Now showing items 1-11 of 11

    • Conference paper

      Aquaculture-based restoration and stock enhancement of tiger shrimps in the Philippines 

      JP Altamirano, N Salayo, H Kurokura, H Fushimi & S Ishikawa - In K Hajime, T Iwata, Y Theparoonrat, N Manajit & VT Sulit (Eds.), Consolidating the Strategies for Fishery Resources Enhancement in Southeast Asia. Proceedings of the Symposium … Strategy for Fisheries Resources Enhancement in the Southeast Asian Region, Pattaya, Thailand, 27-30 July 2015, 2016 - Training Department, Southeast Asian Fisheries Development Center
      In central Philippines, the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD), with strong collaboration and support from the Research Institute for Humanity and Nature (RIHN) of Kyoto, Japan, has been looking into the stock enhancement of tiger shrimp Penaeus monodon in the New Washington Estuary (NWE), province of Aklan, central Philippines. The NWE was a productive fishing ground that has been suffering from degenerating brackishwater fisheries and estuarine environment. Average daily catch declined from 24 kg in 1970s to only 0.7 kg at present. Shrimp fisheries, the most important livelihood, declined in quality and quantity. Tiger shrimps were abundant in catch until the early 1990s when these were observed to decline in volume, replaced by smaller and cheaper species. This was coincidental with the rapid decline in mangrove cover for ponds and huge increase in fishing pressure. It is clear that crucial interventions are required to restore the tiger shrimp fisheries in the NWE in order to increase income of local fishers, while promoting reduction of fishing gears and restoration of mangroves. Stock enhancement of tiger shrimps shows good potential in answering these needs. Site-specific assessments were conducted to evaluate prospects of shrimp stock enhancement in NWE. Conservative simulations of capture of released stocks showed that fishers can increase income by 300%. To decrease fishing pressure in the area, number of gears per fisher may have to be reduced but shrimp catches will be relatively high-priced. Comparative experiments using aquaculture techniques were done to identify strategies especially in the delicate intermediate acclimation rearing. Aquaculture protocols like those for pond preparation were also adapted to be used in a mangrove pen nursery rearing system for shrimps. Supplemental feeding with formulated feeds increased carrying capacity of the culture area, while enhancing growth and survival of stocks. Culture experiments showed that shrimps grow to 0.5 g within 1 mo and >1g in 2 mo. High stocking density of 40-60 shrimps m-2 can be used for <2 mo rearing in a mangrove pen. Release experiments showed that 60-d old shrimps have higher chances of survival when released in the estuaries. With strong support from local communities, government and other sectors, together with effective management and law enforcement, aquaculture-based stock enhancement of tiger shrimps can be a viable intervention to restore livelihood and promote estuarine rehabilitation in the NWE.
    • 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.
    • Book

      Handbook of mangroves in the Philippines - Panay 

      JH Primavera, RB Sadaba, MJHL Lebata & JP Altamirano - 2004 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A 106-page guide is a user-friendly presentation of technical botanical description and illustrations of Philippine mangrove species in Panay Island, Guimaras and Aurora Province. Vegetative and reproductive structures of 34 mangrove species that are readily observed in the field are emphasized and presented in color photographs and as graphic icons. Also discussed: importance of mangroves; mangrove decline and legislation; conservation and rehabilitation; and mangrove-friendly aquaculture.
    • Conference paper

      Influence of fishing gears on excessive use of fishing grounds in Batan Estuary, Aklan, central Philippines 

      R Kamiyama, JP Altamirano, K Yoshino & H Kurokura - In LL Tolentino, LD Landicho, S Wun'Gaeo & K Ikegami (Eds.), 4th International Conference : the multidimensionality of energy, economy and environmental crises and their implications to rural livelihoods : September 7-10, 2010, Bicol University, Legazpi City, Albay, Philippines, 2010 - Asian Rural Sociology Association
      The excessive fishing activities have led to the depletion of many coastal fisheries resources in most of the countries in Southeast Asia. It is therefore necessary to find out the causal factors of excessive fishing in order to build up effective fisheries management system. This paper highlights the results of the study that investigated the overfishing or excessive fishing in Batan Estuary, Aklan, Central Philippines.

      The data were gathered through an interview of selected households in Barangay Pinamuk-an, Aklan from March 2-26 2010. Of the 93 respondent-households, 67 or 72% is engaged in fishing. The most popular fishing gear was the small set net with synthetic fiber, which was introduced to the community in the latter part of 1970s. The relatively lower cost of this small fishing gear, and a few labor force requirement, including its availability in nearby market made it easier for the fisherfolks to acquire this fishing gear. The small set net with synthetic fiber has been widely used by the fishers, which led to the overuse of the fishing grounds in the Batan Estuary. Thus, this paper argues that the introduction of new fishing gear and method triggered the excessive fishing in coastal areas in Philippines.
    • Article

      Mangroves and shrimp pond culture effluents in Aklan, Panay Is., central Philippines 

