Academic literature on the topic 'Fish yield'
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Journal articles on the topic "Fish yield"
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VROMANT, N., L. T. DUONG, and F. OLLEVIER. "Effect of fish on the yield and yield components of rice in integrated concurrent rice–fish systems." Journal of Agricultural Science 138, no. 1 (2002): 63–71. http://dx.doi.org/10.1017/s0021859601001642.
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Many authors report on the effect of rice–fish culture on rice yields. Some reports show increased rice yields, others show no effect or even decreased yields. To verify the impact of rice–fish culture, data gathered over eight experiments (1995–1999) at the Co Do experimental rice–fish station, Vietnam, were analysed through multiple regressions with rice yield and different yield components as the dependent variables. We used eight independent variables: season, water depth, rice variety, rice seeding rate, and the effective stocking density (ESD) of silver barb, Nile tilapia, common carp and snakeskin gourami. Season had the biggest impact on nearly all dependent variables. Rice yields in the wet season were on average 2·42 t/ha lower as compared to the dry season. Higher water levels decreased the number of panicles/m2 and the rice yield. The rice seeding rate affected the yield component variables, but had no impact on the rice yield. Silver barb feeding decreased the number of panicles/m2 but this was compensated by an increased number of grains/panicle. Snakeskin gourami had a positive effect on panicles/m2 and, together with common carp, on sink capacity, probably through improved nutrient cycling in presence of fish and improved nutrient uptake by the rice plant. Snakeskin gourami had a negative effect on the ripening ability, whereas Nile tilapia had a positive effect. Fish did not have any impact on the rice yield. Increased water level and reduced rice arable area, the main two requirements for rice–fish culture, result in lower rice yields from rice–fish systems as compared to monoculture systems.
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Loftus, D. H., C. H. Olver, E. H. Brown, P. J. Colby, W. L. Hartman, and D. H. Schupp. "Partitioning Potential Fish Yields from the Great Lakes." Canadian Journal of Fisheries and Aquatic Sciences 44, S2 (1987): s417—s424. http://dx.doi.org/10.1139/f87-343.
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We proposed and implemented procedures for partitioning future fish yields from the Great Lakes into taxonomic components. These projections are intended as guidelines for Great Lakes resource managers and scientists. Attainment of projected yields depends on restoration of stable fish communities containing some large piscivores that will use prey efficiently, continuation of control of the sea lamprey (Petromyzon marinus), and restoration of high-quality fish habitat. Because Great Lakes fish communities were harmonic before their collapse, we used their historic yield properties as part of the basis for projecting potential yields of rehabilitated communities. This use is qualified, however, because of possible inaccuracies in the wholly commercial yield data, the presence now of greatly expanded sport fisheries that affect yield composition and magnitude, and some possibly irreversible changes since the 1950s in the various fish communities themselves. We predict that total yields from Lakes Superior, Huron, and Ontario will be increased through rehabilitation, while those from Lakes Michigan and Erie will decline. Salmonines and coregonines will dominate future yields from the upper lakes. The Lake Erie fishery will continue to yield mostly rainbow smelt (Osmerus mordax), but the relative importance of percids, especially of walleye (Stizostedion vitreum vitreum), will increase. In Lake Ontario, yields of salmonines will be increased. Managers will have to apply the most rigorous management strictures to major predator species.
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Heino, Mikko. "Management of evolving fish stocks." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 8 (1998): 1971–82. http://dx.doi.org/10.1139/f98-089.
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Mortality caused by harvesting can select for life history changes in the harvested stock. Should this possibility be taken into account in the management of renewable resources? I compare the performance of different harvest strategies when evolutionary change is accounted for with the help of an age-structured population dynamics model. Assuming that age of first reproduction is the only evolving trait, harvesting of only mature individuals selects for delayed maturation and results in increased sustainable yields. Unselective harvesting of both mature and immature fish selects for earlier maturation which causes the sustainable yield to decrease. Constant stock size and constant harvest rate strategies perform equally well in terms of maximum sustainable yield, both before and after evolutionary change. The maximum sustainable yield for fixed-quota strategies is lower. All those strategies have similar evolutionary consequences given a similar average harvest rate. Coevolutionary dynamics between fish stock and the stock manager indicate that the evolutionary benefits of selective harvesting are attainable without incurring yield losses in the near future.
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Lamtane, H.A., Y.D. Mgaya, and R.G. Bailey. "Effects of water quality, flooding episode and management variables on the fish yield from self-stocked ponds in lower Rufiji floodplain, Tanzania." Greener Journal of Agricultural Sciences 3, no. 5 (2013): 320–31. https://doi.org/10.15580/GJAS.2013.5.022613494.
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A study was conducted to determine fish yields from flood depended ponds in Rufiji floodplain, Tanzania. Eight ponds were constructed during dry season in two sites besides two floodplain lakes, Ruwe and Uba. These ponds were self-stocked with different fish species from the lakes. More than eight species were trapped and<em>Oreochromis urolepis, Labeo congoro and Clarias</em> species were considered as good candidates for aquaculture. Other small fish species were harvested immediately after flood recession and the three key species were cultured for the maximum of seven months. However, other species in small quantities were remained in the ponds for the whole period of experiment. Water quality parameters were monitored throughout the study period. The relationships between water quality variables and flooding events were determined using canonical correspondence analysis (CCA). Other parameters included in the relationships were fish density, manure and number of species trapped and cultured. Dissolved oxygen and pH decreased with time in both sites. Fish yields were influenced by some water quality, flooding episode and other management variables. Chlorophyll-<em>a</em> was the only environmental variable that showed a significant correlation with fish yield (P< 0.01). Fish density and number of species trapped showed a significant effect on the fish yield (P<0.05). Re-connectivity between ponds and lakes was strongly positively correlated with yield. It can be concluded that some water quality variables, flooding and management parameters were responsible for the observed yield.
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Leach, J. H., L. M. Dickie, B. J. Shuter, U. Borgmann, J. Hyman, and W. Lysack. "A Review of Methods for Prediction of Potential Fish Production with Application to the Great Lakes and Lake Winnipeg." Canadian Journal of Fisheries and Aquatic Sciences 44, S2 (1987): s471—s485. http://dx.doi.org/10.1139/f87-348.
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Methods for estimating fish production in aquatic ecosystems range from simple empirically derived estimators, such as morphoedaphic indices, to complex ecosystem simulation models. As first-order estimators, the former are attractive to managers because they are simple and relatively inexpensive to apply and interpret. Application of the latter group has been limited because many of the data inputs are difficult and expensive to obtain. Between these extremes are several models, such as the biomass–size spectrum model, that provide useful information for moderate expenditures of time and effort. Existing and new methods are reviewed in the light of production theory and several are applied to Great Lakes and Lake Winnipeg data. Eight empirical models derived from limnological variables were selected from the literature and used to estimate potential fish yield for the Great Lakes and Lake Winnipeg. The models predicted a fairly narrow range of potential yields, but when compared with historic yields, none was consistent for all lakes. The best overall empirically derived estimator of potential yield in the Great Lakes was the morphoedaphic index. Potential fish production estimated from invertebrate production with Borgmann's biomass – size spectrum model was considerably greater than historic yields or the yield estimates from the empirical models. In a third approach, we calculated life history parameters for "small" and "large" fish in the Great Lakes and combined these with Borgmann's production model, empirical information on population production/biomass ratios from the literature, and classical population dynamics theory to estimate potential production and optimum sustained yield for each group. Historic sustained yield, as a percentage of optimum sustained yield, varied from a low of 6 for "small" Lake Ontario fish to 100 for "large" Lake Erie fish.
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Syandri, Hafrijal, Azrita Azrita, Eni Sumiarsih, and Elfiondri undefined. "Nutrient loading and farm characteristics of giant gourami fish aquaculture systems in Lake Maninjau, Indonesia: basic knowledge of production performance." F1000Research 10 (May 12, 2021): 378. http://dx.doi.org/10.12688/f1000research.52613.1.
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Background Aquaculture systems for giant gourami, Osphronemus goramy Lacepède (1801), have significantly improved fish production yields and food security in Indonesia. However, these systems also cause serious problems in terms of eutrophication in waterbodies. This study analysed the nutrient loading and farm characteristics of giant gourami in floating cages in Lake Maninjau. Method A total of 20 floating cages were used to record these nutrients in feed supply, female and male juvenile fish, dead fish and harvested fish to estimate nutrient loading. Data on the harvested fish, production cycle, stock number and cage capacity were used to estimate the stocking density, feeding rate, feed efficiency, and net fish yield, and the relationship between feed supply and nutrient loading and farm characteristics was analysed by least squares regression methods. Results A total of 20 floating cages released nutrients into waterbodies at an average rate of 236.27±60.44 kg/cycle for C, 84.52±20.86 kg/cycle for N and 8.70±3.63 kg/cycle for P. On average, fish production for each floating cage (±SD) was 1226±282 kg wet weight/cycle, and the net fish yield was 12.63±2.82 kg/m3/cycle. Survival rates ranged from 86.33 to 95.27%/cycle. The production cycles varied from 160 to 175 days with feed conversion ratios between 1.60 and 1.75, feed conversion efficiencies were between 0.58 and 0.63. The production parameters that had strong relationships with the net fish yield were feed supply (r2=0.960), stocking rates (r2=0.924) and feeding rates (r2=0.961). In contrast, the length of the production cycle was not strongly related to the net fish yield (r2=0.187). Conclusion Nutrient loading from the supplied feed was greater than that from the harvested fish, juvenile fish and dead fish. Increasing the net fish yield in floating cages was better predicted by the stocking densities and feeding levels than by the other factors.
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Syandri, Hafrijal, Azrita Azrita, Eni Sumiarsih, and Elfiondri undefined. "Nutrient loading and farm characteristics of giant gourami fish aquaculture systems in Lake Maninjau, Indonesia: basic knowledge of production performance." F1000Research 10 (September 22, 2021): 378. http://dx.doi.org/10.12688/f1000research.52613.2.
