Dissertations / Theses: 'Fish production'

1

Triminio, de Meyer Suyapa. "Tilapia fingerling production in Honduras." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Summer/master's/MEYER_SUYAPA_0.pdf.

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2

Shi, Chen. "Potential Biogas Production from Fish Waste and Sludge." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171807.

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In order to decrease the pollution of the marine environment from dumping fish waste and by-catch, alternative use for co-digestion with sludge in anaerobic condition was studied. The purpose of this project is to optimize the methane potential from adjustment of the proportion among mixed substrates. Ten groups of different proportions among fish waste, by-catch and sludge were conducted with AMPTS II instrument under mesophilic condition (37 ± 0.5 ºC), by means of the principle of BMP test. The ratio of inoculums and mixed substrate was set as 3:2. The optimal MP obtained after an experiment with 13 days digestion was 0.533 Nm3 CH4/kg VS from the composition of sludge, by-catch and fish waste as 33 %, 45 % and 22 %. It was improved by 6 % and 25.6 %, to compare with the previous studies by Almkvist (2012) and Tomczak-Wandzel (personal communication, February 2012) respectively.

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3

Laixuthai, Parichart. "A critical study of the production of nampla (Thai fish sauce)." Thesis, Federation University Australia, 1997. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/164970.

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4

Melville, Andrew J., and n/a. "Stable Isotope Tests of the Trophic Role of Estuarine Habitats for Fish." Griffith University. School of Environmental and Applied Science, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060824.144508.

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The role of autotrophic production in different coastal habitats in the production of fish in estuaries is an important consideration in coastal management and conservation. In the estuarine waters of the Australian east coast, many economically important fish species occur over mudflats lacking conspicuous vegetation. I used stable isotope analysis to examine where such fish ultimately derived their nutrition, in the subtropical waters of southern Moreton Bay, Queensland, Australia. I first tested traditional processing methodologies of autotroph samples, in this case of mangrove leaves, and examined variability in mangrove isotope values at different spatial scales. Mangrove leaves processed using time-consuming grinding showed no significant difference in isotope values than coarsely broken leaf fragments. Isotope values of green leaves were not meaningfully different from yellow or brown leaves that would normally be the leaves that actually dropped on to the sediment. Future analyses therefore can use green leaves, since they are more abundant and therefore more easily collected, and can simply be processed as whole leaf fragments rather than being ground to a powder. Carbon and nitrogen isotope values varied at several spatial scales. The proportion of variability partitioned at different scales varied depending on the species of mangrove and element (C or N) analysed. To properly represent a geographic area, isotope analysis should be done on leaves collected at different locations and, especially, from different trees within locations. The autotrophic source(s) supporting food webs leading to fish production on mudflats might be either in situ microphytobenthos or material transported from adjacent habitats dominated by macrophytes. I tested the importance of these sources by measuring ?13C values of 22 fish species and six autotroph taxa (microphytobenthos on mudflats, and seagrass, seagrass epiphytic algae, mangroves, saltmarsh succulents and saltmarsh grass in adjacent habitats) in Moreton Bay. I calculated the distribution of feasible contributions of each autotroph to fishes. All fish ?13C values lay in the enriched half of the range for autotrophs. For over 90% of fishes, the top three contributing autotrophs were seagrass, epiphytes and saltmarsh grass, with median estimates of approximately 60-90% from these sources combined. Seagrass was typically ranked as the main contributor based on medians, while epiphytic algae stood out based on 75th percentile contributions. The other three sources, including MPB, were ranked in the top three contributors for only a single fish. Organic matter from seagrass meadows is clearly important at the base of food webs for fish on adjacent unvegetated mudflats, either through outwelling of particular organic matter or via a series of predator-prey interactions (trophic relay). Modelling results indicate that saltmarsh grass (Sporobolus) also had high contributions for many fish species, but this is probably a spurious result, reflecting the similarity in isotope values of this autotroph to seagrass. Carbon from adjacent habitats and not in situ microphytobenthos dominates the nutrition for this suite of 22 fishes caught over mudflats. The ultimate autotrophic sources supporting production of three commercially important fish species from Moreton Bay were re-examined by further analysing carbon and nitrogen stable isotope data. Mean isotope values over the whole estuary for fish and autotroph sources were again modelled to indicate feasible combinations of sources. Variability in isotope values among nine locations (separated by 3-10 km) was then used as a further test of the likelihood that sources were involved in fish nutrition. A positive spatial correlation between isotope values of a fish species and an autotroph indicates a substantial contribution from the autotroph. Spatial correlations were tested with a newly developed randomisation procedure using differences between fish and autotroph values at each location, based on carbon and nitrogen isotopes combined in two-dimensional space. Both whole estuary modelling and spatial analysis showed that seagrass, epiphytic algae and particulate organic matter in the water column, potentially including phytoplankton, are likely contributors to bream (Acanthopagrus australis) nutrition. However, spatial analysis also showed that mangroves were involved (up to 33% contribution), despite a very low contribution based on whole estuary modelling. Spatial analysis for sand whiting (Sillago ciliata) demonstrated the importance of two sources, mangroves and microalgae on the mudflats, considered unimportant based on whole estuary modelling. No spatial correlations were found between winter whiting (Sillago maculata) and autotrophs, either because fish moved among locations or relied on different autotrophs at different locations. Spatial correlations between consumer and source isotope values provide a useful analytical tool for identifying the role of autotrophs in foodwebs, and were used here to demonstrate that organic matter from adjacent habitats, and in some cases also in situ production of microalgae, were important to fish over mudflats. Whilst recognising that production from several habitats is implicated in the nutrition of fishes over mudflats in Moreton Bay, clearly the major source is from seagrass meadows. Organic matter deriving from seagrass itself and/or algae epiphytic on seagrass is the most important source at the base of fisheries food webs in Moreton Bay. The importance of seagrass and its epiphytic algae to production of fisheries species in Moreton Bay reinforces the need to conserve and protect seagrass meadows from adverse anthropogenic influences.

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5

Melville, Andrew J. "Stable Isotope Tests of the Trophic Role of Estuarine Habitats for Fish." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/367080.

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The role of autotrophic production in different coastal habitats in the production of fish in estuaries is an important consideration in coastal management and conservation. In the estuarine waters of the Australian east coast, many economically important fish species occur over mudflats lacking conspicuous vegetation. I used stable isotope analysis to examine where such fish ultimately derived their nutrition, in the subtropical waters of southern Moreton Bay, Queensland, Australia. I first tested traditional processing methodologies of autotroph samples, in this case of mangrove leaves, and examined variability in mangrove isotope values at different spatial scales. Mangrove leaves processed using time-consuming grinding showed no significant difference in isotope values than coarsely broken leaf fragments. Isotope values of green leaves were not meaningfully different from yellow or brown leaves that would normally be the leaves that actually dropped on to the sediment. Future analyses therefore can use green leaves, since they are more abundant and therefore more easily collected, and can simply be processed as whole leaf fragments rather than being ground to a powder. Carbon and nitrogen isotope values varied at several spatial scales. The proportion of variability partitioned at different scales varied depending on the species of mangrove and element (C or N) analysed. To properly represent a geographic area, isotope analysis should be done on leaves collected at different locations and, especially, from different trees within locations. The autotrophic source(s) supporting food webs leading to fish production on mudflats might be either in situ microphytobenthos or material transported from adjacent habitats dominated by macrophytes. I tested the importance of these sources by measuring ?13C values of 22 fish species and six autotroph taxa (microphytobenthos on mudflats, and seagrass, seagrass epiphytic algae, mangroves, saltmarsh succulents and saltmarsh grass in adjacent habitats) in Moreton Bay. I calculated the distribution of feasible contributions of each autotroph to fishes. All fish ?13C values lay in the enriched half of the range for autotrophs. For over 90% of fishes, the top three contributing autotrophs were seagrass, epiphytes and saltmarsh grass, with median estimates of approximately 60-90% from these sources combined. Seagrass was typically ranked as the main contributor based on medians, while epiphytic algae stood out based on 75th percentile contributions. The other three sources, including MPB, were ranked in the top three contributors for only a single fish. Organic matter from seagrass meadows is clearly important at the base of food webs for fish on adjacent unvegetated mudflats, either through outwelling of particular organic matter or via a series of predator-prey interactions (trophic relay). Modelling results indicate that saltmarsh grass (Sporobolus) also had high contributions for many fish species, but this is probably a spurious result, reflecting the similarity in isotope values of this autotroph to seagrass. Carbon from adjacent habitats and not in situ microphytobenthos dominates the nutrition for this suite of 22 fishes caught over mudflats. The ultimate autotrophic sources supporting production of three commercially important fish species from Moreton Bay were re-examined by further analysing carbon and nitrogen stable isotope data. Mean isotope values over the whole estuary for fish and autotroph sources were again modelled to indicate feasible combinations of sources. Variability in isotope values among nine locations (separated by 3-10 km) was then used as a further test of the likelihood that sources were involved in fish nutrition. A positive spatial correlation between isotope values of a fish species and an autotroph indicates a substantial contribution from the autotroph. Spatial correlations were tested with a newly developed randomisation procedure using differences between fish and autotroph values at each location, based on carbon and nitrogen isotopes combined in two-dimensional space. Both whole estuary modelling and spatial analysis showed that seagrass, epiphytic algae and particulate organic matter in the water column, potentially including phytoplankton, are likely contributors to bream (Acanthopagrus australis) nutrition. However, spatial analysis also showed that mangroves were involved (up to 33% contribution), despite a very low contribution based on whole estuary modelling. Spatial analysis for sand whiting (Sillago ciliata) demonstrated the importance of two sources, mangroves and microalgae on the mudflats, considered unimportant based on whole estuary modelling. No spatial correlations were found between winter whiting (Sillago maculata) and autotrophs, either because fish moved among locations or relied on different autotrophs at different locations. Spatial correlations between consumer and source isotope values provide a useful analytical tool for identifying the role of autotrophs in foodwebs, and were used here to demonstrate that organic matter from adjacent habitats, and in some cases also in situ production of microalgae, were important to fish over mudflats. Whilst recognising that production from several habitats is implicated in the nutrition of fishes over mudflats in Moreton Bay, clearly the major source is from seagrass meadows. Organic matter deriving from seagrass itself and/or algae epiphytic on seagrass is the most important source at the base of fisheries food webs in Moreton Bay. The importance of seagrass and its epiphytic algae to production of fisheries species in Moreton Bay reinforces the need to conserve and protect seagrass meadows from adverse anthropogenic influences.
Thesis (Masters)
Master of Philosophy (MPhil)
School of Environmental and Applied Science
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6

Kose, Sevim. "Investigation into toxins and pathogens implicated in fish meal production." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/15366.

