Wenresti Gallardo

Wenresti Gallardo
Sultan Qaboos University | SQU · Department of Marine Science and Fisheries

PhD Marine Science
Teaching, research & outreach

About

53
Publications
18,559
Reads
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928
Citations
Introduction
My research interests are on aquaculture, aquaponics and aquatic resources management. Since 1989, I have been conducting research and also teaching at the Southeast Asian Fisheries Development (SEAFDEC, Philippines), Nagasaki University (Japan), Asian Institute of Technology (Thailand), and Sultan Qaboos University (Oman). I was a recipient of the Outstanding Young Scientist (OYS) award from the National Academy of Science and Technology (NAST) of the Philippines in 2004.
Additional affiliations
September 2013 - present
Sultan Qaboos University
Position
  • Professor (Associate)
April 2005 - August 2013
Asian Institute of Technology
Position
  • Professor (Associate)
April 1989 - June 2004
Southeast Asian Fisheries Development Center (SEAFDEC)
Position
  • Researcher
Education
April 1997 - March 2000
Nagasaki University
Field of study
  • Marine Science
April 1995 - March 1997
Nagasaki University
Field of study
  • Fisheries
March 1988 - April 1989
University of the Philippines Visayas
Field of study
  • Aquaculture

Publications

Publications (53)
Article
Full-text available
Evaluation of chemical and nutritional compositions and in vitro digestibility of brown seaweed and green seaweed in southern Oman
Article
Full-text available
An experiment was conducted to develop a land-based recirculating integrated multi-trophic aquaculture (IMTA) system using a combination of the Omani abalone (Haliotis mariae) and Asian seabass (Lates calcarifer) as fed species, brown mussel (Perna perna) and seaweed (Ulva fasciata) as extractive species. Specifically, this study was carried out to...
Article
Mariculture cage farming in Oman is in its infancy stage. This study provides important baseline information about the initial state of mariculture in Oman and for the sustainable management of future local cage farming. Our main objective was to evaluate the spatio-temporal variations of water quality and hydrography around a gilthead seabream ( S...
Article
Full-text available
Treated chicken feather meal with 20, 35 and 50% replacement of fish meal (20, 35, 50 CHF), algal meal with 20 and 35% replacement of fish meal (20, 35 AM) and control diet (CNL) were tested for attractability and pa-latability to juvenile gilthead seabream, Sparus aurata. Biochemical analysis of the ingredients revealed that treated chicken feathe...
Article
Full-text available
Objective: The aim of this study was to determine the effects of NaOH addition, autoclaving and their combination on the protein and pepsin digestibility of chicken feathers. Methodology: The first experiment consisted of the following treatments: (1) The 2 h treatment with 1.0 M of NaOH, (2) The 12 h treatment with 1.0 M of NaOH, (3) The 24 h trea...
Article
This study identifies stakeholders’ perceptions of ecosystem services (ESS) along the Mekong River in Vietnam. It evaluates trade-offs made between ESS under different Pangasius catfish development scenarios, and stakeholders’ preferences to these scenarios. The study was conducted through interviews, focus group discussions and a questionnaire sur...
Article
Silver nanoparticles (SNPs) are widely used in a variety of biomedical and consumer products as an antimicrobial additive. The present study was conducted to evaluate the impacts of low-dose SNPs on intestinal physiology of tilapia (Oreochromis niloticus L.) for assessing its apparent environmental risk due to extensive commercial use. SNPs were sy...
Article
Mangrove ecosystems provide a variety of services to people living on the coasts, in particular fishers whose livelihoods depend on healthy stocks of fish and other marine products. Fishers' participation and their understanding about mangroves are vital in mangrove management. This research was conducted to identify the factors contributing to the...
Article
An understanding of traditional local knowledge and practices is widely viewed as critical for the establishment of sustainable local fishery management. Locals‘ perceptions of governmental fishery regulations, the use of local knowledge and local practices in fishery management, and fishers‘ attitudes toward cooperation with the government are of...
Article
Full-text available
Bacterial infection in aquaculture is mainly controlled by the use of antibiotics. However, indiscriminate use of antibiotics is undesirable, as this often leads to the development of drug resistance and therefore to a reduction in the efficacy of drugs. There is urgent need to look for cheaper and more environmentally friendly alternative approach...
Conference Paper
Full-text available
Cobia, Rachycentron canadum, is a widely distributed species from the Indo-Pacific waters to the southern Atlantic Ocean. In Vietnam, it is an indigenous and an ideal species for cage culture. Due to its high market value in both domestic and international markets, the technology for its culture has rapidly developed in the past few years. For its...
Article
Full-text available
Increment of industrial development and energy demands for transportation and electricity have increased diesel-fuel uses to fulfil global energy needs. Carbon emission as impact of high fossil diesel use which pollutes the air gradually increases green house gases (GHG) and increases the intensity of acid rains. Furthermore, scarcity of fossil-fue...
Article
Full-text available
