Coral culture and transplantation and restocking of giant clams in the Philippines

Recently, the Pew Project (2001 to 2005) of the senior author entitled ‘Coral reef habitat and productivity enhancement through coral transplantation and giant clam restocking’ was implemented with the aim to improve the biodiversity and productivity of stressed coral reef habitats in 10 selected demonstration sites in the Philippines. These were meant to serve as models for other communities. Transplantation of corals and reseeding of giant clams were the approaches. Nubbins or small fragments from nearby large coral colonies and abundant solitary forms were transplanted to the target sites. Care was exercised to avoid or reduce any negative impacts on the natural source communities. Only cultured giant clams were used, specifically the threatened Tridacna gigas at sizes that would ensure their chances of survival in the wild (approximately 20-30 cm shell length). Following deployment, monitoring activities were undertaken, focusing on macro-invertebrates and fish, as well as the assessment of the survival and growth of experimental animals. Liaison work was done with local communities to raise their environmental awareness and to ensure their cooperation. This manuscript draws principally from results of the Pew Project. At present, two other restoration projects supported by the European Union and the Global Environment Facility Coral Reef Targeted Research Project are being implemented at the Bolinao Marine Laboratory of the University of the Philippines Marine Science Institute (UP-MSI) in Pangasinan. These projects are testing the efficiency of floating and standing coral nurseries in growing coral nubbins in addition to transplanting fragments or branches of corals to restore degraded coral reefs

An Indo-Pacifc coral spawning database

The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology

Differential consumption of scleractinian and non-scleractinian coral larvae by planktivorous damselfishes

Planktivorous fishes are known to consume coral larvae due to their high nutritional value that can benefit both the individual and their progeny. However, how the consumption of coral larvae varies among coral and fish taxa, between day and night and with the density of coral larvae is not well understood. Here, we used a series of laboratory feeding assays to determine how the consumption of coral larvae by five planktivorous damselfish species (Abudefduf sexfasciatus, Amblyglyphidodon curacao, Dascyllus trimaculatus, D. reticulatus, and Chromis viridis) differed (1) between larvae of the broadcast-spawning scleractinian coral Acropora tenuis and the brooding non-scleractinian coral Heliopora coerulea when offered at a constant density (100 larvae/50 L), (2) between day and night (A. tenuis only), and (3) among larval densities (A. tenuis: 5–500 larvae/50 L; H. coerulea: 5–250 larvae/50 L). When coral larvae were offered at 100 larvae/50 L, all five fish species examined consumed A. tenuis (78–97 larvae h⁻¹) at a greater rate than H. coerulea (23–57 larvae h⁻¹), with these differences likely related to the behavior and/or pigmentation of the larvae. Consumption also varied among the fishes examined, though the differences were small when compared to differences between coral species. Consumption of A. tenuis was twofold higher at day than night likely reflecting the diurnally active feeding behavior of the fishes examined. When the density of coral larvae offered to the fishes was varied, three of five species exhibited a type II functional response (decelerating intake rate) for A. tenuis, while four out of five damselfish species exhibited a type III (sigmoidal intake rate) or type I (linear intake rate) for H. coerulea. This study demonstrates that predation by fishes contributes significantly to coral larvae mortality and that differences in consumption rates among coral species may affect the composition of coral recruits and ultimately coral assemblages

Variation in epibiont communities among restocked giant clam species (Cardiidae: Tridacninae) and across different habitat types

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

Population structure and microbial community diversity of two common tetillid sponges in a tropical reef lagoon

Sponges are predicted to dominate future reef ecosystems influenced by anthropogenic stressors and global climate change. The ecological success of sponges is attributed to their complex physiology, which is in part due to the diversity of their associated prokaryotic microbiome. However, the lack of information on the microbial community of many sponge species makes it difficult to gauge their interactions and functional contributions to the ecosystem. Here, we investigated the population dynamics and microbial community composition of two tetillid sponges identified as Cinachyrella sp. and Paratetilla sp., which are common on coral bommies in a reef lagoon in Bolinao, northwestern Philippines. The sponges ranged in size from 2.75 ± 2.11 to 6.33 ± 3.98 cm (mean ± standard deviation) and were found at an average density of 1.57 ± 0.79 to 4.46 ± 3.60 individuals per sq. m. on the bommies. The tetillid sponge population structure remained stable over the course of four years of monitoring. Prokaryotic communities associated with the sponges were distinct but had overlapping functions based on PICRUSt2 predictions. This convergence of functions may reflect enrichment of metabolic processes that are crucial for the survival of the tetillid sponges under prevailing conditions in the reef lagoon. Differentially enriched functions related to carbon, sulfur, fatty acid, and amino acid metabolism, cellular defense, and stress response, may influence the interactions of tetillid sponges with other biota on the bommies

Preliminary observations of macrobenthic invertebrates and megafauna communities in the upper mesophotic coral ecosystems in Apo Reef Natural Park, Philippines

Quimpo, Timothy Joseph R., Cabaitan, Patrick C., Olavides, Ronald Dionnie D., Dumalagan, Edwin E., Jr, Munar, Jeffrey, Siringan, Fernando P. (2018): Preliminary observations of macrobenthic invertebrates and megafauna communities in the upper mesophotic coral ecosystems in Apo Reef Natural Park, Philippines. Raffles Bulletin of Zoology 66: 1-11, DOI: 10.5281/zenodo.535853

Fish and benthic communities in an offshore and well-managed coral reef after bleaching disturbance in the Philippines

Climate change is perhaps the greatest threat to coral reefs worldwide. However, there is spatial variation in the extent and severity of this disturbance, with offshore and well-managed reefs presumed to be less vulnerable to anthropogenic disturbance. Here, fish and benthic communities at the offshore and well-managed reefs of Apo Reef Natural Park, Philippines, were examined during a bleaching disturbance in 2016 and reassessed 2 (2018) and 3 years (2019) after using scuba surveys. Results showed that benthic communities varied more strongly with year attributed to changes in the benthic cover of coral. These changes were influenced by site, with some sites experiencing coral loss of 41–48%, while other sites exhibited minimal changes. Site differences in coral loss may be associated with coral cover, with sites that had high coral cover prior to bleaching incurring larger loss of coral cover. Fish communities varied more with sites and was associated with differences in the predominant benthos. The stability of fish communities with year despite coral loss may be attributed to the minimal loss of coral cover at some sites. For sites that experienced high losses of coral cover, the presence of alternative and deeper habitats may have provided shelter and food for more mobile fishes maintaining taxonomic composition within sites. This study shows that bleaching disturbance circumvents effective management, but impacts are variable even at small (≤ 3 km) spatial scales. Benthic community composition and presence of alternative habitats potentially alleviate the negative impacts of bleaching on reef fish diversity and abundance