Research on seaweeds and mollusks
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Research on seaweeds focused on the carrageenan-producing Kappaphycus alvarezii and the agar-producing Gracilaria spp. Growth of K. alvarezii was better on horizontal lines than on vertical or cluster lines from bamboo rafts. All morphotypes (brown green, and red) grew faster at 50 cm than at 100 cm below the water surface, but the green morphotype showed better carrageenan properties. A socioeconomic survey of K. alvarezii farming in Panagatan Cays, Antique revealed that a farmer has an average annual production of 3 tons/ha (dry) with the fixed bottom and hanging longline methods. Three species of Gracilaria in natural beds in lloilo showed monthly variations in biomass and agar quality; G. heteroclada had the highest biomass and gel strength. When this species was grown in tanks, growth and agar sulfate content were influenced by the interaction of light, salinity, and nutrients. Enriched and unenriched stocks of G. heteroclada differed in agar quality. When G. heteroclada was grown with the tiger shrimp Penaeus monodon in extensive ponds, the highest growth rate and production were obtained at the seaweed stocking density of 250 g/m2; this was in November when average water temperature, transparency, and salinity were low. Salinity tolerance varies among Gracilaria species.Oyster (Crassostrea iredalei) and mussel (Perna viridis) farming in Western Visayas were assessed in 1992 in terms of the culture methods, socioeconomics, marketing, and profitability. A more localized survey of oyster and mussel fanning was conducted through rapid rural appraisal in two coastal towns in 1993. A farmer-participatory study followed in 1994 for the culture of oysters, mussels, seaweeds, and rabbitfishes in a river mouth in Dumangas, lloilo. Green mussel, brown mussel (Modiolus metcalfei), and seaweeds transplanted to Dumangas from Capiz have reproduced. In another study, the green mussel was tested as a biological filter in tiger shrimp ponds; shrimps stocked with mussels grew better than those without. A nationwide survey on the Placuna placenta fishery in 1993 showed 27 remaining 'kapis' beds; many others have been depleted due to excessive gathering, pollution, siltation, and trawling. Broodstocks are being developed to produce 'kapis' seed for grow-out and restocking. For the first time at AQD, adult donkey-ear abalone Haliotis asinina from the wild spawned naturally in laboratory tanks. Juvenile abalones can be successfully grown on Gracilaria or abalone diet.
Hurtado-Ponce A. Q. (1995). Research on seaweeds and mollusks. In T. U. Bagarinao & E. E. C. Flores (Eds.), Towards Sustainable Aquaculture in Southeast Asia and Japan: Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia, Iloilo City, Philippines, 26-28 July, 1994 (pp. 199-208). Tigbauan, Iloilo, Philippines: SEAFDEC Aquaculture Department.
PublisherSEAFDEC Aquaculture Department
Agar; Stocking density; Mussel culture; Carrageenins; Environmental factors; Chromosomes; Socioeconomic aspects; Research; Seaweeds; Marine crustaceans; Aquaculture techniques; Growth rate; Seed (aquaculture); Biofilters; Transplantation; Shellfish culture; Extensive culture; Stock assessment; Pond culture; Mollusc culture; Polyculture; Oyster culture; Seed production; Spawning; Aquaculture economics; Culture tanks; Cage culture; Marine molluscs; Marine aquaculture; Seaweed culture; Penaeus monodon; Haliotis; Decapoda; Perna viridis; Mollusca; Modiolus metcalfei; Placuna placenta; Kappaphycus alvarezii; Haliotis asinina; Gracilaria heteroclada; Gracilaria; Crassostrea iredalei; Giant tiger prawn; Philippines, Western Visayas; Philippines, Panay I., Antique, Caluya, Panagatan Cays; South East Asia; Philippines, Panay I., Antique; Philippines, Panay I., Iloilo, Dumangas
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Conference paperRF Agbayani - In TU Bagarinao & EEC Flores (Eds.), Towards sustainable aquaculture in Southeast Asia and Japan: Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia, Iloilo City, Philippines, 26-28 July, 1994, 1995 - SEAFDEC Aquaculture DepartmentThe Community Fishery Resources Management Project, launched in 1991 in Malalison Island, Philippines is a development-oriented research project integrating biology, economics, sociology, engineering, and public administration. The general objective is to support, and learn from, the collaboration of people's organization, biologists, and social scientists in applying community-based techniques in fishery management. During Phase I, the Project concentrated on community organizing, institution building, and the introduction of seaweed farming as alternative livelihood. Studies were made on the marine resources of the island, the traditional boundaries and territorial use rights, the economic utilization of resources in the island, and the cultivation techniques for seaweeds. Phase II started in 1994 with the implementation of the territorial use rights in fisheries and the test deployment of prototype concrete artificial reefs. Phase II includes impact assessment (environmental, social, and economic), institutional arrangements in fishery co-management, ethnographic studies, economics of Seafarming techniques, and management of fishery cooperatives.
Potentials of Kappaphycus striatum (Schnitz) and Gracilaria heteroclada Zhang (Ad Xia) to control the growth of luminous bacteria Vibrio harveyi EA Tendencia & MR de la Peña -
The Philippine Agricultural Scientist, 2010 - University of the Philippines Los BañosDifferent aquaculture species such as finfishes and bivalves have been reported to control the luminous bacterial disease of shrimp, usually caused by Vibrio harveyi. The use of seaweeds in shrimp culture system has reportedly improved water quality and reduced the bacterial count. This study evaluated the potentials of two species of seaweeds, Gracilaria heteroclada (Ad Xia) and Kappaphycus striatum (Schnitz), to control the growth of V. harveyi. V. harveyi was inoculated into control tanks containing shrimps only and into treated tanks containing both shrimp and macroalgae. Luminous bacterial counts were monitored daily. From day 2 to day 6, luminous bacterial count in tanks with G. heteroclada was significantly lower than those in tanks with K. striatum. Bacteria isolated from the rearing water containing K. striatum and G. heteroclada and from the seaweed homogenized in sterile seawater showed anti-Vibrio harveyi activity. The seaweed homogenate per se also showed anti-luminous bacterial property. Presence of both G. heteroclada and K. striatum in shrimp culture system has the potential to control the growth of luminous bacteria. G. heteroclada was more efficient and sustainable, as shown by the lower luminous bacterial count and the higher percentage recovery of this macroalga after 11 d in experimental tanks.
Conference paperSM Aypa - In TU Bagarinao & EEC Flores (Eds.), Towards sustainable aquaculture in Southeast Asia and Japan: Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia, Iloilo City, Philippines, 26-28 July, 1994, 1995 - SEAFDEC Aquaculture DepartmentAquaculture is regarded as the most promising source of protein food in the years ahead. Milkfish and Nile tilapia are the major fishes now produced but groupers, sea bass, rabbitfish, red snappers, carps, and catfishes are grown by some farmers. The tiger shrimp is still the most important cultured crustacean, but white shrimps and mudcrabs also have great potential. Oysters and mussels are produced in considerable amounts. Mariculture of the seaweed Eucheuma is now a well established industry, and the pond culture of Gracilaria for agar extraction is beginning to take off.