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Drying of mackerel was conducted using solar biomass hybrid tunnel dryer (S-BHTD) and open sun drying (OSD) at air temperatures 32.4-57.7 degreeC, relative humidity of 23.9-85.8% and air flow rate 0.20-0.6 ms-1. Solar radiation ranged... more
Drying of mackerel was conducted using solar biomass hybrid tunnel dryer (S-BHTD) and open sun drying (OSD) at air temperatures 32.4-57.7 degreeC, relative humidity of 23.9-85.8% and air flow rate 0.20-0.6 ms-1. Solar radiation ranged between 287-898 Wm-2 during the experimentation. During the night time, drying was carried out by combusting biomass. The fresh mackerel dried in experimental dryer and in open sun drying achieved the final moisture content < 17% (w.b.). The drying time required in S-BHTD was 21 h. The overall drying efficiency of the solar-biomass hybrid tunnel dryer was estimated to be about 5.42 during fish drying. S-BHTD significantly influenced the biochemical properties of dried mackerel. Mackerel dried by using S-BHTD showed very high corresponding coefficients of determination, where all R2 were greater than 0.85, except histamine value. In experimental dryer, microbial growth was not found except TPC (< 30 cfu/g) which was within the acceptable limit. Contour plots of dried mackerel in S-BHTD dryers also showed that for all the sensory attributes examined, panelists preferred more the fish dried with S-BHTD than OSD. The optimum points for all sensory attributes of dried mackerel evaluated at temperatures ranged from 45-55 degreeC for 20-30 h. Biochemical, microbial analysis and sensory evaluation showed that the dried mackerel remained acceptable after 120 days of storage at ambient temperature. The data showed that the drying in S-BHTD resulted in high quality dried mackerel. The study suggests that the experimental dryer could be used successfully to produce high quality dry fish.
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An experiment was conducted to evaluate the possibility of using inorganic fertilizer triple super phosphate (TSP), inorganic fertilizer 16:20 (a 16:20 grade fertilizer contains 16 percent N and 20 percent P20 5), rice-bran and... more
An experiment was conducted to evaluate the possibility of using inorganic fertilizer triple super phosphate (TSP), inorganic fertilizer 16:20 (a 16:20 grade fertilizer contains 16 percent N and 20 percent P20 5), rice-bran and duck-manure as phosphorus sources in formulated fish feed for Nile tilapia ( Oreochromis niloticus). Experiment was conducted for a period of 2 months in net-cages suspended in fertilized earthen ponds and all male sex-reversed Nile tilapia (9.39- 10.37 g) were used in the experiment. Seven treatments including one non-feed treatment were used in this experiment. Treatment 1 (non-feed), treatment 2 (-P) where fish fed with phosphorus non-supplemented diet acted as control 1 and treatment 3, 4, 5, 6 and 7 where fish fed with 3% di-calcium phosphate (DCP), 3% triple supper phosphate (TSP), 7% 16:20 inorganic fertilizer, 30% rice-bran and 30% duck-manure supplemented diet, respectively. Results showed that the TSP and 16:20 grade inorganic fertilizer supplementa...
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management systems in Bangladesh to introduce cage culture for resource-poor fisheries
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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... more
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 approaches to improve the immune system of fish than can act as stimulators to control diseases for sustainable aquaculture. In this study, bioactive extracts from five herbs were extracted using aqueous, chloroform and ethanol as solvents. Antimicrobial activity of aqueous extracts of Aegle marmelos, Emblica officinalis & Moringa oleifera, chloroform and ethanol extracts of Azadirachta indica & Toona sinensis were assessed against S. agalactiae Biotype 2 by using disk diffusion assay. The minimum inhibitory concentrations (MIC) of the herbs were determined by using well diffusion method. Aqueous extract of M. oleifera leaves resulted highest anti...