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The major toxins and pathogens in fish meal were investigated because of food industry, public and animal health concerns. The effect of processing, the type of raw material used and storage conditions on the main toxin, histamine which causes gizzard erosion in poultry, and its formation in fish meal were investigated. The results showed that histamine and histamine-like amines in fish meal varied in levels between batches depending on the quality of raw material and type of fish used. The relationship between histamine and histamine-like amines levels was unclear. During laboratory processing of fish meal it was found that most histamine concentrated in the stickwater which had implications for the use of stickwater meal in feeds. Interestingly, histamine was detected in the stickwater meal of cod as well as mackerel. A decrease in histamine in mackerel meal and cod meal during processing was observed with respect to levels in raw material. The decrease maybe originated after the cooking stage especially in the stickwater meal (probably due to bacterial recontamination or enzymatic reactions). The decrease could be due to histamine either adhering to the equipment used or breakdown to its metabolites or derivitising to gizzerosine. Since very low levels of histamine were observed from meals produced from reasonably fresh fish, the control of histamine therefore is best achieved at the raw material stage of production. During storage trials, there was no increase in histamine levels but a decrease occurred gradually with time at 15°C, 70% RH. Rapid loss occurred at 25 and 30°C, 80% RH and heavy mould growth was also observed, although no mycotoxins were detected in analysed samples. Routine analytical methods were studied and compared for the requirements of the fish meal industry and poultry farmers. Problems occurred with the colorimetric method when applied to fish meal and fish samples containing bones due to the presence of calcium. It was modified for routine histamine analysis. Thin Layer Chromatography was the second alternative. Although High Performance Liquid Chromatography was suitable for analysing histamine and histamine-like amines together, it did lack in meeting industrial requirements. Since the modified colorirnetric method was labour intensive, despite its other advantages, there was still a need for a simpler and quicker method of analysis. For this reason, research work was carried out to develop an immunoassay for histamine analysis. The results showed that it was possible to raise antibody against histamine and suggested future research potential. Hygienic conditions of laboratory scale fish meal production were investigated. The presence of Salmonella, which leads to human salmonellosis, and E. coli 0157:H7 which also cause human food poisoning were studied. The results showed that the critical control point of fish meal production was after cooking, since recontamination can occur. Salmonella was present in several batches of commercial and laboratory processed samples, but no E. coli 0157:H7 was detected in analysed samples. Three rapid methods were compared to traditional method for Salmonella analysis particularly in fish meal. The immunoassay method introduced by Institute of Food Research, Norwich was found the most suitable because it was sensitive, specific and took about one day to complete.

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7

Godinho, Irina Sofia Marques. "Production of fish protein hydrolysates by a marine proteolytic strain." Master's thesis, ISA, 2013. http://hdl.handle.net/10400.5/6475.

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Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia
The preparation of fish protein hydrolysates by a fermentative process is an alternative to classical preparation using added proteolytic enzymes, taking advantage of the wide spectrum of proteolytic enzymes produced by microorganisms and increasing the complexity of the peptide mixture obtained. Thus, the objective of this work was to prepare fermentative protein hydrolysates (FPH) from a commercial cod protein hydrolysate (CPH) using an indigenous marine proteolytic strain. The bacterial growth was performed in liquid culture media, containing three concentrations of CPH (1, 2 and 4%), yeast extract (0.5%) and sucrose (0.5%), with continuous shaking, at 30 ºC for 24, 50 and 72 hours. The parameters evaluated were the culture growth, enzymatic activity, protein content and recovery, peptide profile, degree of hydrolysis and antioxidant activity, measured by DPPH and ABTS radical scavenging activity, reducing power and metal chelating activity. Bacterial growth and enzymatic activity reached their maximums after 24 hours of fermentation, and all FPH showed the disappearance of peptides in the range of 200 – 400 Da. In the set of samples, 4 % FPH recorded the highest values of protein content and recovery, but 1 % and 2 % FPH were the samples that presented improved antioxidant activity.

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8

Stephens, Christine Elizabeth. "Marine fish carbonates : contribution to sediment production in temperate environments." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/26195.

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In the past, oceans have strongly influenced atmospheric CO2 levels through organic and inorganic carbon cycling. The inorganic carbon pump relies on the formation of calcium carbonate which releases CO2 into the surface ocean and traps alkalinity in solid form which sinks to deeper ocean layers and sediments. After sinking, calcium carbonate can either then become trapped in the sediments or dissolve increasing the alkalinity of deeper ocean layers. The net effect is of acidifying surface oceans and encouraging release of CO2 to the atmosphere. The present thesis focuses on marine teleost (bony) fish in temperate areas as previously poorly understood but potentially major producers of calcium carbonate in the ocean. Fish in temperate areas may be contributing to carbonate sediment production and as such the inorganic carbon pump. Prior to this thesis only tropical fish have been investigated as major piscine sediment producers. The present thesis describes the composition and morphology of carbonates produced by many different species of temperate fish providing a basis for the understanding the fate of these carbonates in the environments and their potential contribution to sediment production and the inorganic carbon cycle. Characteristics of carbonates produced by fish in the wild were fairly consistent within a species upon examination of carbonates produced by poor cod (Trisopterus minutus) over the course of a year. However, despite the likely consistent and distinct characteristics of fish carbonates, little evidence of them was found in temperate shallow sediments beneath pens of farmed Atlantic salmon (Salmo salar) where there theoretically should be very high production rates. Reduced salinity, often a feature of temperate areas compared to tropical areas, was found to reduce production rates of carbonate from fish compared to higher salinities. However, salinity reductions below the ocean average of 35 psu (practical salinity units) had less impact on production rates than increases above 35 psu. As such it is argued that production rates in temperate environments should still be relatively high considering high fish biomasses in some temperate regions and could still mean fish in temperate areas are an important source of carbonate production and potential sediment production.

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9

Hedström, Per. "Climate change impacts on production and dynamics of fish populations." Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-128007.

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Ongoing climate change is predicted to increase water temperatures and export of terrestrial dissolved matter (TDOM) to aquatic ecosystems influencing ecosystem productivity, food web dynamics and production of top consumers. Ecosystem productivity is mainly determined by the rates of primary production (GPP) in turn controlled by nutrients, light availability and temperature, while temperature alone affect vital rates like consumption and metabolic rates and maintenance requirements of consumers. Increased level of TDOM causes brownification of water which may cause light limitation in algae and decrease GPP and especially so in the benthic habitat. Temperature increase has a been suggested to increase metabolic rates of consumers to larger extent than the corresponding effect on GPP, which suggest reduced top consumer biomass and production with warming. The aim of this thesis was to experimentally study the effects of increased temperature and TDOM on habitat specific and whole ecosystem GPP and fish densities and production. In a replicated large-scale pond experiment encompassing natural food webs of lotic ecosystems I studied population level responses to warming and brownification in the three- spined stickleback (Gasterosteus aculeatus). Results showed overall that warming had no effect on whole ecosystem GPP, likely due to nutrient limitation, while TDOM input decreased benthic GPP but stimulated pelagic GPP. In fish, results first of all suggested that recruitment in sticklebacks over summer was negatively affected by warming as maintenance requirements in relation to GPP increased and thereby increased starvation mortality of young-of-the-year (YOY) sticklebacks. Secondly, brownification increased mortality over winter in YOY as the negative effect on light conditions likely decreased search efficiency and caused lower consumption rates and starvation over winter in sticklebacks. Third, seasonal production of YOY, older, and total stickleback production was negatively affected by warming, while increased TDOM caused decreased YOY and total fish production. The combined effect of the two was intermediate but still negative. Temperature effects on fish production were likely a result of increased energy requirements of fish in relation to resource production and intake rates whereas the negative effect of TDOM likely was a result of decreased benthic resource production. Finally, effects of warming over a three-year period caused total fish density and biomass and abundance of both mature and old fish to decrease, while proportion of young fish increased. The main cause behind the strong negative effects of warming on fish population biomass and changes in population demographic parameters were likely the temperature driven increased energy requirements relative to resource production and cohort competition. The results from this thesis suggest that predicted climate change impacts on lentic aquatic ecosystems will decrease future densities and biomass of fish and negatively affect fish production and especially so in systems dominated by benthic resource production.

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Lehane, David Bernard. "Investigation into bone matrix proteins of selected teleost fish." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268263.

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11

Varvarigos, Panagiotis. "Microcomputer based fish farm production planning : the development of a microcomputerised data recording and production decision support system for individual fish farmers and its implementation on a fresh water trout hatchery." Thesis, University of Stirling, 1987. http://hdl.handle.net/1893/24822.

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In order to develop a system that could provide fish farmers with information to monitor stock performance and plan for a timely production, a computerised recording system was designed and tested on a trout hatchery in Scotland. It facilitated routine data capture on site with a small hand-held computer, programmed in BASIC language, which subsequently downloaded the data to a central desk-top microcomputer for further processing. Both direct and long-distance transmission via the telephone network using modems were possible. The LOTUS 1-2-3 general purpose software package, running on the microcomputer, was customised using 'macro' commands to accept the transmitted data and create files for storage on 'floppy' or 'hard' magnetic disks. Further information could be calculated and graphs and summary reports for stock control could be generated at will. Other customised LOTUS worksheets were developed to allow identification and access of specific historical data in order to calibrate regression equations and provide growth predictions for particular fish types. This information combined with cost and pricing details was further utilised by a linear programming package. Guidelines on optimum policies were formulated and sensitivity analyses could be performed. This production information system was implemented on the IBM-PC and the OLIVETTI M24 desk-top microcomputers and as field devices the SHARP PC 1500A and the HUSKY HUNTER were used. Since existing technology and 'off-the-shelf' software were utilised, the developed information system can be easily adjusted to suit the individual needs of different fish farms. However, the most important requirement for successful implementation would be the commitment and enthusiasm of the fish farm manager.

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12

Bolduc, Melanie B. "Long-term effects of habitat and management changes on steelhead production results from an individual-based model." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-050406-112805/.

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13

Ellis, Timothy Roberts. "Production and mortality of early life stages of flatfishes." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386805.

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Plankton sampling established the presence of a plaice spawning ground off the west coast of the Isle of Man in the Irish Sea. The total production of stage I plaice eggs from this spawning ground in 1993 was estimated at 7.6 x 101 • Theoretically this spawning ground could supply the local nurseries with plaice larvae. Spawning was most intense in March, before the peak in the plankton bloom in the Irish Sea. Predation on plaice eggs by clupeids was studied in March in an area of high plaice egg density to the east of the Isle of Man. Fish eggs formed the bulk of the stomach contents of sprat and herring due to the lack of alternative zooplankton food at this time of year. The later developmental stages of plaice eggs were more vulnerable to predation. This was thought to be due to the increase in pigmentation with embryonic development increasing the contrast between the egg and the water to predators that detect prey visually. Sprat and herring >80 mm showed a strong selection for plaice eggs over smaller pelagic fish eggs. However, the large eggs of plaice had a refuge in size from predation by sprat <80 mm. Smaller clupeids were feeding more actively than larger clupeids, as indicated by stomach fullness and the total number of fish eggs in stomachs. Stomach content data was combined with published biomass estimates and the daily instantaneous mortality rate of plaice eggs due to predation was estimated at 0.023 for sprat and 0.001 for herring. Sprat were therefore an important predator of plaice eggs in the Irish sea, whereas herring seemed of limited significance. Predation by fishes on O-group flatfishes was studied on a Scottish nursery ground by stomach content analysis. Fish predation was shown to be a significant source of mortality and I-group grey gurnards and gadoids were the major predators. Flounder suffered higher predation rates than plaice or dab due to the smaller size at settlement. Predation on plaice and dab was size-selective, concentrated on the smaller individuals. Smaller flatfishes were vulnerable to a greater size range and greater taxonomic range of predators. Predation by O-group cod on O-group dab was limited by the sizes of predator and prey. It was hypothesised that the times of recruitment of flatfishes and their predators to nurseries, and relative growth rates, would affect predation and hence mortality. The handling time of O-group flatfishes by O-group cod in laboratory experiments was positively related to flatfish size and negatively related to cod size. The handling time of plaice was longer than for dab of a similar size due to the difference in body shape. Profitability of flatfishes (wet weight gained per unit handling time) decreased monotonically with flatfish size over the range of prey and predator sizes used. It was therefore predicted that when O-group cod forage in the field the smallest O-group flatfishes would be the most profitable and would be behaviourally selected for. However, the selection of prey by cod was suggested to be determined by both behavioural and physical processes. There was evidence that behavioural selection of prey occurred at the ingestion stage of feeding. The current evidence for density-dependent processes in the juvenile stage of plaice was reviewed. Both the data in support of, and the processes thought to cause, density-dependent mortality in the juvenile phase were equivocal. It was hypothesised that density-dependent mortality occurs in the early egg stages of plaice and evidence, and the rationale for a potential predatory process resulting in such mortality, were presented.

