Now showing items 1-20 of 127

    • Conference paper

      The Agusan Marsh - two years after Pakse 

      JH Primavera - In Proceedings of the Joint Regional Seminar of the Ecotone-SeaBRnet 2007 and the 9th Conference of the China Biosphere … Sustainable Development, Maolan Biosphere Reserve, Libo County, Guizhou Province, P. R. China, 7-12 November 2007, 2008 - UNESCO Office
    • Conference paper

      The Agusan Marsh and the Agusan River Basin: The need for science-based development and management 

      JH Primavera - In MLC Aralar, AS Borja, AL Palma, MM Mendoza, PC Ocampo, EV Manalili & LC Darvin (Eds.), LakeCon2011: Building on the pillars of Integrated Lake Basin Management (Second National Congress on Philippine Lakes), 2013 - PCAARRD-DOST
      Series: Summary of Proceedings No. 1/2013
    • Conference paper

      The Agusan marsh: A situationer with focus on scientific aspects 

      J Primavera & MI Tumanda Jr. - In J Primavera (Ed.), Proceedings of the 1st Scientific Conference on the Agusan Marsh: Butuan City, Agusan del Norte, Philippines, 21-23 May 2007, 2008 - UNESCO Jakarta Office, Philippine Council for Aquatic and Marine Research and Development
      The Agusan Marsh is an extensive floodplain in the middle of the Agusan River Basin in eastern Mindanao where rivers, creeks and tributaries mainly in the provinces of Agusan del Norte, Agusan del Sur and Compostela Valley converge and drain northward to the Agusan River and into Butuan Bay. The main habitats of the Marsh are the freshwater swamp forest (with Terminalia, peat swamp and sago palm forest subtypes), secondary scrub, herbaceous swamp, open water (oxbow/floodplain lakes, pools), and flowing water (rivers, streams). Peat forests have been confirmed in Bunawan and Caimpugan. Over 200 bird species have been known to spend at least part of the year in the Marsh, making it an important site for migratory birds from northern Asia and Siberia. As one of the Philippines' ecologically significant wetlands, the Marsh has been declared a protected site under NIP AS (1994), Presidential Proclamation 913 (1996), and RAMSAR (1999). The Agusan Marsh Wildlife Sanctuary covers -111,540 ha in 8 municipalities of Agusan del Sur. Recently the Agusan Marsh was placed high on the list of Philippine nominations to the World Heritage Natural Sites. Despite all these, very few scientific studies have been conducted on the Marsh but this has not stopped drainage and development for agriculture, construction of dams and reservoirs for irrigation, deliberate or accidental introductions of exotic species, e.g., tilapia, carps, janitor fish, and golden apple snail, and logging in the watershed areas. The latter have been legitimized by Integrated Forest Management Agreements despite the presence of primary forests. The latest proposed intervention is the Agusan River Basin Development Project. There is need for scientific research to provide baseline information on hydrology, sediment dynamics and ecology as prerequisite to any interventions and developments in the Agusan Marsh.
    • Article

      Approaches to stock enhancement in mangrove-associated crab fisheries 

      L Le Vay, MJHL Lebata, M Walton, JH Primavera, ET Quinitio, CR Lavilla, FD Parado-Estepa, E Rodriguez, VN Ut, TT Nghia, P Sorgeloos & M Wille - Reviews in Fisheries Science, 2008 - Taylor & Francis
      Over the last decade, hatchery production of mud crabs has become technically and economically more feasible, enabling evaluation of the potential effectiveness of hatchery release in fisheries enhancement. The high growth rates and limited movement of released crabs means that fisheries’ yields an isolated mangrove systems with restricted recruitment can be enhanced with a few months. Thus, a release program may be an effective strategy for short-term enhancement in carefully selected specific areas. To date, results are very promising; with recovery rates up to 50% and increases in fisheries’ yield up to 46% over baseline catches. In contrast, mark-recapture studies in more open mangrove system populations shows that recruitment success and subsequent stock abundance may be largely determined by habitat availability. For these populations, restoration of lost o degraded mangrove areas has been show to be effective in promoting stock recovery through natural recruitment, with replanted mangroves supporting fisheries of equivalent economic value to that of natural mangroves, though it may take some years to reach these levels. Thus, a balanced approach to stock management could integrate both hatchery-release and habitat restoration programs, depending on local conditions and over different thin scales, with parallel-co-management to support effectiveness.
    • Book chapter