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The Asian seabass Lates calcarifer mostly familiar as barramundi or seabass is a commercially important species. Asian seabass is naturally distributed in the Indo-west Pacific region and cultured from the Persian Gulf, Arabian Gulf,... more
The Asian seabass Lates calcarifer mostly familiar as barramundi or seabass is a commercially important species. Asian seabass is naturally distributed in the Indo-west Pacific region and cultured from the Persian Gulf, Arabian Gulf, southeast Asia and Australia (FAO, 2020). Asian seabass is extremely carnivorous and can tolerate high salinity variations (Rimmer and Russell, 1998). High fecundity, captive breeding and rapid growth rate make this species a suitable candidate for aquaculture (de Jesus-Ayson &amp; Ayson, 2014; Venkatachalam et al., 2018). The ability to tolerate crowding, high turbidity, varying salinities and temperature makes it a relatively hardy species (Boonyaratpalin, 1997; Yue
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A preliminary ecological risk assessment approach was used to determine the potential ecological consequences of pesticide use for aquatic systems in Thailand. Using a two-tiered approach, data from participatory community appraisals and... more
A preliminary ecological risk assessment approach was used to determine the potential ecological consequences of pesticide use for aquatic systems in Thailand. Using a two-tiered approach, data from participatory community appraisals and household surveys were employed to assess exposure risk. Two sites representing monocrop (tangerine) and mixed-crop (vegetables and fruit) systems were studied. In the first tier the Predicted Environmental Concentration (PEC) is based on an 'extreme worst case'loading scenario. ...
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All-female giant freshwater prawn Macrobrachium rosenbergii has a significant growth limitation due to its early sexual maturity. A 60-day trial was carried out to determine the effect of beta-agonist, ractopamine hydrochloride (RAC), on... more
All-female giant freshwater prawn Macrobrachium rosenbergii has a significant growth limitation due to its early sexual maturity. A 60-day trial was carried out to determine the effect of beta-agonist, ractopamine hydrochloride (RAC), on the growth performance, body composition, and gonadal maturation of all-female prawns. Prawn juveniles ( 4.39 ± 0.40 g initial weight) were stocked at 10 prawns/m2 in 15 plastic tanks (1000 liters each) in a completely randomized design with four treatments and a control (0, 5, 10, 15, and 20 mg/kg) in triplicate. The significantly ( p < 0.05 ) highest values of final weight, weight gain, daily weight gain, and specific growth rate (SGR) were observed in the female prawns fed with the diet containing 10 mg/kg RAC, while the lowest values were found in the control tank. Similarly, survival rate, feed conversion rate (FCR), and condition factors were observed among all treatments, which were significantly better than the control (0 mg/kg). Signifi...
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management systems in Bangladesh to introduce cage culture for resource-poor fisheries
Inland aquaculture is one of the promising livelihoods in Asian countries. Over time, accumulation of sediments reduces the capacity of fishponds and threatens the farmers engaged in this industry. Removal and disposal of sediment in... more
Inland aquaculture is one of the promising livelihoods in Asian countries. Over time, accumulation of sediments reduces the capacity of fishponds and threatens the farmers engaged in this industry. Removal and disposal of sediment in fishponds are practiced, but lead to environmental degradation. Nitrate contamination of groundwater and eutrophication of surface water are two major concems associated with improper sediment disposal, which have not yet athacted due attention from researchers. On the other hand, pond sediment is enriched with organic matter, nitrogen, phosphorus, and macro and micronutrients as well, and hence, it can be a potential fertilizer supplement and soil conditioner, which could enhance the soil environment for crops. Agricultural uses of sediment would lead to reduced fertilizer inputs, thus increasing economic benefits while reducing the negative impacts on aquaculture and on the environment, which is promising towards a new dimension in sustainable agricul...