This study employed image enhancement for LANDSAT TM and ALOS imagery to monitor the changing status of coastal resources from 2001 to 2011, object-based classification of high-resolution THEOS imagery to extract fish cage culture sites and interpolation methods to determine marine environmental quality in 2011 in the northern part of Phu Quoc Isla...
Article
Penaeus monodon and Penaeus indicus are found in sandy beaches and mangrove areas in Saadan estuary (Tanzania). Artisanal prawn fishers harvest penaeids in the estuary all year-round causing growth overfishing and reduction of broodstock which in turn affect inshore recruitment and offshore stock recovery. Scientific information on the distribution...
Article
Cobia fish cage is the most popular marine culture species raised in Phu Quoc Island, Vietnam. For its sustainable development, there is a need to determine the carrying capacity to avoid negative marine environmental impact in the future. This study was carried out to collect water samples each two months at the lowest and highest tides at four po...
Article
Most government projects are implemented with little input and participation from the local people. The objective of this study was to assess the fishers' socio-economic status, their perceptions on the aquatic resources and fisheries management, and their recommendations for improvement of fisheries management in the freshwater fishing area of the...
Thesis
A study was conducted to investigate the efficacy of dietary administration of herbal extract for the hematology, immune response and disease resistance of the Nile tilapia against Streptococcus agalactiae Biotype 2. Six herbs were screened for antibacterial activity against the bacterium. Among all the tested herbs, Moringa leaves extract displaye...
Article
Full-text available
This study was conducted to assess the health of the aquatic environment, particularly its physicochemical variables and the diversity of phytoplankton, zooplankton, macrobenthos and nekton in the freshwater fishing area of the Pak Phanang River Basin (PPRB) of Nakhon Si Thammarat Province, southern Thailand, at three different sites (upstream, mid...
Article
Full-text available
Since fishery resources are regarded as an important source of income and food security, these resources need to be protected and conserved for sustainable use. To do this, the government of Cambodia has revised its policies, shifting management and responsibility to the local level. In response to government policy, Krala Peah village community fi...
Article
Full-text available
This study examined the effect of three extenders, Marine Fish Ringer (MFR), sodium citrate (CT), and sodium chloride (NaCl) and two cryoprotectants (10% dimethyl sulfoxide—DMSO and 15% Trehalose) on the cryopreservation of giant grouper, Epinephelus lanceolatus sperm which was later used for hybridization trial with orange-spotted grouper, Epineph...
Article
Full-text available
Stakeholder participation is crucial for collective environmental management. This article unearths factors that influence stakeholder involvement, with emphasis on their associated origins. The management of a drainage canal in Map Ta Phut industrial estate, Thailand, was studied. Seven types of constraints were identified, namely: (a) distrust, g...
Article
We investigated the effects of the stocking density of white shrimp (Litopenaeus vannamei) on shrimp and tilapia growth and nutrient conversion in an integrated closed recirculating system both with and without Nile tilapia (Oreochromis niloticus). A 2 × 3 factorial design involving tilapia presence/absence and shrimp stocking densities of 40, 80 a...
Article
Full-text available
A study was conducted to assess the ecosystem health of Lower Songkhram wetland in Thailand, using a newly developed wetland ecosystem health index (WEHI) based on analysis of field survey and secondary data of the most dominant physical, environmental and socio-economic factors extracted by principal components analysis (PCA). The most influential...
Article
Full-text available
Mudskipper (Pseudapocryptes elongatus) has become a high value species (US$ 8 kg -1 in June 2008) in the markets of Mekong Delta, Viet Nam. This leads to high pressure on its fishery and increasing interest on its aquaculture. An investigation was conducted on 40 juvenile fishermen and 72 mudskipper farmers in Soc Trang and Bac Lieu provinces of th...
Article
Full-text available
This study has depicted a scenario on assessing spatial and temporal land use/cover changes in and adjacent to marine protected areas (MPA) in a study site in Thailand. The measurement of landscape stability and its implications for protection and conservation of coastal resources are emphasized in this study. The methods employed include interpret...
Article
This study attempts to integrate environmental economics and coastal engineering in managing port-induced coastal erosion occurring at a common beach by using Map Ta Phut port in Thailand as a case study. The existence of the port creates coastal erosion which can be considered an externality that affects local inhabitants, and a port owner and shi...
Article
Keywords: Environmental performance indicators ISO14001 Port state control Industrial port and estate Thailand a b s t r a c t This study integrates procedures of ISO14001 and port state control to establish environmental perfor-mance indicators (EPIs), specific to industrial ports and estates. Industrial Estate Authority of Thailand (IEAT), an own...
Article
Full-text available
Natural populations of global inshore fisheries are coming under heavy pressure, primarily due to overexploitation and habitat degradation. Stock enhancement of hatchery-reared seeds is perceived as an alternative strategy to enhance the regeneration process. The Aquaculture Department of the Southeast Asian Fisheries Development Center in the Phil...
Article
Full-text available
