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  • Assessment on the Occurrence of Anisakid and other Endoparasitic Nematodes Infecting Commercially-Important Fishes at Tayabas Bay

    Ramos, Maribeth H.; Argarin, Trazarah Hanoof E.; Olaivar, Beatriz A. (2020)
    Anisakid nematodes are parasites commonly present in the marine environment. Parasites belonging to the family Anisakidae or the genus Anisakis can cause two different clinical manifestations: gastrointestinal disorders and allergic reactions known as anisakiasis. In this study, we examined 7,126 marine fishes belonging to four different commercially-important fish species; Rastrelliger kanagurta, Sardinella lemuru, Atule mate, and Selar crumenophthalmus for the presence of anisakid and other endoparasitic nematode infection. The fishes caught from Tayabas Bay were bought from three different landing sites from March 2017 to February 2018. The gonads, liver, and stomach of each fish species were incubated for 12-18 hours for rapid isolation and endoparasite evaluation. After the isolation of parasites, anisakid nematodes were fixed in vials with 70% ethanol for morphological analysis under the microscope. Six anisakid groups of genera, including Hysterothylacium, Terranova, Anisakis, Contracaecum, Raphidascaris, and Camallanus, and a non-anisakid group Echinorhynchus were identified. The results showed that the prevalence of anisakid infection in all species was 24.18 %, with a mean intensity of infection of 1.91. Rastrelliger kanagurta (Dalahican), Atule mate, and Selar crumenophthalmus were the most infected with 50.90%, 38.98%, and 30.52% prevalence rate, respectively, followed by Rastrelliger kanagurta (San Francisco) (24.18%) and Sardinella lemuru (7.46%). The collected data suggest that commercially-important fish caught in the Tayabas Bay waters are susceptible to parasitization by larvae of the genus Camallanus followed by Hysterothylacium and Terranova in their visceral organs. The prevalence of anisakid infection was almost similar between female (45.3 %) and male (47.21 %) fishes with a mean intensity of 1.95 & 1.96, respectively. Also, larger fishes were heavily infected with anisakid larvae than small fishes. Thus, the intensity and prevalence of the fish parasite can be used as a biological tag for benchmarking and stock assessment purposes.
  • Does the Behavioral Stress Response of Nile Tilapia, Oreochromis niloticus Breeders During Isolation Influence Seed Production?

    Vera Cruz, Emmanuel M.; Jimenez, Eddie Boy T.; Apongol-Ruiz, Bethzaida M. (2020)
    This experiment assessed the effect of breeder’s behavioral stress response [i.e., eye color pattern (ECP)] during isolation on O. niloticus seed production. ECP change was marked by fractional color changes of the iris and sclera, which was transformed into scores ranging from 0 (no darkening) to 8 (total darkening). After isolation, breeders were divided into two social groups: proactive breeders (PB) were those with a mean ECP score of <2, and reactive breeders (RB) with a mean ECP score of >6. Two breeding cycles were done in six (1 m x 2 m x 1 m) net enclosures. Mean spawning rates (SR) in PB during the two cycles were 38.89±14.70% and 33.33±8.87% while 3.33±9.62% and 22.22±2.48% in the RB group. Total seed productions (TSP) in PB were 1,906.22±733.72 and 1,681.19±1,070.48 fry, and those in RB were 996.35±218.11 and 461.39±151.37 fry. There were no significant differences between the two groups on SR and TSP in both cycles. On seed production per female that spawned, however, significantly (P<0.05) higher means (796.33±77.68 and 726.33±124.08 fry) were observed in the PB compared to those in RB (522.73±54.68 and 335.83±44.98 fry). These results demonstrated that seed production in O. niloticus could be increased by selecting proactive breeders through the evaluation of their ECP during isolation.
  • Microbial Community Response to Carbon-Nitrogen Ratio Manipulation in Biofloc Culture

