These papers were contributed by Department staff to various national and international journals.

Recent Submissions

  • Article

    Fish performance, nutrient digestibilities, and hepatic and intestinal morphologies in grouper Epinephelus fuscoguttatus fed fermented copra meal 

    REP Mamauag, JA Ragaza & T Nacionales - Aquaculture Reports, 2019 - Elsevier
    Protein enhanced copra meal (PECM®) is an alternative, cheap, and sustainable source of plant protein for the aquafeed industry, albeit its use on carnivorous fish species has been very limited. A 70-day feeding trial using grouper Epinephelus fuscoguttatus (initial mean body weight of 1.86 ± 0.19 g) tested fermented copra meal as feed ingredient. Six isonitrogenous (crude protein of 45%) and iso-lipidic (crude fat of 11%) diets consisted of PECM®: a control diet at 0% soybean meal replacement (C); four diets replacing soybean meal at 25% (FC25), 50% (FC50), 75% (FC75), 100% (FC100) – all with methionine and lysine supplementation; and 100% soybean replacement without methionine and lysine supplementation (FCW100). Growth and feed performance were not significantly (P > 0.05) affected by PECM® replacement of soybean meal up to 100%, even without methionine and lysine supplementation. Chemical body composition was likewise not significantly (P > 0.05) altered. PECM® when used as a grouper feed ingredient has protein, lipid, carbohydrate and dry matter digestibilities of 89.28%, 78.63%, 82.57%, and 48%, respectively. Hepatic and intestinal morphologies displayed no apparent pathological changes. PECM® can be efficiently utilized by grouper and can replace soybean meal up to 100% (16% in diet) for normal fish performance and digestive organ functions.
  • Article

    Reproductive development of the threatened giant grouper Epinephelus lanceolatus 

    The giant grouper is presumed to follow the reproductive pattern of most Epinephelus species, characterized by protogynous hermaphroditism wherein male maturation is attained through sex reversal of a functional female. This hypothesis, however, has not been verified due to lack of biological data. The present study addresses this gap by investigating the reproductive development of giant groupers from juvenile stage through sexual maturity. Gonad histological analysis of hatchery-bred juvenile giant grouper from Queensland, Australia (0.8–5.2 kg, n = 43) have shown earliest occurrence of primary oocytes (i.e. ovarian differentiation) in 47.8 cm and 2.5 kg fish. Monitoring of sexual maturity by gonadal biopsy was performed in a stock of wild-caught giant groupers (2–52 kg) held in sea cages in the Philippines and Vietnam from 2015 to 2017. Onset of female sexual maturity was at 96.9 ± 1.6 cm and 23.5 ± 1.5 kg in the Philippines, and 103.0 ± 4.1 cm and 33.5 ± 2.5 kg in Vietnam. In both locations, development of primary males was observed wherein fish produced milt (or spermiated) without passing through a functional female phase. The ratio of primary males to females in both locations was about 1:2. Size at maturity of primary males is 86.5 ± 4.8 cm and 17.1 ± 2.1 kg in the Philippines, and 97.3 ± 1.3 cm and 34.3 ± 0.9 kg in Vietnam. To aid in the monitoring of female maturation, we developed a non-invasive method based on immunoassay of vitellogenin in skin mucus and this was shown to be effective in detecting female maturation 9 ± 2 months prior to first observation of oocytes through gonadal biopsy. Our findings suggest that giant grouper is a diandric protogynous hermaphrodite. This study provides novel information on the reproductive biology of giant grouper, an economically important and vulnerable species.
  • Article

    Gonadal response of juvenile protogynous grouper (Epinephelus fuscoguttatus) to long term recombinant follicle-stimulating hormone administration 

