Aquaculture America 2023

February 23 - 26, 2023

New Orleans, Louisiana USA

EFFECTS OF SEX RATIO ON YELLOW TANG Zebrasoma flavescens BROODSTOCK MANAGEMENT

Katie E. Hiew*, Chatham K. Callan

 

Oceanic Institute of Hawaii Pacific University
 41-202 Kalaniana?ole Hwy #9

Waimanalo, HI 96795

khiew@hpu.edu

 



Yellow Tang (Zebrasoma flavescens) are one of the most popular fish in the marine ornamental aquarium industry and were the most collected reef species from Hawaii. Previously, around 300,000 fish annually were removed from reefs to supply the aquarium trade until January 2021, when the State of Hawaii suspended the commercial collection of all aquarium species. This fishery remains closed at present, and Yellow Tang are currently only available through aquaculture.

In 2015, Oceanic Institute of Hawaii Pacific University (OI) was the first to be successful in culturing this important species. Methods used to raise Yellow Tang have allowed for various other new reef species to be aquacultured. These advances may provide the aquarium trade a more sustainable future for obtaining marine ornamentals. Although there has been great progress since 2015, commercial production of the species has been difficult with inconsistent results, primarily inhibited by poor egg production and high larval mortality.

To address these bottlenecks, research focusing on broodstock management of the species will be investigated, aiming to obtain best practices for increased egg production and quality, viability of eggs, survival to hatching and first feeding.

An important aspect of broodstock management deals with social environment, in which proper sex ratios and social hierarchies must be achieved to ensure low stress levels and yield maximum spawning success. Maintaining broodstock is costly and optimizing the number of fish required reduces costs and makes commercial production more economically feasible. Observed social behaviors of Acanthurids include both pair formations and group spawning events of 8-10 individuals. Trials will be conducted in fiberglass, 4000L tanks on a flow-through system involving Z. flavescens in pairs (1M:1F), trios (1M:2F), and quads (1M:3F) to assess if sex ratio impacts egg production and quality. Daily spawns will be assessed as well as hatch rates and early larval survival to first feeding (3 DPH).

Investigating aspects of broodstock management can allow for greater numbers of high-quality eggs and improved early larval survival, thus improving commercialization for this species. Results obtained from this study can help facilitate the development of techniques applicable to other Acanthuridae species.