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1
Wang, Man-ping. "Fish consumption and mortality in Hong Kong Chinese : the lifestyle and mortality study (LIMOR) /". View the Table of Contents & Abstract, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38588432.
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Soares, Silvia. "Fish farm health evaluation : interpretation of site mortality records". Thesis, University of Stirling, 2012. http://hdl.handle.net/1893/9268.
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In aquaculture worldwide, diseases are a significant constraint to economic expansion. The Scottish salmonid industry has experienced many cycles of development, with episodes of little or negative profitability caused by excess of production, and times of crisis due to different disease problems. In Scotland, the early implementation of regulation largely contributed to the control of infectious disease outbreaks. The recent Chilean outbreak of infectious salmon anaemia (ISA) illustrated the threats and the impacts of disease in the aquaculture industry and the importance of implementing good regulation and husbandry practices to reduce the impact of the spread of infectious disease. Databases of site production data have an important role to play in the investigation and understanding of diseases. They store valuable data collected during the time of production, which are essential for the identification of potential health and production problems during the production cycle of farmed fish. Mortality records are one of the most important sources of information on a farm, especially if it includes the cause of death as deformities, predators and diseases. Any deviation from the expected levels of mortality may indicate production problems, infectious diseases, or inadequate welfare. The investigation of increased rates of mortality must include examining farm records, determining the influence of death rate on production and the potential risk factors of diseases in a farm. This project demonstrated the importance of mortality records for setting industry standards of “expected” mortality losses and for investigating the value of recorded mortalities as a tool for aiding in surveillance and control of infectious diseases. It also aimed to determine the utility of reported mortality in supporting and assisting management-strategy decisions at the farm and industry level. In this project, we developed a baseline benchmark curve for expected mortality losses for Atlantic salmon in seawater. This novel approach constitutes a first attempt to establish a baseline curve for normal mortality, which allows detection of potential production problems based on deviations of mortality from the baseline curve of normal mortality. The results of this study also indicated that mortality levels may vary across production cycles, which can again be identified by using the baseline. We found that site was the factor with the highest contribution to variance in mortality. This site-to-site variation in mortality may have resulted from epidemics and environmental incidents, or other local event/effects. Temperature, and/or geographical area were also characteristics that contribute to variation in mortality. The regulator, Marine Scotland Science, with the backing and support of the salmonid industry has suggested potential mortality thresholds as an indicator of presence of infectious diseases, which could be used as alerts for inspection by the official authority. In this study, high mortality rates on fish farms were investigated as an indicator of the presence of infectious disease. The analysis was performed using several analytical approaches: receiver operating characteristic (ROC) curve analysis, measures of sensitivity and specificity, and bootstrap methods. The study was performed by splitting the production cycle into small fish with mean weight below 750 g and large fish with mean weight over 750 g. In the small fish, the results did not suggest reported mortality as a strong indicator of the presence of infectious disease, which may be caused by the lack of records of infectious disease at this stage of the production cycle. In the larger fish, high mortality rates were found to be a strong potential indicator of the presence of infectious diseases, including the suggested mortality threshold. In a survey, the role of traditional diagnosis in the prevention and control of disease outbreaks was assessed. For that, key informant interviews were performed with open questions to the health or farm manager of several trout and Atlantic salmon farms and we also used the diagnostic reports of the Veterinary Diagnostic Services (VDS) from Stirling University to triangulate the data. We showed that disease diagnoses are of great importance for disease identification and control of actual diseases. Farmer’s experience was also indicated as essential in the identification of the first signs of disease, which was principally through the daily monitoring of fish. This study suggested that disease diagnosis starts at the farm level with the daily monitoring of fish and the records of different parameters by the farmer, including mortality. Those records were showed to be vital to identify problems within the production. This thesis illustrated a novel approach to investigate and interpret recorded mortality at the farm level. The results presented in this thesis indicated reported mortality as a vital on-farm tool for identification of diseases and production problems. This thesis suggested priority areas where further investigation is required.
3
Wang, Man-ping, e 王文炳. "Fish consumption and mortality in Hong Kong Chinese: the lifestyle and mortality study (LIMOR)". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39724621.
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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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Alhossaini, Mohsen S. M. H. "Growth and mortality of 0-group plaice, Pleuronectes platessa L., using otolith microstructure". Thesis, Bangor University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352946.
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Breen, Michael. "Investigating the mortality of fish escaping from towed fishing gears - a critical analysis". Thesis, University of Aberdeen, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493592.
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Studies investigating the survival of fish escaping from towed fishing gears have demonstrated a significant mortality. The aim of this thesis was to address criticisms of these studies and establish whether the estimates of escape mortality were biased. This critical analysis focused on the work by Fisheries Research Services, as they were considered to have developed benchmark techniques in this field.
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Williamson, Craig W. "Tournament-associated mortality and the effects of culling in Wisconsin black bass (Micropterus spp.) tournaments /". Link to full text, 2007. http://epapers.uwsp.edu/thesis/2007/williamson.pdf.
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Thesis (M.S.)--University of Wisconsin--Stevens Point, 2007.Submitted in partial fulfillment of the requirements of the degree Master of Science in Natural Resources, College of Natural Resources. Includes bibliographical references (leaves 75-81).
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Adams, Michael J. "Experimental analysis of tadpole mortality factors : effects of bullfrogs and exotic fish in the Puget Lowlands, Washington /". Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/5507.
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Subasinghe, R. P. "Studies on the effects of environmental factors and selected pathogens on morbidity and mortality of hatchery reared Oreochromis mossambicus (Peters) eggs and fry". Thesis, University of Stirling, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375402.
