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National Committee on Marine Sciences (NCMS)

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    Fish predation on mangrove-associated penaeids: The role of structures and substrate
    Primavera, J. H. (Elsevier BV, 1997-08)
    The effect of habitat structure and substratum on predation of the greasyback shrimp Metapenaeus ensis (De Haan), white shrimp Penaeus merguiensis De Man and tiger shrimp Penaeus monodon Fabricius by sea bass Lates calcarifer Bloch and mangrove snapper Lutjanus argentimaculatus (Forsskal) was evaluated. The shrimp juveniles measured 6–15 mm in carapace length; fish measured 6.5–12.5 cm in standard length; structure types were pneumatophores of the mangrove Sonneratia griffithii Kurz and dried coconut leaf bracts; structure densities were 0, 32 and 98 pneumatophores per tank; and sediment particle sizes were pebbles, sand-granules and silt–sand. Predation on shrimp was significantly higher in controls or bare sand (48.7%) than among pneumatophores (29.9%), but not among leaf bracts (43.5%). Shrimp mortality was also significantly higher on bare sand (72.9%) compared to medium-density (54.2%), but not high-density (68.8%), pneumatophores. Fish predation on the burying shrimp M. ensis was affected by predator type but not by sediment size. The generally higher predation rates of snapper may be due to their habit of leaving unconsumed pieces of shrimp, whereas sea bass which devour whole prey require fewer shrimp to reach satiation. Moreover, the presence of structures did not affect sea bass behaviour of chasing prey among pneumatophores and under leaf bracts, but reduced predation by the relatively passive snapper. Predation rates among pneumatophores vs. control, and among medium-density pneumatophores vs. bare sand, were lower for P. monodon but not P. merguiensis. This may be related to the greater and more frequent use of (laboratory) shelters by juvenile tiger shrimp compared to white shrimp. The results demonstrate that the effective provision of shelter depends not only on structure type and density but on the behaviour of predator and prey as well. The use of mangrove structures (pneumatophores) by juvenile shrimp as refuge from predation is also documented for the first time.
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    Increased coral larval supply enhances recruitment for coral and fish habitat restoration
    Harrison, Peter L.; dela Cruz, Dexter W.; Cameron, Kerry A.; Cabaitan, Patrick C. (Frontiers Media SA, 2021-12-01)
    Loss of foundation reef-corals is eroding the viability of reef communities and ecosystem function in many regions globally. Coral populations are naturally resilient but when breeding corals decline, larval supply becomes limiting and natural recruitment is insufficient for maintaining or restoring depleted populations. Passive management approaches are important but in some regions they are proving inadequate for protecting reefs, therefore active additional intervention and effective coral restoration techniques are needed. Coral spawning events produce trillions of embryos that can be used for mass larval rearing and settlement on degraded but recoverable reef areas. We supplied 4.6 million Acropora tenuis larvae contained in fine mesh enclosures in situ on three degraded reef plots in the northwestern Philippines during a five day settlement period to initiate restoration. Initial mean larval settlement was very high (210.2 ± 86.4 spat per tile) on natural coral skeleton settlement tiles in the larval-enhanced plots, whereas no larvae settled on tiles in control plots. High mortality occurred during early post-settlement life stages as expected, however, juvenile coral survivorship stabilised once colonies had grown into visible-sized recruits on the reef by 10 months. Most recruits survived and grew rapidly, resulting in significantly increased rates of coral recruitment and density in larval-enhanced plots. After two years growth, mean colony size reached 11.1 ± 0.61 cm mean diameter, and colonies larger than 13 cm mean diameter were gravid and spawned, the fastest growth to reproductive size recorded for broadcast spawning corals. After three years, mean colony size reached 17 ± 1.7 cm mean diameter, with a mean density of 5.7 ± 1.25 colonies per m–2, and most colonies were sexually reproductive. Coral cover increased significantly in larval plots compared with control plots, primarily from A. tenuis recruitment and growth. Total production cost for each of the 220 colonies within the restored breeding population after three years was United States $17.80 per colony. A small but significant increase in fish abundance occurred in larval plots in 2018, with higher abundance of pomacentrids and corallivore chaetodontids coinciding with growth of A. tenuis colonies. In addition, innovative techniques for capturing coral spawn slicks and larval culture in pools in situ were successfully developed that can be scaled-up for mass production of larvae on reefs in future. These results confirm that enhancing larval supply significantly increases settlement and coral recruitment on reefs, enabling rapid re-establishment of breeding coral populations and enhancing fish abundance, even on degraded reef areas.