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Several studies presented the occurrence of fishing down the marine food web in different part of the world including Thailand. Some data from Gulf of Thailand were conducted from 1966-1982 and 1977-1997 which showed a decline in the mean... more
Several studies presented the occurrence of fishing down the marine food web in different part of the world including Thailand. Some data from Gulf of Thailand were conducted from 1966-1982 and 1977-1997 which showed a decline in the mean trophic level but did not determined the subsequence trends. Therefore, this study was focus on the analyzing of trend in trophic level and fishing-in-balance index to determine the effect of fishing and other factors. The data of trawl survey from 1988-2007 and the data of fish landing from 1990-2007 which used in this study derived from the department of fisheries, Thailand. Base on number of species or groups composition, hierachical cluster was analyzed using 10 trawl stations resulted in two main clusters covered province of Rayong, Chanthaburi and Trad. The data indicated that from 1988 to 2007, mean trophic level decreased from 3.28 to 3.10 (decline 0.09/decade) in cluster1 and 3.27 to 3.13 (decline 0.07/decade) in cluster 2. The fishing-in-...
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Remote sensing (RS) was used to detect land use changes caused by shrimp farming and other activities, to examine the status of shrimp farming, and to recommend a management guideline for sustainable shrimp farming development. The study... more
Remote sensing (RS) was used to detect land use changes caused by shrimp farming and other activities, to examine the status of shrimp farming, and to recommend a management guideline for sustainable shrimp farming development. The study was conducted at Doson and Kienthuy districts of Haiphong, Vietnam, during June-December 2002. Three images for dates in 1990, 1995 and 2000 were used. The images were radiometrically normalized and geometrically registered to a UTM map projection. Each image was separately classified into different categories of aquaculture ponds, agricultural land, salt farms, village mixed orchards, urban and build-up land, mangroves, rangeland, hill-land forest and open water. Visual image classification in conjunction with associated topographic maps and related reports was employed on all images. The classified images produced were analysed for changes in each land use category by overlaying them in a geographical information system (GIS) framework. The result...
This study quantified coastal debris along 3 beaches (Angsila, Bangsaen, Samaesarn) in eastern coast of Thailand. Debris samples were collected from lower and upper strata of these beaches during wet and dry seasons. The results showed... more
This study quantified coastal debris along 3 beaches (Angsila, Bangsaen, Samaesarn) in eastern coast of Thailand. Debris samples were collected from lower and upper strata of these beaches during wet and dry seasons. The results showed that Bangsaen had the highest average debris density (15.5m(-2)) followed by Samaesarn (8.10m(-2)), and Angsila (5.54m(-2)). Among the 12 debris categories, the most abundant debris type was plastics (>45% of the total debris) in all beach locations. Coastal debris distribution was related to economic activities in the vicinity. Fishery and shell-fish aquaculture activities were primary sources of debris in Angsila while tourism activities were main sources in Bangsaen and Samaesarn. Site-specific pollution control mechanisms (environmental awareness, reuse and recycling) are recommended to reduce public littering. Management actions in Angsila should focus on fishery and shell-fish culture practices, while Bangsaen and Samaesarn should be directed...
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This study assessed the microplastic contamination of 3 most abundant sessile and intertidal invertebrates (Rock Oyster: Saccostrea forskalii, Striped Barnacle: Balanus amphitrite, Periwinkle: Littoraria sp.) in 3 beaches of the eastern... more
This study assessed the microplastic contamination of 3 most abundant sessile and intertidal invertebrates (Rock Oyster: Saccostrea forskalii, Striped Barnacle: Balanus amphitrite, Periwinkle: Littoraria sp.) in 3 beaches of the eastern coasts of Thailand. The results showed a significant accumulation of microplastics in the invertebrates at rates of 0.2-0.6 counts/g indicating higher pollution levels along the coastline. Filter feeding organisms showed comparatively higher accumulation rates of microplastics. Thus, contaminated bivalves pose potential health risks for seafood consumers. The plastic pollutant prevalence in sessile and intertidal communities was corresponded with pollution characteristics of contaminated beach habitats where they live. Thus, bivalves, gastropods and barnacles can be used as indicators for contamination of microplastics in the areas. This study also demonstrated the need for controlling plastic pollution in Thai coastal areas.