      JH Primavera, JP Altamirano, MJHL Lebata, AA delos Reyes Jr. & CL Pitogo - Bulletin of Marine Science, 2007 - University of Miami, Rosenstiel School of Marine and Atmospheric Science
      The capacity of a natural mangrove system in Ibajay, Aklan province, central Philippines to process shrimp pond culture effluents was assessed through analysis of mangrove community structure and 24-hr monitoring of water quality parameters (NH3-N, NO3-N, PO4-P, sulfide, and total suspended solids). Results from the latter showed decreased nutrient levels within 6 hrs after daytime draining of effluents into the mangrove stand, but only nitrate reduction was statistically significant. Based on nitrate loss, volume of water drained, mangrove area, and shrimp farming data (e.g., N loss from ponds, feed composition, feeding rate), calculations show that 1.8–5.4 ha of mangroves are required to remove nitrate wastes from 1 ha of shrimp pond. N uptake by the mangrove macroflora was supported by data showing longer nipa palm leaflets and faster mangrove seedling growth in the experimental mangrove receiving effluents compared to a control mangrove, but not from mangrove biomass measurements. These results have significant implications for the Philippine brackishwater pond culture industry to conserve or rehabilitate mangroves as potential pond biofilters, to implement legally mandated 20- and 50-m greenbelts, and to reverse the national 0.5 ha mangrove: 1.0 ha pond ratio.
    • Book

      Milkfish Chanos chanos cage culture operations 

      AG Gaitan, JD Toledo, MT Arnaiz, EGD Ayson, JP Altamirano, RF Agbayani, ND Salayo & CL Marte - 2014 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 58
      A 42-pages extension manual describing the biology, fingerling production, site selection, cage design and construction, measurement & analysis of water & sediment quality parameters and economic analysis.
    • Article

      Practical techniques for mapping small patches of mangroves 

      JP Altamirano, JH Primavera, MRN Banaticla & H Kurokura - Wetlands Ecology and Management, 2010 - Springer
      Practical mapping methods employing GPS field surveys and manual image analyses with affordable software were used to assess two mangrove sites in Aklan Province, NE Panay Island, central Philippines. The Jawili mangroves, absent from current maps, actually included 21.5 ha with 24 true mangrove species. On the other hand, the Batan Estuary mangroves, shown to be 4244 ha in available topographic maps, revealed only 406 ha of scattered patches. Actual mangrove data on specific areas worldwide is limited, especially in the Philippines where available maps show discrepancies from actual mangrove distribution. Remote sensing (RS) techniques provide promising results but require expensive setup, particularly for small areas. Therefore, financially limited users need affordable and rapid mapping alternatives. The practical techniques presented here can be immediately implemented at minimal cost and can produce useful estimates of actual mangrove area, fundamental for coastal management. Basic principles used here also have potential applications in other systems and locations. When resources are available though, additional confirmation and precise mapping are also further recommended.
    • Conference paper

      A preliminary study on the diagnosis of coral reef healthiness and establishment of coral replenishment technology 

      T Azuma, JJR Tan, J Zarate, J Altamirano, J Gatus & F Sotto - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Field surveys for coral reef through line-intercept-transect (LIT) and temperature profiling using data-loggers were done at three layers of 5, 10, and 15 m depths in coral reef areas, Nogas Island, Anini-y, Antique, Philippines. Preliminary data based on the LIT survey showed that both coverages of substrates by any type of organism and by Scleractinia decreased in the deeper layers. For Scleractinia, Porites sp. occurred predominantly in all the depth layers with the occurrence decreasing with depth. Temperature fluctuation was largest in the 5 m depth layer, where effects of tidal level were also confirmed. While the average temperature decreased with depth, this did not differ beyond 1°C between 5 and 15 m layers during November 2012 to March 2013. Fragments of the Porites sp. and Acropora sp. were sampled and transferred to aquaria at the Tigbauan Main Station of SEAFDEC/AQD. Acropora sp. sampled from the deepest layer alone showed bleaching and thereafter, a part of the fragments regained the color. Experimental trials to clarify the effects of ocean acidification and warming on the health of the coral using the live fragments of Porites sp. showed decreasing trends in both photosynthetic rates and daily growth rates in acidic condition (pH = 7.6), while decrease of zooxanthellae density was observed under warmer conditions (31°C ) for one month. A new methodology for the determination of density of zooxanthellae was established using the fragments of Porites sp. In this study, the need for studies on several coral communities as well as further basic research on coral biology, particularly, responses to the changing environments are discussed for diagnosis of coral reef healthiness and establishment of effective coral replenishment technology.
    • Article

      Status of sea cucumber fishery and populations across sites with different levels of management in Palawan, Philippines 

