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  • Breeding and Larval Rearing of Asian Moon Scallop Amusium pleuronectes in Eastern Samar, Philippines

    Cabacaba, Nonita S.; Boiser, Ed-Marie B.; Badocdoc, Kimberly A.; Campo, Cristan Joy M. (2020)
    Asian moon scallop, Amusium pleuronectes, is among the most common commercially harvested scallop in the Philippines. This study investigated suitable conditioning methods, induced spawning, and documented scallop larval development at the Marine Fisheries Research and Development Center (MFRDC) Guiuan, Eastern Samar. Scallops held in tanks with flow-through water system without substrate yielded high survival rate of 48.06 ± 5.95%. Optimum water temperature was 28-29°C for maintaining scallops. Isochrysis galbana and Chaetoceros calcitrans were suitable microalgal feed for A. pleuronectes consumed at 7,388,888 cells min-1 per scallop. These significant results were applied in maintaining scallops at the hatchery. As a result, scallops with an average 19.8 mm shell length (SL) reached 37.5 mm SL within four months with a survival rate of 96.57 ± 2.04%, average daily growth rate (ADGR) of 0.13 ± 0.04, and specific growth rate (SGR) of 3.92 ± 1.31%.d-1. Natural spawning was successful under controlled conditions while induced spawning trial through thermal stimulation, food shock, sexual stimulation, and serotonin injection resulted unsuccessful release of sperm and eggs. The estimated number of fertilized eggs per spawning ranged from 0.22-1.4 million. Fertilized eggs appeared spherical and dark in color with 54.2-62.57 µm in diameter. After nine hours, the larvae developed into trochophore stage with 59.08-84.4 µm in length. D-veliger with 120.37-157.07µm shell length developed after 24 hours. Development of the early umbone stage was reached on day 5; and on day 7, the umbo larvae become well-developed with shell length of 135.45-173.36 µm. On day 9, pedi-veligers were observed in the culture. Spat grew 312.41-509.48 µm on day 16 and survived until four months with final shell length of 4-10 mm. For the larval rearing, stocking density of A. pleuronectes larvae observed highest survival rate of 0.04 ± 0.03% at 200 larvae/L, while no larvae survived at 800 larvae/L due to contamination of protozoans in the culture medium.
  • Status of Fisheries in Agusan Marsh: Lapaz and Talacogon, Agusan del Sur, Mindanao

    Baclayo, Joyce M.; Alcantara, Matt T.; Holoyohoy, Laila M.; Alaba, Letecia A (2020)
    In support to policy formulation of fisheries in Agusan Marsh, a stock assessment was conducted for the period of May 2014 to December 2016 using the data collected from Lapaz and Talacogon, Agusan del Sur within the Agusan Marsh. Results showed that Lapaz contributed 54% of the catch over Talacogon. A total of eighteen species, belonging to 13 genera and 11 families with 7 native and 11 introduced species were found in the marsh. Majority of the total catch consisted of Channa striata, Oreochromis niloticus, and Cyprinus carpio (35%, 27%, and 26%, respectively). Osphronemus laticlavius, Glossogobius celebius and Mugil cephalus were listed as seasonal species. An invasive janitor fish (Pterygoplichthys disjunctivus) was observed as by-catch. A strong pattern of high catch rates occurred during the rainy months of January, February, June, and December. Ten types of commonly used fishing gears were found, majority of which include fish pots, set gillnets, electrofishing and set long lines. Multivariate analysis showed similarity in species composition both in Lapaz and Talacogon. Exploitation of dominant species showed unsustainable level for O. niloticus, C. batrachus, C. caprio, andC. gariepinus, mainly due to excessive capture of immaturesized fishes by major fishing gears. The estimated exploitation rate is beyond the optimum level for O. niloticus and C. carpio in both years and followed by C. striata and C. gariepinus in 2016. Only C. bartachus is estimated to be exploited below the optimum level. Generally, the key species in Agusan Marsh are at risk of overfishing, hence, immediate policy measures must be given high attention.
  • Growth, Development, and Survival of Portunus pelagicus Larvae and Juveniles in Different Feed Regimens, Rearing Media, and Stocking Densities

