menu.header.image.unacom.logo
 

National Committee on Marine Sciences (NCMS)

Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/6

Browse

Filters

2021 - 20232

Settings

Author: search.filters.author.Guest, JamesOcean Decade Challenge: search.filters.odc.Challenge 2: Protect and restore ecosystems and biodiversity

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Latitudinal variation in growth and survival of juvenile corals in the West and South Pacific
    Nozawa, Yoko; Villanueva, Ronald D.; Munasik, Munasik; Roeroe, Kakaskasen Andreas; Mezaki, Takuma; Kawai, Takashi; Guest, James; Arakaki, Seiji; Suzuki, Go; Tanangonan, Jean J. B.; Ang, Put O.; Edmunds, Peter J. (Springer, 2021-08-18)
    Reef-building corals are found across > 30° of latitude from tropical to temperate regions, where they occupy habitats greatly differing in seawater temperature and light regimes. It remains largely unknown, however, how the demography of corals differs across this gradient of environmental conditions. Variation in coral growth is especially important to coral populations, because aspects of coral demography are dependent on colony size, with both fecundity and survivorship increasing with larger colonies. Here we tested for latitudinal variation in annual growth rate and survival of juvenile corals, using 11 study locations extending from 17° S to 33° N in the West and South Pacific. Regression analyses revealed a significant decline in annual growth rates with increasing latitude, whereas no significant latitudinal pattern was detected in annual survival. Seawater temperature showed a significant and positive association with annual growth rates. Growth rates varied among the four common genera, allowing them to be ranked Acropora > Pocillopora > Porites > Dipsastraea. Acropora and Pocillopora showed more variation in growth rates across latitudes than Porites and Dipsastraea. Although the present data have limitations with regard to difference in depths, survey periods, and replication among locations, they provide evidence that a higher capacity for growth of individual colonies may facilitate population growth, and hence population recovery following disturbances, at lower latitudes. These trends are likely to be best developed in Acropora and Pocillopora, which have high rates of colony growth.
    We appreciate volunteers, students, and assistants for data collection. Y.N. especially thank H.-S. Hsieh and C.-H. Liu for data measurement, and V. Denis for his comments on the manuscript. Comments from two anonymous reviewers improve our manuscript greatly. The study was funded by the thematic research grant of Academia Sinica (23-2g) and an internal research grant of Biodiversity Research Center, Academia Sinica to Y.N. The Okinawa survey was partly supported by the Japan Society for the Promotion of Science through NEXT Program #GR083. Temperature data for the Okinawa site were provided by the coral reef survey of Monitoring Sites 1000 Project, operated by the Ministry of the Environment, Japan. Temperature data for Moorea were provided by the Moorea Coral Reef LTER, funded by the US National Science Foundation (OCE-0417412).
  • Thumbnail Image
    Live slow, die old: larval propagation of slow-growing, stress-tolerant corals for reef restoration
    Guest, James; Baria-Rodriguez, Maria Vanessa; Toh, Tai Chong; dela Cruz, Dexter; Vicentuan, Kareen; Gomez, Edgardo; Villanueva, Ronald; Steinberg, Peter; Edwards, Alasdair (Springer, 2023-11-06)
    Efforts to restore coral reefs usually involve transplanting asexually propagated fast-growing corals. However, this approach can lead to outplanted populations with low genotypic diversity, composed of taxa susceptible to stressors such as marine heatwaves. Sexual coral propagation leads to greater genotypic diversity, and using slow-growing, stress-tolerant taxa may provide a longer-term return on restoration efforts due to higher outplant survival. However, there have been no reports to date detailing the full cycle of rearing stress-tolerant, slow-growing corals from eggs until sexual maturity. Here, we sexually propagated and transplanted two massive slow-growing coral species to examine long-term success as part of reef restoration efforts. Coral spat were settled on artificial substrates and reared in nurseries for approximately two years, before being outplanted and monitored for survivorship and growth for a further four years. More than half of initially settled substrates supported a living coral following nursery rearing, and survivorship was also high following outplantation with yields declining by just 10 to 14% over four years. At 6-years post-fertilisation over 90% of outplanted corals were reproductively mature, demonstrating the feasibility of restoring populations of sexually mature massive corals in under a decade. Although use of slower growing, stress tolerant corals for reef restoration may provide a longer-term return on investment due to high post-transplantation survival rates, considerable time is required to achieve even modest gains in coral cover due to their relatively slow rates of growth. This highlights the need to use a mix of species with a range of life-history traits in reef restoration and to improve survivorship of susceptible fast-growing taxa that can generate rapid increases in coral cover.
    We would like to thank Ronald de Guzman, Marcos Ponce, Romer Albino, Jun Castrence (Bolinao Marine Laboratory) and Prof. Chou Loke Ming (Reef Ecology Laboratory, National University of Singapore). This work was supported by the Global Environment Facility/World Bank funded Coral Reef Targeted Research for Capacity Building and Management program, a Singapore Ministry of Education Academic Research Tier 1 FRC Grant (Grant Number: R-154-000-432-112) and the joint University of New South Wales and Nanyang Technological University project: “Development of the Advanced Environmental Biotechnology Centre (AEBC)” under the Research Centre Funding Scheme (RCFS), project No. COY-15-EWI-RCFS/N190-2. We are extremely grateful to David Suggett and one anonymous reviewer whose comments greatly improved the manuscript.