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Sclafani, Matthew. "The role of osmoregulation and nutrition as determinants of buoyancy and short-term mortality of marine fish larvae". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0033/NQ64664.pdf.
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Kulakkattolickal, Augusthy Thevasia. "The effects of surface access and dissolved oxygen levels on survival time of a water-breathing and an air-breathing fish species exposed to a plant toxin (Croton tiglium, Euphorbiaceae, seed extract) /". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66223.
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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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Rylander, Lars. "Dietary exposure to persistent organochlorine compounds and health effects in women and their infants epidemiological studies on birthweight, cancer incidence and mortality /". Lund : Dept. of Occupational and Environmental Medicine, Institute of Laboratory Medicine, Lund University, 1997. http://books.google.com/books?id=rgFrAAAAMAAJ.
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Rydell, Joseph J. "The influence of abiotic factors on gill-net catch rates and the evaluation of mortality rates for yellow perch in southern Lake Michigan". Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1391675.
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I determined differences in yellow perch gill-net catch-per-unit-effort (CPUE) at two depths (10 and 15 m) in the Indiana waters of Lake Michigan during June, July, and August from 1989 to 2006. I evaluated the abiotic factors of water temperature, water clarity, wave height, and wind direction to determine whether they influence the differences in yellow perch CPUE. This study suggests that yellow perch in southern Lake Michigan may select habitat based on water temperature during the summer, moving in response to thermocline changes. We also evaluated mortality rates for two distinct periods (1984-1994 and 2000-2007) in order to identify the response of the population to changes in exploitation. Yellow perch during 1984-1994 (high exploitation) and 2000-2007 (low exploitation) displayed an increase in mortality for fish of harvestable size. In addition, during 2000-2007 (low exploitation) we identified that female yellow perch reached exploitable size earlier in life than males.Department of Biology
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Sauls, Beverly J. "Relative Survival of Gags Mycteroperca microlepis Released Within a Recreational Hook-and-Line Fishery: Application of the Cox Regression Model to Control for Heterogeneity in a Large-Scale Mark-Recapture Study". Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4940.
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The objectives of this study were to measure injuries and impairments directly observed from gags Mycteroperca microlepis caught and released within a large-scale recreational fishery, develop methods that may be used to rapidly assess the condition of reef fish discards, and estimate the total portion of discards in the fishery that suffer latent mortality. Fishery observers were placed on for-hire charter and headboat vessels operating in the Gulf of Mexico from June 2009 through December 2012 to directly observe reef fishes as they were caught by recreational anglers fishing with hook-and-line gear. Fish that were not retained by anglers were inspected and marked with conventional tags prior to release. Fish were released in multiple regions over a large geographic area throughout the year and over multiple years. The majority of recaptured fish were reported by recreational and commercial fishers, and fishing effort fluctuated both spatially and temporally over the course of this study in response to changes in recreational harvest restrictions and the Deepwater Horizon oil spill. Therefore, it could not be assumed that encounter probabilities were equal for all individual tagged fish in the population. Fish size and capture depth when fish were initially caught-and-released also varied among individuals in the study and potentially influenced recapture reporting probabilities. The Cox proportional hazards regression model was used to control for potential covariates on both the occurrence and timing of recapture reporting events so that relative survival among fish released in various conditions could be compared.
A total of 3,954 gags were observed in this study, and the majority (77.26%) were released in good condition (condition category 1), defined as fish that immediately submerged without assistance from venting and had not suffered internal injuries from embedded hooks or visible damage to the gills. However, compared to gags caught in shallower depths, a greater proportion of gags caught and released from depths deeper than 30 meters were in fair or poor condition. Relative survival was significantly reduced (alpha (underline)<(/underline)0.05) for gags released in fair and poor condition after controlling for variable mark-recapture reporting rates for different sized discards among regions and across months and years when individual fish were initially captured, tagged and released. Gags released within the recreational fishery in fair and poor condition were 66.4% (95% C.I. 46.9 to 94.0%) and 50.6% (26.2 to 97.8%) as likely to be recaptured, respectively, as gags released in good condition. Overall discard mortality was calculated for gags released in all condition categories at ten meter depth intervals. There was a significant linear increase in estimated mortality from less than 15% (range of uncertainty, 0.1-25.2%) in shallow depths up to 30 meters, to 35.6% (5.6-55.7%) at depths greater than 70 meters (p < 0.001, R2 = 0.917). This analysis demonstrated the utility of the proportional hazards regression model for controlling for potential covariates on both the occurrence and timing of recapture events in a large-scale mark-recapture study and for detecting significant differences in the relative survival of fish released in various conditions measured under highly variable conditions within a large-scale fishery.
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Barroco, Lorenzo Soriano Antonaccio. "Taxa de mortalidade relacionada à prática da pesca esportiva do cichla spp. na região do médio Rio Negro, Amazonas, Brasil". Universidade Federal do Amazonas, 2013. http://tede.ufam.edu.br/handle/tede/2746.