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Research Interests: Transformation, Food Production, Aquaculture, Phosphorus, Dynamics, and 3 moreModels, Behaviour, and Tropics
Eight drying trials were conducted in each solar tunnel dryer (STD) and compared with open sun drying (OSD). The drying behavior of mackerel drying in STD was studied by comparing eleven different drying models. The Midilli model provided... more
Eight drying trials were conducted in each solar tunnel dryer (STD) and compared with open sun drying (OSD). The drying behavior of mackerel drying in STD was studied by comparing eleven different drying models. The Midilli model provided the highest R2 (0.9928), lowest 2χ(0.000406) and RMSE (0.0164). The drying time required for STD and OSD were 27 and 48 h, respectively. The overall drying efficiency of the STD and OSD was about 19.87 and 12%, respectively. STD significantly influenced the biochemical properties such as Free fatty acid (FFA), Peroxide value (PV), Thiobarbituric acid (TBA), total volatile bases nitrogen (TVB-N), Trimethylamine nitrogen (TMA-N) and histamine of dried mackerel. There was a significant positive relationship between drying temperature and time (R2>0.85). No microbial growth on dried product was found in STD dried fish. Sensory quality of dried mackerel was judged by ten experienced sensory panel experts using a seven point hedonic scale. The fish dried at temperatures ranging from 40-46 oC for 20-30 h were awarded the highest scores by the sensory panel. Contour plots of dried mackerel showed that for all sensory attributes examined, panelists preferred fish dried with STD. Time series sensory evaluation of the shelf-life revealed that dried mackerel stored at ambient temperature is acceptable to the sensory panel until 154 and <98 days, for STD and OSD, respectively. The financial analysis showed that the average net income year-1 (for 10 years) is about 45,223 Indian Rupees (INR) and the pay-back period is <1.5 years. Key words: Solar tunnel dryer, dried mackerel, mackerel quality, mackerel drying modeling; open sun drying
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ABSTRACT Summary (En) 10 ill., 2 tables
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A study was conducted in southwest coastal areas of Bangladesh to assess the status and to understand the degree of awareness of the FAO Code of Conduct for Responsible Fisheries among different stakeholders and its application in the... more
A study was conducted in southwest coastal areas of Bangladesh to assess the status and to understand the degree of awareness of the FAO Code of Conduct for Responsible Fisheries among different stakeholders and its application in the area of shrimp culture in ...
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Research Interests: Geography, Earth Sciences, Land management, Water Availability, Vietnam, and 13 moreEnvironmental Sciences, Environmental Issues, Land Use, Integrated Coastal and Ocean Management, Population Density, Thematic Maps, Soil Quality, Land evaluation, soil pH, Soil Type, Socio Economic Status, Geographic Information System, and Soil Texture
The aquarium fish industry in Sri Lanka has become a valuable foreign exchange earner during the past few years, earning Rs. 530 million in 1998. Sri Lankan ornamental fish exports for the international market include locally wild caught... more
The aquarium fish industry in Sri Lanka has become a valuable foreign exchange earner during the past few years, earning Rs. 530 million in 1998. Sri Lankan ornamental fish exports for the international market include locally wild caught marine, brackish-water and freshwater species as well as captive bred freshwater fish. Presently, there are about 18 registered aquarium fish exporters and
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ABSTRACT Growth performance, survival and feed utilization of diploid (2n) and triploid (3n) sex-reversed male and female Nile tilapia were evaluated at maintenance feeding (1% body weight (BW) day−1), fixed feeding (3% BW day−1) and... more
ABSTRACT Growth performance, survival and feed utilization of diploid (2n) and triploid (3n) sex-reversed male and female Nile tilapia were evaluated at maintenance feeding (1% body weight (BW) day−1), fixed feeding (3% BW day−1) and apparent satiation feeding levels in a freshwater recirculation system comprised of thirty-six 1-m3 concrete tanks at the Asian Institute of Technology, Bangkok, Thailand. Triploid Nile tilapia (3n) was produced by subjecting fertilized diploid (2n) tilapia eggs to heat shock. After hatching, fish were sex-reversed to all-male and all-female populations by oral administration of 17 α-methyltestosterone (60 mg kg−1 feed) and ethynylestradiol (100 mg kg−1 feed) respectively.There was significantly higher growth with increased ration levels in both male and female groups. There were no significant differences in final BW, specific growth rate, survival rate, feed conversion ratio and protein efficiency ratio between diploid and triploid fish. Triploids had lower gonad weights than diploids, and this was particularly evident at the satiation feeding level. Triploid fish had a significantly higher apparent net protein utilization and percentage of gutted weight than diploids at all feeding levels. Higher protein utilization efficiency of triploids might be an advantage for commercial tilapia culture but further research is necessary to make such a conclusion.
