Challenge 03: Sustainably feed the global population
Permanent URI for this collectionhttps://repository.unesco.gov.ph/handle/123456789/22
Ocean Decade
Challenge 03:
Sustainably feed the global population
Generate knowledge, support innovation and develop solutions to optimize the role of the ocean in sustainably nourishing the world’s population under changing environmental, social and climate conditions.
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- Growth, nitrate uptake kinetics, and biofiltration potential of eucheumatoids with different thallus morphologiesNarvarte, Bienson Ceasar V.; Genovia, Tom Gerald T.; Hinaloc, Lourie Ann R.; Roleda, Michael Y. (Wiley, 2021-12-30)The declining production of commercially important eucheumatoids related to serious problems like increasing susceptibility to ice‐ice disease and epiphytism may be ameliorated by nutrition. This ushered to an increasing interest in incorporating seaweeds into an integrated multi‐trophic aquaculture (IMTA) setup to take up excess inorganic nutrients produced by fish farms for their nourishment. In this regard, it is important to understand the nutrient uptake capacity of candidate seaweeds for incorporation in an IMTA system. Here, we examined the growth, nitrate (NO3‐) uptake kinetics and biofiltration potential of Eucheuma denticulatum and three strains of Kappaphycus alvarezii (G‐O2, TR‐C16 and SW‐13) with distinct thallus morphologies. The NO3‐ uptake rates of the samples were determined under a range of NO3‐ concentration (1‐ 48 µM) and uptake rates were fitted to the Michaelis‐Menten saturation equation. Among the examined eucheumatoids, only SW‐13 had a linear response to NO3‐ concentration while other strains had uptake rates that followed the Michaelis‐Menten saturation equation. Eucheuma denticulatum had the lowest Km (9.78 ± 1.48 µM) while G‐O2 had the highest Vmax (307 ± 79.3 µmol · g‐1 · min‐1). The efficiency in NO3‐ uptake (highest Vmax/Km and α) was translated into the highest growth rate (3.41± 0.58 % · d‐1) measured in E. denticulatum. Our study provided evidence that eucheumatoids could potentially take up large amount of NO3‐ and fix CO2 when cultivated proximate to a fish farm as one component of an IMTA system. During a 45‐d cultivation period of eucheumatoids, as much as 370 g NO3‐ can be sequestered by every 1 kg initial biomass E. denticulatum growing at 3% · d‐1. Furthermore, based on our unpublished photosynthetic measurements, the congeneric K. striatus can fix 27.5 g C · kg‐1 DW during a 12‐h daylight period.
- 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.
- Impacts of aquaculture nutrient sources: ammonium uptake of commercially important eucheumatoids depends on phosphate levelsNarvarte, Bienson Ceasar V.; Hinaloc, Lourie Ann R.; Gonzaga, Shienna Mae C.; Roleda, Michael Y. (Springer, 2023-09-14)In an integrated multitrophic aquaculture (IMTA) system, seaweeds serve as extractive species that utilize excess nutrients, thereby reducing the risk of eutrophication and promoting sustainable aquaculture. However, the use of excessive fish feeds and the resultant faecal waste as nutrient streams can contribute to variations in nitrogen and phosphorus levels (e.g., primarily NH4+ and PO4−3) in the surrounding area and this may impact the physiology of the integrated seaweeds, particularly on how these species take up inorganic nutrients. In this study, the effect of different PO4−3 levels on NH4+ uptake of the three commercially important eucheumatoids Kappaphycus alvarezii, Kappaphycus striatus and Eucheuma denticulatum was examined under laboratory conditions. Seaweed thalli (n = 4) were incubated in seawater media containing 30 µM NH4+, and 0, 0.5, 1.0, 1.5, 3.0 or 5.0 µM PO4−3 for 1 h under a saturating light level of 116 ± 7.13 µmol photons m−2 s−1 inside a temperature-controlled laboratory. Species-specific responses to PO4−3 levels were observed. For K. alvarezii, maximum NH4+ uptake (17.8 ± 1.6 µmol gDW−1 h−1) was observed at 0.5 µM PO4−3 and the uptake rate declined at higher PO4−3 levels. For K. striatus, NH4+ uptake increased with increasing PO4−3 levels, with maximum N uptake (6.35 ± 0.9 µmol gDW−1 h−1) observed at 5.0 µM PO4−3. For E. denticulatum, maximum NH4+ uptake (14.6 ± 1.4 µmol gDW−1 h−1) was observed at 1.0 µM PO4−3. Our results suggest that among the three eucheumatoid species, the NH4+ uptake of K. striatus persists even at high levels of PO4−3. However, our results also showed that K. striatus had the lowest range of NH4+ uptake rates. These results should be taken into consideration when incorporating eucheumatoids in the IMTA system, where PO4−3levels significantly vary in space and time.This is contribution no. 500 from the Marine Science Institute, University of the Philippines (UPMSI), Diliman. The AlgaE Team would like to thank the Bolinao Marine Laboratory (BML) for providing the venue to conduct our experiments. BCV Narvarte and MY Roleda acknowledge the Sea6 Energy Pvt. Ltd. for sponsorship during the 24th International Seaweed Symposium (ISS) held on February 19-24, 2023, at Hobart, Tasmania, Australia. Likewise, BCV Narvarte and LAR Hinaloc would like to thank the University of the Philippines- Office of the International Linkages (UP-OIL) for providing them with a travel grant to attend the aforementioned symposium. BCV Narvarte also acknowledges the Department of Science and Technology- Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development (DOST-PCAARRD) for his PhD Scholarship (GREAT- Graduate Research and Education Assistantship for Technology Program).
- Ensuring aquatic food security in the PhilippinesCabral, Reniel; Geronimo, Rollan; Mamauag, Antonio Samuel; Silva, Juan; Mancao, Roquelito; Atrigenio, Michael (National Fisheries Research and Development Institute, 2023-12)The human population of the Philippines is expected to reach 158 million by the year 2050, or an increase of 37% relative to 2022. This implies increased demand for aquatic food (or “fish” hereafter). This begs the question of whether the Philippines can meet the expected increase in fish demand. We estimate that even if the Philippines can maintain its current fish production, the Philippines will still require 1.67 million metric tons more fish per year by 2050 to at least maintain its current per capita fish consumption of 34.27 kg per year. Continued mismanagement of inland and marine fisheries will further widen the gap in fish supply. However, we argue that simultaneously rebuilding overfished fisheries, restoring degraded habitats crucial to supporting productive fisheries, addressing current threats to fisheries sustainability, and expanding sustainable marine aquaculture (or mariculture) have the potential to meet future fish demand in the Philippines. Sustainably expanding mariculture requires careful siting and management of mariculture development areas so that mariculture can improve food security without disenfranchising and marginalizing local coastal communities.This policy brief is the product of the address delivered by RBC during the 44th Annual Scientific Meeting of the National Academy of Science and Technology, Philippines, last July 2022, with the theme Foresight 2050: Science for a Sustainable Future. We dedicate this work in memory of our friend, Lito Mancao, who championed good governance in the Philippine fisheries and has generously supported numerous fisheries researchers and practitioners.