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The expansion of recreational fishing in Brazil started in the 1990 s, when more and more people came to the Amazon in search of peacock bass (Cichla spp.). The behavior of this cichlid, which attacks lures, is especially exciting for anglers. The middle Negro River has become one of the most popular areas of sport fishing of the world, where the largest peacock bass can be found. The importance of catch-and-release fishing as an sustainable fishing strategy has been shown to directly help conserve peacock bass fish stocks in the region. In this study, peacock bass mortality was evaluated in relation to catch-and-release fishing, comparing two types of artificial lures: the jig and a traditional middle-water type. Fish, samples were collected in January/February and October/November of 2012 in the Unini River, a right margin tributary of the Negro River, in the municipal region of Barcelos in Amazonas State. A total of 191 peacock bass were caught, 90 by jig lure and the rest by the middle-water lure. Both fish groups were submitted to experimental confinement during a period of three days. In both groups, 30 fish were confined individually and 60 confined collectively. Additionally, 11 fish from the second group had radio transmitters attached to be used in telemetry. The mortality rate was calculated for each type of lure and type of confinement. No mortality was encountered for the group caught with a jig beat lure. In comparison, the middle-water lure showed a mortality rate of 1.66% for the collective confinement and 18.18% for the monitoring involving telemetry. For both types of lures, no mortality was observed for fish confined individually. The data was plotted using a Kruskal-Wallis variance analysis that showed values of X2 (1.179) = 0,502 and p= 0,478 for confined environments. The same test show values of X2 (1.179) = 1,005 e p= 0,316 for the different lures. The results indicated that neither confinement type or lure type had a significantly negative impact on the peacock bass mortality rate from the catch-and-release fishery, demonstrating that catchand- release fishing has a very small impact on peacock bass mortality. Therefore, this type of recreational fishing is beneficial as a strategy to help conserve peacock bass fish stocksfishery
A expansão da pesca amadora no Brasil teve inicio na década de 90 e tem alcançado os rios de água preta na região Amazônica, principalmente no médio Rio Negro onde são encontrados os grandes tucunarés (Cichla spp.). Com o acentuado crescimento desta atividade na região, a prática do pesque-solte vem sendo proposta como um procedimento sustentável na pesca esportiva dos tucunarés da região. Contudo, em face das dúvidas acerca da eficácia desta modalidade de pesca, avaliamos o efeito do pesque-solte sobre a sobrevivência do tucunaré, comparando dois tipos de iscas artificiais o jig e a meia-água. Foram realizados dois ensaios nos períodos de janeiro/fevereiro e outubro/novembro de 2012 no rio Unini, afluente da margem direita do rio Negro (Barcelos-AM). Em total foram capturados 191 tucunarés: 90 por iscas jig e os demais por iscas de meiaágua. Ambos os grupos de peixes foram submetidos a experimentos de confinamento por um período de 3 dias. Do primeiro grupo, 30 peixes foram confinados individualmente e 60 coletivamente. No segundo grupo, 30 foram confinados individualmente e 60 coletivamente. Adicionalmente, 11 peixes deste grupo foram marcados com transmissores de rádio para monitoramento por telemetria. A taxa de mortalidade foi calculada através do percentual dos indivíduos mortos para cada tipo de isca e ambiente de confinamento. Não houve mortalidade para o grupo de tucunaré capturado com jig. Por outro lado, a isca de meia-água apresentou taxa de mortalidade de 1,66% para o confinamento coletivo e de 18,18% para os monitorados por telemetria, não havendo, portanto mortes de indivíduos confinados individualmente. Estes dados foram analisados por meio de uma análise de variância Kruskal-Wallis, onde apresentaram valores de X2 (1.179) = 0,502 e p= 0,478 para os ambientes de confinamentos. O mesmo teste apresentou valores de X2 (1.179) = 1,005 e p= 0,316 para as iscas utilizadas. Dessa forma, os resultados indicam que ambos, o tipo de ambiente e o tipo de isca, não apresentaram influencia significativa sobre a taxa de mortalidade dos tucunarés na prática do pesque-solte. Estes resultados mostram que a prática desta modalidade de pesca amadora, resulta em baixa taxa de mortalidade para os tucunarés. Sendo assim o pesque-solte se mostra uma atividade que não prejudica a sustentabilidade dos estoques pesqueiros de tucunaré. Palavras-chave: Pesque-solte; tucunaré; pesca amadora; mortalidade de peixes
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Calla, Simon. "Des poissons, des hommes et des rivières : sociologie d'un problème de pollution en Franche-Comté". Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCC020.
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Entre les années 2009 et 2015, plusieurs rivières du département du Doubs ont été le théâtre d’épisodes de mortalité piscicole. Résumant les incertitudes et les inquiétudes à l’égard de la pérennité des pratiques de pêche et de potentiels risques sanitaires, ce phénomène a été le plus souvent expliqué par « la pollution des rivières ». Or, il semble qu’une telle qualification jette un voile sur les tentatives de solutions mises en place par les acteurs. En revenant sur les différentes enquêtes à travers lesquelles les acteurs concernés par cette situation mobilisent des ressources différentes pour comprendre les causes des épisodes de mortalité piscicole et les maîtriser, ce travail montre que la complexité du phénomène, la diversité des enjeux qu’il recouvre ainsi que sa taille géographique dépassent la capacité de résolution singulière propre à chaque groupe (associations de défense de l’environnement, structures représentatives du monde agricole, autorités publiques...) et nécessitent d’engager une activité collective mais toujours incertaine de définition du problème et de ses solutions. Il apparaît également que ces investigations portent le risque de la dénonciation réciproque et de l’imputation de responsabilités. Aussi, alors que les défenseurs des rivières s’engagent dans une dénonciation des activités agricoles et de la gestion de l’assainissement débouchant sur l’ouverture d’une situation conflictuelle, les experts mandatés par les représentants des pouvoirs publics concluent au caractère multifactoriel du phénomène et conduisent à une dilution des responsabilités. La situation reste alors en partie indéterminée et l’explication par « la pollution des rivières » devient une solution politique, voire un « outil diplomatique » pour un problème collectif qui peine à prendre sensBetween 2009 and 2015, several rivers in the Doubs department were the scene of episodes of fish mortality. Summarising the uncertainties and concerns about the sustainability of fishing practices and potential health risks, this phenomenon has most often been explained by "river pollution". However, it seems that such a qualification casts a veil on the attempts at solutions put in place by the actors. Returning to the various surveys through which the actors concerned by this situation mobilize different resources to understand the causes of fish mortality episodes and control them, this work shows that the complexity of the phenomenon, the diversity of the issues it covers and its geographical size exceed the singular capacity of resolution specific to each group (environmental associations, structures representing the agricultural world, public authorities...) and require collective but always uncertain activity to define the problem and its solutions. It also appears that these investigations carry with them the risk of mutual denunciation and attribution of responsibilities. Also, while river advocates are engaged in denouncing agricultural activities and sanitation management leading to the opening of a conflict situation, experts mandated by government representatives conclude that the phenomenon is multifactorial and leads to a dilution of responsibilities. The situation then remains partly undetermined and the explanation by "river pollution" becomes a political solution, or even a "diplomatic tool" for a collective problem that is difficult to make sense of
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SEGNALINI, MARIA. "Caratterizzazione del bacino del Mediterraneo in funzione dell'indice bioclimatico "Temperature Humidity Index" (THI) e relazioni tra THI e mortalità nella bovina da latte". Doctoral thesis, Università Cattolica del Sacro Cuore, 2012. http://hdl.handle.net/10280/1305.