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ABSTRACT Yeast fermentation integrated with water soaking was applied as a method to reduce the levels of some anti-nutritional factors in canola meal. The procedure completely eliminated glucosinolates and it reduced phytic acid content... more
ABSTRACT Yeast fermentation integrated with water soaking was applied as a method to reduce the levels of some anti-nutritional factors in canola meal. The procedure completely eliminated glucosinolates and it reduced phytic acid content by 18%. It also led to increase of 9% of crude protein and 8–32% of some minerals in the meal. A 60-day feeding trial was conducted to evaluate replacement of dietary soybean meal protein with yeast-fermented canola meal for Nile tilapia at ratios of 0, 25, 50, 75 and 100% respectively. Three groups of fish with an initial weight of 10 g were fed with each diet twice a day to an apparent satiation. The results showed that there were non-significant differences (P &gt; 0.05) in growth, survival rate, feed intake and feed conversion ratio for all fish fed with the test diets. However, replacement with 75 and 100% levels significantly reduced (P &lt; 0.05) protein efficiency ratio and nutrient digestibility of protein, lipid, ash, Ca, Mg and P of fish compared with the lower levels. The low retention of protein, lipid, ash, Ca, Mg and P were also observed. These effects seemed to be related to an increased dietary phytic acid.
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Research Interests: Water quality, Vietnam, Production Management, Aquaculture, Risk Analysis, and 12 moreSeasonality, Penaeus Monodon, Technical efficiency, Fisheries Sciences, Stocking Density, Survival Rate, Water Quality, Economic Efficiency, Crop Yield, White Spot Syndrome Virus, Laboratory Tests, and Production Cost
Research Interests: Management, Zoology, Technology, Accounting, Vietnam, and 26 moreLandscape, Aquaculture, Animal Production, Biodiversity Conservation, Difference, Habitat, Rice, Resources, Rights, System, Farming, Systems, Fisheries Sciences, Order, Field, Habitats, Concept, Ecosystem service, Management Practice, Aquatic Habitat Model, Countries, Areas, Aquatic Animals, C, Fields, and Wild animal
A plethora of literature exist regarding the health benefits of polyunsaturated fatty acids (PUFA) to man. Human evolution passed through a stage where ω-3: ω-6 PUFA ratio was 1 but with modernization this ratio has decreased in favour of... more
A plethora of literature exist regarding the health benefits of polyunsaturated fatty acids (PUFA) to man. Human evolution passed through a stage where ω-3: ω-6 PUFA ratio was 1 but with modernization this ratio has decreased in favour of ω-6 PUFA with attendant increases in inflammatory diseases. This review therefore focused on the importance of tilapia as a food fish in human diets and a cursory look at the metabolism of PUFA as well as existing protocols for incorporation in the flesh of tilapia and other food animals with a view to understanding protocols for increased incorporation in tilapia flesh as well as expected benefits. Dietary supplementation ω-3 PUFA: docosahexaenoic acid and eicosa pentaenoic acid (DHA and EPA), as found in fish oil, have been shown to decrease plasma triacylglycerols in humans, which helps to prevent atherosclerosis and coronary heart disease. Vegetable lipid sources in the diets of fish hold promise for sparing fish oil, which is currently a subject of debate between aqua culturists, scientists and conservationists. Linseed oil shows greater promise as a lipid feed constituent with ability to provide required ω-3 PUFA in muscle and plasma of fish with the possibility of transfer to man in the diets of fish
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An experiment was conducted in earthen ponds at the Asian Institute of Technology, Thailand to determine different phosphorus fertilizer dose effects on Nile tilapia production, water quality variables, nutrient utilization and... more
An experiment was conducted in earthen ponds at
the Asian Institute of Technology, Thailand to
determine different phosphorus fertilizer dose
effects on Nile tilapia production, water quality
variables, nutrient utilization and cost-benefit
under supplemental feeding. Five phosphorus fertilization
rates were used as treatments e.g. 100%,
75%, 50%, 25% and 0% of 7 kg P ha week
1.