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Background Aquaculture systems for giant gourami, Osphronemus goramy Lacepède (1801), have significantly improved fish production yields and food security in Indonesia. However, these systems also cause serious problems in terms of eutrophication in waterbodies. This study analysed the nutrient loading and farm characteristics of giant gourami in floating cages in Lake Maninjau. Method A total of 20 floating cages were used to record these nutrients in feed supply, female and male juvenile fish, dead fish and harvested fish to estimate nutrient loading. Data on the harvested fish, production cycle, stock number and cage capacity were used to estimate the stocking density, feeding rate, feed efficiency, and net fish yield, and the relationship between feed supply and nutrient loading and farm characteristics was analysed by least squares regression methods. Results A total of 20 floating cages released nutrients into waterbodies at an average rate of 236.27±60.44 kg/cycle for C, 84.52±20.86 kg/cycle for N and 8.70±3.63 kg/cycle for P. On average, fish production for each floating cage (±SD) was 1226±282 kg wet weight/cycle, and the net fish yield was 12.63±2.82 kg/m3/cycle. Survival rates ranged from 86.33 to 95.27%/cycle. The production cycles varied from 160 to 175 days with feed conversion ratios between 1.60 and 1.75, feed conversion efficiencies were between 0.58 and 0.63. The production parameters that had strong relationships with the net fish yield were feed supply (r2=0.960), stocking rates (r2=0.924) and feeding rates (r2=0.961). In contrast, the length of the production cycle was not strongly related to the net fish yield (r2=0.187). Conclusion Nutrient loading from the supplied feed was greater than that from the harvested fish, juvenile fish and dead fish. Increasing the net fish yield in floating cages was better predicted by the stocking densities and feeding levels than by the other factors.
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Mchunu, Ntobeko, G. Lagerwall, and A. Senzanje. "Aquaponics production simulations using the decision-making tool." African Journal of Food, Agriculture, Nutrition and Development 22, no. 106 (2022): 19040–61. http://dx.doi.org/10.18697/ajfand.106.19860.
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Aquaponics have related food and nutrition security benefit that are important for this country (South Africa). The aim of this study was to apply aquaponics decision-making tool to provide potential aquaponics production data and information for South Africa. This study was designed as 2×3×3 factorial study giving 18 interactions. Because aquaponics are the production of fish and crops concurrently, yield production had two levels- fish and crop, fish stocking density had three levels- low, optimum and higher and aquaponics scale of production had 3 levels- hobby, subsistence and commercial scale. The summary of data of aquaponics variables from the literature was used as optimum level, lower and higher levels were based on experimental design. Yield production (kg) of both fish and plants increased significantly (p<0.05) as fish stocking density was increased. In hobby scale, plants yield was higher than fish yield in all levels of fish stocking density, the plant-fish yield (kg) was 40-33, 80-67 and 150-133, respectively. In subsistence scale, fish-plant yield (kg) was 240-200, 300-267 and 400-333, respectively. In commercial scale, fish-plant yield (kg) was 600-533, 1 100-1 000, 1 500-1 333, respectively. Daily fish feed increased significantly with increase in fish stocking density across all scale of aquaponics production (hobby<subsistence<commercial). In hobby scale, at low fish stocking, 0.65kg feed produced 1 kg fish, at optimum, 0.65kg feed produced 1 kg fish and at higher fish stocking, 0.37kg feed produced 1 kg fish. In subsistence scale at low fish stocking density, 0.38kg feed produced 1 kg fish, at optimum level, 0.63kg feed produced 1 kg fish and at higher level, 0.65kg feed produced 1 kg fish. In commercial scale, in low fish stocking, 0.64kg feed produced 1 kg fish, at optimum, 0.63kg feed produced 1 kg fish and at higher fish stocking, 0.64kg feed produced 1 kg fish. Plant culture have more yield output than fish culture in all aquaponics scale of production. Hobby scale produced the lowest yield than subsistence than commercial scale of production. Hobby scale practise could not produce sufficient yield to support human subsistence. Fish feed closely mirrored yield production. Lower fish stocking density maybe adopted in subsistence scale. Higher fish stocking density maybe adopted in commercial scale. Fish feed could become an economic sustainability constraint in aquaponics production, particularly in a developing country like South Africa. Water availability and quality effects on yield was not determine especially in African context. Key words: Fish stocking density, Yield production, Fish feed, Planting area
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Adepoju, Samuel Adebowale, Ibrahim Adewale Gbadegesin, Oluwaloni Peter Oluwanisola, and Adama Bola Saadu. "Effects of Fish Pond Sediment on Yield and Productivity of Two Varieties of Amaranths (Amaranthus spp.)." Journal of Agriculture, Aquaculture, and Animal Science 2, no. 1 (2025): 1–6. https://doi.org/10.69739/jaaas.v2i1.189.
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The rising costs of inorganic fertilizers have rendered them inaccessible to many farmers, resulting in reduced crop yields. An affordable alternative for enhancing soil fertility is the use of organic materials such as fish pond sediments. These sediments are nutrient-rich and have the potential to enhance soil quality, promote crop growth, and increase yields. This study examined the effect of fish pond sediments on the yield and productivity of two amaranth varieties. The research was conducted at the University of Ilorin Teaching and Research Farm. A 2x6 factorial experiment was employed using a Randomized Complete Block Design. The experiment included six sediment application rates: a control (no sediments) and sediment rates of 5, 10, 15, 20, and 25 Mg/ha, applied to two amaranth varieties (green leaf with Accession IDs NHAM 0116-1-2 and NHAM 0112-1-4). Yield and productivity parameters were assessed after 10 weeks. The findings revealed that fish pond sediment application significantly enhanced the yield of both amaranth varieties. The highest yield (51.36 Mg/ha), Chlorophyll A (1.64 mg/dm2), chlorophyll B (1.76 mg/dm2), and crude fibre content (12.18%) were recorded at the sediment application rate of 25 Mg/ha. The results demonstrate that fish pond sediments are a viable nutrient source for improving soil fertility and boosting the growth and yield of amaranths.
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TSURUTA, TETSUYA. "Effect of fish in rice-fish cultureon the rice yield." NIPPON SUISAN GAKKAISHI 78, no. 4 (2012): 654. http://dx.doi.org/10.2331/suisan.78.654.
Full textDissertations / Theses on the topic "Fish yield"
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Haugland, Anders. "Industrial thawing of fish : to improve quality, yield and capacity." Doctoral thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-955.
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<p>Melting of frozen water in food products is denoted thawing. The phase change requires energy, and takes place at a constant temperature for pure water. For mixtures of water, fat, protein and ashes (i.e. foodstuffs) this phase change will take place at a gliding temperature. Thawing is physically the opposite process to that of freezing. The heat flow is reversed and instead of extracting heat from the product, heat is directed into it. Although opposite processes, thawing is more difficult to carry out with respect to predictability and controllability. This is due mainly to three aspects:</p><p>1. Increased heat flow resistance as the thawing proceeds.</p><p>2. Reduced temperature difference (ΔT) between product and media.</p><p>3. More difficult to monitor the process and product end temperature accurat</p><p>The food processing industry depends on a continuously and safe supply of raw material, in order to utilise process equipment better, improve production planning and to create stable and secure working environment for the employees. The fish industry is very important for Norway, and its export value (NOK 30,6 billion in 2001<sup>1</sup>) is the second highest after oil and higher than gas. The fact that supply of fresh raw material (i.e. fish) often is dependent on seasonal variations, weather conditions, quotes and regulations (governmental and international), has been a great intensive to use frozen raw material in the fish process industry.</p><p>A survey amongst 155 fish processing plants throughout Norway showed that 75 % of them used thawing in their production and further 23% claimed that they would do so in the future. 93 % of the companies that thawed did so in an uncontrolled manner. The challenges in industrial thawing are many:</p><p>• Block frozen products changes size during thawing and are generally more difficult to handle</p><p>• The product texture are temperature dependent</p><p>• Size variations – both single fish and batches</p><p>• Use of both fresh and frozen raw material</p><p>• Company culture</p><p>Thawing by heat transfer through the surface has been studied for three different products; Salmon, Cod and Mackerel. A slightly different approach has been used for these products depending on the raw material availability, industrial needs and relevance.</p>
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Jones, David Frederick. "Effects of Dietary Fish Oil and Vitamin E on Milk yield and composition and plasma neutrophil function /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488187049540325.
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Fritzen, Nalva Alina. "Estudo econômico da produção de tilápia do Nilo (Oreochromis niloticus) em tanques-rede." Universidade Estadual do Oeste do Paraná, 2015. http://tede.unioeste.br/handle/tede/3562.
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Previous issue date: 2015-02-27<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>The objective of this study was to analyze the productive performance, the physical and chemical composition and the cost benefit of tilapia production (Oreochromis niloticus) in cages, in three different weight classes (500, 700 and 900g) termination. 24.000 fish were used, with initial weight of 150 ± 5,4 g for analysis of cost of production, over thirty cages of 6 m3 of useful volume. A sample of five fish for cage was harvested for yield performance, including 10% of those steaks were used for chemical analysis. To survey costs and profitability, we used the Operating Cost (Effective and Total), Depreciation, Total Cost and Profit. At the end it was observed that the smaller fish (500g) showed a smaller amount of lipids (1,76%) and visceral (3,69%) and a higher content of ash (1,40%) in the fillet. The best fillet yield and main trunk was found in larger fish (900g), 32,48% and 50,82% respectively. The profitability of production, the average fish (700g) stood out (19,77%).<br>O objetivo neste trabalho foi analisar o desempenho produtivo, a composição físico-química e o custo benefício da produção de tilápias do Nilo (Oreochromis niloticus) em tanques-rede, em três diferentes classes de peso (500, 700 e 900g) de terminação. Foram utilizados 24.000 peixes, com peso inicial de 150±5,4g, para análise de custo da produção, distribuídos em trinta tanques-rede de 6m3 de volume útil. Uma amostra de cinco peixes por tanque foi abatida para o desempenho produtivo, dos quais 10% dos filés obtidos foram utilizados para análise bromatológica. Para o levantamento dos custos e rentabilidade, utilizou-se o Custo Operacional (Efetivo e Total), Depreciação, Custo Total e Lucro. Ao final observou-se que os peixes menores (500g) apresentaram menor quantidade de lipídeos (1,76%) e gordura visceral (3,69%) e, maior teor de matéria mineral (1,40%) no filé. O melhor rendimento de filé e tronco limpo foi encontrado nos peixes maiores (900g), 32,48% e 50,82% respectivamente. Quanto a lucratividade da produção, os peixes médios (700g) se destacaram (19,77%).
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Littlefield, Joanne. "Raising Fish in the Desert: Aquaculture Yields Fish and Shrimp." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/622264.
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White, Allison Lynn. "Spatial and temporal heterogeneity in life history and productivity trends of Atlantic Weakfish (Cynoscion regalis) and implications to fisheries management." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78707.