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Condizioni meteorologiche e clima influenzano fortemente il settore delle produzioni animali. Lo stress da caldo determina una significativa riduzione dell'attività metabolica, della produzione, della capacità riproduttiva e una maggiore predisposizione alle malattie. Nel contesto biologico, la temperatura dell’aria è sicuramente considerata il principale fattore di stress, tuttavia, un’elevata umidità peggiora l'effetto della temperatura riducendo le perdite di calore per evaporazione e ostacolando quindi l’eliminazione del calore in eccesso.
Scopi principali della ricerca sono stati la caratterizzazione dell’area del Mediterraneo in termini di Temperature Humidity Index (THI) e stabilire le relazioni tra stagione/THI e mortalità nella bovina da latte allevata in un’area geografica Italiana altamente vocata per questo tipo di allevamento.
I risultati suggeriscono che, allevatori e politici che operano nell’area Mediterranea, dovrebbero tenere nella dovuta considerazione variabilità e scenari del THI nella pianificazione degli investimenti nel settore delle produzioni animali. Conoscere in anticipo il verificarsi di condizioni climatiche avverse permetterebbe agli allevatori di metter in atto misure di contrasto sugli effetti negativi delle condizioni climatiche. Inoltre, dovrebbero venire sviluppate misure di adattamento appropriate per contesti specifici in termini di cultura, società, o sistemi politici, che possano contribuire alla sostenibilità ambientale, nonché allo sviluppo economico e alla lotta alla povertà.Weather and climate strongly influence the field of animal production. Heat stress causes a significant reduction in metabolic activity, production, reproductive capacity, and increases susceptibility to diseases. In the biological context, the air temperature is definitely considered the main factor of stress, however, high humidity worsens the effect of temperature by reducing the evaporation heat loss and thus preventing the removal of excess heat. The main purposes of the research were the characterization of the Mediterranean basin in terms of Temperature Humidity Index (THI) and to establish relationships between season/THI and mortality in dairy cattle bred in an Italian geographic area with a high concentration of dairy farms. THI variability and scenarios should be taken into careful consideration by farmers and policy makers operating in Mediterranean countries when planning investments. Investments should at least partially be directed to implementation of adaptation measures, which may support farmers in the transition to climate-smart agriculture and help them to alleviate the impact of hot extremes on animal welfare, performance and health. In addition, measures should be developed appropriate adaptation to the specific contexts in terms of culture, society, or political systems, which can contribute to environmental sustainability and economic development and fighting poverty.
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Marti, Marimon Maria Eugenia. "3D genome conformation and gene expression in fetal pig muscle at late gestation". Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0099.