      Aquaculture 

      M Troell, N Kautsky, M Beveridge, P Henriksson, J Primavera, P Rönnbäck & C Folke - In SA Levin (Ed.), Encyclopedia of Biodiversity, 2013 - Academic Press
      Biophysical impacts of aquaculture, with consequences for biodiversity, vary with species and culture systems and include issues such as: nutrient enrichment/removal, chemicals, land use, species introductions, genetic flow to wild populations, disturbance of balance or introduction of pathogen/parasites, consumption of capture fishery resources, energy, and greenhouse gas emissions. Guiding principles, labeling schemes and various tools are needed to analyze performance and conformance. Ecological footprints and life-cycle analysis aim to capture biophysical performance, including up- and downstream effects of policy decisions. Aquaculture provides a range of services but also makes demands and impacts on ecosystem functions, services, and thus biodiversity.
    • Book chapter

      Aquaculture 

      N Kautsky, C Folke, P Ronnback, M Troell, M Beveridge & JH Primavera - In Encyclopedia of Biodiversity, 2001 - Elsevier
      Aquaculture, the aquatic counterpart of agriculture, has grown rapidly in recent decades to become one of the most important means of obtaining food from the sea. Impacts of aquaculture on biodiversity arise from the consumption of resources, such as land (or space), water, seed, and feed, their transformation into products valued by society, and the subsequent release into the environment of wastes from uneaten food, fecal and urinary products, and chemtherapeutants as well as microorganisms, parasites, and feral animals. Negative effects may be direct, through release of eutrophicating substances, toxic chemicals, the transfer of diseases and parasites to wild stock, and the introduction of exotic and genetic material into the environment, or indirect through loss of habitat and niche space and changes in food webs. Today, large quantities of fish are caught to produce fish meal–the main ingredient in feed–which may result in overfishing and affect marine food chains, including marine mammals and top carnivores. In some types of aquaculture, fish and shrimp larvae are caught in the wild to be used as seed. This may also result in bycatches of large amounts of other larvae, representing losses to capture fisheries and biodiversity. Large areas of critical habitats such as wetlands and mangroves have been lost due to aquaculture siting and pollution, resulting in lowered biodiversity and recruitment to capture fisheries. The magnitude of biodiversity loss generally increases with scale, intensity of resource use, and net production of wastes, but it is very much dependent on which species is cultured and the method of cultivation. In some cases aquaculture may increase local biodiversity, e.g., when ponds are constructed in dry areas and with integrated aquaculture.
    • Conference paper

      Aquaculture and the coastal environment 

      JH Primavera - In AC Alcala & MC Balgos (Eds.), Management of Nearshore Fishery Resources. Proceedings of the Seminar-Workshop on Management of Nearshore Fishery Resources, 23-25 January 1990, Cebu City, Philippines, 1991 - Philippine Council for Aquatic and Marine Research and Development
      Series: PCAMRD Book Series; No. 10/1991
      Philippine aquaculture production mostly comes from pond culture (brackishwater) constituting 47% of the total 1987 production of 560,970 t followed by mariculture of seaweeds, mollusks and finfishes. Fishponds have increased from around 61,000 ha in 1941 to 210,400 ha at present while the 130,000 ha of remaining mangroves constitute only 13-26% of the original area.

      The effects of aquaculture on the coastal environment are apparent in the decline in nearshore fisheries production and loss of services (typhoon buffer, flood control, soil stabilization). Mangrove conversion into ponds, species introductions and transplantations, spread of parasites, pests and diseases, increased organic nutrient loading, use and release of chemicals, sedimentation, extraction of groundwater, and salinification of soil and water supplies, are the identified aquaculture-related practices that lead to the degradation of nearshore resources. Some ecological effects also have social repercussions.