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Markovsky, W. Coult. "The role of the Cape Fear River discharge plume in fisheries production : aggregation and trophic enhancement /." Electronic version (Microsoft Word), 2004. http://dl.uncw.edu/etd/2004/markovskyw/wcoultmarkovsky.doc.

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Hare, Steven R. "Low frequency climate variability and salmon production /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/5318.

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16

Spengler, C. J. "PCR-RFLP typification of microbes used in the production of a fermented fish product." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52397.

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Thesis (MScFoodSc)--Stellenbosch University, 2001.
ENGLISH ABSTRACT: The preservation of various fresh fish products is achieved by either smoking, salting, canning, freezing or fermenting a highly perishable raw product. Since many of these facilities are not readily available, the use of fermentation as a means of preserving the product has been extensively practiced. However, the fermentation of fish is a time consuming practise and only by accelerating the process would it be possible to ensure the production of a more cost effective and readily available safe end-product. The quality of the fermented fish product is partially determined by the fermentation conditions and the metabolic activity of the microbes present. The rapid identification of the microbes present during the fermentation would enable the selection of possible starters to ensure an accelerated production of high quality fermented fish products. This study was thus undertaken to develop identification fingerprints for bacteria isolated from fermented fish products. A 1300 bp fragment of the 16S rRNA genes of each of the bacteria previously isolated was successfully amplified using the PCR technique. The isolates included strains of the genera Bacillus, Staphylococcus, Sphingomonas, Kocuria, Brevibacillus, Cryseomonas, Vibrio, Stenotrophomonas and Agrobacterium. The data obtained can, therefore, be used in the identification of these microbes isolated from other similar fermented fish products. The fingerprints could also be used to assist in determining the dominant microbial populations responsible for the characteristic qualitative changes occurring in the fish product during fermentation. The microbial composition of a fermenting fish product partially determines the quality of the end-product, therefore, the use of selected bacterial starters could result in the accelerated production of a microbial safe fermented fish product. A further objective of this study was to accelerate the production of a fermented fish product by inoculating macerated trout with either selected lactic acid bacteria (LAB) or with selected bacteria with high proteolytic activity over a 30 day fermentation period. The LAB included a combination of Lactobacillus plantarum, Lactococcus diacetylactis and Pediococcus cerevisiae strains, whereas the bacteria with high proteolytic activity included strains of Kocuria varians, Bacillus subtilis, two strains of B. amyloliquefaciens and a combination of these bacterial species. The quality of the fermented product was determined using changes in product pH, titratable acidity (%TA) and free amino nitrogen (FAN) formation as efficiency parameters. The data obtained during the fermentation of the macerated trout showed that the selected starters did not have a significant effect on the pH decrease in the product over a 30 day fermentation period. The LAB strains did not have a significant effect on the %TA of the fermenting fish product, yet the presence of these bacteria appeared to limit the FAN production in the product. The bacteria with high proteolytic activity resulted in slightly enhanced %TA values and a higher FAN content in the fermented product. It was also determined that the LAB and Kocuria varians, in contrast to the Bacillus spp. inoculums, did not survive the fermentation conditions well, possibly due to the low pH environment. The presence of the starter bacteria in the fermenting fish mixture at the end of the fermentation was also successfully determined with the use of the PCR-RFLP technique. The fermented fish product, obtained at the end of the fermentation period, had a good aroma and compared favourably to similar commercially available fermented fish products. The use of different microbial starters could in future enable the production of a diverse range of high quality products, which could be produced and marketed locally.
AFRIKAANSE OPSOMMING: Die preservering van ‘n verskeidenheid vars vis produkte word bereik deur die hoogs bederfbare produk te rook, te sout, te blik, te vries of te fermenteer. Aangesien baie van hierdie fasiliteite nie geredelik beskikbaar is nie, is die gebruik van fermentasie as ‘n preserverings metode al ekstensief beoefen. Die fermentasie van vis is egter 'n tydsame proses en slegs deur die versnelling van die proses sal dit moontlik wees om die produksie van ‘n meer koste effektiewe en geredelike beskikbare veilige eindproduk te verseker. Die kwaliteit van die gefermenteerde vis produk word gedeeltelik bepaal deur die fermentasie kondisies en die metaboliese aktiwiteit van die mikrobes teenwoordig. Die vinnige identifikasie van die mikrobes teenwoordig gedurende die fermentasie sal die seleksie van moontlike suursels om die versnelde produksie van hoë kwaliteit gefermenteerde vis produkte moontlik maak. Hierdie studie is dus onderneem om identifikasie vingerafdrukke vir bakteriee wat gei'soleer is van gefermenteerde vis produkte moontlik te maak. ‘n 1300 bp fragment van die 16S rRNA gene van elkeen van die bakteriee wat voorheen gei'soleer is, is suksesvol geamplifiseer deur die PCR tegniek. Die isolate sluit in stamme van die genera Bacillus, Staphylococcus, Sphingomonas, Kocuria, Brevibacillus, Cryseomonas, Vibrio, Stenotrophomonas en Agrobacterium. Die data kan dus gebruik word in die identifikasie van hierdie mikrobes as dit gei'soleer word van ander gefermenteerde vis produkte. Die vingerafdrukke kan ook gebruik word om die dominante mikrobiese populasies wat verantwoordelik is vir die kenmerklike kwalitatiewe veranderinge wat plaasvind in die vis produk gedurende die fermentasie, te identifiseer. Die mikrobiese samestelling van ‘n fermenterende vis produk bepaal gedeeltelik die kwaliteit van die eindproduk, daarom kan die gebruik van geselekteerde bakteriese suursels die versnelde produksie van ‘n mikrobies veilige gefermenteerde vis produk teweeg bring. ‘n Verdere doel van hierdie studie was om die produksie van ‘n gefermenteerde vis produk te versnel deur fyngemaakte forel met of geselekteerde melksuurbakteriee of met geselekteerde bakteriee met hoë proteolitiese aktiwiteit te inokuleer oor ‘n 30 dag fermentasie periode. Die melksuurbakteriee het ingesluit ‘n kombinasie van Lactobacillus plantarum, Lactococcus diacetylactis en Pediococcus cerevisiae, terwyl die bakterieë met hoë proteolitiese aktiwiteit stamme van Kocuria varians, Bacillus subtilis, twee stamme van Bacillus amyloliquefaciens en ‘n kombinasie van hierdie bakteriese stamme ingesluit het. Die kwaliteit van die gefermenteerde produk is bepaal deur die veranderinge in die pH, titreerbare suur (%TS) en vrye amino stikstof (VAS) vorming van die produk as effektiwiteits parameters te gebruik. Die data wat verkry is gedurende die fermentasie van die fyngemaakte forel het gedui daarop dat die geselekteerde suursels nie ‘n merkwaardige effek op die afname in pH in die produk oor ‘n 30 dag fermentasie periode het nie. Die melksuurbakteriee het nie ‘n merkwaardige effek op die %TS van die gefermenteerde vis produk gehad nie, terwyl dit geblyk het dat die teenwoordigheid van hierdie bakterieë die produksie van VAS in die produk belemmer het. Die bakteriee met hoe proteolitiese aktiwiteit het ‘n effense verhoogde %TS en ‘n hoër VAS inhoud in die gefermenteerde produk veroorsaak. Dit is ook bepaal dat die melksuurbakteriee en Kocuria varians, in teenstelling met die Bacillus spp. inokulums, nie die fermentasie kondisies goed oorleef het nie, moontlik as gevolg van die lae pH omgewing. Die teenwoordigheid van die suursel bakteriee in die fermenterende vis mengsel aan die einde van die fermentasie is ook suksesvol bepaal met die PKR-RFLP tegniek. Die gefermenteerde vis produk, verkry aan die einde van die fermentasie periode, het ‘n goeie aroma gehad en het goed vergelyk met soortgelyke kommersieel beskikbare gefermenteerde vis produkte. Die gebruik van verskillende mikrobiese suursels kan in die toekoms die produksie van ‘n diverse reeks hoë kwaliteit produkte wat plaaslik geproduseer en bemark kan word moontlik maak.

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17

Laurich, Leah Marie. "The Role of Detritivorous Fish in Supporting New Phosphorus and Primary Production in Reservoir Ecosystems." Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1123009958.

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18

Mitchell, Darcy Anne. "Sustainable by design, how to build better institutions for fisheries management in British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ32718.pdf.

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19

Stolley, Dorie S. "Limitations on Canada Goose Production at Fish Springs National Wildlife Refuge, Utah." DigitalCommons@USU, 1998. https://digitalcommons.usu.edu/etd/6580.

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Canada geese (Branta canadensis) recently have become management problems in some areas due to overpopulation At Fish Springs National Wildlife Refuge (NWR). managers are concerned with the opposite situation Despite attempts to boost production, only 18 to 34 goslings of the western Canada goose (B. c. moffitti) were produced per year, from 1989 to 1993. I studied the breeding population from March to July in 1996 and 1997. Results suggest that production is limited in 3 ways: low gosling survival. low nesting success for ground nests, and low number of breeding pairs Gosling survival to fledging was 25% in 1996 and 52% in 1997. I examined the potential causes of low gosling survival, especially the effects of saline drinking water. Specific conductivities in the spring-fed marshes of the desert refuge range from 3.0 to 25.0+ μS/cm. conducted an experiment on captive wild-strain goslings. Three groups received different levels of saline \\ater as measured by specific conductivity: control (0 63 μS/cm), intermediate 12.0 ~1Slcm). and high (18.0 ~1Slcm) I found mortality only at the high level Effects on growth were growth were evident at both the intermediate and high levels, although statistically significant only at the high level. To examine the effects of saline drinking water on survival of free-ranging wild goslings, I collared and radio marked breeding adults, then monitored brood location and gosling numbers. I found that mortality was independent of specific conductivity levels on the brood-rearing impoundments. Observations suggest that the primary causes of low gosling survival involve predation and human disturbance. l compared my results lo the results of other studies. Accuracy of results appears to be related to the estimation technique used. Radio tracking of broods has the potential to be very accurate. Al Fish Springs NWR. l monitored nesting pairs. nests, and broods throughout the breeding season. Ground nests had lower nesting success in both years (56%: 41 %) than artificial nesting platforms (90%, 83%). The number of nesting pairs was 26 and 34 in 1996 and 1997, respectively. Based on these results, l made several management recommendations, including installing more artificial nesting platforms. and minimizing human disturbance.