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Dans le secteur de l’élevage porcin, les truies ont été sélectionnées pendant des décennies pour leur prolificité afin de maximiser la production de viande. Cependant, cette sélection a été associée à une mortalité plus élevée des nouveau-nés. Dans ce contexte, le muscle foetal squelettique est essentiel à la survie du porcelet, car il est nécessaire pour les fonctions motrices et la thermorégulation. Par ailleurs, la structure tridimensionnelle du génome s'est avérée jouer un rôle important dans la régulation de l'expression génique. Ainsi, dans ce projet, nous nous sommes intéressés à la conformation 3D du génome et l'expression des gènes dans les noyaux des cellules musculaires porcines à la fin de la gestation. Nous avons initialement développé une approche originale dans laquelle nous avons combiné des données transcriptomiques avec des informations de localisations nucléaires (évaluées par 3D DNA FISH) d'un sous-ensemble de gènes, afin de construire des réseaux de gènes co-exprimés. Cette étude a révélé des associations nucléaires intéressantes impliquant les gènes IGF2, DLK1 et MYH3, et a mis en évidence un réseau de gènes interdépendants spécifiques du muscle impliqués dans le développement et la maturité du muscle foetal. Nous avons ensuite évalué la conformation globale du génome dans les noyaux musculaires à 90 jours et à 110 jours de gestation en utilisant la méthode de capture de conformation de chromatine à haut débit (Hi-C) couplée au séquençage. Cette étude a permis d'identifier des milliers de régions génomiques présentant des différences significatives dans la conformation 3D entre les deux âges gestationnels. Fait intéressant, certaines de ces régions génomiques impliquent les régions télomériques de plusieurs chromosomes qui semblent former des clusters préférentiellement à 90 jours. Plus important, les changements observés dans la structure du génome sont associés de manière significative à des variations d'expression géniques entre le 90ème et le 110ème jour de gestationIn swine breeding industry, sows have been selected for decades on their prolificacy in order to maximize meat production. However, this selection is associated with a higher mortality of newborns. In this context, the skeletal fetal muscle is essential for the piglet’s survival, as it is necessary for motor functions and thermoregulation. Besides, the three-dimensional structure of the genome has been proven to play an important role in gene expression regulation. Thus, in this project, we have focused our interest on the 3D genome conformation and gene expression in porcine muscle nuclei at late gestation. We have initially developed an original approach in which we combined transcriptome data with information of nuclear locations (assessed by 3D DNA FISH) of a subset of genes, in order to build gene co expression networks. This study has revealed interesting nuclear associations involving IGF2, DLK1 and MYH3 genes, and highlighted a network of muscle specific interrelated genes involved in the development and maturity of fetal muscle. Then, we assessed the global 3D genome conformation in muscle nuclei at 90 days and 110 days of gestation by using the High-throughput Chromosome Conformation Capture (Hi¬ C) method. This study has allowed identifying thousands of genomic regions showing significant differences in 3D conformation between the two gestational ages. Interestingly, some of these genomic regions involve the telomeric regions of several chromosomes that seem to be preferentially clustered at 90 days. More important, the observed changes in genome structure are significantly associated with variations in gene expression between the 90th and the 110th days of gestation
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Rahmani, Alexandra. "Identification des facteurs de pathogénicité de la bactérie Vibrio tapetis, responsable de la maladie de l'anneau brun chez la palourde japonaise Ruditapes philippinarum et de mortalités chez les poissons marins Transcriptomic analysis of clam extrapallial fluids reveals immunity and cytoskeleton alterations in the first week of Brown Ring Disease development, in Fish & Shellfish Immunology 93, October 2019". Thesis, Brest, 2019. http://www.theses.fr/2019BRES0059.
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L’objectif principal de cette thèse est d’étudier les mécanismes liés au pouvoir pathogène de V. tapetis.Pour cela, nous avons développé 2 axes de recherche. Le premier axe vise à étudier la virulence de V. tapetis en répondant aux 2 problématiques suivantes : Quels sont les gènes impliqués dans la virulence de V. tapetis ? et Existe-t-il des marqueurs hôtes-spécifiques de la virulence de V. tapetis ? Le second axe de recherche concerne l’interaction hôte pathogène et répond aux 2 problématiques suivantes : Quels sont les gènes exprimés lors de l’infection chez l’hôte ? et Quelles sont les modulations au sein de l’animal associées au pH et à la température lors de l’infection ?Les principales découvertes de cette thèse sont : (i) La bactérie V. tapetis, dans le cadre de la MAB, induit une sous expression des gènes impliqués dans la réponseimmunitaire et une dérégulation des gènes impliqués dans la stabilisation et la synthèse des filaments d’actine (ii) Ce pathogène induit également une diminution de l’activité lysosomale sur les hémocytes exposés (iii) L’effet de V. tapetis sur le cytosquelette d’actine et sur la diminution de l’activité lysosomale est indépendante du système de sécrétion de type IV (T4SS) (iv) Le système de sécrétion de type IV (T4SS) est impliqué dans le développement de la MAB mais n’est pas essentiel pour induire cette affection(v) Dans le cadre de la MAB et de la perte des adhérences des hémocytes in vitro, V. tapetis est capable de moduler le pH des fluides extra-palléaux, respectivement dans les premiers jours et premières heures de l’infection (vi) Enfin, l’approche de « strains typing » basée sur la technique MALDI-TOF permet de discriminer les souches de V. tapetis en fonction de leur pouvoir pathogène vis à vis de la palourde japonaiseThe main objective of this thesis is to study the mechanisms related to the pathogenicity of V. tapetis. For this purpose, we developed 2 research axes. The first one aimed at studying the virulence of V. tapetis by answering the following 2 issues: What are the genes involved in the virulence of V. tapetis? and Are there host-specific markers of the virulence of V. tapetis? The second research axis concerned pathogen-host interactions and addressed the following 2 issues: What are the genes expressed during infection in the host? and What are the modulations in the animal associated with pH and temperature during infection? The main findings of this thesis are: (i) V. tapetis, in the context of BRD, induces a down expression of genes involved in the immune response anda deregulation of genes involved in the stabilization and synthesis of actin filaments (ii) This pathogen also induces a decrease in lysosomal activity on exposed hemocytes (iii) The effect of V. tapetis on the actin cytoskeleton and on the decrease in lysosomal activity is independent of the type IV secretion system (T4SS) (iv) The type IV secretion system (T4SS) is involved in the development of BRD but is not essential to induce this disease (v) In the context of BRD and of the loss of hemocyte adhesions properties in vitro, V. tapetis is able to modulate the pH of extrapallial fluids, respectively in the first days and hours of infection (vi) Finally, the "strains typing" approach based on MALDITOF makes it possible to discriminate between V. tapetis strains according to their pathogenicity with regard to Manila clam
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Garcia, Armisen Tamara. "Etude de la dynamique des Escherichia coli dans les rivières du bassin de la Seine". Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210795.
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The purpose of our study was to describe the dynamics of E. coli in the rivers of the Seine watershed. This watershed is characterized by a poor microbiological water quality due to an important population density, industrial activities and intensive agriculture. The main objectives of our study were to obtain field microbiological data describing the system and to understand the underlying mechanisms in order to build a model able to describe and predict the fate of the fecal bacteria at the scale of the whole watershed. This model was built in order to help management of microbiological water quality. To be able to describe and modelize the fate of fecal bacteria at the scale of such a large and complex system, it was first necessary to identify and quantify the sources of contamination and to be able to describe the processes affecting these bacteria once discharged to the rivers.