    Cabacaba, Nonita S.; Badocdoc, Kimberly A.; Boiser, Ed-Marie B.; Campo, Cristan Joy M.; Josue, Shaira Lyle A. (2020)
    Various factors in P. pelagicus seed production and grow-out culture were investigated in this study. Experiments were conducted to 1) compare natural and artificial feeds for larval production, 2) evaluate indoor tank and outdoor net cages as rearing media, and 3) assess different stocking densities for grow-out culture. Growth, development, and survival were assessed for the performance of each variable. (I) In larval production, the development of megalopa larvae into crab instar was synchronous in both natural and artificial feed treatments in a 5-day rearing observation. Crab instars began to appear on Day 4 with 27% composition in both feeds. Although survival appeared to be relatively higher in natural feed (43.96 ± 6.04%), this was not significant from survival in artificial feed treatment (33.33 ± 13.34), (t = 0.726, p > 0.05). (II) In Phase I grow-out culture, a two-variable design experiment was conducted to assess growth performance and survival of crab juveniles reared in indoor tanks and outdoor net cages at different stocking densities. Specific growth rate (SGR) differed significantly (t = 2.937, p < 0.05) between indoor tanks (6.39 ± 0.24%.d-1) and outdoor net cages (8.31 ± 1.11%.d-1). However, mean survival rate was better in indoor tanks (20.83 ± 9.24%) than outdoor net cages (8.94 ± 3.58% only), (t = 2.938, p = 0.015). In terms of stocking density, SGR was highest in 75 ind.m-2 (7.87 ± 2.44%.d-1). However, growth performance and survival of juveniles among different stocking densities were not significantly different (p > 0.05). Furthermore, two-factor ANOVA results have shown that growth performance of the juveniles was influenced by both the differences in rearing medium and stocking density, but not in terms of survival (F = 0.120, p = 0.888). (III) In Phase II grow-out culture, juveniles attained highest SGR (3.54 ± 0.56%.d-1) at 5 ind.m-2 stocking density. This was followed by 15 ind.m-2 (3.45 ± 2.39%.d-1) and by 10 ind.m-2 (2.33 ± 0.50%.d-1) (p > 0.05). However, survival rate was highest in 15 ind.m-2 (46.67 ± 0.00%), but the differences among other stocking densities were not statistically significant (p > 0.05). Overall, results suggest that artificial feed can be an alternative for Artemia in rearing megalopae to crab instar stage. Stocking density in Phase I and II grow-out culture did not substantially affect growth performance and survival of juvenile P. pelagicus. However, higher stocking density increases incidence of cannibalism among reared crabs.
  • Estimation of Post-Harvest Losses of Fish Transported Using Ice-chilled Carrier Boats from High Seas Pocket 1

    Montojo, Ulysses M.; Delos Santos, Virginia H.; Narida, Camille M.; Febreo, Ivy Y.; Peralta, Deserie M.; Banicod, Riza Jane S.; Sabal, Omar M. (2020)
    Access of Philippine traditional fresh/ice-chilled seining vessels to High Seas Pocket 1 (HSP-1) lessens fishing pressures in the Philippine Exclusive Economic Zone where juvenile oceanic tunas are more likely to be found. However, catch landed by carrier boats from HSP-1 were observed to be of reduced quality, thus eliciting lower market value. The present study was conducted to evaluate the efficiency of icechilled carrier boats by generating data on the magnitude of post-harvest losses incurred in landed catch from HSP-1. Exploratory Fish Loss Assessment Method and Questionnaire Loss Assessment Method were used to estimate quality losses. Landed catch of ice-chilled carrier boats from HSP-1 recorded an estimated loss of 17.25%. Key players incurred an estimated financial loss amounting to PHP 223 million (USD 4.3 million). Low quality catch commonly sold as raw materials for canning, smoking, and fishmeal processing entail cheaper prices, thus regarded as losses. A positive correlation was established between fishing duration and losses. Results indicate that the current preservation technique in carrier boats could induce quality deterioration in fish given the long distances and transit times involved. Thus, the use of carrier boats with freezing system should be allowed in HSP-1 to sufficiently preserve the quality of the catch. This will reduce losses in post-harvest fisheries, thereby increasing the potential income of HSP-1 players.
  • Stock Assessment of Arius maculatus (Thurnberg, 1792) (Ariidae, Siluriformes) in Panguil Bay, Northwestern Mindanao