    P Palma, J Nocillado, J Superio, EGdJ Ayson, F Ayson, I Bar & A Elizur - Biology of Reproduction, 2019 - Oxford University Press
    The role of follicle stimulating hormone (FSH) in the gonadal development of protogynous hermaphroditic grouper (E. fuscoguttatus) was investigated. Recombinant giant grouper (E. lanceolatus) FSH (rggFSH) was produced in yeast. Its receptor binding capacity and steroidogenic potency were confirmed in vitro. Weekly injections of rggFSH to juvenile tiger grouper for 8 weeks (100 μg/kg body weight, BW) resulted in significantly larger and more advanced oocytes (cortical alveolar stage vs. primary growth stage in control). Sustained treatment with rggFSH (20 to 38 weeks at 200 μg/kg BW) resulted in significant reduction in gonad size, degeneration of oocytes and proliferation of spermatogonial cells, indicative of female to male sex change. Gene expression analysis showed that, while initiating female to male sex change, the rggFSH significantly suppressed the steroidogenic genes cyp11b, cyp19a1a and foxl2 which restrained the endogenous production of sex steroid hormones thus prevented the differentiation of spermatogonial cells. Expression profile of sex markers dmrt1, amh, figla and bmp15 suggests that the observed sex change was restricted at the initiation stage. Based on these results, we propose that the process of female to male sex change in the protogynous grouper is initiated by FSH, rather than sex steroids and likely involves steroid-independent pathway. The cortical alveolar stage in oocyte development is the critical point after which FSH-induced sex change is possible in grouper.
  • Article

    Artificial substratum consisting of poly-β-hydroxybutyrate-based biodegradable plastic improved the survival and overall performance of postlarval tiger shrimp Penaeus monodon 

    G Ludevese-Pascual, JL Laranja, E Amar, P Bossier & P De Schryver - Aquaculture Research, 2019 - Wiley
    The use of artificial substratum consisting of poly‐β‐hydroxybutyrate (PHB)‐based biodegradable plastic for penaeid shrimp culture was investigated in the present study. The survival of postlarval tiger shrimp Penaeus monodon (30 ± 5 mg) provided with PHB substratum made out of PHB type DP9002 (Metabolix GmbH, Köln, Germany) was 88.7 ± 3.4% and this was significantly higher as compared to postlarvae provided conventional substratum consisting of polyvinylchloride (PVC) pipes (67.3 ± 6.5%). However, no significant weight improvement was observed for the postlarval tiger shrimp indicating that PHB could not be used as growth promoter. Nevertheless, a trend of improved robustness against adverse environmental conditions (lethal ammonium chloride concentration) and increased resistance to pathogenic Vibrio was observed in postlarval tiger shrimp provided with PHB substratum as compared to postlarvae provided with PVC substratum. Results indicate higher preference by postlarvae on PHB substratum over PVC substratum. Overall, this study indicates the potential of artificial substratum consisting of PHB‐based biodegradable plastic as replacement for conventional substratum consisting of PVC pipes in enhancing the survival of postlarval tiger shrimp and improving its performance against adverse environmental conditions and disease resistance.
  • Article

    Improved survival, prey selectivity and diel feeding cycle of silver therapon Leiopotherapon plumbeus (Perciformes: Terapontidae) larvae reared in tanks with substrate 

    FA Aya, VSN Nillasca, MJP Sayco & LMB Garcia - Ichthyological Research, 2019 - Springer Verlag
    Physical substrates in the rearing environment can influence the early survival and feeding patterns of captive-reared fish. In this study, we determined whether substrates affect the survival and growth of hatchery-reared silver therapon Leiopotherapon plumbeus larvae as well as examined their prey selectivity and diel feeding cycle. Newly hatched larvae [1.92 mm total length (TL)] were reared for 40 days in triplicate 4 m3 tanks with or without tropical almond Terminalia catappa leaves as substrate. Prey selectivity of larvae reared in tanks with substrate for 35 days from the yolk-sac stage was measured by the Chesson’s selectivity index (αi). Diel feeding cycle of 3-4 days post-hatch (dph) silver therapon larvae reared in tanks exposed to natural light cycle and fed wild zooplankton was also studied. Larvae reared in tanks with substrate had significantly higher survivorship (48.44 ± 7.85%) than those reared in tanks without substrate (26.73 ± 1.60%). However, total length, specific growth rate and body weight of silver therapon larvae from tanks with or without substrate were not significantly different. Silver therapon larvae are generalist predator, demonstrating a degree of prey selectivity in some prey items during early ontogeny. Prey selectivity of silver therapon larvae varied during larval ontogeny, with higher Chesson’s selectivity index for copepod nauplii among the smaller fish larvae (2–5 dph; 2.94–5.17 mm TL), cladocerans (Moina micrura and Bosmina coregoni) among intermediate (6–11 dph; 5.72–9.60 mm TL), and ostracod, cladoceran and insect larvae among larger fish (12–35 dph; 10.28–20.96 mm TL). Larvae showed a diel feeding cycle where they actively fed during daylight hours, with a peak in the late afternoon, and reached a minimum at dark. Together, these findings advance our understanding of the feeding predatory behavior and efficiency of silver therapon larvae and preference for tanks with substrate that improve their survival.
  • Article