    Tanay, Dennis D.; Abella, Tesero T.; Vera Cruz, Emmanuel M.; Sace, Chito F.; Fajardo, Lorenz J.; Velasco, Ravelina R.; Abucay, Jose S. (2020)
    Biofloc technology (BFT) is an alternative aquaculture practice that involves the manipulation of carbon-nitrogen ratio (C:N) to manage nitrogenous waste through microbial assimilation. This study aimed to determine the composition of the microbial community present in BFT and describe the microbial community’s response to C:N manipulation. The experiment had a complete randomized design with two set-ups (i.e., BFT and control) in triplicates. The experimental unit was a 120-L rectangular tank stocked with 15 mixed-sex tilapia fish, Oreochromis niloticus, with an average weight of 15±3 g. The C:N was adjusted to 16:1 using molasses. Illumina MiSeq sequencing platform was used, and bioinformatics was conducted in R using dada2 and phyloseq package. Seventeen (17) phyla were identified, but only seven were remarkably abundant, namely: Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Verrucomicrobia, Planctomycetes, and Fusobacteria. Double Principal Coordinates Analysis (DPCoA), Principal Coordinate Analysis (PCoA) of Weighted Unifrac Distance and Canonical Correspondence Analysis (CCoA) revealed an association of Proteobacteria to low ammonia concentration in BFT treatment. On the other hand, phylum Bacteroidetes was clustered towards the control, characterized by high ammonia. Overall, BFT has increased Shannon and Simpson diversity indices compared to the control. Regime change in the microbial community was not easily caused by organic C supplementation because of community robustness to withstand biotic and abiotic disturbances. Controlled laboratory experiment showed that some bacteria species proliferate as a response to C:N manipulation, but established species remained dominant.
  • Parasitic Anisakid Nematode Isolated from Stranded Fraser’s Dolphin (Lagenodelphis hosei Fraser, 1956) from Central Philippine Waters

    Quiazon, Karl Marx A. (2020)
    Cetaceans, including dolphins, serve as definitive hosts of zoonotic anisakid nematodes, which are important etiological agents for human anisakiasis and allergy-associated health risks. With limited knowledge of these zoonotic parasites from the marine environment in the Philippine waters, the stranding of a Fraser’s dolphin (Lagenodelphis hosei Fraser, 1956) off the central Philippines made it possible to identify the worm species isolated from its gut. Parasitological examinations were carried out using morphological and molecular tools. Morphologically, the SEM and LM data revealed that the specimens belong to the genus Anisakis of the Type 1 group. Molecularly, PCR-RFLP results of the ITS region generated only a single fragment pattern on all worm samples corresponding to the reported molecular keys for A. typica. Further sequence and phylogenetic analyses of both ITS rDNA and mtDNA COX2 genes confirmed the anisakid nematodes’ identity as A. typica. The molecular data obtained in this study support previous findings on the possible existence of local variants of A. typica in this region.
  • Gender Participation in the Fisheries Sector of Lake Taal, Philippines

    Mutia, Maria Theresa M.; Magistrado, Myleen L.; Fermaran, Michelle Joy L.; Muyot, Myla C. (2020)
    Lake Taal is a source of livelihood and provides for more than 2,000 sustenance fisherfolk. Fish production of the open water fisheries has dwindled over the years with the continuous decline of fish catch, which can be attributed to unsustainable fishing practices such as illegal fishing, overfishing, pollution, and the expansion of aquaculture activities in the lake. Women, as a sector, constitute almost one half of the economically active population in Lake Taal. Men and women performed different roles at different stages of fish capture or fish culture. In terms of their economic and social value, the participation of women in pre- and post-production activities are significant. This study assessed the level of gender participation in the fisheries sector of Lake Taal. Specifically, it determined the roles of men and women in the different fishing activities and described the fisherfolk’s socioeconomic profile. A total of 407 randomly selected respondents were interviewed in 11 barangays from eight municipalities in Lake Taal, represented by 54% male and 46% female, consisting of 214 fishers, 76 fish vendors, four processors, 51 helpers, and 62 fish cage or fish pond owners, managers, and caretakers. Profiling of the socioeconomic status was done to assess families’ living conditions and constructed primary data based on household’s present roles, activities, responsibilities, access to and control over resources, problems, and constraints of men and women. The roles of both men and women in fisheries were categorized into three sectors: capture, post-harvest, and aquaculture.
  • Value Chain Analysis of Maliputo, Caranx ignobilis in the Philippines