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20

Waning, Kate M. "Two Bioeconomic Studies on Haddock Culture: Live Feed and Juvenile Production." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/WaningKM2002.pdf.

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21

Zhou, Wen Xu. "Two-peak resonance of swimbladders in fish (acoustic measurement and analytical model)." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/17504.

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22

Snellgrove, Donna Leanne. "Dietary availability and retention of selected minerals associated with the intensive production of rainbow trout (Oncorhynchus mykiss)." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/2325.

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This research programme aimed to review the nutritional requirements for the main minerals, (namely calcium, phosphorus, magnesium and zinc) formulated in commercial diets that are essential for the health and growth performance for salmonid fish. This was undertaken with the aim of improving our knowledge of their physiology, metabolism and fate in the rainbow trout, Oncorhynchus mykiss. Phosphorous (P) featured strongly in this work due to its adverse role in pollution and the environmental impact of intensive fish farming. The first chapter surveyed the gross nutritional requirements of fish and focused on the mineral requirements in particular. Typically the P requirements for trout were found to range from 0.5-0.8% of the diet. The problems of P loading as a consequence of dietary loses was addressed and the physiological and metabolic roles of both calcium and phosphorous were especially noted in relation to fish health and for phosphorous its environmental implications were addressed. Experimental approaches were evaluated and it was decided to conduct both standard growth trial studies as well as digestibility trials to provide the basis of most investigations with the rainbow trout. Novel approaches and strategies were used in relation to specific experiments such as examining the mineral levels in blood, and various tissues and the testing of different feed ingredients, dietary supplements and mineral sources in successive investigations. Initial investigations appraised commercial diets of varying nutritional profile with respect to mineral retention and availability for rainbow trout under controlled laboratory conditions. The effects of diets containing different fishmeal sources: i.e. brown versus white fishmeals, elevated ash content and also varying in the levels of oil were tested on juvenile rainbow trout in closed recirculated systems. Diet composition caused a significant effect on mineral retention and distribution profile in fish tissues and organs. Typically, both P and Ca were of highest concentration in vertebrae of trout (60mg/g-dry weight), compared with P concentrations for all other major organs/tissues, which were fairly even between 11-20mg/g. A small increase in dietary P level (1.08% vs. 1.22%) did not affect any growth parameters for trout for the first two commercial feeds tested but there were interesting observations with respect to the amount of P excreted in the bile with a 25% increase from 0.8mM to 1.2mM. The P levels in plasma of these fish did not reflect any dietary changes. However, there was a noticeable reduction in the digestibility of P in the diet containing the white fishmeal source (26%) compared with 49% for the higher grade fishmeal diet. High ash content feeds resulted in a marked reduction in the net mineral retention of this element (16% compared to 27% for the lower ash diet). The same was also true for Ca (12% compared with 26%). The effect of oil levels in diets on mineral utilization was investigated under farmed conditions and was of particular interest given the demand for nutrient dense feeds in the industry. There was a strong tendency for improved P and Ca digestibility coefficients at each incremental increase in oil level for juvenile production sized fish (50-l00g). This ranged from 55% to over 70% when oil levels were over 26%. However this was not observed for larger fish of over 200g in weight. Experimental investigations followed are described in (Chapter 4) where fishmeal based diet was supplemented with varying levels of inorganic phosphorous. Phosphorous, calcium and other mineral absorption characteristics in addition to retention were measured in a series of growth and digestibility trials. Interestingly, there was no apparent change in the distribution of P with increasing dietary levels ranging from 1.39-2.16%. These were above known requirements for these fish with minerals being in excess. Similar results were noted for all other minerals measured in rainbow trout. There was a significant rise in the P concentration of plasma of rainbow trout fed a diet containing over 2% P and this may infer that the homeostatic regulation of P is unable to function at this level. Other haemato-logical parameters were not affected. Although not significant, there appeared to be slight trend in elevated bile P with increasing dietary P supplementation. The faecal concentrations for each of the minerals showed that elevated P in fish meal diets led to increased faecal output from 25mg/g to over 40mg/g for the highest P diet. Overall digestibility coefficients were lower as dietary P increased above that in the fishmeal control diet. These ranged from 50% to 39% for P, Ca and Mg were not greatly affected. The net retention of P was calculated and this fell from 30% to just below 20% for the range of dietary P used in the investigation. A preliminary study, reported in chapter 5A, was useful in providing information about the relative absorption profiles for differential mineral absorption from the various regions of the gastro intestinal tract of rainbow trout. A standard commercial diet was fed to large trout (>200g) and subsequently, digesta was removed from fish and analysed. For all minerals and protein, the pyloric and mid intestinal region was the main site for digestion, release and absorption of the macro elements concerned. The protein and mineral digestibility of suitable feedstuffs commonly employed in the formulation of complete diets for trout resulting from a sequence of experimental trials are presented in chapter 5B. These included a selection of marine, animal and plant by-products which were substituted into a reference basal diet designed for salmonids. This involved the inert marker- yttrium oxide and calculations based on nutrient digestibility from diet and faecal concentrations. Mineral digestibility coefficients were found to vary considerably and a number of anomalies such as negative values were obtained for Ca and Zn in certain feedstuffs. Combined diets (reference and test ingredient) gave values that were more consistent and P digestibility ranged from 47-59% in marine and animal protein concentrates compared with plant sources (24-37%). Negative values for Ca and Zn were thought to be attributable to complex interactions with other feed components. Additionally, a group of inorganic mineral supplements were tested by inclusion into a series of diets. These included mono calcium phosphate, di-calcium phosphate (DCP), mono di-calcium phosphate and magnesium phosphate. DCP produced lower Ca and P digestibility values, 31 and 50% respectively, compared with the other sources (44-62%), indicating the importance of choice of mineral supplement in aquafeeds. A critical appraisal of this work is provided in Chapter 6 and formed a retrospective review of the results generated and integrated these findings into a foundation for further research and development. Nutritional investigations using the rainbow trout as the model salmonid species raised many more questions and possibilities and broadened the scope of the topic. The subject of mineral requirements for fish is very complex and numerous factors are involved at several physiological and biochemical levels in fish. Although the research on rainbow trout involved whole animal studies under both laboratory and commercial farm conditions, the need to explore alternative in vitro methods and to utilize larger scale farm and sea cage trials for salmon were suggested. The advent of more advanced diet formulations and feeding strategies were mentioned and the scope for more scientific investigations to improve the utilization and reduce phosphorous discharge into the environment proposed.

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23

Hastings, Trevor Stewart. "Studies on the production, properties and immunogenicity of extracellular factors of Aeromonas salmonicida." Thesis, University of Aberdeen, 1986. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU004678.

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The potential role in pathogenicity of extracellular products (ECP) of the fish pathogen Aeromonas salmonicida was investigated. Evidence is presented that determinants of host damage are produced extracellularly by A. salmonicida. In vitro, the bacterium produced a number of extracellular enzymic and ctyolytic activities, including proteases and an heterogeneous haemolysin which was active against rainbow trout erythrocytes. Solubilization of trout erythrocytes in vitro resulted from the cooperative effects of the haemolysin and a caseinolytic protease. The caseinolytic protease was implicated in host damage; the in vivo effects of the caseinase may have been potentiated by haemolysin. The production of extracellular proteolytic and haemolytic activities by a number of isolates of A. salmonicida was studied; some potentially important differences between isolates were found. Evidence is presented that rainbow trout possess humoral mechanisms of resisting the toxic products of A. salmonicida. Proteolytic and haemolytic activities of ECP were inhibited, and the in vivo toxicity of ECP was neutralized, by normal trout serum. In vitro, factors in normal trout serum appearaed to form soluble complexes, as well as insoluble precipitates, with component(s) of ECP. In vitro, ECP caused a reduction in circulating levels of an alpha-2 macroglobulin analogue in rainbow trout. As putative determinants of pathogenicity, extracellular factors of A. salmonicida are potentially important in conferring protective immunity against furunculosis. The humoral immune response of rainbow trout and rabbits to components of ECP was investigated. At least 15 components of ECP, including the caseinase and haemolysin, were immunogenic in the rabbit. In the trout, antibodies to only 4 components of ECP were detected and no antibody to the caseinase or haemolysin was found. It is suggested that the effectiveness of furunculosis vaccines might be improved if the immunogenicity in trout of certain ECP components could be enhanced.

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24

Goosen, Neill Jurgens. "Investigation of potential bio-active properties and effects on production performance of aquafeed ingredients derived from fish processing waste by way of enzymatic autolysis." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95907.

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Thesis (PhD) -- tellenbosch University, 2014.
ENGLISH ABSTRACT: This study is part of the continuing global research effort dedicated to finding alternative aquafeed ingredients, which not only replace fish meal and fish oil as sources of essential nutrients in aquafeeds, but also provide specialist functional properties when included in feeds. Due to constraints in supply of fish meal and fish oil originating from wild capture fisheries, the continually growing aquafeed industry requires new sources of raw materials for the production of high quality feeds. The aim of the study was to investigate the specialist functional properties of feed ingredients (with emphasis on immune-stimulation potential) derived from fish processing waste after enzymatic hydrolysis by endogenous proteolytic enzymes (autolysis). Further aims were to (i) quantify effects of these feed ingredients on production performance of two species relevant to the South African aquaculture industry, namely Mozambique tilapia Oreochromis mossambicus and South African abalone Haliotis midae, (ii) compare performance to commercially available enzymatically produced feed ingredients, and (iii) separate the functional effects of these fish processing waste derived feed ingredients from the acid used to preserve them against bacterial spoilage during the autolysis process. Oil recovered after autolysis of rainbow trout viscera proved to be an attractive feed ingredient due to favourable effects on the non-specific cellular immune function of both Mozambique tilapia and South African abalone. However, in South African abalone, increased immune function due to inclusion of fish oil was accompanied by a significant decrease in production performance. The inclusion of hydrolysed proteins, obtained by autolysis of fish waste, in aquaculture feeds also improved non-specific immunity and survival of Mozambique tilapia significantly – independently of the preserving acid – although the same was not observed for South African abalone. Production performance was dependent on dietary hydrolysed protein inclusion levels in both species; excessive inclusion resulted in decreased production performance. The performance of dietary hydrolysed protein from autolysis and those from commercial production processes were significantly different, possibly as a result of different raw material origins and production processes. It is further shown that formic acid can contribute to improved water stability in abalone feeds, a novel mode of action not previously described. The study concludes that the simple autolysis process for processing of fish waste can provide aquafeed ingredients with immune stimulatory potential, which can contribute to improved production performance in the Mozambique tilapia and the South African abalone. The result can contribute to improved sustainability of the aquafeed industry, through substitution of fish meal and fish oil derived from capture fisheries with processed fish waste components.
AFRIKAANSE OPSOMMING: Hierdie studie vorm deel van die voortdurende en wêreldwye soeke na nuwe akwakultuur voerbestanddele wat nie net vismeel en –olie kan vervang as bron van noodsaaklike voedingstowwe nie, maar wat ook gespesialiseerde funksionele eienskappe openbaar wanneer dit in akwavoere ingesluit word. As gevolg van beperkings in die voorsiening van vismeel en –olie afkomstig vanaf wilde visserye, word die voortdurend groeiende akwavoer bedryf genoodsaak om nuwe grondstowwe te benut vir die vervaardiging van hoë kwaliteit voere. Die doelwit van die studie was om moontlike gespesialiseerde funksionele eienskappe (met spesifieke klem op potensiële immuun-stimulasie) van voerbestanddele te ondersoek wat herwin is vanaf reënboogforel proseseringsafval, na ensiematiese hidrolise d.m.v. endogene ensieme teenwoordig in die afval (outolise). Verdere doelwitte was om (i) effekte op produksie prestasie van hierdie bestanddele te kwantifiseer in twee akwakultuur spesies relevant tot die Suid- Afrikaanse bedryf (naamlik die Mosambiekse kurper Oreochromis mossambicus en die Suid- Afrikaanse perlemoen Haliotis midae), (ii) om produksie prestasie te vergelyk met kommersieel beskikbare voerbestanddele voorberei d.m.v. ensiemtegnologie, en (iii) om die moontlike effekte van die voerbestanddele te skei van die van die sure gebruik om die bestanddele te preserveer tydens die outolitiese proses. Daar is bevind dat olie herwin na outolise van reënboogforel ingewande ‘n goeie voerbestanddeel is wat gunstige effekte op die nie-spesifieke, sellulêre immuniteit van beide Mosambiekse kurper en Suid-Afrikaanse perlemoen gehad het. In die Suid-Afrikaanse perlemoen het verbeterde immuunfunksie gepaard gegaan met ‘n verswakking in produksie prestasie. Die gehidroliseerde proteïen komponent van ge-outoliseerde prosesseringsafval het ook beduidende verbetering in nie spesifieke immuniteit en oorlewing van Mosambiekse kurper tot gevolg gehad - onafhanklik van die preserverende suur - maar dieselfde is nie in die Suid-Afrikaanse perlemoen waargeneem nie. Produksie prestasie was afhanklik van die insluitingsvlakke van gehidroliseerde proteïen in beide spesies en dit is bevind dat oormatige insluiting produksie nadelig beïnvloed. Prestasie van proteïen afkomstig van outolise en die van ‘n kommersiële produksieproses het beduidend verskil, moontlik as gevolg van verskillende grondstowwe en prosesseringstegnieke. Daar is verder vir die eerste keer getoon dat mieresuur ‘n beduidende verbetering in waterstabiliteit in sekere perlemoenvoere teweeg kan bring. Die studie kom tot die slotsom dat die eenvoudige outolise proses funksionele akwavoerbestanddele kan produseer wat kan bydra tot ‘n verbetering in produksie prestasie in die Mosambiekse kurper en Suid-Afrikaanse perlemoen. Die resultaat kan bydra tot verbeterde volhoubaarheid van die akwavoer bedryf, deur vismeel en –olie afkomstig van wilde visserye, te vervang.