    Disaster management practices of academic libraries in Panay island, Philippines: Lessons from typhoon Haiyan 

    DL Superio, SB Alayon & MGH Oliveros - Information Development, 2019 - SAGE Publications
    A disaster management plan is essential because it can guide library personnel on what to do in a critical time. Using an eight-part survey instrument, this paper documents the impact of Typhoon Haiyan on 22 academic libraries in Northern Panay, Western Visayas, Philippines and the disaster management practices that were implemented. The results revealed that although the majority of the libraries do not have a disaster management plan, they all had common disaster management practices that enabled them to save parts of their collections. Moreover, the study revealed that librarians lacked knowledge and skills on disaster management. This paper was presented at the 40th International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC) Annual Conference, Noumea, New Caledonia, September 14–18, 2014.
  • Article

    Female-specific SNP markers provide insights into a WZ/ZZ sex determination system for mud crabs Scylla paramamosain, S. tranquebarica and S. serrata with a rapid method for genetic sex identification 

    Mud crabs, Scylla spp., are commercially important large-size marine crustaceans in the Indo-West Pacific region. As females have the higher growth rate and economic value, the production of all female stocks is extremely essential in aquaculture. However, the sex determination mechanism is still unclear. Development of sex-specific genetic markers based on next-generation sequencing proved to be an effective tool for discovering sex determination system in various animals.
  • Article

    Immunization regimen in Asian sea bass (Lates calcarifer) broodfish: A practical strategy to control vertical transmission of nervous necrosis virus during seed production 

    R Pakingking Jr., EG de Jesus-Ayson, O Reyes & NB Bautista - Vaccine, 2018 - Elsevier
    Outbreaks of viral nervous necrosis (VNN) in Asian sea bass (Lates calcarifer) at the larval stages via vertical transmission of nervous necrosis virus (NNV) from asymptomatic broodfish remain as a major deterrent during seed production. A five-year study was conducted to produce NNV-specific-free sea bass broodfish reared in land-based tanks through an annual immunization regimen with the formalin-inactivated NNV. We primarily immunized (intraperitoneal injection) sea bass juveniles (5 g) and monitored the neutralizing antibody (Nab) titers in the sera of these fish at scheduled intervals post-immunization. Nab titers in the sera of immunized fish peaked at Month 2 (titer: 1:4480 ± 1185) but thereafter gradually declined and significantly dropped (1:260 ± 83) at Month 12 post-primary immunization. Booster immunization of these fish at Month 12 post-immunization led to abrupt increases in Nab titers in booster immunized (B-Im) fish at Month 1 (1:12800 ± 6704) but thereafter declined and dropped at Month 12 (1:480 ± 165) post-booster immunization. The annual booster injections with the inactivated vaccine or L-15 (Unimmunized [U-Im]) were consecutively conducted for 4 years until the fish became sexually mature. Mature fish from both groups were successively induced to spawn twice (1-month interval) via intramuscular injection with luteinizing hormone-releasing hormone analogue (LHRH-a; 100 µg/kg BW). NNV was not detected by RT-PCR in oocytes and milts, and spawned eggs of B-Im fish. In contrast, oocytes and milts, and spawned eggs of U-Im fish were NNV positive. Spawned eggs of B-Im broodfish exhibited Nab titers ranging from 1:192 ± 34 to 1:240 while such was not detected (<1:40) in eggs of U-Im fish. Taken together, current data clearly demonstrate that annual immunization regimen with inactivated NNV vaccine is a pragmatic approach for sustaining immunocompetent sea bass broodfish reared in land-based tanks and circumvent the risk of vertical transmission of NNV from asymptomatic broodfish to their offspring under stress of repetitive spawning.
  • Article

    The sea cucumber fishery in Palawan, Philippines 

    JBS Jontila, HM Monteclaro, GF Quinitio, SM Santander-de Leon & JP Altamirano - Kuroshio Science, 2018 - 高知大学大学院黒潮圏海洋科学研究科
    This paper presents the nature of sea cucumber fishery in Palawan, Philippines with information on gathering practices, commonly traded species and secondary accounts on wild populations. Current issues on sea cucumber fishery are also presented here along with recommended doable management measures.
  • Article

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

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

    Responsible aquaculturists: The information-seeking behavior of milkfish farmers in Iloilo, Philippines 

