry and spawning strategies for black snook (Rhody et al. 2014). Developing larval rearing and fingerling production protocols to support pilot-scale, experimental stock enhancement releases of black snook in Golfo Dulce is a research goal for this project. Using the aquaculture protocols developed for common snook in Florida, it appears that this goal can be achieved in the next five years. Larval rearing research will focus on identifying optimal husbandry protocols, including live food requirements, environmental parameters, system dynamics and stocking densities. Acknowledgments We thank the staff at Mote Marine Laboratory, Mote Aquaculture Research Park, who provided assistance with this research: Dr. Nicole Rhody, Carole Neidig, Dr. Nathan Brennan, and Paula Caldentey. We also thank Martha Campbell (Florida Marine Aquaculture, Inc.) for assistance in developing shipping protocols, Dr. Harry Grier (Florida Fish and Wildlife Research Institute) for assistance with staging oocytes, and Dr. Yonathan Zohar and John Stubblefield at University of Maryland Baltimore County, Department of Marine Biotechnology, for advice and providing the GnRHa implants. This research was supported by Tranquility Management, R.L. and Mote Marine Laboratory. All animal procedures used in this study were reviewed and approved by the Institutional Animal Care and Use Committee at Mote Marine Laboratory. Notes Matthew Resley*, Michael Nystrom, Carlos Yanes-Roca, Kenneth M. Leber and Kevan L. Main, Mote Marine Laboratory, Directorate of Fisheries and Aquaculture, 874 WR Mote Way, Sarasota, FL 34232, USA; Corresponding author: E-mail: resleymj@mote.org 1 Nathan Brennan, unpublished data FIGURE 9. Black snook embryo 10.5 hr after fertilization. (CONTINUED ON PAGE 34) FIGURE 10. Newly hatched black snook larvae 15 hr after fertilization.
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