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Journal Articles - UP - MSI

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AGROVOC Keyword: search.filters.agrovoc.sea cucumbersAuthor: search.filters.author.Juinio-Meñez, Marie Antonette

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    Sargassum sp. juice as an early juvenile supplemental feed for Stichopus cf. horrens
    Ibañez, Glaiza; Cabanayan-Soy, Rona; Baure, Jerwin; Juinio-Meñez, Marie Antonette (Springer, 2022-09-28)
    The development of an efficient and low-cost feed is important to reduce the production and maintenance costs of microalgae. In this study, two experiments were conducted to evaluate the feasibility of using Sargassum sp. juice (SARG) to boost the growth and survival of post-settled Stichopus cf. horrens juveniles. Experiment 1 tested whether SARG improves growth compared with live microalgae diets, Chaetoceros calcitrans (Cc), combined Cc and Navicula ramosissima (Nr), and an unfed treatment. Experiment 2 determined the best SARG concentration—high feeding regime (HFR; 1 mL ind−1), medium (MFR; 0.5 mL ind−1), or low (LFR; 0.25 ml ind−1), relative to live microalgae Chaetoceros muelleri (CM). Juveniles in both experiments were reared for 30 days. In Experiment 1, the average daily growth rate (DGRL) of juveniles in SARG (0.04 ± 0.01 cm d−1) was the highest although not significantly different from Cc and Cc + Nr, but was significantly higher than the control. In Experiment 2, DGRL at day 14 in HFR (− 0.02 ± 0.02 cm d−1) was significantly lower than LFR (0.01 ± 0.01 cm d−1) and MFR (0.02 ± 0.02 cm d−1). Survival was higher in all SARG treatments compared with CM, while a significant decrease in feeding activity was observed in HFR by day 30. Results indicate that concentrations of 0.25–0.5 mL SARG per juvenile can boost growth and be an alternate diet for post-settled juveniles during early rearing. However, SARG alone is not sufficient to maintain growth beyond 3 weeks. With SARG feed supplementation and water quality management, the scaling-up of juvenile production of this emergent culture species can be accelerated.
    Our sincere gratitude to Mr. Tirso Catbagan and Mr. Garry Bucol for their assistance in the set-up of the experiments. We also thank Ms. Rose Angeli Rioja and Ms. JayR Gorospe for providing inputs to improve this paper. We also thank the Sea cucumber Research Team and the staff of the University of the Philippines—Marine Science Institute, Bolinao Marine Laboratory for their support and assistance during the conduct of the study.
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    Pseudocryptic diversity and species boundaries in the sea cucumber Stichopus cf. horrens (Echinodermata: Stichopodidae) revealed by mitochondrial and microsatellite markers
    Lizano, Apollo Marco D.; Kim, Kenneth M.; Juinio-Meñez, Marie Antonette; Ravago-Gotanco, Rachel (Nature Research, 2024)
    Morphologically cryptic and pseudo-cryptic species pose a challenge to taxonomic identification and assessments of species diversity and distributions. Such is the case for the sea cucumber Stichopus horrens, commonly confused with Stichopus monotuberculatus. Here, we used mitochondrial cytochrome oxidase subunit I (COI) and microsatellite markers to examine genetic diversity in Stichopus cf. horrens throughout the Philippine archipelago, to aid species identification and clarify species boundaries. Phylogenetic analysis reveals two recently diverged COI lineages (Clade A and Clade B; c. 1.35–2.54 Mya) corresponding to sequence records for specimens identified as S. monotuberculatus and S. horrens, respectively. Microsatellite markers reveal two significantly differentiated genotype clusters broadly concordant with COI lineages (Cluster 1, Cluster 2). A small proportion of individuals were identified as later-generation hybrids indicating limited contemporary gene flow between genotype clusters, thus confirming species boundaries. Morphological differences in papillae distribution and form are observed for the two species, however tack-like spicules from the dorsal papillae are not a reliable diagnostic character. An additional putative cryptic species was detected within Clade B-Cluster 2 specimens warranting further examination. We propose that these lineages revealed by COI and genotype data be referred to as Stichopus cf. horrens species complex. © The Author(s) 2024.