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03. Science and Technology (Natural Sciences) Committee

Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/3

In creating a culture of peace and addressing sustainable development challenges, UNESCO aims to cultivate the generation and application of scientific knowledge among its Member States. At UNACOM, we facilitate access to UNESCO’s international programmes in the sciences, such as the Intergovernmental Oceanographic Commission (IOC), Man and the Biosphere (MAB) Programme, and International Geoscience and Geoparks Programme (IGGP), among others.

Through this sector, the Commission aims to contribute to the following SDGs: 11 - Sustainable Cities and Communities, 13 - Climate Action, 14 - Life Below Water, and 15 - Life On Land. With the overarching vision of the 2023-2028 Philippine Development Plan (PDP), UNACOM targets grassroots-inspired cultural heritage and biodiversity protection and conservation, as well as multi-stakeholder partnerships for SDGs promotion.

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1988 - 198921990 - 19921

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End date: 1999Scientific name: search.filters.scientificname.Tridacna gigas

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    Status of giant clam resources of the Philippines
    Juinio, Marie Antoinette R.; Meñez, Lambert Anthony B.; Villanoy, Cesar L.; Gomez, Edgardo D. (Oxford University Press (OUP), 1989-11-01)
    Field surveys were conducted to determine distribution and abundance of giant dam resources in the Philippines. All seven known species of giant clams were recorded with Tridacna crocea, T. maxima and T. squamosa occurring the most frequently. The larger species T. derasa, T. gigas, Hippopus hippopus and H. porcellanus were relatively rare. The reduction of giant dam stocks in the Philippines is due to the uncontrolled exploitation of this resource which is primarily gathered for shellcraft and as supplementary diet in coastal villages.
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    Passive greenhouse heating, recirculation, and nutrient addition for nursery phase Tridacna gigas: Growth boost during winter months
    Braley, Richard D.; Sutton, David; Mingoa, S. Suzanne M.; Southgate, Paul C. (Elsevier, 1992-11)
    The impetus for this study was winter-related mortality of juvenile Tridacna gigas along Australia's Great Barrier Reef. Heating nursery tank water by passive solar heating in a greenhouse and the addition of dissolved inorganic nitrogen (DIN) was assessed for effect on the growth and survival of cultured juvenile clams. Two age classes of T. gigas were used, with means of 1.2 cm and 17.0 cm shell length. Treatments consisted of nutrient-spikes of 20 μ M and 40 μ M ammonium chloride daily or on alternate days, plus s spike of 2.3 μ M phosphate once per week vs. controls without nutrient addition. Three rearing systems were used: (1) recirculating water enclosed in a greenhouse; (2) flow-through water enclosed in a greenhouse; (3) flow-through water with ambient conditions. In the older clams growth in weight was best in system 2, while growth in shell length (SL) was best in system 1, and DIN treatments significantly increased growth compared with controls. In the younger clams, growth in SL was best in system 1. DIN treatments produced significantly greater growth than controls, but there was no difference between 20-μ M and 40-μ M treatments. Survival was 100% for larger clams but for smaller clams mean survival was highest overall in system 1, while 20-μ M DIN treatments within systems produced the best overall survival. The highest levels of DIN in the nursery tanks were found in the 40-μ M DIN treatments, particularly in system 1. The wet tissue weight/shell length ratio for 40-μ M DIN treatments was highest in system 1 and decreased in systems 2 and 3, while controls were similar. Dry shell weight/shell length was highest in the 40-μ M DIN treatment over the control in system 1 only. The zooxanthellae index (no. of algal cells/g clam) was significantly higher in the 40-μ M DIN treatment than in the control in all three systems. Biochemical analysis of whole animals showed higher carbohydrate content in system 2 and in treatments receiving 20 μ M DIN. Tissue protein content did not differ significantly between systems but increased with increasing nutrient concentration. Lipid content was highest in system 1 and decreased with increasing nutrient concentration. Tissue water content of clams at the 20-μ M DIN level was lower than clams in other treatments, indicating superior condition. The combination of passive solar heating, recirculated water, and nutrient addition for the giant clam land nursery phase opens possibilities for culture of this tropical bivalve in subtropical zones or in the tropics distant from the ocean.
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    Fishing mortality rates of giant clams (Family Tridacnidae) from the Sulu Archipelago and Southern Palawan, Philippines
    Villanoy, Cesar L.; Juinio, Antoinette R.; Meñez, Lambert Anthony (Springer, 1988-05)
    Average size frequency distributions of Tridacna squamosa, T. gigas, Hippopus hippopus and H. porcellanus harvested from the Sulu Archipelago and Southern Palawan areas from 1978–1985 were derived from export records and a warehouse inventory of giant clam shells. Average species mortality rates (Z) were estimated and were used to approximate average fishing mortality rates (F) over the period 1978–1985. Crude estimates of exploitation rates (F/Z) indicate that populations of these species are already overexploited. These findings have serious implications in view of the fact that the Sulu Archipelago and Southern Palawan are thought to be the last strongholds of giant clams in Philippine waters.