      Recommended measures to solve these problems include: rationalized use of mangroves and mangrove reforestation; regulation of groundwater extraction, import/ use of chemicals, disposal of organic wastes, and introductions/transplantations; research (bacteriology of aquaculture facilities, effects of organic wastes, effects of sedimentation, effects of chemicals on marine organisms including antibiotic resistance, etc.); training and extension; and improvement of interagency coordination.
    • Conference paper

      Aquasilviculture trials in mangroves in Aklan province, Panay Island, central Philippines 

      JH Primavera - In JIRCAS International Workshop on Brackish Water Mangrove Ecosystems - Productivity and Sustainable Utilization, 29 February - 1 March 2000, Tsukuba International Congress Center, 2000 - Japan International Research Center for Agricultural Sciences
      To integrate production of crabs and shrimp with mangrove conservation, the SEAFDEC Aquaculture Department initiated studies on Mangrove-Friendly Aquaculture (MFA). Culture pens and ponds in old growth and newly regenerating mangrove sites in Aklan, central Philippines were stocked with mudcrab Scylla olivacea/S. tranquebarica. Investments costs, survival and production, and cost-return analysis for mudcrab culture in pens and ponds are reported in the paper.

      Aside from the aquasilviculture trials in collaboration with local government units, other activities in the Aklan mangrove sites are the survey and mapping of the 75-ha area in Ibajay, construction of a treehouse, and the educational use as field site by Coastal Resources Management trainees (of SEAFDEC-AQD) and field biology students (of the University of the Philippines in the Visayas).
    • Article

      Are mangroves worth replanting? The direct economic benefits of a community-based reforestation project 

      MEM Walton, GPB Samonte-Tan, JH Primavera, G Edwards-Jones & L Le Vay - Environmental Conservation, 2006 - Cambridge University Press
      Competition for coastal land use and overexploitation have reduced or degraded mangrove coverage throughout much of their distribution, especially in South-east Asia. Timber production was the initial motivation for early mangrove reforestation projects. More recently, benefits from protection against erosion and extreme weather events and direct improvements in livelihoods and food security are perceived as justifications for such restoration efforts. This study examines the socioeconomic impacts of a community-led reforestation project in the Philippines through a survey of the local fishers. Revenues from mangrove fisheries, tourism and timber result in an annual benefit to the community of US$ 315 ha−1 yr−1. This figure is likely to be considerably more if the contribution of the mangrove to the coastal catch of mangrove-associated species is included. This estimate only includes direct benefits to the community from mangroves, and not intangible benefits such as coastal protection, which paradoxically is perceived by the community as one of the most important functions. More than 90% of all fishers, regardless of where they fished, thought the mangrove provided protection from storms and typhoons and acted as a nursery site and should be protected. Those fishing only in the mangrove perceived more benefits from the mangrove and were prepared to pay more to protect it than those fishing outside. This study concludes that replanting mangroves can have a significant economic impact on the lives of coastal communities. Acknowledgement of the value of replanted mangroves compared with other coastal activities and the benefits they bring to the more economically-vulnerable coastal dwellers should support better informed policy and decision-making with regard to coastal habitat restoration.
    • Technical Report

      Artificial fertilization of eggs and early development of the milkfish Chanos chanos (Forskal) 

      H Chaudhuri, JV Juario, JH Primavera, R Mateo, R Samson, ER Cruz, EO Jarabejo & JT Canto Jr. - In Induced spawning, artificial fertilization of eggs and larval rearing of the milkfish Chanos chanos (Forskal) in the Philippines, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Technical report / SEAFDEC Aquaculture Department; 4
      Hydrated eggs obtained from a female milkfish were artificially fertilized with the milt collected from a male injected with acetone-dried pituitaries of salmon. The fertilized eggs (1.1 to 1.25 mm in diameter) developed normally in seawater in basins and Petri dishes at a salinity of 30-34 ppt and successfully hatched in 25 to 28½ hours at a temperature of 26.4-29.9°C. The yolk was completely absorbed in about 2½ days and at this period many postlarvae died. A few larvae were reared up to 5 days but all died within 6 days. Effects of feeding the postlarvae from the third day with freshly hatched trochophore larvae of oysters obtained from eggs artificially fertilized in the laboratory could not be ascertained.
    • Article

