46 MARCH 2025 • WORLD AQUACULTURE • WWW.WAS.ORG To quantify the growth of diatoms on the artificial grass blades, we used a dilution technique. The average blade measured 25 mm long and 1 mm wide. After 5 days of growth, 3 blades were collected, placed in 5 mL of distilled water, and cleaned mechanically for about 2 minutes then observed with the compound microscope to observe if the blades had shed all microalgae. From each sample of dilutions, two counts were carried out using a Neubauer counting plate. This was an approximate count since it was impossible to remove 100 percent of the cells from the artificial grass blades. We measured the length of the conch initially, at 14 days and after 26 days in the experiment. The conch shells were measured from the apex to the siphonal canal. Initial measurements and day 14 measurements were done with an ocular micrometer (Figure 8). When the samples reached 10mm a caliper was used. The third test included the use of concrete. Concrete was mixed and cured in a segmented 3” PVC pipe cut in half lengthwise. The artificial grass was then attached to the concrete semicircles (Figure 6). This method effectively overcame the buoyancy problem, keeping the artificial grass at the bottom of the tank. To initiate microalgae growth, we introduced elements from natural environments, including rocks with naturally growing algae, and cultured Chaetoceros gracilis. This approach aimed to create a diverse microalgal community, mirroring the natural diet of juvenile queen conch. Figure 7 shows the final setup, with juvenile conch in control trays and in trays containing the artificial grass. Control groups were provided with daily feedings of Chaetoceros gracilis microalgae: 5 mL of flocculate during the first two weeks of the experiment, increased to 10 mL in the last three weeks. In contrast, groups exposed to artificial grass substrates were not given supplemental algae; instead, they relied on the naturally growing microalgae in their tanks and on the artificial grass. The artificial grass was changed weekly with grass that was submerged and exposed to sunlight for seven days to encourage natural microalgae growth before being placed in the trays. Data Collection. Our study collected and analyzed data on the diatom and algae species present and the growth rates of the queen conch juveniles to assess the effectiveness of these feeding sources. We conducted a detailed examination of the diatom species that grew on the artificial grass blades using a compound microscope with 100X and 400X magnification. Samples were taken every two to three days to observe the composition of the diatoms, and other algae were identified to genus. FIGURE 8. Measurement with the ocular micrometer. FIGURE 7. Left: Control tray with juvenile conch. Right: Tray with juvenile conch that have access to artificial grass. FIGURE 9. Diatom growth on artificial turf blades after 5 days of growth. Species observed include: A. Nitzschia sp., B. Pinnularia sp., C. Tabellaria sp., D. Navicula sp., E. Stephanodiscus sp., F. Licmophora sp., G. Melosira sp. FIGURE 10. Left petri dish: individuals from the ART group after 26 days. On the right, individuals from the CONT group after 26 days.
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