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25

Lubbe, Beatrix. "Characterisation and utilisation of microbes in the production of fish sauce and paste." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51649.

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Thesis (MSc Food Sc )--Stellenbosch University, 2000.
ENGLISH ABSTRACT: Fermented fish products are popular food products mainly consumed and produced in Southeast Asia. These products are not produced in South Africa, and those available to the public are imported. The main action during the production and fermentation of this sort of product, is that of proteolysis, either by the bacteria or enzymes naturally present in the fish. The prevalent microbes present in six fermented fish samples from Bangkok (Thailand) and seven from Khon Kaen (Thailand), were determined, and using numerical methods, clustered into similarity groups using the calculated dendrogram .distance (Do) technique to determine their relation to reference strains. Forty-seven different bacterial strains were isolated, but no yeasts, moulds or lactic acid bacteria were found. Five Gram-negative, oxidase-positive species, five different Staphylococcus species and nine different endospore-forming species of the genus Bacillus, were isolated and identified using the API systems. The data indicated that members of the genus Bacillus were the prevalent organisms in all the products examined. The isolates were also scanned for general enzyme activity using the API Zym technology, and the production of proteases was investigated using the Standard Methods Caseinate and the Universal Protease Substrate methods. It was found that most of the isolated organisms produced protease, which is of major importance in the production of fermented fish products. Proteolytic cultures from the fermented fish products, as well as lactic acid starters, were used in the production of a fermented fresh water fish product. Production parameters including: glucose, inoculum, moisture content and incubation time, were evaluated in order to select optimum fermentation conditions. Fermentation efficiency was determined by measuring the final pH, titratable acid and the free amino nitrogen content. Optimum efficiency was obtained with 5% (w/w) added glucose at a moisture level of 150 ml water per 100 g fish. A factorial design (3 x 3 x 3) was used to indicate viable trends to facilitate optimisation of the fermentation process. The main effects, two-factor and three-factor interactions were calculated. Optimum trends obtained were a glucose concentration of 5% (wlw) , inoculum concentration of 1x10⁸ kve.ml ̄ ¹, an incubation period of 15 days and temperature of 30°C. Three lactic acid starters (226 - Lactobacillus plantarum, 140 - Lactococcus diacetylactis and 407 - Pediococcus cerevisiae) were selected as they produced some of the best fermentation results and are safe to use in food. It was found that a combination of all three strains (226, 140 and 407) yielded the best results. By using the above parameters, an acceptable product was produced in terms of consistency, colour and aroma. Further studies need to be conducted to optimise the safety of the product as well as the flavour, both chemically and sensorically optimisation of the product.
AFRIKAANSE OPSOMMING: Gefermenteerde visprodukte is populere voedselprodukte in die lande van Suidoos-Asie. Die produkte word nie in Suid-Afrika geproduseer nie, maar slegs ingevoer. Die hoof aksie tydens die fermentasie proses is proteolise deur die bakteriee en ensieme wat natuurlik teenwoordig is in vis. Die oorheersende mikrobes teenwoordig in ses gefermenteerde vis produkte van Bangkok (Thailand) en sewe van Khon Kaen (Thailand), is bepaal. Numeriese metodes is gevolg om die isolate in groepe te sorteer en te groepeer deur gebruik te maak van die berekende dendrogram afstand (Do) tegniek om hul verwantskap ten opsigte van die verwysingsorganisme te bepaal. Sewe-en-veertig verskillende bakteriee is ge·isoleer, maar geen fungi of melksuurbakteriee is ge·identifiseer nie. Vyf Gram-negatiewe, oksidase-positiewe spesies, vyf verskillende Staphylococcus spesies en nege verskillende endospoorvormende spesies van die genus Bacillus, is geisoleer en ge·identifiseer deur gebruik te maak van die API CHB sisteme. Die data het getoon dat lede van die genus Bacillus die oorheersende organismes was. Die isolate is daarna ondersoek vir algehele ensiemaktiwiteit deur van die API Zym tegnologie gebruik te maak. Daar is veral klem gelê op die protease aktiwiteit en dit is gemeet deur van die "Standard Methods Caseinate Agar" metode asook die "Universal Protease Substrate" metodes gebruik te maak. Daar is gevind dat die oorgrote meerderheid organismes proteolitiese ensieme produseer wat belangrik is in die produksie van gefermenteerde visprodukte. Kulture wat ge·isoleer is uit gefermenteerde visprodukte asook melkssuurkulture is gebruik vir die produksie van 'n gefermenteerde varswater visproduk. Produksieparameters insluitende: glukose-, inokulum- en voginhoud asook inkubasie tyd is ondersoek om die optimum fermentasie kondisies te bepaal. Optimum effektiwiteit is gevind by 'n 5% glukose konsentrasie en vogvlakke van 150 ml water per 100 9 vis. 'n Faktoriale ontwerp (3 x 3 x 3) is gebruik om die optimum kondisies te bepaal. Die hoof effekte asook die twee faktor en drie faktor interaksies is bereken. Optimum neigings is gevind by 'n glukose konsentrasie van 5%, inokulum konsentrasie van 1x10⁸ kve.ml ̄ ¹, 'n inkubasie tydperk van 15 dae en temperatuur van 30°C. Drie melksuurbakteriee (226 - Lactobacillus plantarum, 140 - Lactococcus diacetylactis en 407 - Pediococcus cerevisiae) is gekies aangesien hulle die beste resultate gelewer het en veilig vir gebruik in voedselprodukte is. Daar is gevind dat die drie melksuurkulture saam in kombinasie die beste fermentasie resultate opgelewer het. Deur gebruik te maak van die bogenoemde fermentasie kondisies, kon 'n aanvaarbare produk, in terme van kleur en geur, gelewer word. Verdere studies moet gedoen word om die veiligheid asook die geur, chemies asook sensories, te optimiseer.

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26

Gomes, Igor Gabriel Rodrigues Ferreira. "Phycocyanin production assessment for the marine microalgae Arthrospira platensis, cultivated in fish effluent." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16605.

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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
The phycocyanins are water-soluble proteins that function as accessory pigments and exhibit various properties, as immunostimulatin, cholesterol lowering effect, anti-inflammatory, antiviral, anticancer and antioxidant action, in addition to application as a natural dye. The focus of the commercial production of phycocyanin has fallen in most of the microalgae Arthrospira platensis. This cyanophyceae is rich in compounds as proteins, vitamins, essential amino acids, minerals, essential fatty acids, antioxidants, pigments, among others. Aquaculture is an activity of great importance, generating income and producing quality protein for human consumption. However, their activity generates large amounts of effluents with high nutrient load. The use of microalgae for aquaculture waste production is quite used, yielding good results in the cultivation of several species. This study aimed to evaluate the production of phycocyanin by A. platensis microalgae grown in fish effluent. For this, the microalgae was exposed to growing in Venkataraman modified medium and effluent from the Nile tilapia farming, in indoor and outdoor systems. After the end of the crop, the biomass obtained was exposed to phycocyanin extraction process, which consisted of freezing and thawing of wet biomass obtained from the culture in indoor system and subsequent extraction in sodium acetate buffer pH 5.0 for 48 h. The biomass produced in the outdoor system was dried at 60 Â C for 24 h in an oven with recirculating air. The dried biomass was resuspended in sodium acetate buffer pH 5.0 for 48 h. After that, the extracts were centrifuged at 4,700 rpm at 4 ÂC for 30 min. The supernatant was collected and evaluated in a spectrophotometer at 280 nm wavelength for proteins, 615 nm for phycocyanin,and and 652 nm for allophycocyanin. After this process, the crude extracts obtained from phycocyanin were subjected to purification by ion exchange chromatography. There wasnt significant difference between the performance of algae grown under the same conditions. However, algae exposed to outdoor system showed superior results. The phycocyanin concentrations were higher in the treatments that used Venkataraman medium, while the proportions of the pigment found in indoor systems were higher. The process of purification by ion exchange chromatography resulted in higher concentrations of pigment for fractions eluted with 0.2 M NaCl to all crude extracts of phycocyanin.
As ficocianinas sÃo proteÃnas solÃveis em Ãgua que funcionam como pigmentos acessÃrios e apresentam diversas propriedades, como aÃÃo imunoestimulante, efeito redutor do colesterol, efeitos anti-inflamatÃrio, antiviral, anticÃncer, antioxidante, alÃm de aplicaÃÃo como corante natural. O foco da produÃÃo comercial de ficocianina tem caÃdo em maior parte sobre a microalga Arthrospira platensis. Essa cianofÃcea Ã rica em proteÃnas, vitaminas, aminoÃcidos essenciais, minerais, Ãcidos graxos essenciais, pigmentos antioxidantes, dentre outros. A aquicultura Ã uma atividade de grande importÃncia, geradora de renda e produtora de proteÃna de qualidade para alimentaÃÃo humana. No entanto, sua atividade gera grandes quantidades de efluentes com alta carga de nutrientes. O uso de efluentes aquÃcolas para a produÃÃo de microalgas Ã bastante empregado, gerando bons resultados no cultivo de diversas espÃcies. Este trabalho teve como objetivo avaliar a produÃÃo de ficocianina pela microalga A. platensis cultivada em efluente piscÃcola. Para isto a microalga foi exposta Ã cultivo em meio Venkataraman modificado e efluente, proveniente de cultivo de tilÃpias do Nilo, em sistemas indoor e outdoor. ApÃs o tÃrmino dos cultivos a biomassa obtida foi exposta a processo de extraÃÃo de ficocianina que consistiu no congelamento e descongelamento da biomassa Ãmida obtida do cultivo em sistema indoor e posterior extraÃÃo em tampÃo acetato de sÃdio pH 5,0 durante 48 h. A biomassa produzida no sistema outdoor foi seca a 60 ÂC durante 24 h em estufa com recirculaÃÃo de ar. A biomassa seca foi ressuspendida em tampÃo acetato de sÃdio pH 5,0 durante 48 h. ApÃs isso, os extratos foram centrifugados a 4.700 rpm a 4 ÂC durante 30 min. O sobrenadante foi coletado e avaliado em espectrofotÃmetro nos comprimentos de onda de 280 nm, para proteÃnas, 615 nm, para ficocianina e 652, para aloficocianina. ApÃs esse processo, os extratos brutos de ficocianina obtidos foram submetidos a purificaÃÃo por cromatografia de troca iÃnica. NÃo houve diferenÃa significativa entre o desempenho das algas cultivadas nas mesmas condiÃÃes. No entanto, as algas expostas ao sistema outdoor mostraram resultados superiores. As concentraÃÃes de ficocianina foram superiores para os tratamentos que utilizaram o meio Venkataraman, enquanto que as proporÃÃes do pigmento encontradas nos tratamentos expostos ao sistema indoor foram maiores. O processo de purificaÃÃo por cromatografia de troca iÃnica resultou em maiores concentraÃÃes do pigmento para as fraÃÃes eluÃdas com NaCl 0,2 M para todos os extratos brutos de ficocianina.

