National Committee on Marine Sciences (NCMS)
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- Community structure of periphytic diatoms in early-stage marine biofilms in a mariculture-impacted areaBaure, Jerwin; San Diego-McGlone, Maria Lourdes; Juinio–Meñez, Marie Antonette (Science and Technology Information Institute, 2022-07-06)Periphytic diatoms constitute a major part of complex unicellular aggregations called marine biofilm or periphyton, of which little is known about in tropical marine environments. The early-stage community structure of periphytic diatom genera on two artificial substrates – glass slide and polycarbonate sheets was characterized. These artificial substrates were placed underwater for 6 d and examined on Days 1, 3, and 6 in four sites around Santiago Island, Bolinao, Pangasinan, Philippines, with different relative distances from the intensive milkfish mariculture area. Correlations of diatom community structures in these sites with physico-chemical factors were investigated. The five most abundant diatom genera – namely, Cylindrotheca, Nitzschia, Navicula, Amphora, and Pleurosigma – exhibited a weak correlation with nutrients. Less abundant genera Pseudonitzschia, Haslea, Bacillaria, Thalassionema, Rhizosolenia, Eucampia, Diploneis, Asterionellopsis, Chaetoceros, Bacteriastrum, Licmophora, Skeletonema, Lioloma, Thalassiosira, and Thalassiothrix showed a positive correlation with nutrients. Among sites, the highest benthic diatom cell densities (4.6 × 105 cells cm−2) after 6 d was found in Lucero. Generic richness and diversity varied among sites, with the highest diversity (H’ = 1.58) on Day 1 in Tomasa, the site nearest to the mariculture area, whereas the highest richness (D = 2.17–3.26) for all days and diversity (H’ = 1.38–1.52) for Days 3 and 6 were recorded in Silaqui, the most distal site. Generally, the highest diversity and richness were found on Day 1, which then decreased on succeeding days in all sites. The lack of a clear patternin community structure among sites relative to the proximity of these sites to the mariculture area may in part be attributed to the presence of other nutrient sources. Results of the study provide baseline information on the variability of periphytic diatom community structure in a mariculture-impacted area, and insights on how benthic diatoms may be used in monitoring the impacts of nutrient pollution.This work was supported by the Department of Science and Technology–Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development under Grant QMSR-MRRDMEC-295-1449. The authors would like to thank Tirso O. Catbagan and Garry R. Bucol for their assistance during field sampling, and Timothy James Cipriano for the site map. We would also like to thank the Marine Biogeochemistry Laboratory of the Marine Science Institute, University of the Philippines Diliman for providing environmental data.
- Evolving governance structures in community-based sandfish mariculture and their interactions with livelihood outcomes: Evidence from the PhilippinesFabinyi, Michael; Gorospe, Jay R; McClean, Nicholas; Juinio–Meñez, Marie Antonette (Frontiers Media SA, 2022-11-02)Sea cucumber mariculture is an important emerging field of practice and applied research in the coastal tropics. This is due to the existing importance of tropical sea cucumber fisheries for wealth generation and poverty reduction, and the potential for mariculture to contribute to the longer term sustainability of these fisheries while generating benefits additional to those from wild caught sea cucumber. Understanding the optimal institutional arrangements for sea cucumber mariculture is an important area of focus in this field, with a variety of arrangements currently in place. This paper documents the establishment of a communal form of sea ranching in the Philippines, as a case study of community level institutional processes. It describes the background to establishment of the sea ranch in the community of Victory, challenges encountered and how these were managed, and the evolution of governance arrangements. In charting this process, we assess the impacts on livelihood outcomes, highlighting this as a crucial aspect influencing this evolution and the nature of community involvement in the sea ranch. While the sea ranching project generated a range of benefits for livelihoods, including possible spillover effects for the surrounding fishery, substantial economic returns from harvests did not occur. Thus, the system of governing the sea ranch evolved from a communal model to a more exclusive household model primarily to improve operational efficiency. In order for possible benefits of the sea ranch to be sustained and enhanced, greater integration with fisheries management and government support will be needed.We are grateful to the Samahan ng Maliliit na Mangingisda ng Barangay Victory, Inc., the local government unit of Barangay Victory and Bolinao for their support to the Sea cucumber Research Program. We are also thankful to Tirso Catbagan, Josh Caasi, Rona Cabanayan-Soy, and Garry Bucol for their invaluable assistance during the field monitoring of sandfish in the sea ranch.