    Jumawan, Celestina Q.; Metillo, Ephrime B.; Mutia, Maria Theresa M. (2020)
    Arius maculatus, commonly known as spotted catfish and locally known as Tambangongo, has a great potential as an aquaculture species, but there is very limited information known for the stocks in Panguil Bay. This study aimed to assess the wild stocks of A. maculatus, and make an inventory of the fishing boat and gears in two stations in Panguil Bay, namely: Tangub, Misamis Occidental and Baroy, Lanao del Norte. Length frequencies were analyzed to provide estimates of growth, mortality, exploitation ratio, and recruitment pulse of A. maculatus in the bay. A total of 589 boats (324 motorized boats and 265 non-motorized boats) were recorded from the sites. There were 473 units of 15 types of fishing gear used in the sites and 6 types of these were only used in catching A. maculatus. A total of 3,259 specimens were collected for 12 months from the sites. The aquatic habitat of A. maculatus from the two sites was characterized by a pH range of 7.9-8.1, temperature of 28.5-29.1°C, salinity of 13.31-15.9 ppt, dissolved oxygen levels of 4.0-5.41 ppm, and total suspended solid values of 0.1-0.6 g/L. Reproductive biology analysis indicates that eggs start to mature from October to December, then spawning starts from January to March, and the fish fry recruitment starts in April and May. A. maculatus can grow up to 98.95 cm with an asymptotic length of 98.86 cm (K value = 0.35) equivalent to asymptotic weigth of 8,750 g. Mortality Z = 0.99, with natural mortality M = 0.67 and fishing mortality F = 0.33. This study revealed that A. maculatus in Panguil Bay is not over-exploited since the exploitation rate (E = 0.33) is minimal and large individuals can still be collected from the field.
  • Searching the Virtually Extinct Tridacna gigas (Linnaeus, 1758) in the Reefs of Palawan, Philippines

    Mecha, Niño Jess Mar F.; Dolorosa, Roger G. (2020)
    Tridacna gigas (Cardiidae: Tridacninae) is the largest extant reef-associated bivalves that occur abundantly in the Indo-West Pacific Region. However, unregulated exploitation had caused localized extinction in many parts of its distribution range. In Palawan, the species was considered virtually extinct in the 1980s, and since then, no study has been done to monitor their status in the wild. In the absence of updated studies about T. gigas, we gathered information through field reports, key informants, and field visits. Within five months of data gathering, we recorded 97 empty shells (14 in pairs and 83 single shells) with 65.86 cm (range: 42-112 cm) average shell length, which were estimated to be from 5 to >76 years old. Most (78.36%) of the empty shells were used for decoration and landscaping. On the other hand, 29 live individuals with 73.69 cm (range: 42-109 cm) average shell length were estimated to be 5 to >76 years old. Tubbataha Reefs Natural Park and some island resorts harbored the highest number of live T. gigas. The presence of live T. gigas in these areas reflects years of effective management and the resorts’ essential contribution to resource conservation. These remaining live individuals could be used in breeding and restocking programs to restore their lost populations.
  • Ciguatera in the Philippines: Examining Reef Fish Vectors and Its Causative Benthic Dinoflagellates in Visayan and Sibuyan Seas

    Montojo, Ulysses M.; Tanyag, Bryan E.; Perelonia, Karl Bryan S.; Cambia, Flordeliza D.; Oshiro, Naomasa (2020)
    Ciguatera Fish Poisoning (CFP) is primarily caused by ingesting reef fishes contaminated with ciguatoxins (CTX) produced by the Gambierdiscus species. The unpredictability of this type of food poisoning poses risks to public health and adversely affecting the fish trade industry. This study aimed to provide useful information on ciguatera in the Philippines. Different reef fish species and host-macroalgae for benthic dinoflagellates were collected in Visayan and Sibuyan Seas. Ciguatoxins were extracted from reef fish samples, and toxicity was determined qualitatively using mouse bioassay. Meanwhile, cell density estimation of toxic benthic dinoflagellates isolated from the host-macroalgae was done through microscopy. It was observed that 4.46% of the total reef fish samples were positive with ciguatoxins. Spatially, Carles, Iloilo in Visayan sea had the highest number of toxic specimens belonging to Epinephelus merra, Lethrinus lentjan, Lutjanus campechanus, Scarus quoyi, Siganus guttatus, and Sphyraena barracuda. Based on data gathered from three sampling sites, fish toxin occurrence is observed to be site-specific. Geographical conditions affect the frequency of toxic samples. Moreover, fish weight is not a good predictor of fish toxicity. For toxic benthic dinoflagellates, Gambierdiscus spp. were observed to have the lowest cell density count among other dinoflagellates averaging 7-115 cells per 100 g macroalgae. On the other hand, Ostreopsis spp. had the highest average cell density of 118-1,455 cells per 100 g macroalgae, followed by Prorocentrum spp. (207-594 cells per 100 g macroalgae). Fish toxicity is directly proportional to the occurrence of benthic dinoflagellates in areas as seen during dry season. Monitoring and management of CFP on identified reef fish vectors and its causative benthic dinoflagellates in the area are necessary to promote food safety and fair trade practice.
  • Estimation of Nutrient Load from Aquaculture Farms in Manila Bay, Philippines