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27

Rodrigues, Ana Sofia de Figueiredo. "Industrial production of omega-3 polyunsaturated fatty acids from fish oil and microalgae." Master's thesis, ISA/UTL, 2012. http://hdl.handle.net/10400.5/5257.

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Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia
ω-3 polyunsaturated fatty acids (PUFAs) ingredients, especially eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acid (DHA, 22:6ω3) are known for its vital and unique role in human health and well-being by an extensive scientific research. These facts are widely spread by media. At present, the major source of ω-3 PUFAs is fish oil from oily fish like sardine (Sardina pilchardus). This work proposes the use of heterotrophic microalgae such as Crypthecodinium cohnii as an alternative source of interest for the commercial production of ω-3 EPA and DHA. It is also suggested the use of a common process suitable for both feedstock. EPA and/or DHA production are accomplished through oil saponification and PUFAs concentration winterization and urea concentration. PUFAs purification by chromatography is only necessary when oil is extracted from fish since fractions obtained from C. cohnii have high proportions in DHA and they do not require further purification steps for food applications. The combination of traditional (seasonal) and alternative sources (year-round) using a common production process shows an economic advange with increasing earnings for market development.

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28

Chao, Han. "What is the most sustainable system for fish production in the Amazon Basin?" Thesis, Linköpings universitet, Institutionen för tema, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167387.

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There is a need of increasing fish production due to the rapidly growing population. The Amazon basin has around 1 million km2 of freshwater area, and a substantial part could be an ideal base for the development of the fish rearing industry. Currently, small-scale fish farming and fishery is commonly observed in the Amazon Basin, but these systems can negatively impact the environment, for example, via eutrophication and overfishing. Here I compare several fish production systems reported for the Amazon Basin to evaluate what is the most sustainable system that should be preferably implemented in that region. I also analyzed the potential of expanding fish farming at the Amazon basin, including a suggestion of the kind of the Amazonian water type and the fish species that should preferentially be recommended as the most appropriate for sustainable production. Blackwater and clearwater main tributaries have been pointed out as the most appropriate areas for fish farming and are recommended as the potential base of fish farming. As there is an existing market for the fishes Colossoma macropomum (Tambaqui); Arapaima gigas (Pirarucu) and Piaractus mesopotamicus (Pacu), these have been pointed out as the main species to start a sustainable fish production. The analysis of the fish production systems was performed in a way to allow a proper combination of the water self-purification mechanism and the fish culture industry. My main suggestion for sustainable fish production is that: a) fish rearing location should be changed on a yearly basis in order to decrease the local environmental impact. Water self-purification mechanisms are suggested as the main process to help to ameliorate the environmental impacts of fish farming. b) Tree seeds and fruits from 26 types of trees that naturally grow in the Amazon basin should be used for fish feeding, especially for tambaqui and pacu.

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29

Haylor, Graham S. "The culture of African Catfish, Clarias gariepinus (Burchell) in Africa, with particular reference to controlled hatchery production." Thesis, University of Stirling, 1992. http://hdl.handle.net/1893/3267.

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A rationale is presented for a primary nursing strategy and an on-growing strategy for Clarias gariepinus (Burchell) culture in Africa, thus providing a potential model for the development of culture technology for the species. Existing information pertaining to the production strategies identified is reviewed, highlighting the attributes of African catfish for aquaculture. Some of the current deficiencies and inconsistencies in available information pertaining to controlled hatchery production are addressed. The early developmental stages of Clarias gariepinus are defined, in order to promote consistent use of terminology and help farmers better address the changing needs of their developing stock. The pattern of growth and survival of larvae and fry is investigated at higher stocking densities than those used experimentally to provide a database for planning full-scale commercial operations. Tank design and water flow rates appropriate for Clarias gariepinus in hatcheries are investigated and recommendations made. Finally, in order to promote maximal growth rates of hatchery stocks the maximum daily feed intake of larvae in relation to different feeding regimes is estimated based on rates of gastric evacuation and return of appetite. An overview of the controlled hatchery production of Clarias gariepinus is presented.

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30

Adikwu, I. A. "Studies on the utilization of dietry carbohydrates by tilapia (Oreochromis niloticus)." Thesis, University of Edinburgh, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377538.

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31

Myers, Bonnie Jean Evaline. "Variations in Community Fish Production and Diversity Across the Appalachians: Implications for Climate Change." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/25803.

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Climate change is considered a major threat to freshwater ecosystems through altering biodiversity, structure, and function. Having a thorough understanding of how diverse ecosystems respond to temperature change is vital to ecosystem management and conservation. During summer 2012, I quantified fish biomass, somatic growth, secondary production, and habitat data for fish communities in 25 Appalachian streams from Vermont to North Carolina. Multiple statistical tests were conducted to determine the relationship between community fish production and air and water temperature, species thermal guild production and air and water temperature, and the relationship between community fish production and diversity. Community fish production estimates ranged from 0.15 to 6.79 g m-2 yr-1 and community P/B ratios ranged from 0.21 to 1.07. No significant differences existed between mean community production estimates at the cold-water, cool-water, warm-water, and extreme northern sites (P=0.19), but P/B ratios in the extreme northern streams were statistically higher than mean community P/B in cold- and cool-water streams in the southern Appalachians (P=0.002). Water temperatures had a positive effect on community fish production (P=0.01) while air temperatures did not (P=0.10). Both air and water temperatures were significant in predicting whether community production would be dominated by cold-water or cool-water fish (P=0.001, P<0.0001, respectively). Community fish production was significantly, positively related to species richness (R2=0.38, P=0.001) and was one of the highest correlates of community production (R2=0.52). As climate change alters freshwater ecosystems, fish communities may transform by means of shifting fish abundance, biomass, and production among species ultimately affecting ecosystem structure, function, and biodiversity.
Master of Science

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32

Cyterski, Michael John. "Analysis of the Trophic Support Capacity of Smith Mountain Lake, Virginia, for Piscivorous Fish." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/28185.

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This investigation examined the adequacy of the forage base to meet current demand of piscivores in Smith Mountain Lake, Virginia. Surplus production, or the maximum sustainable supply, of alewife (Alosa pseudoharengus) and gizzard shad (Dorosoma cepedianum) were determined using data on the biomass, growth, and mortality of each species. Mean hydroacoustic alewife biomass from 1993-1998 was 37 kg/ha and mean gizzard shad cove rotenone biomass from 1990-1997 was 112 kg/ha. Mean annual alewife surplus production was determined to be 73 kg/ha and mean annual gizzard shad surplus production totaled 146 kg/ha.

Bioenergetics modeling and population density estimates were utilized to derive the annual food consumption (realized demand) of the two most popular sport fish in the system, striped bass (Morone saxatilis) and largemouth bass (Micropterus salmoides). The striped bass population consumed 46 kg/ha of alewife and 27 kg/ha of gizzard shad annually. Largemouth bass ate 9 kg/ha of alewife and 15 kg/ha of gizzard shad annually. Annual consumption by ancillary predators was estimated to be 13 kg/ha of alewife and 35 kg/ha of gizzard shad.

Prey supply to predators is limited by morphology, behavior, and distribution. The cumulative effect on prey availability of these three factors, in addition to consumption by other predators, was quantified. For largemouth bass, available supply of alewife and gizzard shad exceeded demand by 20% and 53% respectively. For striped bass, available supply of gizzard shad surpassed demand by 30% but available alewife supply was only 4% greater than demand. Annual demand of all predators was 94% of total available clupeid supply.

Striped bass stockings were increased by 50% in 1998 and will remain at this level in the near future. A predator-prey simulation model of alewife and striped bass populations was developed to explore the consequences of increased predator demand. This model incorporated dependencies between alewife abundance and mortality and the mortality, abundance, and growth of striped bass. Model output showed that a 50% stocking increase has a near-zero probability of increasing the mean annual number of legal and citation striped bass in Smith Mountain Lake.
Ph. D.

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33

Simonson, Martin Albert. "Modeling Nearshore Fish Community Responses to Shoreline Types in Lake Erie." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1501861205611006.

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34

Locascio, James Vincent. "Passive Acoustic Studies of Estuarine Fish Populations of Southwest Florida." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1700.

