Recent Submissions

  • Tank-Based Nursery Production of the Sea Cucumber Holothuria scabra in Various Seaweed Feed Regimens

    Campo, Cristan Joy M.; Cabacaba, Nonita S.; Cosmiano, David N. Jr. (2022)
    The Philippine Journal of Fisheries
    This study explored the feasibility of Laurencia papillosa, Sargassum spp, and Gracilaria bailinae crude extracts as feeds for the juvenile sea cucumber Holothuria scabra in a tank-based system. Post-metamorphic juveniles (~1 mm) were harvested from larval tanks and were reared until the late juvenile stage in indoor tank systems at 300 ind./tank stocking density for 45 days. Growth and survival rates of H. scabra juveniles were monitored to assess the performance of each seaweed treatment. L. papillosa consistently yielded the best growth (SGR: 7.63-11.32%.d-1) and highest survival rates (54.6–56.8%) of H. scabra juveniles. The performance of L. papillosa did not differ from that of Sargassum spp., while G. bailinae yielded poor growth (SGR of 5.01–9.38%.d-1) and low survivorship of juveniles (8.77–19.77%). Growth and survival rates were similar between fresh and dried seaweeds (p>0.05), suggesting dried seaweeds' applicability as feeds for juvenile H. scabra. Moreover, increased feed rations resulted in better growth of juveniles, but survival rates among feed rations (4.5, 6.0, 7.5, and 9.0 L.d-1) did not differ significantly (p>0.05). The monthly mean water temperature ranged from 26.6°C to 28.8°C, salinity of 33.2–35.1 ppt, dissolved oxygen of 6.1–8.3 mg/L, and pH of 8.1–8.3. High yields of sea cucumber juveniles were observed during the dry season, while low survival rates (<20%) were observed during wet months. The success of this study could set forth the application of tank-based nursery systems for H. scabra, especially during the season of high rainfall and extreme weather conditions that heavily affects cage rearing in the open-sea setting.
  • Population Parameters of Shortfin scad Decapterus macrosoma (Bleeker, 1851) in Antique, Philippines

    Magallanes, Sagrado; Monteclaro, Harold; Gonzales, Benjamin; Quinitio, Gerald; Mediodia, Dominique (2022)
    The Philippine Journal of Fisheries
    Growth, mortality, exploitation rate, and recruitment of Decapterus macrosoma in the waters off Antique province, Philippines, were investigated based on the length-frequency data collected from April 2019 until March 2020. Using the FISAT-II software, D. macrosoma growth parameters were computed as follows: L∞ = 26.18 cm TL, K = 1.00 yr-1, ø' = 2.836 yr-1, and an estimated life span of 3 years. Mortality values were estimated as: total mortality (Z) = 4.66 yr-1; natural mortality (M) = 1.88 yr-1; and fishing mortality (F) = 2.78 yr-1. The exploitation rate (E) was computed as 0.60 while Emax was 0.42 yr-1. The length at first capture Lc/L50 was estimated at 11.96 cm TL. There were two recruitment events in one year: July and December. D. macrosoma in Antique was growing isometrically and in good condition with the relative condition factor (Kn) values ranging from 0.99 to 3.39. The computed exploitation rate suggested that D. macrosoma faces a high level of exploitation in Antique waters. These results offer valuable information on the utilization, conservation, and management of D. macrosoma in the East Sulu Sea area.
  • Method Standardization and Guidance Value Determination for Regulation on Formaldehyde in Round Scad (Decapterus spp.).

    Dela Cruz, James; Cudia, Paul Bryan Karlo R.; Seguerra, Aira Mae M.; Romero, Marc Lawrence J. (2022)
    The Philippine Journal of Fisheries
    There are reports of traded Galunggong (Fil.), Decapterus spp., adulterated with formaldehyde (FA) to lengthen shelf life. FA is a noxious substance with negative repercussions to general consumer health. This warrants the determination of a guidance value due to a lack of a local regulatory value specific to Galunggong amidst rising Filipino public concern in the wake of importations complicated by the natural occurrence of FA in the marine fish post-mortem. Comparisons were made on FA levels of fish treated with different conditions exposure and with colorimetric measurements using 405 nm and 412 nm via Nash’s method optimized for a fish matrix with no significant difference in measurement to at most 30 ppm FA in an aqueous matrix. There is also no significant difference in FA content of samples measured immediately from those frozen overnight. Therefore, in line with the regulatory mandates of the Bureau of Fisheries and Aquatic Resources (DA-BFAR) of the Department of Agriculture (Republic of the Philippines), a guidance value of 46.24 μg FA/g of Galunggong or 46.24 ppm is suggested, which is obtained from FA measurements of fish subjected to minimal anthropogenic treatments in different conditions of adulteration. Samples from different Metro Manila wet markets serve as the baseline. The guidance value is suggested to be used as a reference for regulatory purposes and can be improved with a more widespread sampling of fish from landing to selling.
  • Status of coral reefs, butterflyfishes, and benthic macro-invertebrates in Araceli and Dumaran, Palawan, Philippines