    Montojo, Ulysses M.; Baldoza, Bernajocele Jalyn S.; Perelonia, Karl Bryan S.; Cambia, Flordeliza D.; Garcia, Lilian C. (2020)
    Waste from aquaculture is considered as one of the possible causes of water quality deterioration in Manila Bay. Aquaculture in the area accounts for almost 30% of the total production in the Philippines. This high production entails intensified application of inputs that could possibly contribute to the nutrient (nitrogen, N and phosphorus, P) load in the bay. Thus, estimation of the N, P and SO4 loaded from aquaculture farms is necessary to develop more responsive intervention to reduce nutrient load in Manila Bay. Water samples were collected throughout the rearing period from different aquaculture systems in Cavite, Bulacan, Pampanga, and Bataan. The annual estimated N and P loaded from aquaculture farms were 12, 696.66 MT and 2, 363.01 MT, respectively. Fish pens/cages recorded the highest contribution accounting for 88% N and 86% P of the total load. It can be attributed to the direct release of uneaten feeds into the bodies of water. Roughly, 12% N and 14% P were obtained from the fishponds. Furthermore, the annual SO4 loaded from fishponds was estimated at 36,917.54 MT. Results of the study suggested that there should be an extensive monitoring of the environmental impacts and annual load of aquaculture farms for the sustainable regulations and management of aquaculture activities to reduce nutrient load and improve the aquaculture production as well. Finally, strict compliance to the regulatory guidelines and ordinances must be imposed to achieve the effluent quality standards.
  • Validation of Ultra High Pressure Liquid Chromatography (UHPLC) with Pre-column Derivatization Method for Quantitative Analysis of Histamine in Fish and Fishery Products

    Perelonia, Karl Bryan S.; Cambia, Flordeliza D.; Montojo, Ulysses M.; Fisheries Post Harvest Research and Development Division - Integrated Research Laboratory National Fisheries Research and Development Institute Quezon City, Philippines (2019)
    A pre-column derivatization-ultra high performance liquid chromatographic (UHPLC) method is described for the determination of histamine in fish and fishery products. The homogenized samples were extracted with trichloroacetic acid (TCA) solution and derivatized with o-phthaldialdehyde. Histamine was separated using reversed-phase column and determined using UHPLC with fluorescence detection. The linear calibration range was 10 to 60 µg/mL with a correlation coefficient of 0.9993. Good recoveries were observed for the histamine under investigation at all spiking levels, and average recoveries were higher than 89% with a precision smaller than 8.46%. The detection and quantification limit were 2.7 and 8.3 µg/g, respectively. The uncertainty was estimated to be ± 0.45. The performance of the proposed method was checked with a proficiency test sample from the Food Analysis Performance Assessment Scheme (FAPAS) as external quality control; the resulting z-score was -0.2, which was found within acceptable range of -2 ≤ z ≤ 2. The results indicated that this HPLC method was reliable, sensitive, reproducible, and practical for the routine analysis of histamine in fish and fishery products.
  • A Ranked Inventory of Commercially-important Mollusks of Panay, West Central Philippines as a Guide to Prioritize Research

    del Norte-Campos, Annabelle G.C.; Burgos, Lorelie A.; Villarta, Karen A.; Marine Biology Laboratory, Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas 5023 Miagao, Iloilo (2019)
    A first-ever effort to rank commercially-important mollusk species of Panay Island was conducted based on an extensive survey between March and April 2018. Ranking was based on the following criteria, namely: commercial value (40%), catch rates (20%), sources of threats (type of gear, processing plants, and number of fishers) (20%), frequency in the markets and source sites (10%), and literature available (10%), modified to a certain extent. A total of 90 mollusk species categorized into bivalves (49), gastropods (32), and cephalopods (9) were ranked. The comb pen shell Atrina pectinata (Pinnidae), Indian squid Uroteuthis duvaucelii (Loliginidae), and the scallop Mimachlamys sanguinea (formerly Chlamys senatoria) (Pectinidae) formed the top three species in the list strongly attributed to their high commercial value and thus catch rates. Squids, in general, are caught by trawls, whereas most of the other species are harvested primarily by gleaning and diving. The study highlights the high diversity of the malaco-fauna of Panay, as well as the multi-gear character of tropical fisheries. This ranked inventory can be used in prioritizing research on mollusks, by identifying target species for more in-depth studies useful for establishing their present status.
  • Growth, Development and Survival of Holothuria scabra Larvae in Different Microalgal Regimens and Water Rearing Media