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Recordings of fish sound production were made in Charlotte Harbor, Florida using Long Term Acoustic Recording Systems (LARS) programmed to record 10 seconds of sound every 10 minutes. Results demonstrated a strong circadian pattern in fish sound production that occurred within a few hours of dusk each evening. Sound production lasted on average 8.7 hrs each evening during the peak spawning season. LARS were deployed when Hurricane Charley crossed Charlotte Harbor in August, 2004. The hurricane did not inhibit nightly chorusing events of spawning fish. Rather, sound levels produced by spawning fish on the night of and 3 days after the hurricane were higher and lasted longer than any of the 9 days recorded prior to the hurricane. Acoustic time series data recorded at multiple sites in Charlotte Harbor during 2005 revealed changes in the spatial distribution of fish sound production in response to increased freshwater inflow and consequent decreased bottom dissolved oxygen concentrations in early June. Fish sound production decreased rapidly over several days at study sites in the northern portion of the harbor most immediately affected by changes in environmental conditions. Meanwhile, fish sound production increased at the study site furthest seaward where normoxic levels were sustained. By August levels of fresh water inflow decreased substantially, bottom dissolved oxygen levels increased and sound production resumed at sites previously affected by these conditions. Fish sound production began intermittently in February and ended in November. Peak levels were reached by mid-late April / early May and continued throughout the summer time. Seasonal patterns of sound production match the reported spawning periods of estuarine sciaenid species recorded. Black drum sound production was measured in the canal systems of Cape Coral and Punta Gorda, Florida during the 2004-2006 spawning seasons. The circadian pattern of sound production was similar to other sciaenids documented in Charlotte Harbor. Seasonal patterns of black drum sound production occurred during October through April and peaked in February. This seasonal period of sound production also matched patterns of black drum reproductive readiness and spawning reported in the literature for the Gulf of Mexico. A hydrophone array was used in the Cape Coral canal system to localize calling black drum and measure source levels and propagation of calls. Source level estimates averaged 165 dBRMS re: 1muPa SPL (SD=1.0) (n = 1,025). Call energy was concentrated in the fundamental frequency (94 Hz) and first two harmonics (188 Hz and 282 Hz). A square root model best described propagation of the fundamental frequency and first harmonic and a log 10 model best described the second harmonic. Based on the mean RMS source level, signal propagation, background levels, and hearing sensitivity, the communication range of black drum at the study site was estimated at between 33 and 108 meters and was limited by background levels, not auditory sensitivity. The timing and levels of sound production and egg production were compared in black drum. Eggs were collected hourly from 1800 - 0400 by surface plankton tows on two consecutive evenings while black drum sound production was continuously recorded. This sampling effort was conducted five separate times from January through April, 2006. Evidence of the time of spawning was indicated by the collection of blastodiscs (fertilized single cell eggs) or back calculated early cleavage stage eggs. Neither the timing nor the quantity of sound production was positively correlated with egg production on a nightly basis and the greatest densities of eggs were collected on evenings which had the lowest levels of sound production. This may have been due to differences in the fecundity of individual females spawning on the evenings when sampling was conducted.

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35

Lin, Zhi Ying. "Trends in aquaculture production and its role in meeting human protein needs." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/4994.

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Regional and global trends in aquaculture production, value and price are assessed for the last 30 years relative to trends in wild caught species. Based on data from the Fisheries and Aquaculture Department of the Food and Agriculture Organization of the United Nations for aquaculture production, data is extracted for the first time to address regional (Europe, North America, South America, Africa, Oceania and Asia) trends in production focused on the top five aquaculture produced species. Previous uses of the database have largely focused on global production. Of the top five species (whiteleg shrimp Penaeus vannamei, Atlantic salmon Salmo salar, silver carp Hypophthalmichthys molitrix, common carp Cyprinus carpio, and giant tiger prawn Penaeus monodon), Asia accounts for most of the global production (with the exception of Atlantic salmon Salmo salar). The central issue considered in this thesis concerns the likelihood and capacity of aquaculture production of fish and shellfish protein for human consumption relative to that of exploited wild stocks. Over the last 30 years or so, aquaculture production has risen exponentially and captures of wild caught fish have now plateaued. The relative status, rearing practices, production and basic economic perspectives of the principle aquaculture produced species globally are compared with wild caught production. The principle finding is that total global aquaculture production will exceed that of commercial wild caught species by about 2015. The significance of this is discussed in terms of current views of environmental (e.g. pollution, disease and habitat degradation) and economic (e.g. production level, farm price, marketing economics, fixed costs (facility and equipment depreciation, loan interest, land lease, fixed wages), variable costs (cost of seed stock, feed, energy)) impacts of aquaculture. Similarly, these issues are considered for the fishing industry (e.g. fishing down the food web, likelihood of expansion of bottom fisheries into deeper waters, reduction of biodiversity, declining global catches). It is concluded that aquaculture is a necessity and that if current trends continue aquaculture production can more than supplement human fish protein needs even in the given context of the rapid growing population, but that in the long term aquaculture production will itself be substantially supplemented by “rebounding” wild fishery production.

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36

Lückhoff, Paul Daniël. "Application of the condition factor in the production of African sharptooth catfish Clarias gariepinus /." Link to the online version, 2005. http://hdl.handle.net/10019/1098.

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37

Wallace, Fiona Anne. "Dietary fatty acids affect inflammatory mediator production by murine and human macrophages and lymphocytes." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326785.

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38

Jenkelunas, Peter. "Production and assessment of Pacific hake hydrolysates as a cryoprotectant for frozen fish mince." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43921.

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Frozen storage has long been used as a means to slow down the microbial and enzymatic degradation of fish. Unfortunately, over time frozen fish will lose protein solubility and water holding capacity leading to declining quality. To minimize the degradation of frozen fish, cryoprotectants (often a blend of sucrose and sorbitol) are employed. Although successful in limiting protein denaturation and aggregation, sugar based cryoprotectants are not suitable for diabetics or those who dislike sweet tasting fish products. A possible alternative is fish protein hydrolysate (FPH). Current knowledge on the use of FPH as a cryoprotectant, however, is limited. It is necessary to determine how FPH production parameters can be optimized for cryoprotection. It is also necessary to determine the optimal dosage of FPH in fish mince, and how FPH affects the taste of frozen fish products. In this study, response surface methodology was used to optimize processing variables, namely pH, % enzyme/substrate, and hydrolysis time for production of cryoprotective FPH. The optimization study revealed higher cryoprotective efficacy in all 20 FPH samples produced according to a central composite rotatable design compared to a sucrose/sorbitol cryoprotective blend; however, there was little difference among FPH samples. Based on these findings, it is suggested to produce FPH with 1% enzyme/substrate, 1-hour hydrolysis and no pH adjustment because these are the most economical conditions within the central composite rotatable design. FPH produced at the suggested conditions was added to cod fish mince at levels of 2, 4, 6, and 8 percent (w/w). Evaluation of expressible moisture, cook loss, salt extractable protein, and differential scanning calorimetry profiles showed no significant difference between unfrozen and freeze/thawed fish mince samples when containing at least 4 percent FPH. Sensory evaluation by trained panelists showed that the addition of FPH into fish ball products increased the fishiness, saltiness, bitterness, and firmness while decreasing the level of moistness. Panelist comments suggested a taste preference of fish products containing FPH over fish products containing sucrose/sorbitol. Based on the cryoprotective effectiveness and taste acceptability of FPH, it can be concluded that FPH is a viable alternative to sugar based cryoprotectants.

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39

Wiff, Rodrigo. "Predicting food consumption and production in fish populations : allometric scaling and size-structured models." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/935.

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Life-history traits in fish populations are highly correlated. A subset of these correlations are called allometric scaling, they refer to biological processes which can be described using body size as independent variable. Particularly, allometric scaling related with food consumption (Q) and biomass production (P) has gained the attention of ecologists for several decades. This thesis proposes a quantitative framework for food consumption, which allows both the identification of the mechanisms underlying the allometric scaling for Q and the development of a predictive model for consumption to biomass ratio (Q/B) in fish populations. This thesis is based on the fact that food consumption can be inferred from first principles underlying the von Bertalanffy growth model. In addition, it has been noticed in the literature that biomass production and food consumption show similar allometric scaling dependence, therefore, both can be derived from these first principles. Thus, a similar quantitative framework was used to produce models for P/B in fish populations. Once functional forms for production and food consumption were identified, a third model was developed for the ratio between production and consumption (P/Q). This ratio is usually named ecological efficiency because it determines how efficiently a population can transform ingested food into biomass. Several authors have noticed that P/Q remains invariant (independent of body size) across species. From a theoretical point of view, the results presented here allow the first quantitative explanation for the existence of the allometric scaling for Q/B and the invariance of P/Q across fish species. These results, together with the explanation for allometry in P/B reported in the literature, suggest that the regular across-species pattern for the trio {P/B,Q/B,P/Q} can be explained by basic principles that underpin life-history in fish populations. This quantitative framework for the trio {P/B,Q/B,P/Q} is based on an explicit dependence with body size, which simplifies the estimation of these quantities. Model complexity depends, in part, on which data are available. Models were applied to real data from commercially important species fished in Chile. Statistical properties of the new models were evaluated by an intensive resampling approach. The simplest possible model for the trio {P/B,Q/B,P/Q} rests on the assumption of a stable age distribution. These quantities have a key importance in ecosystem modelling because they determine population energetics in terms of food intake by predation and the transformation of this energy into population biomass of predators. Application of the new models produces results which were comparable to those given by standard methods. This thesis is a result of multidisciplinary research which attempts to make a contribution to the understanding of the mechanisms underlying the allometric scaling of food consumption and production in fish populations. It proposes models for the trio {P/B,Q/B,P/Q} and thus, has the potential to be widely applicable in fisheries science.

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40

Singh, Sahdev. "A computer simulation model for wastewater management in an integrated (fish production-hydroponics) system." Diss., Virginia Tech, 1996. http://hdl.handle.net/10919/37764.

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41

Jacob, Annie Philip. "Ecological effects of chemicals used in pond culture of catfish and percid fishes." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1211989438.

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42

Briland, Ruth. "Optimizing Larval Fish Survival and Growth through an Analysis of Consumer and Resource Interactions in Percid Culture Ponds." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1268153735.

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43

Potts, Warren Mason. "Towards the development of species-specific fish production models for small reservoirs in Southern Africa." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1005176.

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The fish populations in small southern African reservoirs are largely unexploited and there is potential for fisheries development. However, the development of sustainable fisheries requires reliable estimates of potential yield or production. Empirical models that have been developed to predict fish production only apply to large water bodies and only predict total fish production, not the production of individual species. Small reservoirs generally have few commercially important species and therefore species-specific fish production models are an alternative approach. The small reservoirs of the Eastern Cape are dominated by the moggel (Labeo umbratus). The principal objectives of this thesis were to gain an understanding of the ecology of small reservoirs and the function of moggel in these systems. This information was used to design a research approach to rapidly develop species-specific models for small reservoirs in southern Africa. The limnology of two small reservoirs was compared. During the study period the reservoirs were turbid and showed a warm, monomictic pattern of thermal stratification. Anthropogenic pressure in the reservoir catchments appeared to be the overriding factor increasing the nutrient input to the reservoirs and consequently, influencing the biomass of algae in the reservoirs. The feeding biology of moggel in Katriver and Laing reservoirs was examined. Moggel are detrivorous and successfully digested diatoms. The slower growth rate of moggel in Katriver reservoir was attributed to the poorer nutritional value of the diet as a consequence of the lower concentration of diatoms in the detrital aggregate. The reproductive characteristics of moggel were examined in four reservoirs. Moggel were able to reproduce successfully in the reservoirs. This could be attributed to their r-selected reproductive strategy, with a high fecundity and an extended spawning season and their ability to spawn in a floodplain environment. Differences in recruitment success between years were found to be a consequence of the timing and duration of seasonal rains. The number of mature females in a population and the availability of suitable spawning habitat influenced recruitment success. The life history of the moggel in five reservoirs was compared. Growth appeared to be related to food availability, while mortality was lower in the populations where food was abundant and there were less predatory species. Size and age at maturity were not affected by environmental factors, but were dependent on growth and mortality. Three contrasting methods were used to estimate moggel gillnet selectivity. The Sechin, direct fyke net method and length-structured model all yielded similar results and correction factors obtained from the selectivity study were applied to the gillnet data to estimate the fish population size and structure in each reservoir. Using information from the life history and selectivity studies, the biomass and production of five moggel populations was estimated and related to abiotic and biotic factors in the reservoirs and their catchments. Moggel biomass and production was dependent on the biomass of algae, which was dependent on morphoedaphic characteristics of the reservoirs. Small, shallow reservoirs with a reasonable amount of human habitation in their catchments would sustain the highest algal biomass and provided they had adequate spawning habitat would also have the highest moggel biomass and production. The future research requirements for small reservoir fisheries are outlined and include a three-year program to develop a species-specific production model for any of the dominant species.