The quantification of E. coli in the natural aquatic systems through the traditional culture-based techniques has been strongly questioned during the last years because they have a long response delay (24 to 48 h) and they do not take into account the viable but not culturable bacteria (VBNC) which nevertheless could represent a health thread. For this reason we developed in this study two alternative methods: the direct (without passing through a cultivation step) measurement of the â-D-glucuronidase activity and a fluorescent in situ hybridization with an E. coli specific probe coupled with a viability test. The first has the main advangate to give a very rapid evaluation of the E. coli content of the water while the second one was able to enumerate VBNC E. coli.
The study of the sources of contamination of the rivers revealed the predominance, in this anthropogenicised watershed, of the point sources (effluents from wastewater tretament plants). Diffuse sources soil leaching and surface runoff) may nevertheless be locally important and have also be quantified. The influence of the land use on these diffuse sources has been quantified demonstrating that soil leaching and surface runoff of grazed areas was mainly responsible of fecal contamination in rural areas.
The attachment of E .coli to particles in the river waters was studied as it can influence the fate of this kind of bacteria in the aquatic systems. A linear regression was found between the percentage of particle-associated E. coli and the SM content of the water. Settling velocities of particle-associated E. coli were determined. The mortality rate of E. coli was analysed following various perspectives: the river order, the attachment of E. coli to particles, the importance of the cultivability loss in the disappearance of these bacteria and the importance of protozoan grazing. The results confirmed the importance of grazing and showed that the abondance of free living E. coli bacteria decreased two times more rapidly than particle-associated E. coli. In the Seine river, we showed that the net loss of culturable E. coli was 1.5 time higher than the net loss of viable E. coli. Finally, no relationship was found between mortality rate and river order.
These results have been used to build two models CF-SENEQUE and CF-SiAM-3D which describe E. coli dynamics respectively for the whole Seine river watershed and for the Seine for the estuary. Comparisons model calcultaions with field data of fecal coliforms abundances showed that these models correctly simulated the longitudinal distribution of fecal colifoms in the main rivers of the Seine watershed and in the estuary. These models were used to test the impact on the microbiological water quality of various scenarii of wastewater management .
Doctorat en sciences, Spécialisation biologie animale
info:eu-repo/semantics/nonPublished
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Schoenebeck, Casey Walter. "An evaluation of yellow perch Perca flavescens mortality in South Dakota /". 2009. http://wfs.sdstate.edu/wfsdept/Publications/Theses/Schoenebeck,%20Casey%20W.%20Ph.D.-2009.pdf.
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Whalen, Kevin Gerard. "Smolt production and overwinter mortality of Atlantic salmon (Salmo salar) stocked as fry". 1998. https://scholarworks.umass.edu/dissertations/AAI9823788.
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Research was completed to determine factors affecting smolt production and overwinter mortality of Atlantic salmon (Salmo salar) stocked as fry in Vermont tributaries of the Connecticut River. Specific focuses included: (1) timing of smolt migration relative to environmental and physiological factors; (2) effect of ice formation on habitats selected and winter distribution of parr; (3) effect of maturation on parr growth and smolt recruitment; and (4) smolt production dynamics and recruitment modeling. Smolt migration timing and recruitment was determined using net weirs and counting fences and mark-recapture and winter habitat studies were completed by night snorkeling. Tributaries differed in the timing of smolt migration with the tributary warming earliest in the spring generally experiencing earlier smolt migration. Initiation and cessation of smolt migratory activity appeared to be linked to smolt physiological development. Peaks in river discharge increased smolt migratory activity after water temperature thresholds were surpassed, yet only while smolts maintained elevated gill Na$\sp+,$ K$\sp+$-ATPase activity. Ice formation caused significant changes in the physical stream environment, including a reduction in the abundance of habitats often selected by parr. Changes in the distribution of parr over the winter generally corresponded to changes in the distribution of high velocity habitats they rarely selected and low velocity habitats they often selected. Mature parr were abundant across and within tributaries. Percent mature in October/November was positively correlated with mean size the preceding June. Studies on individually marked parr showed that mature parr exhibited poorer June to October growth than immature parr resulting in large differences in fall size. Mature parr were recruited to smolt at a reduced frequency relative to immature parr and modeling analysis indicated that this difference resulted primarily from a one-third probability of smolting for mature parr rather than differences in fall to spring survival. Simulation modeling revealed that losses in potential smolt production attributable to parr maturation may be as high as 35% when maturation percentages reach the maximum of 45% observed in this study. It is concluded that smolt physiology, winter habitat, and parr maturation are primary factors affecting smolt production and overwinter mortality of Atlantic salmon stocked as fry.
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BARTOŇ, Daniel. "Effects of hydropeaking on the attached eggs of a rheophilic cyprinid species". Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-391741.
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Effects of artificial water fluctuations called hydropeaking on the detachment rates of adhesive eggs were studied using a rheophlic fish (asp Leuciscus aspius) as a model species. I attempted to relate egg density to abiotic conditions of the spawning ground and identify optimal conditions for the eggs. Egg densities were also studied during spawning season when hydropeaking occurred. In the experimental setup, egg detachment rates were tested with different speeds, substrate type and exposition time and critical conditions for the eggs were assessed.
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Overholtzer-McLeod, Karen L. "Population dynamics of coral-reef fishes : spatial variation in emigration, mortality, and predation". Thesis, 2003. http://hdl.handle.net/1957/30593.
