44 MARCH 2025 • WORLD AQUACULTURE • WWW.WAS.ORG This current study is aimed at enriching the diet of juvenile queen conch by exploring innovative methods to cultivate more natural and nutritious foods, while remaining cost effective in a controlled environment. Building on existing knowledge of microalgae growth on artificial substrates, such as those observed with plastic pollution in marine environments (Nava and Leoni 2021), we investigated the use of artificial turf as a substrate and growth medium for cultivating diatoms and other microalgae. Our study addressed the research goal to determine if artificial turf can advance sustainable aquaculture practices for growing queen conch juveniles for conservation and restoration. The primary objective was to compare the growth rate of juvenile queen conch fed diatoms and other microalgae on artificial turf to that of juveniles fed the more traditional flocculated diatom Chaetoceros gracilis. Our specific questions included: • Can artificial turf offer an expanded surface area for microalgae to grow on in conch holding tanks? • Will this enhance the nutritional diversity of the diet available to juvenile conch? • And, will this promote growth compared to standard feeding practices? Material and Methods Queen Conch and Systems. We selected 60 juveniles from a single hatchery batch that ranged in size from 3.5 to 4.1 mm shell length and were 54 days old. For the experiment, 30 conch were divided in groups of 10 in 3 screen trays with artificial grass (ART). The other 30 conch, 10 per tray, were placed in screen trays without artificial grass and were only provided flocculated Chaetoceros gracilis (CONT). This species is a diatom known for its nutritional value and is used as a staple in the diet of cultured queen conch in hatcheries, including the Queen Conch The queen conch (Aliger gigas, formally known as Strombus gigas) is a large, marine gastropod mollusk found in the warm waters of the Caribbean Sea. The species is currently facing a significant decline in wild populations (Horn et al. 2022) and this alarming trend underscores the urgent need for effective conservation strategies. In response to this ecological challenge, the Queen Conch Hatchery located at the Curaçao Sea Aquarium is dedicated to developing technologies for culturing these iconic invertebrates, with the ultimate goals of helping repopulate overfished stocks and restoring natural populations. The life cycle of the queen conch includes a critical juvenile phase, where diet plays a pivotal role in determining growth and survival rates. Juvenile conch primarily feed on benthic microalgae, particularly diatoms and other epiphytic microorganisms, which are essential for development and overall health (Davis and Cassar 2020). Despite their ecological and economic significance, the optimal rearing conditions for A. gigas juveniles in aquaculture settings remain under-researched, especially concerning dietary requirements. Current practices in aquaculture often fail to replicate the complexity and diversity of natural algal communities, potentially limiting the nutritional quality of the diet provided to these juveniles (Davis and Cassar 2020). One study that provided valuable information regarding optimal rearing conditions involved comparable conch aquaculture practices, however with dog conch (Laevistrombus canarium), which are only present in Pacific tropical regions (Chang et al. 2021). The authors demonstrated that co-culturing (or polyculturing) was much more beneficial to juvenile conch growth and survival compared to mono-culturing without the presence of other species and usually with a single food source. This suggests that juvenile conchs prefer a more natural environment, and can benefit from an enriched or seminatural environment when cultivated in captivity. Artificial Grass as a Substrate for Microalgae Growth to Feed Hatchery-Reared Juvenile Queen Conch Manuel Jove, Steffen van Heijningen, Licet Hernandez and Megan Davis FIGURE 1. Custom made trays with mesh bottom screens that each house 10 juvenile conch. For the control treatment (CONT). FIGURE 2. Fiberglass raceway tanks showing the screen trays used to accommodate the smaller trays that house the juvenile conch. For the artificial grass treatment (ART).
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