Garpa, Tomilyn JanCaasi, Olivier Josh C.Juinio–Meñez, Marie Antonette2025-03-222024-03-07Garpa, T. J. S., Caasi, O. J., & Juinio-Meñez, M. A. (2023). Metamorphic success and production cost of Holothuria scabra reared on microalgal concentrates compared with live microalgae. The Philippine Journal of Fisheries, 31(1), 109-125.10.31398/tpjf/31.1.2023-0032https://repository.unesco.gov.ph/handle/123456789/173This study was funded by Australian Centre for International Agricultural Research (ACIAR) through the project FIS/2016/122 “Increasing technical skills supporting community-based sea cucumber production in Vietnam and the Philippines” and administrative support from the Marine Environment and Resources Foundation (MERF), Inc. We would also like to thank the Bolinao Marine Laboratory of the University of the Philippines Marine Science Institute for the use of facilities and equipment. We are grateful to our collaborators, Jon Altamirano and Roselyn Noran, and SEAFDEC AQD for guidance on the methods used for preparation and protocols of microalgae concentrate feeding regimen. Special thanks to JayR Gorospe for comments on the earlier draft and Jerwin Baure for copyediting this manuscript. The assistance of Mr. Tirso Catbagan in the culture of larvae and maintenance of the experimental tanks was invaluable during the experiment.The production of live microalgae poses challenges for the expansion of sandfish hatcheries, hindered by high costs and limited technical resources. In relation to this, the use of three imported commercial concentrates (Instant Algae®) - TW1200 (Thalassiosira weisflogii), TISO1800 (Isochrysis sp.), and Shellfish1800 (mixed diatom) - were compared with live Chaetoceros calcitrans (CC). The diet efficacy was evaluated based on larval development, growth, and survival to late auricularia (LA) with hyaline spheres (HS), and the number of post-settled juveniles. Larvae reared with TW did not progress beyond LA, while those fed CC exhibited earlier LA development, larger sizes (1028.43 ± 19.38 µm), and significantly more post–settled juveniles (9,268 ± 2,183.79) compared to SHELL and TISO. Although TISO larvae reached a larger size during LA (855.7 ± 62.67 µm), SHELL resulted in a higher number of post-settled juveniles. The better performance of CC and SHELL may be attributed to their higher carbohydrate content. Despite SHELL and TISO having lower juvenile yields and longer feeding durations, the estimated cost per juvenile using SHELL, TISO, and CC were PHP 2.00, PHP 11.77, and PHP 0.52, respectively. Results showed that microalgae concentrates are not a cost-effective option under the studied conditions. The potential use of microalgae concentrates as supplemental feeds and further research to develop the use of local microalgae concentrates to sandfish larval culture are discussed.enSea cucumbersMicroalgaeGrowthArticleSDG 14 - Life below waterSDG 2 - Zero hungerSDG 12 - Responsible consumption and productionsea cucumbersmicroalgaelarvaedietsea cucumber culturemetamorphosisfeedsproduction costsgrowthChallenge 3: Sustainably feed the global populationChallenge 4: Develop a sustainable and equitable ocean economy