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The biological characteristics of fisheries stocks that are assessed for management considerations are rarely homogeneous over time or space. However, stock assessment scientists largely ignore this heterogeneity in their models. This thesis addresses the effects of spatial and temporal heterogeneity on stock assessment models using Atlantic Weakfish (Cynoscion regalis) as a case study. First, spatial and temporal variation was incorporated into length-, weight-, and maturity-at-age estimates using mixed-effects models (Chapter Two). The resulting heterogeneous weight and maturity parameters then were applied to per-recruit analyses to examine the sensitivity of biological reference points to spatial and temporal variation in life history attributes (Chapter Three). Mixed-effects life history models incorporating spatial and temporal variation revealed distinct regional and annual trends that were not visible from standard homogeneous models. In several instances, the homogeneous modelling approach produced life history estimates that varied significantly from the spatial and temporal means produced by the heterogeneous models. In some cases, this difference was so great that the homogeneous means were much higher or lower than the heterogeneous means for all regions or years. Minimized AIC statistics revealed that spatially and temporally integrated mixed-effects models were more robust and descriptive of Atlantic Weakfish life history than the standard homogeneous models. Per-recruit and biological reference points derived from these life history estimates in Chapter Three were found to be highly sensitive to spatial and temporal variations in weight parameters. In several cases, reference points used as management targets were so significantly different that ignoring spatial and temporal heterogeneity in Atlantic Weakfish life history would likely cause overfishing and decline of Weakfish in certain regions and years.<br>Master of Science
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Eyng, Cinthia. "Avaliação nutricional da farinha de resíduos da indústria de filetagem de tilápias na alimentação de frangos de corte." Universidade Estadual do Oeste do Paraná, 2009. http://tede.unioeste.br:8080/tede/handle/tede/1601.
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Previous issue date: 2009-03-12<br>Three experiments were carried out aimed to nutricional evaluation of meal from tilapia filleting industrial waste (TM) in broiler chickens feeding. On the first experiment the chemical composition, apparent metabolizable energy (AME), corrected apparent energy (AMEn) and it s coefficients of metabolizability were determined. The total excreta collecting method was used to determinate the energy values, where 60 broiler chicken Cobb, aging 22 days, were shared in a completely randomized design, with six replications and five birds per experimental unit. According to the chemical composition results of TM, it depends of fish specie and meal production process. The AME, AMEn, CAME and CAMEn values to TM were: 3.733 kcal/kg, 3.082 kcal/kg, 78,13 e 64,50, respectively. On the second experiment, the true digestibility coefficients and the values of true amino acid digestibility of TM were determined in cecectomized roosters by the forced feed method. The experiment was analyzed as a complete randomized design with one test ingredient (TM), one fast, six replicates and one rooster per experimental unit. The average values of essential and non essential true amino acids digestibility coefficients, in percentage, were as follows: 92,04 and 87,49. On the experiment III, the performance of broilers feeding with different inclusion levels of TM (0, 2, 4, 6 and 8%) was analyzed. Four hundred and eighty day-old chicks were used in a completely randomized design with five treatments, six replicates and sixteen birds per experimental unit. Weight gain, final weight, feed intake, feed conversion and mortality from 1 to 21 days and 1 to 42 days of age were evaluated. In the end of experimental period the blood parameters (calcium, phosphorus, triglycerides), carcass, breast, thigh, drumstick, wing yield, liver relative weight and percentage of abdominal fat were calculated. Protein and fat deposition rate in breast and legs (thigh/drumstick) were determined. Forty five not trained tasters were used to sensorial analysis of meat. The samples were assessed using the nine-point structured hedonic scale for the characteristics: flavour, taste, color, texture and global quality. The experimental diet cost, economic efficiency index and cost index were calculated on analysis of economic viability. The data analyses showed difference (P<0,05) between inclusion levels of TM and the evaluate characteristics on 21 days of age. Despite of quadratic effect of treatments, the Linear Response Plateau (LRP) model provided the best data fit, the levels of inclusion were estimated in 2,10 and 2,02, which are the plato point for final weight and weight gain, respectively. The LRP was the only model that showed adjustment for feed intake and the level of inclusion was estimated in 1,86, which are the plato point. On the total period (1 to 42 days) the inclusion of 8% of TM in broiler chickens feeding did not affected performance, yield parameters, protein and fat deposition rate on carcass and sensorial quality of meat. Despite of linear increasing on blood triglycerides values, this level of inclusion reduced blood P and Ca values and provided the best economic efficiency.<br>Foram conduzidos três experimentos para avaliação nutricional da farinha de resíduos da indústria de filetagem de tilápias (FT) na alimentação de frangos de corte. No experimento I, foram determinados os valores de composição química, os valores de energia metabolizável aparente (EMA), aparente corrigida (EMAn) e seus coeficientes de metabolizabilidade. Para determinação dos valores energéticos foi utilizado o método da coleta total de excretas, onde 60 aves da linhagem Cobb, com 22 dias de idade foram distribuídas em delineamento inteiramente casualizado, com seis repetições e cinco aves por unidade experimental. De acordo com os resultados encontrados de composição química para a FT constatou-se que as composições dependem da espécie de peixe utilizada e processamento pelo qual a farinha é obtida. Os valores de EMA, EMAn, coeficiente de metabolizabilidade da EMA (CEMA) e coeficiente de metabolizabilidade da EMAn (CEMAn) para FT foram de 3.733 kcal/kg, 3.082 kcal/kg, 78,13 e 64,50, respectivamente. No experimento II, objetivou-se determinar os coeficientes de digestibilidade e valores de aminoácidos digestíveis verdadeiros da FT. Utilizou-se o método da alimentação forçada, com galos adultos cecectomizados, em um delineamento experimental inteiramente casualizado, composto por um alimento-teste (FT) e um jejum, com seis repetições e um galo por unidade experimental. Os coeficientes médios de digestibilidade verdadeira dos aminoácidos essenciais e não-essenciais, em porcentagem, foram, respectivamente, 92,04 e 87,49. No experimento III, foi avaliado o desempenho de frangos de corte alimentados com diferentes níveis de inclusão de FT (0, 2, 4, 6 e 8%). Foram utilizados 480 pintos de um dia, da linhagem Cobb, distribuídos num delineamento experimental inteiramente casualizado, com cinco tratamentos, seis repetições e 16 aves por unidade experimental. As características avaliadas foram ganho de peso, peso final, consumo médio de ração, conversão alimentar, mortalidade de 1 a 21 dias e 1 a 42 dias de idade. Ao final do período experimental foi mensurado os parâmetros sanguíneos (cálcio, fósforo e triglicerídeos), rendimento de carcaça, peito, coxa, sobrecoxa, asa, peso relativo do fígado e percentual de gordura abdominal. Determinou-se a taxa de deposição de proteína e gordura do peito e pernas (coxa/sobrecoxa). A análise sensorial da carne foi realizada por 45 provadores não treinados. As amostras foram avaliadas utilizando a escala hedônica estruturada de nove pontos para as seguintes características: aroma, sabor, cor, textura e qualidade global. Dentro da análise da viabilidade econômica foram calculados os custos das dietas experimentais, o índice de eficiência econômica e o índice de custo. Observou-se diferença (P<0,05) dos níveis de inclusão da FT sobre as características avaliadas aos 21 dias de idade, sendo que na análise de regressão para a fase de 1 a 21 dias, embora tenha variado de forma quadrática, o modelo Linear Response Plateau (LRP) se ajustou melhor aos dados de peso final e ganho médio de peso, estimando a ocorrência de platô a partir do nível de inclusão de 2,10 e 2,02, respectivamente. Para consumo médio de ração o modelo LRP foi o único que se ajustou aos dados, estimando a ocorrência de platô a partir do nível de inclusão de 1,86. No entanto, considerando o período total (1 a 42 dias) pode-se incluir 8% de FT nas rações de frangos de corte, sem prejuízo para o desempenho produtivo, parâmetros de rendimento, deposição de gordura e proteína na carcaça e qualidade sensorial da carne. Apesar do aumento linear dos valores de triglicerídeos sanguíneo, este nível de inclusão reduziu os valores de P e Ca sanguíneo e proporcionou o melhor desempenho econômico
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MARTINI, Petra. "High-Yield Cyclotron Production of Metallic Radioisotopes for Nuclear Medicine." Doctoral thesis, Università degli studi di Ferrara, 2018. http://hdl.handle.net/11392/2487885.
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The main purpose of LARAMED project (LAboratoty of Radioisotopes for MEDicine), founded at LNL-INFN, is the R&D on cyclotron production of conventional, such as Tc-99m (TECHN-OSP projects), and emerging, such as Cu-67 (COME project), metallic medical radioisotopes. The aim of my PhD has been the development, optimization and automation of post-irradiation target processing systems, enabling to recover in high yield highly pure radioisotopes (RI), one of the most critical steps in the RI cyclotron production.
The possibility of a reactor-produced molybdenum-99 shortage, used as parent nuclide of in 99Mo/99m Tc generators, is still a potential scenario. The direct cyclotron-production of Tc-99m through the (p,2n) reaction on a Mo-100 target seemed to be a reliable solution. In the framework of TECHN-OSP project, a technology for enabling the in-hospital cyclotron self-production of Tc-99m, in order to afford the availability of the most used radiometal in diagnostic applications in case of shortages, has been developed. The Tc-99m cyclotron-production optimization included the design of a solid target, the development of an automatic module for target processing and enriched target material recovery study. In this thesis, the description of Tc-99m production experiments, performed in collaboration with the Sant’Orsola Hospital in Bologna, and the development of the automatic module for target processing, are well detailed.
During my PhD I had the opportunity to collaborate with the Canadian research group at TRIUMF (Vancouver, CA), also working on Tc-99m cyclotron-production, by contributing at the optimization and automation of molybdenum target dissolution and purification procedure of cyclotron-produced Tc-99m. In this thesis a comparison between the two developed, Italian and Canadian, target processing setup is also reported.
Alongside that, I have collaborated to COME project whose purpose is the evaluation of the cyclotron production efficiency of Cu-67, a particularly interesting RI for its application in “theranostics”. The large scale cyclotron-production of this RI is still a poorly studied key point. In order to define the Cu-67 best cyclotron-production route, we focused our attention on unknown cross-section measurement of nuclear reactions on a Zn-70 target (35-70MeV energy range). Essential for this project was the development and optimization of a high yield separation and purification procedure of Cu-67 from the Zn-70 bulk and the co-produced Ga-67 contaminant that, having the same γ-lines of Cu-67 (both decay to Zn-67 with similar half-lives), poses a serious issue for the determination of the activity of Cu-67. The description of the experiments, performed in collaboration with ARRONAX, is reported in this thesis.