A growth hormone (GH)-like substance was extracted from the rotifer Brachionus plicatilis and subsequently purified by gel filtration and ion exchange chromatography. The GH-like substance had a molecular weight of approximately 28 kDa and had cross-reactivity with salmon GH antibody. In vivo bioassay showed a higher intrinsic rate of increase and...
Article
A method of marking abalone (Haliotis asinina Linne) for sea ranching and stock enhancement purposes was developed. Three-month-old abalone juveniles (11.8-mm shell length, 0.28 g) were fed artificial diets for 1, 2, or 3 weeks. The width of the bluish-green shell band produced by abalone juveniles was 1.7, 2.6, and 4.2 mm after 1, 2, or 3 weeks of...
Article
Different biological films reportedly effective in larval settlement of other abalone species were tested on the tropical abalone Haliotis asinina to determine the most effective settlement inducers for the species. Larval attachment was significantly higher on mucus, Navicula, Navicula+mucus, and mixed diatoms+mucus than on mixed diatoms and the b...
Article
Full-text available
Gamma-aminobutyric acid (GABA) has been shown to enhance the reproduction of the rotifer Brachionus plicatilis Muller in stressful culture conditions. During the enrichment of rotifers for feeding to marine fish larvae, they are usually stressed as a result of exposure to different marine oils and high population densities. This typically results i...
Article
Techniques to culture rotifers at high-density (2000 to 20 000 ind./ml) have been developed by utilizing condensed phytoplankton products. Many public hatcheries in Japan have introduced automated systems for culturing and harvesting rotifers. Research has been conducted on the diagnosis of rotifer culture status and chemical treatment for reducing...
Article
gamma-Aminobutyric acid (GABA) and 5-hydroxytryptamine (5-HT) have been shown to increase the reproduction of the Brachionus plicatilis (NH3L strain). In the present study, the endogenous presence of GABA and 5-HT in the rotifers B. plicatilis (NH3L and Kamiura strains) and Brachionus rotundiformis (Langkawi strain) were confirmed by dot blot immun...
Article
Juvenile hormone (JH) and serotonin (5-HT) were previously shown to enhance mictic (sexual) female production of the rotifer Brachionus plicatilis in batch cultures. To explore the basis of these effects, experiments were conducted on isolated individuals. JH treatment of maternal rotifers with 5 and 50 µgml(-1) (18.8 and 187.7 µM) resulted in sign...
Article
Based on the results of individual and batch culture experiments in small volumes, we conducted experiments in larger volumes of 100 mL, 1 L and 10 L to determine: (1) at what phase of population growth would gamma-aminobutyric acid (GABA) treatment be most effective; and (2) whether GABA treatment of concentrated rotifers for several hours before...
Article
Growth hormone (GH, 0.0025 and 0.025 I.U. ml−1) and γ-aminobutyric acid (GABA, 50 μg ml−1) enhance rotifer population growth in batch cultures. In order to further understand the mechanism of their actions, we conducted experiments culturing isolated females at low food and high free ammonia levels. At an optimum food level of 7×106Nannochloropsis...
Article
Full-text available
Eight vertebrate and invertebrate hormones were screened for their effect on population growth, mictic female production, and body size of the marine rotifer Brachionus plicatilis. Growth hormone (GH) or human chorionic gonadotropin (HCG) at 0.0025–25 I.U. ml−1 and estradiol-17ß (E2), triiodothyronine (T3), 20-hydroxyecdysone (20-HE), 5-hydroxytryp...
Article
Rapid Rural Appraisal (RRA) was conducted in the fishing village of Lakaran, in the municipality of Dumangas, Iloilo province to identify the resources, livelihood, problems, opportunities, and socioeconomic condition of the villagers prior to the conduct of farmer participatory research on mussel farming. RRA tools such as the construction of the...
Article
The window-pane shell Placuna placenta or ‘kapis’ has great economic importance in the Philippines. The translucent shell is used in the manufacture of lampshades and other shellcraft items exported to Europe, USA and Japan. Due to its high demand, excessive and uncontrolled gathering of kapis has been noted over the past years. Its possible deplet...
Article
A study was conducted to determine a suitable algal diet for the window-pane oyster, Placuna placenta Linnaeus, during gonad development. Sexually immature P. placenta (70 mm shell height) were fed Isochrysis galbana Parke, Tetraselmis tetrahele (G.S. West) Butch, or their 1:1 combination, at 100 000 cells per ml divided into two rations per day. T...
Article
The catch composition, annual catch and its monetary values of Pak Phanag mangroves fisheries, Nakhon Si Thamarat province, South Thailand were studied during September 2004 to February 2005. Samples of catches were taken four times from each type of gear used by the fishermen in the locality. Samples were preserved in 10% formalin solution and bro...
Article
The abundance, biomass, diversity and community structure of fish in natural and reforested natural mangrove habitats were studied in Cogtong Bay, Bohol, Philippines to determine whether a reforested mangrove habitat can function as well as the natural mangrove habitat. After a history of heavy exploitation of mangroves along the bay, mangroves hav...
Article
長崎大学学位論文 学位記番号:博(海)甲第179号学位授与年月日:平成12年3月31日

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Projects

Projects (7)
Archived project
Archived project
Project
To replace fish meal with chicken feather meal and algal meal. To study the digestibility of the diets. To investigate the attractability and palatability of the diets.