    Campo, Cristan Joy M.; Cabacaba, Nonita S.; Cosmiano Jr., David N.; National Fisheries Research and Development Institute – National Marine Fisheries Research and Development Center (NFRDI-MFRDC); Bureau of Fisheries and Aquatic Resources – Guiuan Marine Fisheries Development Center (BFAR-GMFDC) (2019)
    Different aspects of Holothuria scabra larval production, including feeding regimen and water treatment, were investigated under experimental conditions. This study highlights the optimization of techniques and simplification of the requirements of sea cucumber larval rearing. The growth performance, development, and survivorship of H. scabra larvae were measured to assess which treatment provides optimum results. Chaetoceros gracilis (Cgr) and Chaetoceros calcitrans (Cc) were administered singly and in combination (Cgr-Cc) to sea cucumber larvae. Growth was highest in combined Cgr-Cc feed with mean final length of 2088µm, followed by Cc with 1855 µm and Cgr with 1800 µm, but with no significant difference (p > 0.05). Similarly, survival rates among treatments were not statistically different (Cgr-Cc = 2.23%; Cgr = 1.6%; Cc = 1.3%) (p > 0.05). However, larval development was better in combined Cgr-Cc and Cc single diet, with 90% and 100% composition of early juveniles on Day 30. Slower development was observed in Cgr single feed, with only 90% early juveniles observed later on Day 35. Different microalgal concentration of Cgr-Cc (10,000, 30,000 and 50,000 cells.mL-1) were also tested. Juveniles (~3 mm) yielded from 50,000 cells.mL-1 microalgal concentrations were five times larger than when fed at 10,000 cells.mL-1 microalgae. Development of larvae was also faster in 50,000 cells.mL-1, yielding harvestable juveniles in 25 days. However, water replenishment in tanks with high microalgal density should also be regularly done at 50-70% rate in two days interval to mitigate fouling. In addition, sand-filtered, chlorinated, and UV-treated seawater were also tested for their efficiency as culture media. Growth rates were significantly highest in sand-filtered seawater (68.3 µm.d-1), followed by UV-treated seawater (52.4 µm.d-1), and by chlorinated seawater (34.8 µm.d-1) (p < 0.05). Larval development did not differ in sand-filtered and UV-treated seawater, yielding ~1 mm juveniles as early as Day 25. Likewise, sand-filtered seawater rendered highest survival of larvae (10.24%) followed by UV-treated seawater (6.24%); chlorinated seawater yielded lowest (2.60%) (p < 0.05). Although a sterilization process is advised, findings on sand-filtered seawater as a rearing medium were notable.
  • First-phase Juvenile Rearing of the Sea Cucumber Holothuria scabra in Eastern Samar, Philippines

    Cabacaba, Nonita S.; Campo, Cristan Joy M.; National Fisheries Research and Development Institute – National Marine Fisheries Research and Development Center (NFRDI-MFRDC); Bureau of Fisheries and Aquatic Resources – Guiuan Marine Fisheries Development Center (BFAR-GMFDC) (2019)
    Experiments were conducted to optimize the nursery rearing methods for the sea cucumber Holothuria scabra at the BFAR-GMFDC, Eastern Samar. The growth performance and survivorship of juveniles were compared in different locations, seasonality, stocking densities, and rearing media. For the experiments on location and seasonality, nursery rearing was conducted in Guiuan and in Salcedo, Eastern Samar during April-May, July-August, and September-October 2018. The mean total weight gain (TWG) and specific growth rate (SGR) of juveniles were significantly better in Guiuan (3.78 g and 13.09%.d-1, respectively) compared to Salcedo (1.997 g and 11.70%.d-1, respectively) (p < 0.05). However, survival rates were significantly higher in Salcedo (75.67%) compared to that of Guiuan (66.89%) (t=-1.732, p>0.05). Predatory crabs and parasitic isopods (Cymodoce sp.) infiltrated the net cages in Guiuan, which increased the mortality of juveniles. Highest growth and survivorship were observed during dry months in April-May 2018 (TWG of 3.71 g, survival of 71.39%) but were lowest during the wet season in September-October 2018 (TWG of 2.26 g, survival of 70.89%). However, the growth and survival results did not significantly differ among different months (p>0.05). For the experiment on stocking density, juveniles stocked at 300 ind./cage had the highest growth (TWG of 5.19 g, SGR of 13.86%.d-1) while juveniles at 1000 ind./cage had the lowest growth (TWG of 1.28 g, SGR of 10.70%.d-1) (p < 0.05). Survival rates of the juveniles in 300 ind./cage were also highest (80.30%). This study recommends stocking juveniles at 500 ind./cage since survival at this density did not significantly differ with that of 300 ind./cage (p>0.05). In terms of rearing medium, growth was better in floating net cages (TWG of 2.60 g, SGR of 11.67%.d-1) compared to indoor tanks (TWG of 0.18 g, SGR of 6.38%.d-1). However, indoor tanks yielded higher survival rate (67.83%) than floating net cages (56.11%) (p>0.05). Higher mortality in net cages was caused by intruding predators and fluctuations in water quality.
  • Status of Ornamental Fish Industry in the Philippines: Prospects for Development