Finally, the clinical needs of larger amount of the PET radiometal generator-produced Ga-68 prompted TRIUMF Life Sciences division to investigate Ga-68 cyclotron-production from liquid target since it is based on the existing medical-cyclotron network and technology. This technique will improve the availability of Ga-68 in hospitals housing an appropriate cyclotron by making them independent self-producers. Since the major problem affecting liquid targets is the contamination with radioactive/stable metals (e.g. iron) coming from the dissolution of some material from vacuum isolation or target body components during the irradiation, a separation and purification procedure together with a semi-automatic system, particularly focused on the purification of Ga-68 from Zn and Fe, have been developed. The main purpose is to obtain a final product suitable for medical use and to enable radiolabeling and in-vivo imaging studies with cyclotron produced 68Ga-DOTATOC.<br>Il progetto LARAMED (LAboratoty of Radioisotopes for MEDicine), fondato presso i LNL-INFN, ha come scopo l’R&D per la produzione da ciclotrone di radioisotopi metallici convenzionali, come il Tc-99m (progetto TECHN-OSP, ed emergenti, come il Cu-67 (progetto COME), per uso medicale. L'obiettivo del mio dottorato di ricerca è stato lo sviluppo, ottimizzazione e automazione di sistemi di processamento dei target irraggiati al fine di estrarre, in alta resa e purezza, il radioisotopo (RI) di interesse, uno dei passaggi più critici nella produzione da ciclotrone dei RI per la medicina.
La possibilità di un’ulteriore crisi di produzione da reattori nucleari di Mo-99, nuclide genitore nei generatori Mo-99/Tc-99m, è ancora uno scenario possibile. La produzione diretta di Tc-99m da ciclotrone per mezzo della reazione nucleare Mo-100(p,2n) sembra essere una soluzione alternativa affidabile. Nell’ambito del progetto TECHN-OSP è stata sviluppata una tecnologia in grado di rendere le radiofarmacie delle Medicine Nucleari, che ospitano un ciclotrone appropriato, indipendenti nella produzione di Tc-99m al fine di sopperire ad ogni eventuale carenza nell’approvvigionamento dei generatori. L’ottimizzazione della produzione ha previsto la progettazione di un target, lo sviluppo di un modulo automatico per il processamento del target e lo studio del recupero del materiale arricchito costituente il target stesso. In questa tesi sono descritti i test di produzione di Tc-99m, eseguiti in collaborazione con l'ospedale Sant'Orsola di Bologna, ed in particolare lo sviluppo di un modulo automatico di processamento del target.
Nel corso del dottorato, ho avuto l'opportunità di collaborare con il gruppo di ricerca canadese al TRIUMF (Vancouver, CA), anch’esso coinvolto nell’ottimizzazione della produzione di Tc-99m da ciclotrone, contribuendo all'ottimizzazione e automazione delle procedure di dissoluzione e purificazione di Tc-99m da target di Mo-100. In questa tesi viene anche riportato un confronto tra i due sistemi di processamento target da me sviluppati, in Italia e in Canada.
Parallelamente ho collaborato al progetto COME il cui obiettivo risiede nella valutazione dell'efficienza di produzione di Cu-67 da ciclotrone, RI particolarmente interessante per le sue applicazioni in “teranostica”. La produzione da ciclotrone su larga scala di questo RI è ancora un punto chiave scarsamente studiato. Al fine di definire la migliore via di produzione di Cu-67, abbiamo focalizzato l’attenzione su misure di sezioni d’urto inedite (target Zn-70, protoni incidenti di energie 35-70MeV). Essenziale per questo progetto è stato lo sviluppo di un processo altamente efficiente di separazione di Cu-67 dal target e dal Ga-67, coprodotto che, avendo le stesse linee γ del Cu-67, crea problemi nella determinazione dell'attività di Cu-67. La descrizione degli esperimenti, eseguita in collaborazione con ARRONAX, è riportata in questa tesi.
Infine, le esigenze cliniche di una maggiore quantità di Ga-68, RI PET attualmente prodotto da generatore Ge-68/Ga-68, hanno spinto il gruppo di ricerca del TRIUMF a studiare la produzione di Ga-68 da ciclotrone a partire da un target liquido di Zn-68, al fine di migliorare la disponibilità di Ga-68 negli ospedali che ospitano un ciclotrone appropriato rendendoli produttori indipendenti. Poiché il problema principale che colpisce la produzione da target liquido è la contaminazione da metalli (es. Fe) provenienti dalla degradazione di alcuni componenti del corpo del target, è stata sviluppata una procedura di separazione e purificazione del Ga-68 da Zn e Fe. Lo scopo principale è quello di ottenere un prodotto finale adatto all’uso medico e di consentire la radio-marcatura di (Ga-68)-DOTATOC e studi di imaging in vivo con Ga-68 prodotto da ciclotrone.
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Righetto, Marcello. "Optical Nanostructures for Excitonic Devices." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3425292.
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Unrelenting advances in the field of nanoscience are fostering the progress in diverse research fields, ranging from light-emitting to medicine and diagnostics, from energy conversion to communication technologies. Besides representing the most paradigmatic example of nanoscience, semiconductor quantum dots (QDs) avowedly brought revolutions in many of the research fields mentioned above. Nowadays, some QDs-based devices and applications reported efficiencies almost as good as current state-of-the-art technologies. The founding concept of QDs is the application of quantum confinement effects on excitons, i.e., the main players of optical properties in bulk semiconductors. Among the wealth of ensuing properties, the size- and shape- tunability of the electronic excitations and increased coupling with light field aroused much interest. Also, the colloidal approach endows QDs with high processability and low cost, thereby encouraging their implementation in existing technologies and extending their impact to other fields. Howbeit, despite three decades of investigations, the bottom line has not been reached yet, and researchers are still delving deeper into the photophysics of these nanosystems. Though many of the low hanging fruit of QDs have been harvested, higher-lying ones seem to be even more succulent.
This thesis deals with the quest for highly performing nanostructures, as a prerequisite for some high impact optoelectronic applications, e.g., QD-Lasers and QD-Solar Cells. Within this framework, the struggle against fast Auger recombinations and trapping of either hot carriers or cold excitons was addressed mainly by sophisticated core/shell technologies. Thus, the first part of the thesis reports how tuning different shell parameters (e.g., the smoothness of the interface potential, the height of the confining potential, and the interfacial strain) it is possible to exert control on these detrimental recombination processes. Though often disregarded, even the role of organic capping ligand is reconsidered in promoting the outcoupling of QDs excited states and addressing their interaction. Besides the useful and technologically relevant advice gathered within these studies, the primary inheritance of the first part is the comprehensive photophysical scenario, portrayed by a phenomenological model that successfully describes many aspects of the exciton dynamics in QDs. This amount of knowledge was capitalized in the second part of this thesis, dealing with the quest for novel materials, potentially outpacing conventional CdSe-based QDs. Perovskite-based QDs reported promising results, whereas some pitfall in the conventional characterization of carbon-based QDs were discovered. The rationalization of both nature and dynamics of this materials is expected to expedite their development as alternative (and potentially superior) technologies concerning those studied in the first part.<br>---
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Filippi, Daniele. "Local Fluidization of Concentrated Emulsion in Microfluidic Channels Textured at the Droplet Scale." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3426365.
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The rheology of soft-flowing systems, such as concentrated emulsions, foams, gels, slurries, colloidal glasses and related complex fluids, has a larger and larger impact in modern science and engineering. Much of the fascination of these systems stems from the fact that they do not fall within any of three basic states of matter, gas-liquid-solid, but live rather on a moving border between them. To understand the flow mechanism, it is necessary to have a look at the micro-scale dynamics of its constituents (i.e, droplets for emulsions, bubbles for foams, blobs for gels, etc.). In fact, in these fluids, the flow occurs via successive elastic deformations and plastic rearrangements, which create fragile regions enhancing the “fluidization” of the material. Despite the fluidization of Soft Glassy Materials (SGMs) is strongly affected by the surface roughness, the role played by the density, the orientation and the periodicity of rough elements has not been quantitatively addressed so far. In fact, predict and control the flow of SGMs is particularly important for an ample variety of technological applications from food to pharmaceutical industries.
In this work, we study the flow of concentrated emulsions in microfluidic channels, one wall of which is patterned with micron-size grooves with different patterns. Using equally spaced grooves, we find a scaling law describing the roughness-induced fluidization as a function of the density of the grooves, thus fluidization can be predicted and quantitatively regulated. Furthermore, we quantitatively report the existence of two physically different scenarios. When the gap is large, compared to the droplets in the emulsion, the droplets hit the solid obstacles and easily escape scrambling with their neighbors. Conversely, as the gap spacing is reduced, droplets get trapped inside, creating a “soft roughness” layer, i.e., a complementary series of deformable posts. Introducing an asymmetrical micro-roughness (herringbone pattern), the flow presents, in turn an asymmetric behavior. The emulsion flows faster in the same direction of the herringbone groove respect when it flows in the opposite direction.
Our experimental observations are suitably complemented and confirmed by lattice Boltzmann simulations. These numerical simulations are key to highlight the change in the spatial distribution of the plastic rearrangements caused by surface roughness and to elucidate the micro-mechanics of the roughness induced fluidization.<br>La reologia dei sistemi soffici, quali emulsioni concentrate, schiume, gel, fanghi, vetri colloidali ha un grande impatto in ambito scientifico e ingegneristico. Gran parte del fascino di questi sistemi deriva dal fatto che essi non si collocano in nessuno dei tre stati base della materia, gas-liquido-solido, ma si posizionano ai limiti di ciascuna di esse. Per comprendere il meccanismo con il quale questi materiali scorrono è necessario osservare la dinamica dei loro costituenti (gocce per le emulsioni, bolle per le schiume, etc.) su scala microscopica. Infatti, il flusso è caratterizzato da una successione di deformazioni elastiche e riarrangiamenti plastici. Questi, creano delle regioni a maggior ``fluidità” in cui il materiale scorre. Il processo di fluidizzazione degli Soft Glassy Materials (SGMs) è fortemente influenzato dalla presenza di rugosità sulla superficie con cui sono a contatto, tuttavia il ruolo giocato dalla periodicità, l’orientazione e la forma degli elementi che costituiscono questa rugosità non è ancora stato del tutto compreso. Infatti, prevedere e controllare il flusso di questi SGMs è fondamentale in numerose applicazioni tecnologiche che vanno dall'industria alimentare a quella farmaceutica.
In questo lavoro di tesi abbiamo studiato il flusso di emulsioni concentrate in canali microfluidici. Questi ultimi presentavano una rugosità controllata, su scala micrometrica, posizionata sul fondo del canale.