    Mutia, Maria Theresa M.; Muyot, Myla C.; Balunan, Rielyn L.; Muyot, Frederick B. (2020)
    Maliputo (Caranx ignobilis) is a high-value food fish in the Philippines with limited studies on market potential. This value chain analysis study was conducted to understand the industry, to identify the key actors, supply and value chain, and to identify issues and concerns to support the development of C. ignobilis industry. A survey interview was conducted using purposive sampling in nine maliputo-producing regions with 224 respondents, and focus group discussion validated the analyzed data. Key chain actors identified are fishers, fish cage operators, fish buyers categorized as small-scale (local vendors and peddlers) and large-scale intermediaries (commission agents and wholesalers), and processors (restaurants and resorts). Annual production was 188,722 kg valued at PHP 33,752,859.79 with 58.12% coming from capture fisheries and 41.88% from aquaculture. Major producing regions for captured and cultured C. ignobilis are Regions 2 (Cagayan), 6 (Iloilo), and 3 (Central Luzon). The industry’s value chain map showed a gross value addition of PHP 116.58, 135.65, 75.04, 23.58, and 749.71 per kg maliputo for capture, aquaculture, small-scale fish buyer, large-scale fish buyer, and processors, respectively. Processors attained the highest net returns while fishers got the lowest. This study noted that C. ignobilis is a non-target species in capture fisheries resulting in an inconsistent supply of the fish. For aquaculture, there is a need to improve its culture technology, develop seed production technology, and formulate an artificial diet. Various upgrading strategies to improve the industry and to increase the benefits derived by the key actors had been identified and presented in the paper.
  • Reproductive Biological Performance of Otolithes ruber (Bloch and Schneider 1801) in San Miguel Bay, Philippines

    Lanzuela, Noemi SB.; Gallego, Errol M.; Baltar, Jethro Emmanuel P. (2020)
    The tigertooth croaker, Otolithes ruber (Bloch and Schneider 1801), was studied to determine its reproductive biology characteristics for 34 months from March 2015 to November 2017. A total of 7,977 individuals were sampled and the measured total lengths (TL) ranged from 8.1 cm to 32.1 cm (16.70 ± 2.53 cm ) and 10.0 cm to 33.5 cm (17.95 ± 2.95 cm) for male and female, respectively. The length-weight relationship can be summarized as W = 0.00521 L3.18 and W = 0.00837 L3.01 for female and male, respectively. The length at first maturity of this species was determined to be 13.95 cm, which is smaller compared to other studies. The overall sex ratio of this species was 1:0.8, with males dominating the female sex (P < 0.05, X2 = 64.3). In addition, synchronized development of male and female gonads was observed. It was also verified that mature individuals were present all throughout the study period indicating that this species spawn continuously and the presence of juveniles during the sampling period indicated continuous recruitment. Mean monthly GSIs indicate July to November as the main spawning season of this species. The in-site occurrence of mature and juvenile stocks in the bay further implicates that San Miguel Bay is a nursery ground for this species. The fecundity varied between 3,420 to 422,100 with an average fecundity of 86,142 eggs. Lastly, the spawning potential ratio is still above the limit reference point (SPR = 0.36), indicating that the stock can still replenish their biomass.
  • New Scales to Guide the Assessment of Hard Coral Cover and Diversity in the Philippines

    Licuanan, Wilfredo Y. (2020)
    Key Points: -Coral reefs supply vital ecosystem services to the Philippines. -Safeguarding these services requires the rapid identification of reefs that provide most services, and identification is best made by measuring hard coral cover and diversity and using updated and locally relevant assessment scales on these measurements. -The use of these assessment scales has advantages and is recommended to update and improve Philippine laws.
  • 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.

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