    Muyot, Frederick B.; Mutia, Maria Theresa M.; Manejar, Arvie Joy A.; Guirhem, Gency L.; Muñez, Margielyn J.; National Fisheries Research and Development Institute, National Freshwater Fisheries Research and Development Center (2019)
    The ornamental fish business is a lucrative industry worldwide with huge prospects for livelihood and trade, but the Philippines has not developed this industry to its full potential due to some constraints. This study was conducted to assess the ornamental fish industry in the Philippines using purposive survey interview and focal group discussions in major production areas in the country to determine aspects for development. Information on key stakeholders in the marine and freshwater ornamental fish sector; quantity and value of production by region and by species; and trade were generated from the study. Approximately 8,911,879 pieces of marine ornamental fish were exchanged per year, contributing to PHP 137,165,576 in the country’s annual trade. Production of freshwater ornamental fish was 14,304,739 pieces valued at PHP 145,958,667. The bulk of marine ornamental fish supply came from regions with coral reef areas teeming with marine ornamentals, namely: Regions IV-A (65.56%), III (23.18%), and VII (4.63%). Freshwater ornamental fish were produced mainly by Regions IV-A (34.29%), XI (35.41%), VI (11.96%) and III (10.43%) which have existing local markets. The center of trade for marine ornamental fish is Metro Manila and Cebu City due to the presence of international airports. Meanwhile, freshwater ornamental trade is concentrated in major cities and municipalities given the significant number of local hobbyists. An ornamental fish development program is needed to attain the full potential of the industry with an emphasis on (1) captive breeding of marine ornamental and freshwater indigenous fish, (2) tapping the export market for freshwater ornamental fish, and (3) promoting the sustainability of wild-caught marine ornamental fish.
  • First Report of the Non-native Midas Cichlid, Amphilophus citrinellus (Gunther, 1864), in Laguna de Bay, Philippines

    Poniente, Jennifer A.; Dela Peña, John T.; Pol, Romualdo M.; Zapanta, Levita H.; Santos, Mudjekeewis D.; Genetic Fingerprinting Laboratory, National Fisheries Research and Development Institute; National Inland Fisheries Technology Center, Bureau of Fisheries and Aquatic Resources (2019)
    In recent years, increasing global trade, travel, and transport had rapidly increased the rate of introduction and diversity of non-native fish species. Once established, some introduced fish species can become aggressive and dangerously invasive. Here, we provide the first report of the occurrence of a non-native Midas cichlid Amphilophus citrinellus in Laguna de Bay using morphological analysis and genetic marker, specifically the mitochondrial gene cytochrome c oxidase subunit 1 (CO1). The results provide important information on the presence of another invasive species in Laguna de Bay that needs to be addressed since this species can competitively exclude, predate, and displace native species
  • Effects of Net Depth Reduction to Bigeye Tuna (Thunnus obesus) Catch