Utilizzando come micro-rugosità una sequenza di ``grooves" (solchi) posti ortogonalmente al flusso, abbiamo osservato che la fluidizzazione indotta dipende dalla densità e dalla periodicità dei solchi. Ne consegue che, la fluidizzazione può essere controllata e regolata in modo quantitativo agendo sulla spaziatura di questi solchi. Inoltre, abbiamo osservato l’esistenza di due scenari con meccaniche di riarrangiamento differenti. Quando la spaziatura dei solchi è grande, rispetto alla dimensione delle gocce, queste colpiscono gli ostacoli e facilmente riarrangiano andando ad interagire con altre gocce vicine. Al contrario, riducendo lo spazio tra i solchi, le gocce ve ne rimangono intrappolate creando uno strato di ``rugosità soffice" creando a loro volta una nuova serie di ostacoli deformabili. Con l’introduzione di rugosità dalla geometria asimmetrica (a spina di pesce) abbiamo osservato che, anche il flusso all’interno del canale presenta un comportamento non simmetrico. L’emulsione, infatti, scorre più velocemente nello stesso verso della spina di pesce, rispetto a quando scorre nel verso opposto.
Le nostre osservazioni sperimentali sono e supportate e confermate da simulazioni lattice Boltzmann. Queste simulazioni, cruciali per evidenziare le variazioni nella distribuzione spaziale dei riarrangiamenti plastici, sono un potente mezzo per studiare e comprendere le micro-dinamiche che portano alla fluidizzazione del materiale.
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Cochrane, Kevern Laurence. "The population dynamics and sustainable yield of the major fish species in Hartbeespoort dam." Thesis, 2015. http://hdl.handle.net/10539/16939.
Full textBooks on the topic "Fish yield"
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Deinstadt, John M. Survival, growth, and yield of brown trout stocked as fingerlings in Hot Creek, California. State of California, Resources Agency, Dept. of Fish and Game, 1998.
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Commission, Mekong River, ed. Consumption and the yield of fish and other aquatic animals from the Lower Mekong Basin. Mekong River Commission, 2007.
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Roach, Stafford M. Abundance, composition, sustainable yield, and risk analysis of the northern pike population in Harding Lake, 1998. Alaska Dept. of Fish and Game, Division of Sport Fish, Research and Technical Services, 1999.
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Coggins, Lewis G. Effects of sample size and ageing error on estimates of sustained yield. State of Alaska, Dept. of Fish and Game, 1997.
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Station, Sherkin Island Marine, ed. Maximum sustainable yield from fish stocks: A challenge to fishermen & managers : proceedings of the conference held at the Imperial Hotel, Cork, on 14th and 15th May, 1993. Sherkin Island Marine Station, 1994.
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Crapo, Chuck. Recoveries and yields from Pacific fish and shellfish. Alaska Sea Grant College Program, University of Alaska, 1988.
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Crul, R. C. M. Models for estimating potential fish yields of African inland waters. Food and Agriculture Organization of the United Nations, 1992.
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The effect of water clarity on Walleye (stizostedion vitreum) habitat and yield. Ontario Ministry of Natural Resources, 2002.
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Org, Food and Agriculture. Yield and Nutritional Value of the Commercially More Important Fish Species (Fao Conservation Guide). Food & Agriculture Organization of the UN (FA, 1989.
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All the fish in the sea: Maximum sustainable yield and the failure of fisheries management. University of Chicago Press, 2011.
Find full textBook chapters on the topic "Fish yield"
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Kaitala, Veijo. "Maximizing Yield in Some Fluctuating Fisheries." In Essays on the Economics of Migratory Fish Stocks. Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-84565-9_4.
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Beverton, Raymond J. H., and Sidney J. Holt. "A Simple Model Giving the Annual Yield in Weight from a Fishery in a Steady State." In On the Dynamics of Exploited Fish Populations. Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-2106-4_4.
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Brämick, U. "Estimation of the Fish Yield Potential of Lakes in North-East Germany." In Management and Ecology of Lake and Reservoir Fisheries. Blackwell Publishing Ltd, 2007. http://dx.doi.org/10.1002/9780470995679.ch3.
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Lavrentyeva, Galina M., and Peter J. Lavrentyev. "The relationship between fish yield and primary production in large European freshwater lakes." In The First International Lake Ladoga Symposium. Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1655-5_41.
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Kembara, Gilang. "Hook, Line and Cooperate: A Three-Staged Approach to Regional Fishery Cooperation." In The South China Sea: The Geo-political Epicenter of the Indo-Pacific? Springer Nature Singapore, 2025. https://doi.org/10.1007/978-981-97-8209-3_7.
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Abstract Fishery constitutes an important living resource that often straddles between political maritime boundaries, including in disputed maritime areas. This has become a contentious issue between states seeking to establish maritime cooperation, as they would debate their respective rights to fish these resources. To bridge the differences, a three-stage approach is proposed to enable countries to better organize fishery cooperation between parties. First, parties must assess their level of trust between each other, and manage any trust deficit to allow further maritime cooperation to proceed without prejudice. Second, a thorough assessment of the fish stock level in the area is to be carried out through a joint maritime research and surveillance. By having the data of the resources could parties then advance to the final stage by establishing a framework to manage the living resources of the area, and to develop a fishery mechanism to ensure that parties adhere to the maximum sustainable yield of the resources catch to allow for replenishment of the resources.
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Martinez, L. A., and A. H. Buschmann. "Agar yield and quality of Gracilaria chilensis (Gigartinales, Rhodophyta) in tank culture using fish effluents." In Fifteenth International Seaweed Symposium. Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1659-3_48.
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Tito de Morais, L. "Fish Population Structure and its Relation to Fisheries Yield in Small Reservoirs in Côte d'Ivoire." In Management and Ecology of Lake and Reservoir Fisheries. Blackwell Publishing Ltd, 2007. http://dx.doi.org/10.1002/9780470995679.ch10.
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Okike, Iheanacho, Seerp Wigboldus, Anandan Samireddipalle, et al. "Turning Waste to Wealth: Harnessing the Potential of Cassava Peels for Nutritious Animal Feed." In Root, Tuber and Banana Food System Innovations. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92022-7_6.
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AbstractIn Nigeria, processing cassava for food and industry yields around 15 million tons of wet peels annually. These peels are usually dumped near processing centres to rot or dry enough to be burned. Rotting heaps release methane into the air and a stinking effluent that pollutes nearby streams and underground water, while burning produces clouds of acrid smoke. However, when properly dried, peels can be an ingredient in animal feed. Previous attempts over two decades to use peels in animal feed failed to yield profitable options for drying wet peels at commercial scale, but recent research suggests that cassava peels can be processed into high-quality cassava peel (HQCP) products to be used as nutritious, low-cost animal feed ingredients. The core innovation was to adopt the same steps and equipment used for processing cassava roots into gari, the main staple food in the country. When dried, 3 tons of wet peels yield a tonne of healthy and energy-rich animal feed, containing nearly 3,000 kilocalories per kilogram of dry matter (kcal/kgDM). Adopting this innovation at scale in Nigeria’s poultry and fish sectors alone has the potential to turn approximately 3.6 million tons of wet peels into 1.2 million tons of feed ingredients capable of replacing approximately 810,000 tons of largely imported maize. The innovation has great potential to increase feed availability and lower its cost while saving cereals for human consumption, reducing the import bill, creating new business opportunities, and protecting the environment. This research was initiated by CGIAR centres and taken up by the CGIAR Research Program on Roots, Tubers and Bananas (RTB) over the past decade with strategic input from the CGIAR Research Program on Livestock to accelerate development of the innovation, and this chapter documents the potential and progress in taking this innovation to scale.
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Leung, Daren Shi-Chi. "Reviving Community Agrarianism in Post-socialist China." In Beyond Global Food Supply Chains. Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3155-0_6.
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AbstractTasked with feeding 1.4 billion people, China often promotes its success in food security in relation to its self-sufficient grain production. In the post-socialist context, the reformist state has been pursuing a capital-based vertical model to integrate millions of smallholding producers into the market. Yet, the introduction of high-yield hybrid rice to increase production has resulted in a set of related crises, including widespread environmental pollution, food-safety issues and adverse impacts on rural life. However, agrarian communities are challenging these state-imposed practices of food production. This chapter explores an endogenous form of regenerative agriculture that has emerged in South China since the early 2000s, a Chinese form of food and farming activism for reviving community agrarianism. I argue that the revitalization of “traditional” farming practices as a form of xaingtu (rural) knowledge has evolved with and through local peasants’ experience and struggle over the decades. One example that combines diverse aspects of such knowledge is the “fish-duck-rice paddy”, a well-known symbiotic method of pest control that also works with native varieties, organic manure and cooperative labour. This method revives peasants’ experience of the Mao era as a cultural reference for community agrarianism. The revival of community agrarianism allows farming to be narrated as an evolving social and historical practice, not “wasting” peasants’ knowledge, in contrast to the capitalist agrarian transformation.
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Palm, Harry W., Ulrich Knaus, Samuel Appelbaum, Sebastian M. Strauch, and Benz Kotzen. "Coupled Aquaponics Systems." In Aquaponics Food Production Systems. Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-15943-6_7.
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AbstractCoupled aquaponics is the archetype form of aquaponics. The technical complexity increases with the scale of production and required water treatment, e.g. filtration, UV light for microbial control, automatic controlled feeding, computerization and biosecurity. Upscaling is realized through multiunit systems that allow staggered fish production, parallel cultivation of different plants and application of several hydroponic subsystems. The main task of coupled aquaponics is the purification of aquaculture process water through integration of plants which add economic benefits when selecting suitable species like herbs, medicinal plants or ornamentals. Thus, coupled aquaponics with closed water recirculation systems has a particular role to fulfil.Under fully closed recirculation of nutrient enriched water, the symbiotic community of fish, plants and bacteria can result in higher yields compared with stand-alone fish production and/or plant cultivation. Fish and plant choices are highly diverse and only limited by water quality parameters, strongly influenced by fish feed, the plant cultivation area and component ratios that are often not ideal. Carps, tilapia and catfish are most commonly used, though more sensitive fish species and crayfish have been applied. Polyponics and additional fertilizers are methods to improve plant quality in the case of growth deficiencies, boosting plant production and increasing total yield.The main advantages of coupled aquaponics are in the most efficient use of resources such as feed for nutrient input, phosphorous, water and energy as well as in an increase of fish welfare. The multivariate system design approach allows coupled aquaponics to be installed in all geographic regions, from the high latitudes to arid and desert regions, with specific adaptation to the local environmental conditions. This chapter provides an overview of the historical development, general system design, upscaling, saline and brackish water systems, fish and plant choices as well as management issues of coupled aquaponics especially in Europe.
Conference papers on the topic "Fish yield"
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Triastuti, Warlinda Eka, Suprapto Suprapto, Regeta Salsabila Putri Hani, and Helia Dewi Lestari. "The Effect of Bromelain Enzyme on Crosslinking Fish - Based Halal Gelatin." In 8th International Conference on Advanced Material for Better Future. Trans Tech Publications Ltd, 2025. https://doi.org/10.4028/p-e9jftu.