      JBS Jontila, HM Monteclaro, GF Quinitio, SM Santander-de Leon & JP Altamirano - Ocean and Coastal Management, 2018 - Elsevier
      This study was conducted to investigate the sea cucumber fishery and compare populations between exploited and unexploited sites. Three islands were selected, the Arrecife Island as the unexploited site and the Johnson and Green Islands representing the exploited sites. In each site, sea cucumber species richness, diversity and densities were assessed by laying as much as 15 transects (50 m × 5 m) per habitat in each island. Differences in species richness, diversity and relative densities across sites and habitats were tested using a Two-way Analysis of Variance (ANOVA) and Tukey test for post hoc comparisons. An interview with gatherers, key informants and focus group discussions were also conducted to gather information on the sea cucumber fishery and its management. Results showed that the unexploited site had a higher species richness (14 vs. 7 and 7). Relative density of species was also higher in the unexploited site at 1245 ind ha-1 while it was only 78 and 39 ind ha-1 in exploited sites (p < 0.05). Interviews and a focus group discussion revealed that national regulations on permit system and size limits were not enforced at the local level and that gatherers had low levels of awareness regarding regulations on sea cucumber harvest. Current management measures appear to be ineffective and insufficient, leaving the sea cucumbers in areas open to exploitation at risk of depletion. Given that sea cucumbers provide substantial income to local communities, the depletion of this resource could compromise the livelihood of people in island communities that rely heavily on marine resources for living. Thus, this study highlights the need to review national policies on sea cucumber fishery and place the management at the local level.
    • Article

      Substrate preference for burying and feeding of sandfish Holothuria scabra juveniles 

      JP Altamirano, CP Recente & JC Rodriguez Jr. - Fisheries Research, 2017 - Elsevier
      Substrate preference for both burying and feeding of sandfish Holothuria scabra juveniles (3–6 g wet body weight) and their associated daily behavior, growth and survival were investigated in laboratory and field experiments using different coastal substrate types (silty mud, sandy mud, and coarse sand) to determine the ideal habitat for potential grow-out culture, sea ranching or stock enhancement of this important sea cucumber species. During the peak hours of burying (03:00–09:00 h) and feeding (15:00–03:00 h), a significantly greater number of sandfish juveniles preferred to bury in (28.3%) and feed on (21.5%) sandy mud, typical of intertidal coastal sand flats. Silty mud was the least preferred substrate for feeding (13.5%) and burying (13.8%). Burying and feeding preferences of sandfish juveniles were not significantly influenced by the presence of seagrass (Thalassia hemprichii) on coarse sand. Growth of sandfish juveniles in the first two weeks of rearing in tanks was significantly greater on coarse sand (growth rate: 0.59 g d−1 or 7.0% d−1), followed by sandy mud (0.34 g d−1 or 4.72% d−1) while OM content of these sediments remain almost unchanged. On silty mud, sandfish juveniles constantly shrunk (−0.02 g d−1 or −0.63% d−1) for 8 weeks while sediment OM content increased. In the field, silty mud substrate of a mangrove pond caused total mortality of sandfish within two weeks, while sandy mud substrate of a sand flat provided significantly higher growth than the control (no sediment), but not significantly different than coarse sand of a seagrass bed. Sandy mud to coarse sand substrates of intertidal sand flats were most preferred by sandfish juveniles while silty mud associated with muddy mangroves and culture ponds seems to be unsuitable that sandfish would opt to avoid. Our results will contribute to the selection of suitable sites for sandfish sea ranching and stock enhancement in coastal areas.
    • Article

      Viability of a bottom-set tray ocean nursery system for Holothuria scabra Jaeger 1833 

      JRC Gorospe, JP Altamirano & MA Juinio-Meñez - Aquaculture Research, 2017 - Wiley
      Scaling up the hatchery production of juvenile sandfish Holothuria scabra is constrained by limited hatchery space and the associated high operational costs. To shorten the hatchery rearing phase, ocean nursery systems like floating hapa nets have been used with good prospects but with limitations during rough sea conditions. In this study, the potential of bottom‐set trays (0.14 m2) as an alternative ocean nursery system for early sandfish juveniles (0.5 ± 0.1 cm) was evaluated. The effects of stocking density and presence of artificial substrates (AS) on the growth and survival were determined in a 60‐day field experiment. Average length and growth rates at lower stocking density treatment (100 individuals tray-1) were significantly higher (1.45 ± 0.22 cm; 0.03 ± 0.01 cm day-1) than at higher stocking density treatments (400 and 500 individuals tray-1) 0.95 ± 0.06 cm; 0.03 ± 0.004 cm day-1) with or without AS (p < .05) respectively. The coefficient of variation in length (CV) at high stocking densities were significantly higher than at low densities (p < .05) and growth rate was strongly negatively correlated with density. Survival was significantly higher (55% ± 9%) in trays with AS across all stocking density treatments than in trays without AS (34% ± 2%). Results suggest that AS may have reduced intra‐ and interspecific interactions, resulting to significantly lower growth variations and higher survival. The bottom‐set tray with AS can be a practical alternative ocean nursery unit for rearing early sandfish juveniles particularly when the sea surface condition is rough. With improved design and density management, survival and growth may be further enhanced.