Nitrogen fertilization rate was fixed at 28 kg
N ha week
1 for all the treatments. Sex-reversed
Nile tilapia were stocked at 3 fish m
2, and 30%
CP floating feed fed at 50% satiation feeding rate.
Nutrient budget showed higher phosphorus fertilizer
input resulted in higher phosphorus sink in
the sediment. Mean weight, mean weight gain,
daily weight gain and net yield were not significantly
different among treatments (P > 0.05).
Total Kjeldahl nitrogen, total phosphorus and soluble
reactive phosphorus were significantly different
among treatments. Economic analysis showed
phosphorus fertilization resulted in positive net
returns. Though the gross income was not affected
by different fertilization rates, significantly lowest
cost was found in the treatment using 25% phosphorus
fertilizer. It can be concluded from the
research that 25% phosphorus fertilization might
be used as an alternative strategy of Nile tilapia
pond culture in terms of economic return and
nutrient loss in sediment.
the Asian Institute of Technology, Thailand to
determine different phosphorus fertilizer dose
effects on Nile tilapia production, water quality
variables, nutrient utilization and cost-benefit
under supplemental feeding. Five phosphorus fertilization
rates were used as treatments e.g. 100%,
75%, 50%, 25% and 0% of 7 kg P ha week
1.
Nitrogen fertilization rate was fixed at 28 kg
N ha week
1 for all the treatments. Sex-reversed
Nile tilapia were stocked at 3 fish m
2, and 30%
CP floating feed fed at 50% satiation feeding rate.
Nutrient budget showed higher phosphorus fertilizer
input resulted in higher phosphorus sink in
the sediment. Mean weight, mean weight gain,
daily weight gain and net yield were not significantly
different among treatments (P > 0.05).
Total Kjeldahl nitrogen, total phosphorus and soluble
reactive phosphorus were significantly different
among treatments. Economic analysis showed
phosphorus fertilization resulted in positive net
returns. Though the gross income was not affected
by different fertilization rates, significantly lowest
cost was found in the treatment using 25% phosphorus
fertilizer. It can be concluded from the
research that 25% phosphorus fertilization might
be used as an alternative strategy of Nile tilapia
pond culture in terms of economic return and
nutrient loss in sediment.
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This study investigated the on-farm feed formulation and its management strategies for enhance higher economic efficiency of Tilapia culture (Oreochromis niloticus). The feed was prepared on the basis of feed requirement of tilapia. The... more
This study investigated the on-farm feed formulation and its management strategies for enhance higher economic efficiency of Tilapia culture (Oreochromis niloticus). The feed was prepared on the basis of feed requirement of tilapia. The new proposed feed formulation and feeding method contributed significantly in reducing operational cost of tilapia farming. This was better than the existing practice carried by the small scale fish farmers. The total cost of new formulated feed was Rs.16.71 kg-1 on wet basis (moisture 8.91 per cent) and the new formulated feed cost accounts 43- 57.36 per cent in the gross revenue with 80 per cent satiation. Partial replacement with fish meal @ 22 per cent, soybean meal @ 26 per cent, rice bran @ 26 per cent and maize flour @ 22 per cent with corn oil 2 per cent, vitamin premix 1 per cent and mineral premix 1 per cent in the new feed formulation was contributed in reducing feed cost and more economic efficiency in tilapia farm operation. The formulat...