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It is important for consumers to be aware of the source of gelatin due to religious restrictions, as pork is forbidden for consumption by Muslims and Jews, and cows are forbidden for consumption by Hindus. Fishery waste, such as fish bones and scales, can be a promising alternative raw material for gelatin production, as they are halal for consumption. The process of gelatin preparation involves several stages, including pretreatment, degreasing, demineralization, and hydrolysis using bromelain enzyme. hydrolysis process using bromelain enzyme ranging from 1, 2, 3, 4, 5, 6 and 7% at 300 rpm and temperature 55 °C. Hydrolysis was carried out for 6 hours and 9 hours for each concentration. Characterizations of gelatin was conducted for pH, water content, ash content, Fourier Transform-Infrared Analyzer (FTIR), X-ray Fluorescence (XRF) Spectrometry and Gas chromatography (GC). Based on the research, the optimum conditions for produce halal gelatin from red snapper scales was obtained at 5% bromelain enzyme for 9 hours for hydrolized collagen to gelatin with a yield of 11.414%, pH of 5.3, water content of 7%, ash content of 2.1%, and free from alcohol and heavy metals. The FTIR spectra show that the absorption at wavenumber 2944.5, 1628.74, 1524.55, and 1332.14 cm-1 respectively, indicating the presence of C–H, C=O, C=C and C–N stretching. The presence of absorption peaks of that functional groups show gelatin has been formed. XRF analysis show the absence of heavy metals as Hg, Pb, Cd, and Zn. Fish-based gelatin in this study is produced through a halal process, using halal ingredients, and its product does not contain alcohol, thus the gelatin produced in this study is a halal product.
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SKORUPSKAITĖ, Virginija, Eglė SENDŽIKIENĖ, and Milda GUMBYTĖ. "POSSIBILITIES TO USE FISH WASTE FOR ENERGY PRODUCTION." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.073.
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The secondary raw materials of fish can be used for various purposes in food industry, agriculture, etc. No less important way for usage of secondary raw fish, dead fish and fish farming sludge is the utilization of mentioned feedstocks for energy purposes, i.e. biofuels production. In this reearch, the possibilities of the consumption of dead fish and fish farming sludge for biodiesel and biogas production has been studied. The influence of the basic biodiesel production parameters, including the methanol to oil molar ratio, amount of catalyst, temperature and process duration on transesterification yield was determined. The guantitative and gualitative research of biogas production using different substrates such as fish waste, fish farming sludge and substrates composed of fish waste (de-oiled and non de-oiled biomass)+fish farming sludge and fish farming sludge+wastewater sludge was performed. The biodiesel yield higher than 96.5% could be achieved under the following process conditions: methanol/oil molar ratio – 4:1, amount of enzyme content – 7% from oil mass, temperature – 40 ° C, reaction time – 24 hours. The highest biogas yield (1224 ml/gVS) was determined using wet fish waste biomass and mixed substrates consisted of fish waste and fish farming sludge. The results of qualitative biogas research revealed, that biogas produced from both homogeneous and heterogeneous substrates contained more than 60% of methane. The highest calorific value (app. 70% of methane) had biogas gained from fish waste biomass.
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Undeland, Ingrid. "Strategies to prevent hemoglobin-mediated lipid oxidation in fish." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/trvy8914.
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During the last 20 years, numerous studies have revealed how hemoglobin (Hb) strongly controls development of lipid oxidation in fish muscle; more so than the total lipid content or the relative amount of polyunsaturated fatty acids. In Chalmers, three main routes have been explored to combat Hb-mediated lipid oxidation in fish muscle; (i) preventing lysis of the red blood cells (RBC), (ii) removing Hb during processing, or (iii), introducing natural antioxidants. Key results from these strategies will be revealed. In (i), which is mainly applicable to very early steps of the fish process chain, we have found for example that avoiding osmotic or mechanic pressure as well as temperature raises keeps the RBC intact. Important RBC-stabilizing factors were also identified in blood plasma of herring and trout. In terms of Hb-removal, washing or pH-shift processing of different types of fish raw materials have been studied. Among findings are that repeated washing of fish mince (3×3 volumes), e.g. in surimi production, can remove nearly 85% heme and yield relatively stable minces. On the other hand, limited washing (1×1 volumes) destabilizes fish mince despite >60% heme removal, pointing at wash-out of antioxidants counteracting the effect of Hb removal. Work with antioxidants has been done both in simpler models such as washed fish mince and with more complex systems as filleting rest raw materials. Particularly interesting results have been found when using bladderwrack (Fucus vesiculosus) or rosemary extracts as well as grape or lingonberry press cakes. Extracts/solutions provides the possibility to apply antioxidants onto the surface of intact fish tissue via dipping or incubation treatments which is easy to implement in industry. The solid materials can on the other hand be co-processed with fish (rest)raw materials proving a sustainable concept to valorize different food side streams while at the same time preventing oxidation.
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Mrad, Nadia, Maria Paraschiv, Fethi Aloui, Mohand Tazerout, and Sassi Ben Nasrallah. "Production of Liquid Hydrocarbon Fuel by Catalytic Cracking of Waste Fish Fat in Continuous Pilot System." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-17012.
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Liquid fuels can be produced from triglyceride sources via thermo-catalytic process. In the present work, the production of bio-fuel by catalytic cracking of waste fish fat in a continuous reactor at atmospheric pressure has been studied. Different catalysts were used and maximum bio-oil yield of 66% with the lowest acidity of 4.3 mgKOH/goil was obtained with a controlled reaction temperature of 500°C and Na2CO3 as a catalyst. After chemical treatment of this bio-oil, the acidity decreases to 1.5mgKOH/goil. These bio-fuels were characterized according to their physico-chemical properties, and compared with the diesel fuel. The results show that the catalytic cracking process represents an alternative method to produce bio-fuels with physico-chemical characteristics similar to petroleum fuels from fish oil industrial residues.
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Firoozkoohi, Reza, and Senthuran Ravinthrakumar. "Case Studies of Elastic Closed Fish Cage Concepts in Waves." In ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/omae2024-130136.
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Abstract This paper demonstrate usage of a coupled linear hydrodynamic and structural model to assess the elastic response of closed fish cages in waves. From a design point of view it is important to avoid coupling between internal sloshing and the structure. This problem is addressed by assessing the elastic response of two closed fish cages made of an uniform elastic material. A vertical cylinder cage (bucket concept) and an ellipsoidal cage (egg concept inspired by Ovum AS design) with similar internal volume are investigated. WAMIT which is a software based on Boundary Element Method is used to compute hydrodynamic forces on rigid and elastic modes of motion. LSDYNA which is a Finite Element Method software is used to compute dry elastic mode shapes to be used as basis functions in the modal analysis. The computations were performed in frequency domain. The effective stress, i.e, Von Mises stress, is computed for the maximum responses in frequency domain to be compared with yield stress of the manufacturing material. The focus is on elastic cages for which the manufacturing material withstands bending. The effect of variation of stiffness on elastic response and its interaction with sloshing is addressed. The numerical method is explained briefly and its advantages and shortcomings are addressed. It is shown that the egg concept has a much smaller hydroelastic response than the bucket concept for the same material properties.
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Goh, A. L., B. Han, and K. T. Ooi. "Experimental Study of Nature-Inspired Enhanced Microscale Heat Transfer." In ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6733.
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Microscale heat transfer in macro geometry has been proven to yield comparable heat transfer performance to that of typical microchannels. This paper takes it a step further by looking at three passive heat transfer enhancement techniques to improve the heat transfer performance of the newly proposed system for single-phase liquid flow. The novelty of the study lies in that the enhancement features are designed based on inspiration from nature. Fish scale, Durian (a thorny tropical fruit), and Inverted Fish Scale enhancement profiles are considered. In this study, an annular microchannel is formed by securing a cylindrical insert of mean diameter 19.4 mm within a cylindrical pipe of internal diameter 20 mm. The enhancement features are introduced on the surface profile of the insert, while the heat is supplied to the flow via the cylindrical pipe of fixed surface area. Therefore, heat transfer is improved by increasing convective heat transfer coefficient, for a constant heat transfer area. The enhancement features serve to increase heat transfer coefficient by disturbing the flow and thermal boundary layers. Experiments were carried out to investigate the effect of the three enhancement profiles on the heat transfer and flow characteristics of the microscale flow. The extent of enhancement is computed with the Plain profile as benchmark. The constant parameters include microchannel length of 30 mm, mean hydraulic diameter of 600 μm, and heat input of 1000 W. Reynolds number range is 1,300 to 4,600, with water as working fluid. Results show that the Inverted Fish Scale profile doubles the Nusselt number as compared to the Plain profile. However, when friction factor increment is considered, Durian profile yields the best overall thermal performance, nearly 1.4 times better than the Plain profile. In the whole study, the maximum convective heat transfer coefficient achieved is 45.0 kW/m2·K, using Inverted Fish Scale profile at Reynolds number of 4,300. The pressure drop values of the system are all less than 3 bars, which may easily be achieved by a commercially available pump.
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Sherman, Scott. "Development of Low Force Shear Blades for High Strength Coiled Tubing." In SPE/ICoTA Well Intervention Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204403-ms.
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Abstract As coiled tubing grades have evolved over the past 20 years from 70 grade with a minimum yield strength of 483 MPa (70,000 psi) to 140 grade with a minimum yield strength of 965 MPa (140,000 psi) and wall thicknesses have increased, the resulting force required to shear coil has more than doubled. Most coiled tubing units have a maximum pressure of 20.7 MPa (3000 psi) available for the blow out preventers (BOP) hydraulic circuits. There was an industry need to develop a shear blade for BOPs that could cut high strength coiled tubing using legacy pressure control equipment already in use. Additionally, the new shear blades must create a fish that can be easily retrieved from a wellbore. Shear strength is estimated using the maximum distortion criterion (von Mises yield criterion) as follows:Shear strength/Yield strength=1√3=.577 Since the maximum distortion criterion is merely an approximation and unique blade geometries are difficult to take into consideration using the above calculation, a considerable amount of hands on lab testing was required to design and optimize an elegant shear blade for cutting high strength coiled tubing with minimal hydraulic forces. The paper will share the iterative process as novel shear blades were developed that significantly reduced shear forces. Multiple piercing tip geometries were tested, including embodiments with several piercing tips. Success criteria was reduced shear force, acceptable fish profile on the lower piece of coiled tubing, and no damage to the blades after use. The embodiment that showed the most promise, based on lab testing was further optimized to improve its performance over multiple cuts. The result was a novel shear blade that is able to cut high strength coiled tubing with 50% of the normal shear force. As the industry continues to push the limits of coiled tubing with extended reach applications thought impossible only a few years ago, higher strength coiled tubing with increased wall thicknesses will continue to evolve. The new shear blade geometry developed in this project ensures that not only can the latest grades of coiled tubing be sheared in legacy pressure control equipment, but also future grades of coiled tubing that are in development.