      Assessment of the effectiveness of mangrove rehabilitation using exploited and non-exploited indicator species 

      ME Walton, L Le Vay, JH Lebata, J Binas & JH Primavera - Biological Conservation, 2007 - Elsevier
      Mangrove forests have been cleared at an alarming rate over the last century to allow space for settlements, agriculture and aquaculture and are still used today for fuel and construction. However, in the last few decades the value of the range of services and products that mangroves supply are being increasingly appreciated by policy makers. Mangrove replanting is frequently used as a method of restoring ecological function and associated goods and services but this may not be justified as once diverse forests are often replanted with mono-genus stands. In the present study the abundance of the commercially important mud crab Scylla olivacea, a top benthic predator, was used as an indicator of the ecological function of mangrove habitats. Abundance was estimated using catch per unit effort (CPUE) data obtained from an experimental standardized trapping grid. The same commercial traps also catch two other smaller non-exploited competing species, Baptozius vinosus and Thalamita crenata that are discarded by fishers. The relative abundance of these three species was used to separate the effects of habitat from fishing pressure and recruitment limitation. Four sites on Panay Island, central Philippines were selected to represent different types of mangrove habitat; a replanted fringing area predominantly of Rhizophora spp., a natural fringing area predominantly of Sonneratia spp., a diverse natural basin mangrove area and a degraded mangrove site. The relative abundance of mud crabs was found to be equivalent in the natural fringing mangrove (1.89 crabs trap−1 day−1) and the replanted mangrove area (1.71 and 0.81 crabs trap−1 day−1). Lower densities of S. olivacea in the basin mangrove area (0.33 crabs trap−1 day−1) appear to be due to limited recruitment, and at this site there was instead a higher abundance of the other non-commercial crab species. No mud crabs were caught in the degraded mangrove area and CPUE for other crab species was also low. Overall, the study suggests that replanting of mangroves even in mono-genus stands was effective in restoring mud crab populations, indicating recovery of an ecological function to a level equivalent to that of natural mangrove environments. The use of CPUE as an indictor of relative abundance of S. olivacea was supported by single release mark–recapture studies and a multiple release mark–recapture study in the replanted mangrove site.
    • Article

      Baseline assessment of fisheries for three species of mud crabs (Scylla spp.) in the mangroves of Ibajay, Aklan, Philippines 

      MJHL Lebata, L Le Vay, JH Primavera, ME Walton & JB Biñas - Bulletin of Marine Science, 2007 - University of Miami, Rosenstiel School of Marine and Atmospheric Science
      Stock enhancement through habitat restoration and habitat release have both been considered as approaches to the management of declining Scylla spp. Prior to stock enhancement trials, the present study was conducted to monitor recruitment and yields of three Scylla spp. in ∼70 ha of natural mangroves in Aklan, Panay, Philippines. Results showed that Scylla olivacea (Herbst, 1796) was the most abundant mud crab species, comprising 95% of the catches over the 4 yr sampling period. Size distribution for this species indicated year-round recruitment with peaks in the numbers of smaller, immature crabs during the summer months. The decreasing mean size at capture, yield and CPUE in terms of weight throughout the 4-yr sampling period is an indication that the area has been subjected to heavy fishing pressure. The constant CPUE in terms of numbers of crabs suggests that recruitment is constant, though this is likely to be lower than in other mangrove areas due to the topography of the site with limited access to the open sea, resulting in relatively low crab abundance and yields. Combined with the fidelity of S. olivacea to the mangrove habitat, this indicates a suitable population for investigation of the effectiveness of a hatchery-release program.
    • Conference paper

      Bridging traditional knowledge with mainstream technology to sustain cultural and biological diversity in the product development of wild honey: Focus on the indigenous peoples of the Palawan Biosphere Reserve, Philippines 