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Understanding the dynamics of open marine populations is difficult.
Ecological processes may vary with the spatial structure of the habitat, and this
variation may subsequently affect demographic rates. In a series of observational
and experimental studies in the Bahamas, I examined the roles of emigration,
mortality, and predation in the local population dynamics of juvenile coral-reef
fishes. First, I documented mortality and emigration rates in populations of
bluehead and yellowhead wrasse. Assuming that all losses were due solely to
mortality would have significantly underestimated survivorship for both species on
patch reefs, and for yellowheads on continuous reefs. Mortality differed between
species, but emigration did not differ between species or reef types. Mortality of
blueheads was density-dependent with respect to both conspecific density and total
wrasse density on continuous reefs. In contrast, mortality of yellowheads varied
inversely with the density of blueheads on patch reefs. Emigration rates varied
inversely with distance to the nearest reef inhabited by conspecifics. In subsequent
experiments, I manipulated densities of yellowhead wrasse and beaugregory
damselfish, and determined that the relationship between density and mortality
varied with reef spatial structure. On natural reefs, mortality rates of the wrasse
were highly variable among reefs. On artificial reefs, mortality rates of both
species were density-dependent on spatially isolated reefs, yet high and density-independent
on aggregated reefs. Heterogeneity in the spatial structure of natural
reefs likely caused variation in predation risk that resulted in high variability in
mortality rates compared to artificial reefs. A final experiment demonstrated that a
single resident predator caused substantial mortality of the damselfish, regardless of
reef spacing. Patterns suggested that resident predators caused density-dependent
mortality in their prey through a type 3 functional response on all reefs, but on
aggregated reefs this density dependence was overwhelmed by high, density-independent
mortality caused by transient predators. These results (1) suggest
post-settlement movement should be better documented in reef-fish experiments,
(2) demonstrate that the role of early post-settlement processes, such as predation,
can be modified by the spatial structure of the habitat, and (3) have ramifications
for the implementation of marine reserves.Graduation date: 2004
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Lin, Ding Rong, e 林頂榮. "Age､growth and total mortality of lizard fish (saurida tumbil) in the southern part of the east China sea". Thesis, 1994. http://ndltd.ncl.edu.tw/handle/07366326371683808458.
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Lin, Ding-Rong, e 林頂榮. "Age﹑growth and total mortality of lizard fish (saurida tumbil) in the southern part of the east China sea". Thesis, 1994. http://ndltd.ncl.edu.tw/handle/17508731761591161809.
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Kempf, Alexander [Verfasser]. "Diet selection and predation mortality in the North Sea fish assemblage : improving multi species stock assessment / vorgelegt von Alexander Kempf". 2009. http://d-nb.info/992717434/34.
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Dimoff, Sean. "Insight into coral reef ecosystems: investigations into the application of acoustics to monitor coral reefs and how corallivorous fish respond to mass coral mortality". Thesis, 2021. http://hdl.handle.net/1828/12666.
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Coral reefs around the world are threatened by a variety of sources, from localized impacts, including overfishing and coastal development, to global temperature increases and ocean acidification. Conserving these marine biodiversity havens requires both global and local action informed by scientific research. In this thesis, I use data collected from the coral reefs around Kiritimati atoll (Republic of Kiribati) in the central equatorial Pacific, first to assess the applicability of two common metrics used in passive underwater acoustic research, and second to examine the effects of a marine heatwave and local human disturbance on an assemblage of corallivorous fish. Using acoustic data recorded in 2017 and 2018 on reefs around Kiritimati, I assess how sound pressure level (SPL) and the acoustic complexity index (ACI) respond to changes in fish sounds in a low frequency band (160 Hz – 1 kHz) and snapping shrimp snaps in a high frequency band (1 kHz – 22 kHz). I found that while SPL was positively correlated with increases in fish sounds and snap density, changes in ACI were dependent upon the settings chosen for its calculation, with the density of snaps negatively correlated with ACI across all settings. These findings provide evidence that despite its quick and prolific adoption, acoustic metrics like ACI should be thoroughly field-tested and standardized before they are applied to new ecosystems like coral reefs. Next, using underwater visual censuses (UVCs) of reef fish assemblages, I quantified how two functional groups of corallivores, obligate and facultative, responded to a mass coral mortality event created by the 2015-2016 El Niño. Declines in abundance of both groups were largely driven by the response of coral-associated damselfishes, Plectroglyphidodon johnstonianus in the obligate group and Plectroglyphidodon dickii in the facultative group, to heat stress and subsequent coral mortality. I also observed a significant decline in the species richness of obligate corallivores, and a continued decline in the abundance of obligate corallivores three years after the mass coral mortality event. Additionally, facultative corallivore abundance increased with disturbance, although the effect was modulated by year, likely due to their more adaptable diets. Corallivore assemblage structure was also influenced by the heat stress event, recovery, and local human disturbance. These results detail how an entire corallivorous assemblage is impacted by a coral mortality event and incidentally provide a timeline for corallivore decline. Together, these results provide information about new ways of monitoring coral reefs, and the ways in which two components of the reef fish community, obligate and facultative corallivores, respond to a mass coral mortality event.Graduate
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STRAPINA, Josef. "Srovnání rozsahu poškození a mortality ryb jako úlovku sportovních rybářů ponechaných v klasickém vezírku a speciálním saku {--} {\clq}tunelu`". Master's thesis, 2009. http://www.nusl.cz/ntk/nusl-51345.