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Kelly, John, Yu Pan, and Haibo Dong. "Body Shape Effects on the Hydrodynamic Performance of Bio-Inspired Undulating Swimmers." In ASME 2022 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fedsm2022-87645.
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Abstract In this study, numerical simulations are performed to study the effects of body shape on propulsive performance in a carangiform-like swimming motion. A focus is given to the variation in performance due to changes in the maximum thickness, maximum thickness location, leading-edge radius, and boattail angle of an undulating foil. An immersed boundary method-based incompressible flow solver is implemented to solve for the propulsive performance of two-dimensional undulating foils. The resulting flow simulations yield the thrust, drag, efficiency, and flow for each body shape. From this study, we have found that better propulsive performance comes from a thinner maximum thickness, a maximum thickness location closer to the head of the fish, a narrower boattail angle, and a larger leading-edge radius. Particular care is given to the analysis of the boattail angle, because of the surprising and significant results. In changing only the boattail angle the efficiency is shown to vary by 10.3%. Changes in the leading-edge radius varies the efficiency by 4.4%, the maximum thickness by 4.0%, and the maximum thickness location along the body by 5.0%. The large improvement observed in the thinner boattail angle cases are caused by the increased curvature around the middle of the fish body leading to a high-pressure region at the tail that improves the thrust performance. The results can be used to improve understanding of fish body shapes observed in nature as well as better informing the design of bio-inspired underwater robots.
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Erturk, Alper, and Ghislain Delporte. "Hydroelastic Power and Thrust Generation Using Macro-Fiber Composite Piezoelectrics." In ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5176.
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Flexible piezoelectrics offer several advantages to use in energy harvesting and biomimetic locomotion. These advantages include ease of application, high power density, silent and effective operation over a range of frequencies as well as light weight. Piezoelectric materials exhibit the well-known direct and converse piezoelectric effects. The direct piezoelectric effect has received growing attention for low-power generation to use in wireless electronic applications while the converse piezoelectric effect constitutes an alternative to replace the conventional actuators used in biomimetic locomotion. In this paper, underwater thrust and electricity generation are investigated experimentally by focusing on biomimetic structures with macro-fiber composite piezoelectrics. Fish-like bimorph configurations with and without a passive caudal fin (tail) are fabricated and compared. The favorable effect of having a passive caudal fin on the frequency bandwidth is reported. The presence of a passive caudal fin is observed to bring the second bending mode close to the first one, yielding a wideband behavior in thrust generation. The same smart fish configuration is tested for underwater piezoelectric power generation in response to harmonic excitation from its head. Hydrodynamic loads resulting from base excitation yield considerably larger power output as compared to in-air base excitation at the same acceleration amplitude. This work also discusses the feasibility of thrust generation using the harvested energy toward enabling self-powered swimmer systems.
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Giorgadze, Anatoli, and Marine Barvenashvili. "Local and endemic animal genetic resources of Georgia." In Scientific and practical conference with international participation: "Management of the genetic fund of animals – problems, solutions, outlooks". Scientific Practical Institute of Biotechnologies in Animal Husbandry and Veterinary Medicine, 2023. http://dx.doi.org/10.61562/mgfa2023.15.
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The article describes some of animal external characteristics and yield indicators. The mentioned animals are important for the country's agro-biodiversity, having valuable genes and their alleles, the loss of which will significantly limit the possibilities and efficiency of providing breeding works. Also Georgia is a country of great diversity of freshwater fish species that is facilitated due to the landscape diversity and richness of water resources. In addition, local breed varieties and populations are valuable because they are considered as the best adapted to local conditions and resistant to various diseases. Unfortunately, today their number is significantly reduced, their genetic purity is also in question. We consider the use of in- situ, ex- situ, in vivo, in vitro conservation methods to be the best way out of the situation.
Reports on the topic "Fish yield"
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Naddafi, Rahmat, Göran Sundblad, Alfred Sandström, et al. Developing management goals and associated assessment methods for Sweden’s nationally managed fish stocks : a project synthesis. Department of Aquatic Resources, Swedish University of Agricultural Sciences, 2023. http://dx.doi.org/10.54612/a.31cfjep2i0.
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This report summarizes and synthesizes results from the Swedish Agency of Marine and Water Management (SwAM, or HaV) funded project “Förvaltningsmål för nationella arter (Management goals for nationally managed species)”. The objectives of the project have been to promote the development of management goals and associated status assessment methods and indicators, as well as reference points, for some nationally managed fish stocks both in coastal as well as freshwater areas. The report focusses largely on species and stocks that can be defined as data-poor. Such stocks are characterised by marked limitations in data availability and/or resources allocated to detailed analytical stock projections. Data-poor stocks also often lack carefully formulated management goals and associated methods and indicators for assessing stock status. In this report, we provide an overview of potential assessment methods and indicators and try to synthesise how they work and what the strengths and weaknesses are by applying them to selected data poor stocks such as pikeperch, pike, whitefish, and vendace. We also discuss how they relate to different potential management goals and provide recommendations for their application. We grouped the indicators and assessment methods by the three categories that are now used in the yearly status assessment framework provided by SLU Aqua (Resursöversikten/Fiskbarometern) – i) mortality, ii) abundance/biomass and iii) size/age structure. The results are also described for these three main categories of assessment indicators. Included is also a status report from a size- and age-based population dynamics model (Stock Synthesis 3) that is being developed for pikeperch in Lake Hjälmaren. An important experience from the project is that to improve the assessment methods for Swedish national fish stocks, it is important that managers develop both general as well as more detailed quantitative goals for the individual stocks. This should ideally be conducted in various forms of collaboration with the main stakeholders and scientists involved with assessment as participatory processes foster legitimacy. Carefully articulated management goals, which are possible to translate into quantitative targets, will facilitate the development of various approaches and methods to monitor stock statuses. Given the strong and complex interactions of fish and their environments it is also important to consider other pressures than fisheries when developing indicators and assessment methods. Our synthesis highlights a number of areas where the assessment of data-poor stocks can be improved: 1. Apply precautionary principles for data-limited stocks, particularly ones that are known to be vulnerable to exploitation. 2. Tailor approaches to how fisheries are managed in Sweden. Swedish nationally managed fish stocks are not managed by quotas (with one exception, vendace in the Bothnian Bay) and do not aim for maximum sustainable yield. Instead, the coastal and inland fisheries are managed by regulating the effort in the small-scale commercial fisheries (number of fishers/licenses and amount of gear). Regulation of recreational and subsistence fisheries effort, in terms of licenses or number of fishers) is not applied, nor possible since the fisheries is lacking obligatory notification and reporting systems. All national fisheries, however, are regulated by various technical measures (closed areas, size-limits, bag-limits, gear restrictions etc). Thus, goals and assessment methods that result in harvest limits or quota recommendations expressed in e.g. biomass/numbers are difficult to use as basis for management. Instead, there is a need for alternative management goals and associated assessment methods. 3. Use best practice methods and indicators and adapt as scientific knowledge is developed. Data-limited methods are developing rapidly, and new methods/approaches are proposed in the scientific literature every year. It is thus important to be updated on the most recent developments. 4. Clearly describe limitations/assumptions of methods used. It is important to be aware of and critically evaluate the assumptions underlying the analyses, and to carefully communicate uncertainty together with the stock status assessment. 5. Be particularly careful with low sample numbers. Many indicators and methods can be applied also on small sample sizes, however, the accuracy and precision of the estimates risk being low in such cases. 6. Accept that there is no "gold standard" for fisheries assessment. Each case study is unique and needs to be balanced against data availability, local needs and other important factors. This also means that analysts need to be careful when using generic reference levels or “borrowing” data from other stocks. 7. If possible, use several different methods/indicators. Although several indicators aim to measure similar aspects of the stock, small methodological differences can support the overall interpretation of individual indicator values. It is particularly important to incorporate many aspects and indicators (size/age/abundance/mortality) in order to produce a balanced assessment. 8. Develop means of communication. Indicators and goals should be easy to understand. However, interpretation of results from multi-indicator frameworks can be challenging. There is thus a need for finding ways of communication that can convey complicated results in a simple-to-understand manner. 9. For details on additional improvements, we refer the reader to the sub-header “recommendations for the future” found under each chapter. The implementation of Stock Synthesis for pikeperch in Lake Hjälmaren showed that it is possible to develop a more ambitious and detailed stock assessment model for a relatively data-poor stock. The model results partly support earlier interpretations of the development of the stock and the importance of the changes in regulations in 2001 (increased minimum size, increased mesh size and reduced mortality of undersized pikeperch). Before the model can be implemented and used for practical management, a number of actions for improvement are needed, which are highlighted in the relevant chapter. The most important next step is establishing management goals and reference levels for this stock. We recommend that such a dialogue is initiated by managers. The fisheries management goals should consider both biomass, fisheries mortality and size-based targets. To conclude, we stress the importance of improving all ongoing aspects related to the assessments of data-poor Swedish stocks. Strong local stocks and sustainable fisheries are vital for a variety of fisheries-related businesses and practices, particularly in rural areas, providing economical and societal value. Fishes also have important roles in aquatic food-webs and it is important that ecological values are managed wisely in order to reach targets for water quality, ecosystem structure and diversity. Given the strong and complex interactions of fish and their environments it is also important to consider other pressures than fisheries when developing indicators and assessment methods.
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Yaron, Zvi, Martin P. Schreibman, Abigail Elizur, and Yonathan Zohar. Advancing Puberty in the Black Carp (Mylopharyngodon Piceus) and the Striped Bass (Morone Saxatilis). United States Department of Agriculture, 1993. http://dx.doi.org/10.32747/1993.7568102.bard.