      JF Pontillas & JH Primavera - In Proceedings of the Joint Regional Seminar of the Ecotone-SeaBRnet 2007 and the 9th Conference of the China Biosphere … Sustainable Development, Maolan Biosphere Reserve, Libo County, Guizhou Province, P. R. China, 7-12 November 2007, 2008 - UNESCO Office
      Declared a Man and Biosphere Reserve in 1991, the Palawan Biosphere Reserve in the Philippines is a biologically diverse province and home to a number of Indigenous Peoples particularly the Pala’wan, Tagbanua and Batak tribes. These IPs are dependent on their traditional wildlife hunting and gathering practices for food. The province-wide federation of the Indigenous Peoples, the Nagkakaisang Mga Tribung Palawan (NATRIPAL) or the United Tribes of Palawan, is undertaking projects in the area of education, health, organizing, advocacy and livelihood programs towards building a better future for the tribal peoples. A key initiative is the development for the mainstream market of specialty products such as the wild honey traditionally gathered for household consumption and at a limited scale for the local market. The opportunities, challenges and strategies in the development of this specialty product based on customary knowledge and practices of gathering enhanced by mainstream technology and enterprise management scheme(s) is discussed in the context of sustaining cultural and biological diversity of the indigenous peoples of Palawan Biosphere Reserve.
    • Conference paper

      Broodstock management and seed production of Penaeus monodon (Fabricius) 

      FD Parado-Estepa & J Honculada-Primavera - In JV Juario & LV Benitez (Eds.), Seminar on Aquaculture Development in Southeast Asia, 8-12 September 1987, Iloilo City, Philippines, 1988 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Research on the maturation of Penaeus monodon at AQD has focused on three broad areas, namely, reproductive biology and ecology, induced maturation and broodstock management. Studies on reproductive biology provided information on the life cycle, ovarian maturation stages, courtship and mating behavior, minimum size at sexual maturation (sperm occurrence, first spawning), and morphological egg types. Induced maturation has mainly been done through the eyestalk ablation method. Nutritional and environmental parameters were studied to enhance reproductive performance or as an alternative to ablation. Pond-reared and wild broodstock sources and marine pen and land-based tanks as maturation systems were also tested and compared. Size, shape, color, substrate material and other aspects of tank design and construction, sex ratio, stocking density, water management, and other parameters of the management system were also studied and refined.

      Early techniques in larval and postlarval rearing of P. monodon at AQD were based on the community culture method of growing natural food in larval tanks. However, low and inconsistent survival led to a shift in rearing methods toward pure phytoplankton culture grown in separate tanks as food for the larvae. Henceforth, refinement of rearing methods have been conducted to improve larval survival through effective water management, nutrition, and disease control. Efforts are continuously being geared toward making the technology affordable to Filipino farmers.
    • Book

      Broodstock of sugpo, (Penaeus monodon Fabricius) 

      JH Primavera - 1989 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 7
      The manual provides information on the technology involved in induced maturation and broodstock of Penaeus monodon . Following background material on basic aspects of reproductive biology of the species such as mating, maturation, spawning and fecundity, a detailed discussion is presented on the broodstock tank and pen system and the ablation process.
    • Meeting report

      Capacity of mangroves to process shrimp pond effluents. 

      JH Primavera - 2004 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Shrimp culture has been criticized for causing mangrove loss and discharging effluents laden with chemicals, organic matter and nutrients into waterways. Hence the SEAFDEC Council mandated SEAFDEC/AQD to undertake studies that integrate aquaculture with mangroves. Thus, the Mangrove-Friendly Shrimp Culture Project follows two models: (a) the use of mangrove forests as filters to process effluents from intensive culture ponds, and (b) aquasilviculture which integrates low-density culture of crabs, etc. with mangroves. Worldwide only a few projects to date have tested mangroves as nutrient filters, hence the need to focus on this property of mangroves.
    • Article

      Choosing tropical portunid species for culture, domestication and stock enhancement in the Indo-Pacific 