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Práce je založena na pokusech, ve kterých se srovnával rozsah poškození a mortality kapra obecného (Cyprinus carpio, L.) ponechaného v klasickém vezírku (zpevněném i nezpevněném) a speciálním saku {--} "tunelu". Hlavním cílem práce je jednak rozšířit poznatky pro rekreační (sportovní) rybolov a především přispět k poznání správného způsobu uchovávání ulovených živých ryb, které si rybář rozhodl ponechat v živém stavu tak, aby byly minimalizovány negativní důsledky jejich držení před usmrcením a poukázat na šetrnější zacházení s rybou, ne-li zamezit jejich týrání.
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Venturelli, Paul Anthony. "Life History, Maternal Quality and the Dynamics of Harvested Fish Stocks". Thesis, 2009. http://hdl.handle.net/1807/19305.
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Knowledge of offspring production (recruitment) is fundamental to understanding and forecasting the dynamics of a population. In this thesis, I focus on two demographic characteristics of fish stocks that are important to recruitment: population density and age structure. First, populations produce more recruits at low density, but quantifying this response has proven difficult. Using data from hundreds of populations of walleye (Sander vitreus), an economically important freshwater fish, I demonstrate that the growing-degree-day metric (a temperature index) is better than age at explaining variation in density-dependent growth and maturity both within and among populations. I then incorporate multi-lake measures of density-dependent life history change into a temperature-based biphasic model of growth and reproduction to predict sustainable rates of mortality for walleye throughout most of their range. Second, the age (or size) structure of a population may also affect recruitment because of positive effects of maternal age on offspring production and survival; however, evidence for these ‘maternal influences’ on recruitment is limited. Using both an analytical model and a meta-analysis of stock-recruitment data from 25 species of exploited marine fish, I show that (i) maximum reproductive rate increased with the mean age of adults in a population, and (ii) the importance of age structure increased with a species’ longevity. I then demonstrate a similar effect of maternal influences on reproductive rate in a detailed study of Lake Erie walleye. By highlighting the importance of fisheries-induced demographic change to recruitment, this thesis provides insight into past and present failures. However, it also demonstrates clearly the benefits of proactive management strategies that (i) identify and respect the limits of exploitation, (ii) protect from exploitation reproductively valuable individuals—principles that apply generally to any freshwater, marine, or terrestrial species that is of recreational, commercial, or conservation value.
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RICHTEROVÁ, Zuzana. "Vliv pyrethroidových pesticidů na ryby". Doctoral thesis, 2016. http://www.nusl.cz/ntk/nusl-260863.
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Pyrethroids are ones of the most used pesticides worldwides. The widespread use and high stability of pyrethroids lead to the assumption of that their occurrence in the environment could be quite frequent. They can reach water ecosystem as pollutants. Residues of pyrethroids are not only detected in the water column, but also in sediments and in fish tissues. The first study was devoted to the product Nexide containing 60 g.l-1 of active substance gamma-cyhalothrin. Tested Nexide concentrations were 5, 25, 50, 100, and 250 µg.l-1. Early life stage test was used.Common carp (Cyprinus carpio) was tested. There were significant mortalities in all concentrations except the lowest concentration during the trial. The lowest concentration tested 5 µg.l-1 only caused a slightly increased mortality. This lowest concentration influenced the growth in length and weight negatively, decelerated ontogenetic development, and made the body surface of the individuals darker. Histopathology of individuals from this concentration revealed dystrophy in liver. Examination of kidney, intestine and gills did not show significant histopathological differences compared with control. The evaluation of selected parameters of oxidative stress demonstrated a significantly higher activity of detoxification enzyme glutathione-S.transferase (GST) and a significantly lower activity of defensive enzyme glutathione peroxidase (GPx) compared with the control group. The other examined parameters of oxidative stress such as catalase (CAT), glutation reductase (GR), and lipid peroxidation determined by using the thiobarbituric acid-reactive substances (TBARs) were comparable to the control group. Changes in oxidative stress parameters suggest that exposure of the organism to the product Nexide in the given concentration leads to dysbalance of defensive enzymes. The second study was devoted to the product Cyperkill 25 EC containing 250 g.l-1. Tested Cyperkill 25 EC concentrations were 7.2, 36, 72, 144, and 360 µg.l-1. The procedure of the trial was the same as the preceded one. There were 100% mortalities in all concentrations except the lowest concentration during the trial. The lowest tested concentration 7.2 µg.l-1 allowed 90% of individuals to stay alive till the end of experiment. The lowest concentration influenced the growth in length and weight negatively and decelerated ontogenetic development compared with the control. Any individual exposed to this concentration did not reach juvenile stage until the end of the trial. Dark pigmentation was visible in 68% of these exposed individuals on the last day. Similar darkening was visible in individuals from higher concentrations shortly before death too. Histological examination did not revealed significant changes in intestine, liver, kidney, and gills compared with the control group. Evaluation of selected parameters of oxidative stress demonstrated significantly lower activities of GST, GR, and GPx. Activities of CAT and TBARS were comparable with the control group. Changes in oxidative stress parameters suggest that exposure of the organism to the product Cyperkill 25 EC in the given concentration could induce oxidative stress and interfere with the activities of antioxidant enzymes. The presented thesis summarises actual data about pyrethroids and their influence on fish. The demonstrated effects confirm high susceptibility of early developmental stages of fish to tested pesticides. When interpreting the results, we have to take into account the fact that studies showed this risk even on single pyrethroid substances. But water organisms are exposed to many other more or less toxic products and substances in a real environment. These xenobiotics could react with each other and their mixture could even potentiate negative effects. The performed studies also clearly show the significant differences in the sensitivity of embryonic and embryolarval tests.