    We thank the Australian Centre for International Agricultural Research (ACIAR) for funding this research: grant ACIAR/FIS/2014/063 to PH, PC and J. Bennett. Thanks to ACIAR staff Chris Barlow, Ann Fleming, and Mai Alagcan for their ongoing support. Sincere thanks to the Galsim Family for use of Tanduyong Island as a field research base during the coral restoration fieldwork. We also thank staff and students at the Bolinao Marine Laboratory, Marine Science Institute, University of the Philippines, Diliman for their assistance with reef work: Elizabeth Gomez, Charlon Ligson, Rickdane Gomez and Fernando Castrence (including fish surveys), Marcos Ponce, Joey Cabasan, Sheldon Boco, Gabriel de Guzman, Albert Ponce, and Allan Abuan. We also thank Grant Cameron for field support and helping design, build and refine the prototype floating spawn catcher frames in 2016 and 2017.
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    Multi-scale coral reef and seascape habitat variables combine to influence reef fish assemblages
    Sievers, Katie T.; McClure, Eva C.; Abesamis, Rene A.; Russ, Garry R. (MDPI, 2024-04-15)
    While benthic characteristics of coral reef habitats are a major driver of the structure of coral reef fish assemblages, non-reef habitats adjacent to coral reefs (e.g., mangroves, seagrass beds, and macroalgal beds) can affect reef fish assemblages. Here, we investigate how reef fish assemblages respond to local-scale benthic habitats within a coral reef and larger-scale adjacent seascape features (habitats within 500 m of coral reefs) on Siquijor Island in the Philippines. We examined an abundance of species for the entire reef fish assemblage and within the assemblages of parrotfishes (subfamily Scarinae) and wrasses (family Labridae). Five distinct habitat types were identified in a cluster analysis, which incorporated benthic characteristics within coral reefs and habitats adjacent to coral reefs. We found that the diversity and structure of coral reef fish assemblages were affected by benthic characteristics within coral reefs and also by benthic habitat types adjacent to coral reefs. Individual species responses and juveniles of certain species demonstrated uniquely high abundances in habitat clusters characterized by the non-reef habitats surrounding coral reefs. Considering coral reef habitats and adjacent non-reef habitats as a holistic, interconnected seascape will provide better estimations of the drivers of the structures of coral reef fish assemblages.
    This work would not have been possible without the invaluable contributions of the late Angel Alcala. His groundbreaking work paved the way for research in the Philippines, and his lifelong dedication to exploring and protecting the natural ecosystems of his country granted us access to crucial research sites. He also provided essential logistical and administrative support, significantly enhancing the feasibility of this project.
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    Variation in epibiont communities among restocked giant clam species (Cardiidae: Tridacninae) and across different habitat types
    de Guzman, Ian Joseph A.; Cabaitan, Patrick C.; Hoeksema, Bert W.; Sayco, Sherry Lyn G.; Conaco, Cecilia (Springer, 2023-07-07)
    Giant clam shells provide a solid substrate for various species of epibionts. Yet, it is not well known how epibiont communities vary among populations of different giant clam species and in giant clams restocked in different habitat types. Here, we examined differences in the epibiont communities of three species of giant clams with different shell morphology (Tridacna gigas, Tridacna derasa, and Hippopus hippopus), and characterized the epibiont communities on T. gigas from three different habitat types (sandy reef flat, seagrass bed, and coral reef). Tridacna gigas had higher species richness, abundance, and cover of epibionts compared to the other two species. Tridacna gigas in coral reef habitat also displayed higher species richness and cover of sessile epibionts, while the same species in the sandy reef flat had higher species richness and abundance of mobile epibionts. Epibiont communities were more variable across habitat types than among different giant clam species restocked in a similar area. Differences in abundance of Trochus sp., Pyramidella sp., and crustose coralline algae contributed to the variability in epibiont communities among the giant clam species and across habitats. A few taxa were observed only on specific giant clam species and sites. For instance, Diadema sp. and Echinometra sp. were found only on T. gigas, and Diadema sp. was present only in the sandy reef flat. Both the complexity of the giant clam shells and habitat type contribute to differences in associated epibiont communities. This further emphasizes the ecological importance of giant clams as habitats for other invertebrates.
    The authors acknowledge Jun Castrence and the staff of Bolinao Marine Laboratory for assistance with field work. We also acknowledge the assistance of Edwin Dumalagan with coral and algae identification, Timothy Quimpo for his assistance and advice on statistical analysis, and Elizabeth Gomez for her assistance in generating the map of study sites. Lastly, we would like to thank members of the Coral Reef Ecology Laboratory (CoRE) for their helpful comments and suggestions on the study. This study was supported by a grant from the Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development of the Department of Science and Technology to PCC and CC (QMSR-MRRD-MEC-314-1542) and a Department of Science and Technology ASTHRDP Scholarship and University of the Philippines Marine Science Institute Thesis Writing Grant 2020 to ID. We thank the reviewers for the suggestions that helped improve our paper.