      MJ Williams & JH Primavera - Asian Fisheries Science, 2001 - Asian Fisheries Society
      Large and long-term investments in research, development and technology verification are required for the successful culture, domestication and coastal stock enhancement of any species, including crabs. As more species options are sought for culture, the choice of candidate species could be guided by ex-ante assessments to help identify suitable species and anticipate future constraints and opportunities. Focusing on tropical Indo-West Pacific Portunidae, we propose multiple criteria for domestication and stock enhancement that include life cycle, diet and feed conversion efficiency, behavior, disease resistance, growth rate, marketability, farming systems, profitability and environmental impact. The chief candidate species (four species of Scylla, Portunus pelagicus, P. sanguinolentus, and Charybdis feriatus) are considered against the criteria. Experience in the stock enhancement of P. trituberculatus, a subtropical portunid, is reviewed. We conclude that full domestication will not occur in the next 5 to 10 years and that the main constraints to be overcome are the aggressive behavior of the crabs, their carnivorous diet and competition for suitable coastal farm sites. We also recommend considering the tropical Portunus and Charybdis species examined here as additional or alternative options to the Scylla species. Stock enhancement may be feasible in some locations, provided suitable fisheries management and industry institutions are created.
    • Article

      Coastal ecosystem-based management with nonlinear ecological functions and values 

      E Barbier, EW Koch, BR Silliman, SD Hacker, E Wolanski, JH Primavera, EF Granek, S Polasky, S Aswani, LA Cramer, DM Stoms, CJ Kennedy, D Bael, CV Kappel, GME Perillo & DJ Reed - Science, 2008 - American Association for the Advancement of Science
      A common assumption is that ecosystem services respond linearly to changes in habitat size. This assumption leads frequently to an “all or none” choice of either preserving coastal habitats of converting them to human use. However, our survey of wave attenuation data from field studies of mangroves, salt marshes, seagrass beds, nearshore coral reefs, and sand dunes reveals that these relationships are rarely linear. By incorporating nonlinear wave attenuation is estimating coastal protection values of mangroves in Thailand, we show that the optimal land use option may instead be the integration of development and conservation consistent with ecosystem-based management goals. This result suggests that reconciling competing demands on coastal habitats should not always result in stark preservation-versus conversion choices.
    • Book

      Code of practice for sustainable use of mangrove ecosystems for aquaculture in Southeast Asia. 

      TU Bagarinao & JH Primavera - 2005 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This 47-page guidebook presents the 22 concepts, principles or policy statements that prescribe the preferred ways of doing and acting to ensure the sustainable use of mangroves for fish farming. It is annotated with definitions, explanations and many examples. Published jointly by ASEAN and SEAFDEC, this guidebook is a result of a Southeast Asian-wide consultation with core experts and country representatives in 2004 to 2005.
    • Article

      Collection of the clam Anodontia edentula in mangrove habitats in Panay and Guimaras, central Philippines 

      JH Primavera, MJHL Lebata, LF Gustilo & JP Altamirano - Wetlands Ecology and Management, 2002 - Kluwer Academic Publishers
      The mangrove clam Anodontia edentula is highly prized in the Philippines for its flavor and large size. Because this infaunal species is found down to one meter deep in mangrove areas, harvesting the clam reportedly damages mangrove stands. To evaluate such reports, a survey of collection methods was undertaken in Panay and Guimaras, central Philippines in August 1997-December 1999. Host to chemosynthetic bacterial symbionts that utilize sulfide as energy source, A. edentula are strategically situated in sulfide-rich anoxic substrates but also gain access to oxygenated seawater through a ventilation burrow or tube. By locating the opening of this burrow, collectors can detect the presence of a buried clam and harvest it nondestructively with a blade or bare hands. In contrast, the indiscriminate tilling of wide mangrove areas can damage mangrove plants. Most collectors were 40-45 years old with 22-30 years collection experience, married with 5-7 children, and had low educational attainment. They sold clams directly in the local markets or through middlemen (to restaurants and beach resorts); sales provided from 10% to 100% of daily family income. Collectors complained of decreasing clam sizes and numbers and the physically strenuous work of collecting.