    DL Superio, ES Nemiz, MGH Oliveros, VEV Pacullo, AMA Yap-Zerrudo & JB Canaman - Information Development, 2018 - SAGE Publications
    Compliance with a policy, law, standard or code requires understanding of its provisions. However, for someone to understand it, he must be aware of its existence and be provided access to it. A qualitative-quantitative research was conducted to determine the awareness of milkfish farmers about the Philippine Code of Practice for Aquaculture in the municipalities of Leganes and Zarraga, Iloilo Province, the Philippines and their information-seeking behaviors. Results revealed that the majority of the respondents were not aware of the existence of the Code, hence, there is a low level of compliance. When seeking everyday life information, the majority of the milkfish farmers depended on television, personal or person-to-person communication and radio, while when seeking for fish farming information, personal communication was the preferred source. None of the respondents was aware of the existence of their municipal libraries.
  • Article

    Limit of colour vision in dim light in larvae of the giant freshwater prawn Macrobrachium rosenbergii 

    G Kawamura, TU Bagarinao, ASK Yong, AB Faisal & LS Lim - Fisheries Science, 2018 - Springer Verlag
    Colour vision depends on sufficient ambient light and becomes ineffective at a particular low light intensity. It is not known how decapod crustaceans see colour in dim light. In the present study we investigated the colour vision threshold in larvae of the giant freshwater prawn Macrobrachium rosenbergii in a tank under natural illumination. Plastic beads of different colours (blue, red, yellow and white) in various combinations were suspended in the tank. The larvae swam straight toward the beads and gathered around them. The number of larvae was highest on the blue and white beads. The luminance in the tank was then gradually decreased by covering it with different numbers of layers of black cloth, and the response of the larvae to the beads was video-recorded under infrared illumination. The preference for blue and white beads remained manifest as the luminance was reduced from 418 to 0.07 cd/m2, but not at 0.02 cd/m2, indicating a colour vision threshold between 0.07 and 0.02 cd/m2. The larvae have apposition compound eyes with large optical parameters, comparable to those of apposition eyes of nocturnal insects, which presumably capture more light and show enhanced sensitivity, enabling the larvae to see colour in dim light.
  • Article

    Larval rearing of mud crab (Scylla): What lies ahead 

    K Waiho, H Fazhan, ET Quinitio, JC Baylon, Y Fujaya, G Azmie, Q Wu, X Shi, M Ikhwanuddin & H Ma - Aquaculture, 2018 - Elsevier
    The increasing global demand for mud crabs (genus Scylla) and threats to the wild populations highlight the urgency of fully rearing them in captivity. Despite considerable progress in mud crab production, most crab farms still rely heavily on wild-caught crablets and juveniles while the low and inconsistent success rates of larviculture remain as the main bottleneck impeding the development of mud crab aquaculture. Over the years, numerous studies have been conducted to determine the optimum larval rearing parameters, the ontogenic changes in digestive function and feeding behaviour, and the diets for different larval stages. These data, however, are dispersed and not summarised to inform culture practices. This review provides an update on the current progresses and to pinpoint the gaps in knowledge regarding mud crab larval rearing. We include all four mud crab species under the genus Scylla, i.e. Scylla serrata, Scylla olivacea, Scylla tranquebarica and Scylla paramamosain. Knowledge compiled in this review serves as an important guideline for prospective mud crab larviculture. Future research should gear towards filling in the gaps in our knowledge to advance mud crab larval rearing, thus fully incorporating mud crab into the aquaculture sector.
  • Article

    Dietary onion or ginger modulates the stress response and susceptibility to Vibrio harveyi JML1 infection in brown-marbled grouper Epinephelus fuscoguttatus juveniles 