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The black carp (bc)GtH IIb cDNA was amplified and isolated, cloned and sequenced. Comparison of the bcGtH IIb deduced a.a. sequence with that of GtH IIb from other teleosts revealed high homology to cyprinid species and a lower homology to salmonid or perciform fish. The gene coding for the GtH IIb was isolated and sequenced. Three bc recombinant phages which hybridized to the goldfish GtH Ib cDNA probe were isolated and are currently being characterized. The region coding for the mature GtH IIb was expressed in a bacterial expression vector resulting in the production of a recombinant protein. In vitro folding resulted in a protein only 1.3% of which displaced the native common carp GtH II in a RIA. Therefore, the common carp GtH RIA was utilized for the physiological studies at the current phase of the project. Two non-functional sites were identified along the brain-pituitary gonadal axis in the immature black carp. The pituitary is refractory to GnRH stimulation due to a block proximal to the activation of PKA and PKC probably at the level of GnRH receptors. The gonads, although capable of producing steroids, are refractory to gonadotropic stimulation but do respond to cAMP antagonists, indicating a block at the GtH receptor level. Attempts to advance puberty in 2 and 3 y old black carp showed that testosterone (T) stimulates GtH synthesis in the pituitary and increases its sensitivity to GnRh. A 2 month treatment combining T+GnRH increased the circulating GFtH level in 3 y old fish. Addition of domperidone to such a treatment facilitated both the accumulation of GtH in the pituitary and its response to GnRH. The cDNA of striped bass GtH a, Ib and IIb subunits were amplified, isolated, cloned and sequenced, and their deduced a.a. sequences were compared with those of other teleosts. A ribonuclease protection assay was developed for a sensitive and simultaneous determination of all GtH subunits, and of b-actin mRNAs of the striped bass. GnRH stimulated dramatically the expression of the a and GtH IIb subunits but the level of GtH Ib mRNA increased only moderately. These findings suggest that GtH-II, considered in salmonids to be involved only in final stages of gametogenesis, can be induced by GnRH to a higher extent than GtH-I in juvenile striped bass. The native GtH II of the striped bass was isolated and purified, and an ELISA for its determination was developed. The production of all recombinant striped bass GtH subunits is in progress using the insect cell (Sf9) culture and the BAC-TO-BAC baculovirus expression system. A recombinant GtH IIb subunit has been produced already, and its similarity to the native subunit was confirmed. The yield of the recombinant glycoprotein can reach 3.5 mg/ml after 3 days culture. All male striped bass reach puberty after 3 y. However, precocious puberty was discovered in 1 and 2 y old males. Females become vitellogenic during their 4th year. In immature 2 y old females, T treatment elevates the pituitary GtH II content while GnRH only potentiates the effect. However, in males GnRH and not T affects GtH accumulation in the pituitary. Neither GnRH, nor T treatment resulted in gonadal growth in 2 y old striped bass, indicating that either the accumulated GtH II was not released, or if released, the gonads were refractory to GtH stimulation, similar to the situation in the immature black carp. In 3 y old female striped bass, 150 day GnRHa treatment resulted in an increase in GSI, while T treatment, with or without GnRHa, resulted in a decrease in oocyte diameter, similar to the effect seen in the black carp. Further attempts to advance puberty in both fish species should take into account the positive effect of T on pituitary GtH and its negative effect of ovarian growth.
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Gantt, Elisabeth, Avigad Vonshak, Sammy Boussiba, Zvi Cohen, and Amos Richmond. Carotenoid-Rich Algal Biomass for Aquaculture: Astaxanthin Production by Haematococcus Pluvialis. United States Department of Agriculture, 1996. http://dx.doi.org/10.32747/1996.7613036.bard.
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The synthesis of carotenoids has been studied toward enhancing the production of ketocarotenoids, since fish and crustaceans raised by aquaculture require astaxanthin and other ketocaroteinoids in their feed for desirable pigmentation. Notable progress has been made in attaining the goals of determining improved conditions for ketocarotenoid production in Haematococcus pluvialis and in elucidating the carotenoid biosynthetic pathway. For production of astaxanthin a number of strains of the green alga Haematococcus were evaluated, a strain CCAG was found to be optimal for photoautotrophic growth. Of four mutants, selected for enhanced carotenoid production, two hold considerable promise because caroteinoid accumulation occurs without encystment. The biosynthetic pathway of carotenoids was elucidated in photosynthetic organisms by characterizing novel genes encoding carotenoid enzymes and by examining the function of these enzymes in a bacterial complementation system. Two cyclases (b- and e-) were cloned that are at a critical branch point in the pathway. One branch leads to the formation of b-carotene and zeaxanthin and astaxanthin, and the other to the production of a-carotene and lutein. Cyclization of both endgroups of lycopene to yield b-carotene was shown to be catalyzed by a single gene product, b-lycopene cyclase in cyanobacteria and plants. The formation of a-carotene was found to require the e-cyclase gene product in addition to the b-cyclase. By cloning a b-hydroxylase gene we showed that a single gene product forms zeaxanthin by hydroxylatin of both b-carotene rings. It is expected that a second hydroxylase is required in the synthesis of astaxanthin, since canthaxanthin rather than zeaxanthin is the precursor. Evidence, from inhibitor studies, suggests that astaxanthin is formed from canthaxanthin and that b-carotene is a major precursor. Feasibility studies with the photobioreactors have shown that a two-stage system is the most practical, where Haematococcus cultures are first grown to high cell density and are then switched to high light for maximal astaxanthin production. The basic knowledge and molecular tools generated from this study will significantly enhance Haematococcus as a viable model for enhanced astaxanthin production.
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Montagna, Tea', Luis De Leo'n, Nina McDonnell, et al. Natural resource assessment of the Barrett?s Farm Unit: Minute Man National Historical Park. National Park Service, 2024. http://dx.doi.org/10.36967/2305887.
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This study used a combination of field surveys, historical data, literature review, and formal methods to assess the biodiversity and habitat integrity of vertebrates, excluding mammals at Barrett?s Farm unit (BFU). A one season full inventory of the herpetofauna was completed in 2023. The herpetological survey documented ten species commonly found in Massachusetts (4 frogs, 1 toad, 2 salamanders, 1 snake and 2 turtles), with only one species (Lithobates pipiens, Leopard Frog) being seen in large numbers. Several species (Ambystoma maculatum, Spotted Salamander; Dryophytes versicolor, Gray Treefrog; Chelydra serpentina, Snapping Turtle) were only recorded once during the survey. While no additional inventories were performed, data on several additional vertebrate groups (birds, fish) were examined using historical and participatory science data. Additional assessments included wetland health using amphibians as a metric, examining vegetative communities, and observations of other organisms (mammals, arthropods). The vertebrate faunal communities of the BFU are of mixed condition. The AmphIBI index of wetland health was conducted on the wetland areas within the unit and found that all but one were in poor health. The remaining wetland that was rated ?superior health? can be attributed to low sample size of organisms and is not reflective of the site. The avian community at the unit is interesting as it includes 163 species and is one of the more heavily birded sites in Middlesex County. Formal assessment for breeding forest birds yields a ?cautious? rating while a similar process for grassland birds yielded a poor rating. The fish community assessment lacked historical data and participatory science data, so the condition could not be assessed. The habitat at the farm is extremely disturbed from the active farming that occurs, and the edges of the property are heavily colonized by invasive plants, so perhaps the poor quality of the faunal communities is unsurprising. Several data gaps exist including the lack of assessment of arthropod communities, fish communities, and mammal communities. Additionally, more directed studies of the wetland areas within the unit would be beneficial.
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Siripong, Absornsuda. The linkage of EI Nino and La Nina on the environment and resources at Ban Don Bay and Surat Thani : final research report. Chulalongkorn University, 2007. https://doi.org/10.58837/chula.res.2007.38.
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The Landsat data in 3 periods: which are during the El Nino years (1993, 1994,1997 and 2002); the La Nina years (1988, 1998 and 2000); and Normal year (1989, 1996 and 1999), are classified for landuse types and by NDVI (Normalised Difference Vegatation Index), We found that during El Nino years, the rainfall anomalies are minus (less than normal), the air temperature anomalies are plus (hotter than normal), Tapi river dischange anomalies are minus, and NDVI’s are lower than normal (less growing vegetations). During La Nina years, the rainfall anomalies are plus (higher than normal), the air temperature anomalies are minus (colder than normal), the Tapi river dischange anomalies are plus, and NDVI’s are higher than normal (much growing vegetations). In 1998, first half of the year was El Nino, and last half of the year was La Nina. However, we used the data on 27 April 1998, which is in the El Nino period, so it received the impact of El Nino. For fisheries statistics at Surat Thani during El Nino years, the quantity of fish catch and the yields of aquacultures (shrimp and fish) were higher than average. During the La Nina years the same parameters were lower than average the areas of shrimp ponds have been increased with the increasing population. The population of Surat Thani has been increased every year. During the El Nino years, the areas of natural and mangroves were decreased, while during the El Nina years, the areas were increased. El Nino caused higher frequency of tropical cyclone. La Nina also caused tropical cyclone but lesser than El Nino linkage. The linkage of ENSO on MSL is not very clear owing to the small quantity of data. During La Nina years, MSLs show plus and minus anomalies for one each year. However, we may conclude that El Nino causes higher MLS than mean value. El Nino caused lower river runoff than normal. La Nina caused higher runoff than normal.
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Fisheries Habitat and Yield in the Lower Mekong River Basin. Mekong River Commission Secretariat, 2015. http://dx.doi.org/10.52107/mrc.ajg82r.
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Consumption and the Yield of Fish and other Aquatic Animals from the Lower Mekong River Basin. Mekong River Commission Secretariat, 2007. http://dx.doi.org/10.52107/mrc.ajhzbv.
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Technical guidance for fisheries yield assessment at the landscape scale in the Lower Mekong River Basin. Mekong River Commission Secretariat, 2024. http://dx.doi.org/10.52107/mrc.bgu8bl.
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The Technical Guidance aims to establish a systematic framework for generating, acquiring, and analyzing data using GIS in order to estimate the yield of fish and other aquatic animals (OAAs) from the Lower Mekong Basin. This approach, which is based on catch data from fishers, provides a novel method to determine the yield per unit of habitat area and extrapolate catch data from the Basin. By doing so, it offers increased certainty to all stakeholders involved in joint fisheries initiatives, particularly in transboundary areas, by clarifying roles and responsibilities. In addition, the document outlines quality control procedures for ensuring the reliability of the data, including fish catch verification, data validation, and method calibration.
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Assessment of fisheries yield in the Lower Mekong River Basin 2020. Mekong River Commission Secretariat, 2024. http://dx.doi.org/10.52107/mrc.bivw7w.
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MRC conducts periodic assessments of fisheries yield in different regions of the Lower Mekong Basin ):MB) to inform policy decisions and understand trends in catches and the value of aquatic living resources over time. The assessments conducted in 2020 suggest that the annual finfish yield from the LMB falls within the range of 1.51 to 1.71 million tonnes, while the harvest of other aquatic animals (OAA) is approximately 443,000 tons. These findings reveal a considerable decline in catches, amounting to approximately 25-30%, compared to the assessments conducted in 2000 and 2010. The estimated value of the fish catch varies from USD 7.13 billion to USD 8.37 billion annually. In addition, the estimated value of the OAA harvest is approximately USD 1.13 billion.