    Dela Cruz, William S.; Demo-os, Marlo B.; Tanangonan, Isidro C.; Ramiscal, Rafael V.; Vessel Operations Center of Bureau of Fisheries and Aquatic Resources (BFAR); Bureau of Fisheries and Aquatic Resources-National Marine Fisheries Development Center(NFAR-NMFDC); Capture Fisheries Division, Bureau of Fisheries and Aquatic Resources (BFAR) (2019)
    Analysis on the catch of Bigeye tuna (Thunnus obesus) from purse seine and ring nets of various net depths was conducted to assess the effect of reducing net depth as a compatible measure the Philippines has implemented and reducing the catch of Bigeye in its internal waters and the Exclusive Economic Zone (EEZ). The study was based on observer reports from ring net and purse seine fishing vessels operating in internal waters and EEZ as well as from group seine operations in the high seas pocket 1. Nets were classed by depth to determine and compare variations on the catch of Bigeye, catch rates and relative proportion, species composition, and fishing grounds. Results indicated that the catch of Bigeye is correlated with the depth of net, with a significantly higher catch of Bigeye in deeper nets. The result of the study is consistent with other studies elsewhere, and in consonance with the implementation of Fisheries Administrative Order 236 limiting the depth to 115 fathoms for ring net and purse seine operating in Philippine internal waters and the EEZ as a compatible measure to reduce the catch of Bigeye.
  • Effectiveness of Predator Control Set-up for Aquatic Pest Control in Earthen Ponds for Extensive Culture of Penaeus monodon (Fabricius, 1798)

    Ledesma, Rene Geraldo Guerrero; Department of Agriculture, National Fisheries Research and Development Institute (2019)
    The effectiveness of a conventional predator system for tiger prawn ponds consisting of a net barrier and fence interwoven around a modified pond gateway (set-up 1) was compared to an expanded system that directed water-borne pests to a fish compartment (set-up 2). The compartment had two confinement areas holding fifty, 5 g sea bass fingerlings and nineteen, 300-400 g tiger grouper juveniles separated by a fine mesh net gate secured to a sluice structure. Regardless of the set-up employed, after 88 days of culture, three pest categories were identified inside the ponds: prawn predators, opportunistic feeders, and benthic scavengers. Wet biomasses of fish pests were 1.92 kg and 2.12 kg, while that of mangrove snail was 29 kg and 80 kg in setups 1 and 2, respectively. Prawn length-weight frequency from 30% biomass manifested negatively skewed population curves with the highest frequency size range of 111-120 mm: set-up 2 had a smaller skewness value (-10.68) than set-up 1 (-20.64). A significant t-value of -1.39 (p < 0.10; df18 at t90) indicated that prawns raised in set-up 2 were larger than those grown under set-up 1. Finfish pests collected from set-up 2 were fewer than those in set-up 1, consisting predominantly of smaller (81-120mm) Megalops cyprinoides and Tilapia mossambicus: pests with total lengths below 81 mm were presumed to have been eaten by the sea bass and tiger grouper in the fish compartment. In both predator control systems, the period where tiger prawns are most vulnerable to predation pressure was during the first two months of culture, at lengths less than 111 mm and weights below 12.9 g.
  • Heavy Metal Contamination in Water and Fishery Resources in Manila Bay Aquaculture Farms

    Perelonia, Karl Bryan S.; Abendanio, Camille C.; Raña, Joan A.; Opinion, April Grace R.; Villeza, Jordan T.; Cambia, Flordeliza D.; Fisheries Post Harvest Research and Development Division, National Fisheries Research and Development Institute (2017)
    Heavy metals (HM) are high-atomic weight elements hazardous at very low concentrations. Despite the health risk HM contamination brings, studies conducted were only confined to the offshore and marine portions of the bay. Hence, this study was conducted to establish baseline information and compare the spatial and seasonal distribution of heavy metal contamination in water and fishery resources in aquaculture farms and coastal areas in Manila Bay. Water and major aquaculture commodities were collected in November 2014, February 2015 and April 2015 and were analyzed for lead (Pb), cadmium (Cd), and mercury (Hg) using the following methods: (1) Graphite Furnace Atomizer-Atomic Absorption Spectrophotometry (GFA-AAS) for Pb and Cd and (2) Mercury Vaporizing Unit-AAS (MVU-AAS) for Hg. Cd (Bataan, Cavite, Bulacan, and Pampanga) and Hg (Cavite and Pampanga) in water were found significantly higher during the dry season (p < 0.05). In contrast, Pb in water was relatively higher during the wet season but levels were not significantly different with those in the dry. Several sites in Bataan, Bulacan, and Cavite, exceeded DENR regulatory limits for Pb and Hg in water by 1.35 to 1.8%. As for the fishery commodities, 2/12 milkfish samples and 1/9 exceeded regulatory limit for Pb in finfish (0.3 mg/kg) by 1.03 to 3.57% while 1/12 milkfish samples and 1/13 oyster samples exceeded the limit for Hg in bivalves (0.5 mg/kg) by 0.45 to 0.75%.
  • Contamination of Coliform Bacteria in Water and Fishery Resources in Manila Bay Aquaculture Farms

