Showing items related by title, author, creator and subject.

• 

  Research on seaweeds and mollusks 

  Hurtado-Ponce, Anicia Q. (Aquaculture Department, Southeast Asian Fisheries Development Center, 1995)

  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.
• 

  Coastal fisheries and mollusk and seaweed culture in Southeast Asia: Integrated planning and precautions 

  McManus, John W. (Aquaculture Department, Southeast Asian Fisheries Development Center, 1995)

  Capture fisheries in Southeast Asia are characterized by rampant overfishing, made worse in many areas by problems of overpopulation and by inappropriate management strategies based on misconceptions about tropical fisheries. Mollusk culture and seaweed culture are frequently cited as means to alleviate fishing pressure and to provide substitute protein. There is great potential for expansion of these types of mariculture in terms of area used, species employed, and products generated. However, large-scale mariculture rarely provides significant employment, and the provision of low-cost protein in markets does not alleviate poverty in countries where food production is the primary means of employment. In cases where conflicts have arisen between mariculture development and ecosystem maintenance, mariculture has been favored by inappropriate economic valuations. Small-scale mariculture designed to provide alternative livelihood for fishers is worth developing, although limited by larval supplies and suitable farming areas. Mariculture should be approached as a species-diverse, small-scale enterprise within the framework of integrated coastal management.
• 

  Economic and social considerations in seafarming and searanching 

  Chong, Kee-Chai. (Aquaculture Department, Southeast Asian Fisheries Development Center, 1994)

  Sustainable development of seafarming and searanching calls for careful planning. Investments in seafarming must take into account environmental, biotechnological, and socioeconomic considerations. Investment planning must be carefully examined as well as the physical design of production systems such that its negative impact is minimized and the positive impact is accentuated.Supply from the wild may not be expected to grow much higher than present levels. Many of the major commercially valuable fisheries are now overfished at or close to their respective minimum sustainable yield levels. Seafarming can attract some of the fishermen out of overcrowded fisheries.Production cost of seafarming produce is a major concern which has to be examined closely if these are to compete with and gradually supplant the supply of fish from the wild. Feed is one of the main inhibiting factors, hence, efficient consideration calls for constantly improving feed conversion and productivity per unit input.Existing government policies are not clear nor conducive to seafarming in terms of use rights of coastal waters. To attract potential investors into seafarming, governments are encouraged to review existing policies governing use rights to coastal waters, package the necessary technology consistent with the country's wage and price structure, and develop investment profile for seafarming opportunities using conservative criteria.