    EC Amar, MJS Apines-Amar & JP Faisan Jr. - Journal of Aquatic Animal Health, 2018 - American Fisheries Society
    Onion Allium cepa and ginger Zingiber officinale have health‐promoting properties that qualify them as functional foods. The effect of repeated acute stressors was examined in juvenile Brown‐marbled Grouper Epinephelus fuscoguttatus that were fed four diets supplemented with onion at 1.8%, ginger at 1.8%, vitamin C at 0.86%, and β‐glucan at 0.8% of the diet. The non‐supplemented diet served as the control. After 12 weeks of feeding, fish were exposed to stressors and were experimentally infected with a fish pathogen, the bacterium Vibrio harveyi JML1. After repeated exposure to hypoxia, cortisol levels rose significantly in the non‐supplemented fish compared to those fed onion, ginger, β‐glucan, or vitamin C. Within groups, postexposure cortisol levels in the onion‐, ginger‐, and vitamin C‐fed fish did not change relative to pre‐stress levels, whereas significant increases in poststress values were observed in the control and β‐glucan groups. The net cortisol increase was also significantly greater in the non‐supplemented group compared to the supplemented groups. The net cortisol increase did not vary among the supplemented groups except that the β‐glucan‐fed group exhibited a higher net increase than the onion‐fed group. Similarly, repeated acute exposure to osmotic stress significantly increased the plasma cortisol level in the non‐supplemented group compared to groups that received supplements; no differences were found in the supplemented groups except the β‐glucan group. Within groups, significant increases in poststress values relative to pre‐stress levels were found only in the control and β‐glucan groups. Repeated acute exposure to hypoxia significantly increased cumulative mortality in the control group compared to the supplemented groups (except the β‐glucan group), whereas repeated exposure to acute osmotic stress significantly increased cumulative mortality only in the control group 10 d after infection with V. harveyi JML1. Based on our collective results, most of the supplemented groups performed better than the control, but the best supplements were onion and ginger in terms of enhancing stress tolerance and increasing survival of Brown‐marbled Grouper upon infection with V. harveyi JML1.
  • Article

    Genetic assessment of milkfish (Chanos chanos Forsskal) stocks based on novel short tandem repeats for marker-aided broodstock management 

    MRR Romana-Eguia, BS Santos, M Ikeda, ZU Basiao & A Kijima - Aquaculture Research, 2018 - John Wiley and Sons
    Milkfish hatchery broodstock are either from on-grown wild-caught or hatchery-produced fry/juveniles. To determine if a marker-assisted management scheme can be formulated for improved milkfish hatchery production, milkfish stocks were genetically characterized using nine novel short tandem repeats or microsatellites. Eight wild-bred Philippine stocks (CLA, CUR, CAM, SIH, SBH-I1, HH, PAL and ZH-P0), four hatchery-bred stocks (SBH-I2, SBH-D, BoH and ZH-F1), two farm stocks of known mixed lineages (SPH and BDH) and one Indonesian hatchery-bred stock (WJH) were assessed. WJH was included since milkfish fingerlings from Indonesia reared in Philippine farms could be developed into future broodstock. Mean allelic richness (Ar) was highest in wild-bred stocks (9.5) and lowest in hatchery-bred spawners (9.1). Mean expected heterozygosities (He) were relatively similar in all stocks with wild-bred stocks slightly higher (0.67) than the others. An analysis of molecular variance indicated significant yet low genetic differentiation among stocks (FST = 0.013; p = .000) where variation (98.6%) was explained by intra-stock differences. In some of the domesticated stocks, reductions in mean allelic richness were observed in first generation hatchery broodstock (e.g. ZH-F1; Ar = 8.3), compared with their founder stock (e.g. ZH-P0; Ar = 9.4). The Indonesian stock was similar to local wild-bred stocks based on genetic variability indices; thus, it might be likely that the local stocks’ fitness traits could be comparable with the imported milkfish stock which has been perceived to be better. The quality of locally available farmed milkfish and prospects of formulating a broodstock management scheme for the production of good quality milkfish seedstock are herewith discussed.
  • Article

    Characterisation of Vibrio isolates recovered from the eyes of cage-cultured pompano (Trachinotus blochii) infested with caligid parasites (Lepeophtheirus spinifer) 

    R Pakingking Jr., NB Bautista, D Catedral & EG de Jesus-Ayson - European Association of Fish Pathologists Bulletin, 2018 - European Association of Fish Pathologists
    Exophthalmia was documented among sea cage-cultured pompano (Trachinotus blochii) broodstocks with caligid parasite (Lepeophtheirus spinifer) infestation in the Philippines. Following sequencing, and based on the results of both diagnostic investigations and infection experiments, V. harveyi likely had a role in the reported exophthalmia cases, and this was initiated by L. spinifer infection.
  • Article

    Low ph water impairs the tactile sense of the postlarvae of the giant freshwater prawn Macrobrachium rosenbergii 