    Raña, Joan A.; Domingo, Jonacel E.; Opinion, April Grace R.; Fisheries Post Harvest Research and Development Division, National Fisheries Research and Development Institute (2017)
    The coliform group of bacteria is widely used as an indicator of pollution related to the presence of pathogenic bacteria linked to fecal contamination, which poses great health risk. This study aimed to establish baseline information on the coliform contamination in water and fishery resources in Manila Bay aquaculture farms. Water samples and major aquaculture commodities were collected twice per season from representative aquafarms in the coastal provinces of the bay and were analyzed for total coliform (TC), fecal coliform (FC), and E. coli (EC) using the Multiple Tube Fermentation method of the Bacteriological Analytical Manual. TC, FC, and EC in water were found higher during the wet season, their average concentrations being 8,747, 2,808, and 1, 216 MPN/100mL, respectively; while those in the dry being 6,255, 1,223, and 286 MPN/100mL, respectively. More samples exceeded the DENR Standard Limit for TC (5,000 MPN/100mL) in the wet season than in the dry season (roughly 25% vs 10%). Farmed fishery resources, on the other hand, had higher EC concentrations during the dry season. The following are the percentages of samples that exceeded DENR Standards: 25% of mussels, 24.44% of shrimps, 16% of tilapia, 14.67% of oysters, 8.89% of crabs, and 6.67% of milkfish.
  • Spatial and Seasonal Nutrient Trends in Manila Bay Aquaculture Farms

    Opinion, April Grace R.; Raña, Joan A.; Perelonia, Karl Bryan S.; Abendanio, Camille C.; Cambia, Flordeliza D.; Fisheries Post Harvest Research and Development Division, National Fisheries Research and Development Institute (2017)
    Sampling was done in duplicates during dry (May 2014 and February 2015) and wet season (September 2014 and November 2014) following the blocking scheme for the nutrient trends. As for the nutrient loading, water samples were collected in three ponds after flooding (water intrusion) and prior to draining (water release). Colorimetric analyses by UV-Vis Spectroscopy following the US EPA standard methods were used to determine the samples’ nutrient levels specifically, ammonia, nitrate, nitrite, and phosphorus. Results showed that ammonia had the highest levels followed by phosphorus, nitrate, and nitrite. Geographically, higher concentration of nitrogen and phosphorus were observed in Eastern Bulacan aquaculture farms, which is attributed to the farmers’ disregard of the important pond preparation activities. Varying seasonal trends were noted among nutrient species due to the different reactions of each analyte under changing climatic conditions. Nutrient levels in sediments were several folds higher than that in the water column. Results of correlation analyses of nutrients in water and sediments showed: a) a good correlation for phosphorus, b) weak correlation for ammonia, and c) no correlation for nitrites and nitrates, implying that sediments maybe a possible contributor of phosphorus and ammonia in water but not nitrite and nitrate. Ammonia and TKN were significantly higher during the flooding suggesting that water coming in to the pond already contains high levels of said nutrients possibly due to higher organic load. Conversely, nitrite and nitrate levels were significantly higher during the draining suggesting transformation of ammonia into these less toxic substances by nitrifying bacteria.
  • Review of Aquaculture Practices and Anthropogenic Activities in Manila Bay Aquaculture Farms

    Opinion, April Grace R.; Raña, Joan A.; Fisheries Post Harvest Research and Development Division, National Fisheries Research and Development Institute (2017)
    Environmental problems arising from aquaculture activities have been a concern worldwide, especially in Manila Bay. Thus, this study was implemented to identify the aquaculture practices of fish farmers and assess whether these practices are in accordance with the good aquaculture practices (GAqP) guidelines. Information was collected through survey and interview of fishpond operators from provinces around the bay. The study found that most fish farmers around the Bay do not observe the guidelines on GAqP evidenced by their high non-compliance with buffer zone, lack or utilization of improper water quality monitoring methods, non-implementation of important steps in pond preparation (e.g. soil testing), and application of illegal and noxious chemicals (e.g. cyanide). The calculated FCR, DMR and WPR in selected farms greatly varied. Farmers domesticated and/or allowed wading of animals on pond embankments predisposing contamination of both water and culture species. Anthropogenic activities such as sewage and garbage disposal, industry, and agriculture possibly added to deterioration of water quality in the fish ponds. On the other hand, notable practices were also observed in the areas such as the adoption of polyculture and semi-intensive fish farming methods, and the stocking of seeds from hatcheries.

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