    Aludia, Geofrey; Mecha, Niño Jess Mar; Cornel, Anton Rey; Acebuque, Ace Niño Andrew; Rodriguez, Jomil; Miguel, Jona; Menardo, Ian; Dolorosa, Roger (2022-12-16)
    The Palawan Scientist
    As a major fishing ground in Palawan, the reefs in the municipal waters of Araceli and Dumaran are continuously facing anthropogenic and climate-related threats. Hence, to provide information about the reef conditions, surveys were undertaken in three sites of each municipality as the basis for management. Data collection used the C30 method where a 75 m x 25 m sampling area was established at the upper reef slope (2-5 m deep) of each site. Substrates were photo-documented at predetermined random positions and the photos were processed using Coral Point Count with excel extension software (CPCe) to determine the percent substrate categories. Identification and counting of butterflyfishes and benthic macro-invertebrates were also undertaken. The hard-coral cover (HCC) ranged between 27.10 and 53.88% (fair to very good) for Araceli and 22.66 and 48.62% (fair to good) for Dumaran. The number of species and density of butterflyfishes largely varied across reefs. The benthic macro-invertebrates only included the blue Linckia starfish and giant clams. The current reef condition calls for urgent management actions.
  • Growth and Survival of Black-lip Pearl Oyster Pinctada margaritifera (Linnaeus, 1758) in Bamboo and Metal-framed Pocket Net Baskets Subjected to Cleaning and Without Cleaning Conditions

    Cueba, Francis Rey A.; Diaz, Redentor D.; Villanueva, Elmer G; Mecha, Niño Jess Mar F.; Anunciado, Sharon Rose P.; Dolorosa, Roger G.; City Agriculture Office, Puerto Princesa City, Philippines; College of Fisheries and Aquatic Sciences, Western Philippines University; Napsan National High School, Puerto Princesa City, Philippines; College of Arts and Sciences, Western Philippines University, Aborlan, Palawan, Philippines; et al. (2022)
    The Philippine Journal of Fisheries
    The farming of black-lip pearl oyster Pinctada margaritifera (Linnaeus, 1758) has been a viable industry for small and large-scale farmers in the South Pacific, but not in the Philippines, where it is monopolized by large-scale farms primarily based on the gold-lip pearl oyster Pinctada maxima. To promote the industry among small-scale players, we simplified the culture method by using bamboo slats as frame materials and compared them to the common material used in pearl oyster culture, metal rods. A total of 400 individuals seven-month-old hatchery-produced P. margaritifera were used as experimental animals, distributed in the following treatments with five replications: T1 (metal-framed pocket net basket with monthly cleaning), T2 (metal-framed pocket net basket without monthly cleaning), T3 (bamboo-framed pocket net basket with monthly cleaning), and T4 (bamboo-framed pocket net basket without monthly cleaning). Growth was fast in the first four months and slowed down after that. Two-way analysis of variance found no significant differences between the average anteroposterior shell (APS) length increments of pearl oysters between two types of frame, and between two cleaning conditions. Survival rates did not significantly differ between types of basket frame, and between cleaning conditions. Parameters of the “Typical” von Bertalanffy growth model (L∞ = 118.41 mm, K = 1.03 year-1, and t0 = 0.12) suggested that oyster would take about 23.16 months to reach 100 mm APS length, a size suitable for nucleus implantation. The life span of bamboo slats as basket frame was half of the metal frame, and the absence of cleaning has reduced the operational cost by up to 82.08%.
  • 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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine JournaL of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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 Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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.
  • 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)
    The Philippine Journal of Fisheries
    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)
    The Philippine Journal of Fisheries
    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.

View more