    G Kawamura, T Bagarinao, ASK Yong, SN Noor & LS Lim - Tropical Life Sciences Research, 2018 - Penerbit Universiti Sains Malaysia
    The effect of low pH on the tactile sense of Macrobrachium rosenbergii postlarvae was determined in the laboratory by means of two behavioural assays: shelter (netting) occupancy and jumping response to touch stimuli (taps) by a glass micropipette. The postlarvae were acclimated to pH 4, pH 5, pH 6 and pH 7.5 (control) in 45 L aquaria 5−7 d before the experiments. Shelter occupancy decreased with pH and was significantly lower at pH 4 and pH 5 than at pH 6 and in the control. The jumping response instantly followed a tap 93−98% of the time in the control, pH 6 and pH 5 treatments. However, the postlarvae showed significantly lower jumping response (65%) at pH 4, indicating an impaired tactile sense. Low pH 4−5 probably degrades the chitin of the sensory setae and inhibits the surface mechanoreceptors of the prawn postlarvae.
  • Article

    Does age matter?: The information-seeking behavior of Filipino aquaculture researchers 

    DL Superio - Journal of Library Administration, 2018 - Taylor & Francis
    Findings of previous studies revealed that regardless of the objective, age does affect the information-seeking behavior of an individual. Likewise, this study found the same results. Although all of the younger Filipino aquaculture researchers preferred the Internet to begin their search process, it was found that they were more frequent library users, and more reliant on librarians than their older counterparts. Likewise, they preferred the combination of print and electronic formats when reading. Thus, they would print and save the retrieved electronic copy of information at least very often. The study is a valuable addition to the information-seeking behavior studies on Filipinos, and the first to tackle the effects of age on the information-seeking behavior of Filipino aquaculture researchers.
  • Article

    Effects of the dietary fermented tuna by-product meal on growth, blood parameters, nonspecific immune response, and disease resistance in juvenile olive flounder, Paralichthys olivaceus 

    FO Oncul, FA Aya, A Hamidoghli, S Won, G Lee, KR Han & SC Bai - Journal of the World Aquaculture Society, 2018 - World Aquaculture Society
    This study evaluated the effects of dietary fermented tuna by‐product meal (FTBM) in juvenile olive flounder, Paralichthys olivaceus. Five diets were formulated to replace fishmeal (FM) with FTBM at 0% (FTBM0), 12.5% (FTBM12.5), 25.0% (FTBM25), 37.5% (FTBM37.5), or 50% (FTBM50). After 8 wk, weight gain, specific growth rate, and feed efficiency of fish fed FTBM0 and FTBM12.5 diets were significantly higher than fish fed the other diets (P < 0.05). Also, mean cumulative survival rates (%) of fish fed the FTBM0 and FTBM12.5 diets were significantly higher than those fed FTBM50 diet at Day 9 postchallenge with Edwardsiella tarda (P < 0.05). Protein efficiency ratio of fish fed FTBM0 and FTBM12.5 diets was significantly higher (P < 0.05) than fish fed diets FTBM37.5 and FTBM50. Broken‐line regression analysis of weight gain showed an optimal FM replacement level of 10.65% with FTBM. Therefore, the optimal dietary inclusion of FTBM in juvenile olive flounder diets could be greater than 10.65% but less than 12.5% without any adverse physiological effects on fish health.
  • Article

    Quality assessment of newly hatched mud crab, Scylla serrata, larvae 

    ET Quinitio, JJ dela Cruz-Huervana & FD Parado-Estepa - Aquaculture Research, 2018 - Wiley
    Starvation and exposure to formalin were investigated as possible stress tests for evaluating the quality of mud crab, Scylla serrata, larvae. For the starvation stress test, newly hatched zoeae stocked in 150-ml containers were either starved or fed rotifers. Similarly, newly hatched zoeae were stocked in containers with seawater of 0 (control), 20, 30 and 40 mg/L formalin for the formalin stress test. The zoeae from the same batches were used for seed production to monitor their performance and validate the results of stress tests. Starvation was found to be unsuitable for larval quality evaluation. However, the impact of initial food deprivation on the newly hatched larvae indicates that feeding immediately after hatching is necessary for mud crab larvae. Exposure of larvae to 40 mg/L formalin for 3 hr appeared to be a reliable and practical method for larval quality assessment as the survival of larvae in the mass production tanks validated the classification of good and poor quality batches in the stress tests. On this basis, a hatchery operator can decide which batch should be cultured further. Finally, there appears to be a link between the quality of larvae and the performance at the megalopa and early juvenile crabs.

View more