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Chung, Ming-long, and 鍾名朗. "The regulation of lipid peroxidation and pheromone production in medaka fish under exogenous oxidative stress." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/209487.

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45

Girard, Joshua James. "Feasibility of Wastewater Reuse for Fish Production in Small Communities in a Developing World Setting." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3119.

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Eradicating poverty, malnutrition, and the burden of disease have been included as three of the major issues facing the world. The United Nation member countries, having set forth the Millennium Development Goals, have committed themselves to solving these problems. Two major factors which affect solutions to these problems are increasing water stress and implementing improved sanitation. Integration of tilapia aquaculture and reuse of wastewater has been suggested as a solution which addresses both of these factors. The objective of this study is to examine the feasibility, and explore the benefits and drawbacks, to implementing small community wastewater fed (WWF) aquaculture systems in the developing world. The water quality characteristics of treated effluent from nine wastewater treatment (WWT) plants were compiled from other studies. The concentration of total nitrogen in the effluent and the flow rate were of most importance, as they were used to calculate the nitrogen loading at each WWT plant. The nitrogen loading was then used to estimate the total pond size which could be supported by each WWT plant, the expected yearly yield for tilapia, and the percentage of the population who would benefit from provision of protein associated with the integration a fish farming system with the WWT plant. Results show that WWF, semi-intensive tilapia culture can provide 10 grams per day of dietary protein for 11% - 52% of the population of the communities in this study when integrated with a community managed wastewater treatment system. To assess potential risks to human health, associated with WWF aquaculture, the level of fecal coliform (FC) contamination was compared to the standard set by the World Health Organization; less than 105 FC per 100 mL for reuse in fish ponds. The level of FC contamination in the WWT plant effluents ranged from 653 to 1.78 × 105 FC per 100 mL, exceeding this standard. Given the context, the level of fecal coliforms should not rule out integrated reuse and aquaculture as an option. The nutrients found in wastewater are valuable resources in tilapia culture; therefore, allowing their persistence through treatment for reuse, while optimizing wastewater treatment technologies for pathogen removal is an appropriate solution for small communities in developing countries for reducing poverty, malnutrition, and disease burden of waterborne illnesses.

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Salter, Michael A. "The production and preservation of fish-derived carbonates in shallow sub-tropical marine carbonate provinces." Thesis, Manchester Metropolitan University, 2013. http://e-space.mmu.ac.uk/314039/.

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Recent studies have demonstrated that marine bony fish (teleosts) precipitate inorganic calcium carbonate in their gut as a by-product of osmoregulation, subsequently excreting it into the open water column as loosely aggregated millimetre-scale pellet. These studies have primarily focused on physiological aspects of this process and the fate of resulting carbonates in pelagic settings, which is likely to be dissolution at depth. However, the implications of such carbonate production in shallow tropical and sub-tropical carbonate provinces has also begun to be considered, and it is thought that fish may contribute significant quantities of morphologically distinctive mud-grade high-Mg calcite in certain habitat settings. However, most studies of carbonate mud in modern subtropical settings do not report particles that are obviously fish-derived, and questions concerning fish-derived carbonate characteristics and post-excretion stability thus arise. The present work therefore provides more detailed characterisation of the carbonate products of an expanded range of Caribbean fish species and determines their short-term preservation potential in a sub-tropical carbonate province (the Bahamas). Following collection of carbonates from 22 fish species (all starved), precipitates were characterised using scanning electron microscopy and a suite of complimentary chemical analysis techniques. The form in which these carbonates are likely to be incorporated into surface sediments was investigated by disaggregating pellets and characterising the liberated particles by performing detailed image-based grain size analyses, with additional experiments demonstrating the likely rate and extent of pellet disaggregation by placing them in agitated seawater. Finally, short-term preservation potential was determined in a series of experiments whereby excreted precipitates were exposed to surface seawater and shallow subsurface porewater conditions for several months. Results indicate that, at the point of excretion, fish-derived carbonates are morphologically and mineralogically more varied than previously thought, although most morphotypes (e.g., ellipsoids, dumbbells, spheres, rhombohedra) are seemingly unique in shallow sub-tropical marine settings. ii High-Mg calcite, typically containing 20–35 mol% MgCO3, is the dominant product of about half the species investigated, but Mg calcite with lower MgCO3 contents (in the range 2–20 mol%) is also common, as is aragonite, which can represent up to 27 wt% of carbonates excreted by some species. In addition, amorphous magnesium carbonate (AMC) and magnesium-rich amorphous calcium carbonate (ACC), both of which are strongly hydrated, represent the dominant precipitation products of some species, with a hydrated crystalline phase (monohydrocalcite) occasionally accompanying the latter. A non-carbonate phase, brucite, is nearly ubiquitous as a volumetrically minor phase. Where analysed, all of these phases are further found to differ from other carbonate sediments in the Bahamas with regard to their stable carbon and oxygen isotope compositions; a consequence of the important role of metabolic HCO3 - in the precipitation process. Detailed grain size analyses indicate that most morphotypes are released from pellets upon disaggregation as individual mud-grade particles that retain their distinctive forms. However, extreme agitation can result in polycrystalline forms releasing their fibre-like components; these particles being less distinctive than their parent forms. In contrast, some particles are intergrown and do not disaggregate beyond particle clusters that are up to fine sand sized. Moreover, excreted pellets do not necessarily always disaggregate, with moderate agitation in seawater resulting in a significant proportion of carbonate being retained as intact pellets, albeit smaller (typically fine sand sized) and more well-rounded than initial pellets (typically fine to coarse sand sized). In quiescent settings pellet diminution is less extensive, and it is thus hypothesised that a significant proportion of fish-derived carbonates excreted in the Bahamas is preserved as sand-grade pellets. Despite the highly distinctive nature of fish-derived carbonates, particles that can be attributed to production by fish nevertheless remain elusive in studies of Bahamian surface sediments. It is thus necessary to invoke post-excretion processes of dissolution and/or recrystallisation to explain the apparent disparity between production rates and occurrence as sedimentary particles. Indeed, it is demonstrated here that AMC, brucite, and large quantities of ACC undergo complete dissolution in seawater within a few days of excretion, with the remaining ACC apparently crystallising to form fine sand-grade (50–200 μm diameter) polycrystalline calcite spheres over similar timescales. iii Monohydrocalcite, also undergoes complete dissolution or alteration (to calcite) during 3 month exposures to artificial seawater, and is predicted to alter in a similar manner in natural settings. Conversely, anhydrous crystalline phases remain largely unchanged after porewater and seawater exposures lasting several months, although two important post-excretion processes are observed. Firstly, high-Mg calcite ellipsoids appear to undergo partial dissolution (with preferential loss of MgCO3) and possible recrystallisation, and, based on these observations, it is predicted that longer exposure times will result in changes being pervasive, possibly obscuring the piscine origin of initial crystals. Secondly, carbonate pellets containing minor amounts of aragonite at the point of excretion appear, in some cases, to stimulate post-excretion growth of abundant aragonite needles that are morphologically similar to aragonite needles that dominate Bahamian carbonate muds. It is further apparent that these processes are inhibited in uncleaned samples, possibly due to surface adsorption of organic compounds, but the evidence after 3 month exposures indicates that inhibiting factors might eventually be overcome. Based on these results and modelling of carbonate excretion across shallow platform areas of the entire Bahamian archipelago, it is predicted that about 18 % of excreted carbonates will dissolve after excretion, while a further 53 % may alter beyond recognition within a very short period (perhaps on the order of years). Moreover, characterisation of carbonates produced by three species of normally feeding fish indicates they produce only amorphous carbonates, despite producing crystalline phases when starved. This difference, attributed to the inhibition of CaCO3 crystallisation by dietary phosphate, indicates that loss of fish-derived carbonate to dissolution might be considerably higher than 18 % under normal natural circumstances. The sedimentary significance of fish-derived carbonates thus remains enigmatic, but results presented herein indicate that they follow very different preservation pathways depending on their excreted form, and that they may make previously unrecognised contributions to: i) the carbonate sand fraction (as peloids); and ii) aragonite needle muds (as crystals grown post-excretion).

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47

Schmidt, Brian A. "Determining the Habitat Limitations of Maumee River Walleye Production to Western Lake Erie Fish Stocks." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1463067261.

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48

Johnson, Harry D. "Potential Fish Egg Production by Mnemiopsis leidyi Determined by Hydrography at the Chesapeake Bay Mouth." W&M ScholarWorks, 1987. https://scholarworks.wm.edu/etd/1539617579.

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49

McCabe, Anthony Joseph. "The role of polyunsaturated fatty acids on the expression and production of matrix metalloproteinases and their inhibitors." Thesis, University of Ulster, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326126.

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50

AGUILAR, GARCIA ERIK DANIEL. "Influence of Dietary Supplementation of Ensiled Devil Fish and Staphylococcus saprophyticus on Equine Fecal Greenhouse Gases Production)." Tesis de Licenciatura, EDSON BRODELI FIGUEROA PACHECO, 2019. http://hdl.handle.net/20.500.11799/104577.

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Article history: The present context was designed to investigate the efficacy of devil fish (DF; Plecostomus sp.) silage and Staphylococcus saprophyticus on fermentation characteristics as well as greenhouse gases production mitigation attributes in horses. Four levels of ensiled DF at 0% (control DF0), 6% (DF6), 12% (DF12), and 18% (DF18) were added into the diet. Moreover, three doses of S. saprophyticus (0, 1, and 3 mL/g dry matter [DM]) were used for in vitro fecal fermentation. The use of ensiled DF resulted in increased (P < .0001) pH during fermentation. The asymptotic gas production was the highest (P < .0001) in DF6, whereas other supplementation caused lower production than that of control. Lag time for the asymptotic gas production de creased (P < .05) with increasing dietary DF doses. Inclusion of S. saprophyticus resulted in the lowest (P <.05) gas production and mL/0.5 g DM incubated and thus, the reduced gas production up to 23.17% than that of control. The interaction of DF × S. saprophyticus showed the lowest gas production at DF18, whereas the highest production was estimated at DF6 without S. saprophyticus after 48 hours. The lowest emission of CO2 (P < .0001) was observed in DF18 inclusion, which was 15.25% lower than that of control at 48 hours of fermentation. In contrast, the lowest hydrogen (H2) production was estimated in DF0, whereas DF18 exhibited the highest. Inclusion of DF12 and DF18 reduced (P < .09) methane (CH4) emission by 58.24% and 59.33%, respectively. However, DF, S. saprophyticus, and DF × S. saprophyticus interaction had no significant effect (P > .05) on CH4 production. In conclusion, ensiled DF and S. saprophyticus could be supplemented in equine diet as promising alternatives to corn for mitigating the emission of greenhouse gases effectively

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Dissertations / Theses on the topic 'Fish production'

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