Mercury (Hg) is a global pollutant, yet Hg biomagnification, the increase in Hg with trophic level, remains poorly characterized in many regions, especially at subtropical latitudes. The present study assessed subtropical reservoirs of eastern China, which provided an opportunity to quantify Hg biomagnification under highly altered conditions that included high atmospheric Hg deposition, use of reservoirs for fisheries, manipulation of food webs through stocking and high fishing pressure, and increasing eutrophication. Despite China’s Hg emission and deposition rates that are among the highest worldwide, low fish Hg concentrations and Hg biomagnification rates were found; this was explained by food web structure and fish species characteristics. Stocked species occupied lower trophic levels and had significantly lower Hg concentrations relative to wild fishes. Evidence of decreased Hg concentrations with eutrophication (as indicated by chlorophyll-a) was observed, suggesting algal biodilution and/or somatic growth dilution. Relative to temperate lakes, zooplankton density dilution may also be causing reduced Hg concentrations in subtropical biota. Hydrogeomorphic features, such as water retention time and percent crop cover, explained Hg bioaccumulation factors and Hg concentrations at the base of the food web. Eutrophication and hydrogeomorphic features also influenced the bioavailability of selenium, which can protect against the toxicity of Hg at adequate concentrations, and the concentration of eicosapentaenoic acid, a beneficial fatty acid, in the planktivorous Bighead Carp (Hypophthalmichthys nobilis). This may indicate that the risk of exposure to the neurotoxicant methylmercury relative to benefits of fish consumption may increase with eutrophication in some fish species. Overall, the findings of this study suggest food web structure, eutrophication, and hydrogeomorphic features together explain low Hg concentrations in anthropogenically modified subtropical reservoirs in eastern China. / Thesis (Ph.D, Biology) -- Queen's University, 2014-07-01 11:35:12.637

Common carp (Cyprinus carpio) have been hypothesized to contribute to declines in aquatic macrophytes, waterfowl, and water clarity in Delta Marsh, an 18,500 ha freshwater coastal wetland on Lake Manitoba, Canada. Ten ponds (1-13 ha) were chosen for a two-year experimental manipulation study. Following a year of baseline monitoring, manipulations were conducted in 2002. To facilitate access by carp into isolated ponds, channels were blasted from the main marsh into two ponds. Meanwhile, to restrict or exclude carp access into ponds, channels were either screened or diked to four ponds. Two connected and two isolated ponds functioned as controls. Although common carp were the original subject of the study, it became apparent that hydrological connection to the surrounding marsh had a paramount importance on the abundance and diversity of the fish, amphibian and water-column invertebrate communities. Connectivity, or lack of connectivity, played an important role in the distribution of the fish community, and subsequently the composition and abundance of water-column invertebrates and amphibians. Ponds with direct connection had diverse, mixed-species fish assemblages, with fewer invertebrates and amphibians. Ponds with restricted connections had fish communities composed of tolerant small-sized species and increased abundance of invertebrates and amphibians. Ponds that lacked connection could freeze and lose all fish, and had higher numbers of invertebrates and amphibians. An absence of adult common carp may have been responsible for increased amphibian numbers in the screened ponds, however more study is needed. Confounding impacts of fluctuating water levels made it impossible to implicate common carp for most changes observed within ponds in Delta Marsh.

In einem interdisziplinären Forschungsprojekt wurden die Übertragungswege der Koi-Herpesvirus-Infektion (KHV) untersucht. Die Erkrankung verminderte das Speisekarpfenaufkommen in Sachsen um 40 % und verursachte dadurch bei den betroffenen Teichwirtschaften hohe wirtschaftliche Schäden. Die Ergebnisse zeigen, dass Teichablaufwasser und Wildfische weniger an der Weiterverbreitung der Erkrankung beteiligt sind als bisher angenommen. Hauptinfektionsweg ist die Übertragung durch infizierte Karpfen. Die Weiterverbreitung erfolgt entweder durch Besatz latent erkrankter Fische oder durch Verschleppung kranker oder frisch getöteter Karpfen durch Wildtiere. Eine erfolgreiche Sanierung von Karpfenteichen durch Trockenlegung, Branntkalkapplikation und Besatz mit virusfreien Fischen ist möglich. Bei den bisher angewandten Branntkalkdosierungen von ca. 1 t/ha konnte eine Gefährdung adulter Amphibien, aber auch der in Karpfenteichen vorkommenden Amphibienlarven in situ bisher nicht festgestellt werden.

Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Gıda Mühendisliği Anabilim Dalı, 2007. / Bibliyografya var.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Commercial formulations of the herbicide clomazone have been widely used in agriculture and fish farming to control weeds. Fish can be affected when the water reaches the drainage waterways, causing an imbalance in the aquatic ecosystem. In order to evaluate a possible contamination, we determined LC50 (96h) using a commercial formulation containing clomazone (Gamit®). We verified the metabolic, enzymatic, and genotoxic parameters as well as the oxidative stress in juvenile carp (Cyprinus carpio). Firstly, in order to determine the LC50 for the acute toxicity test, , the animals were exposed to the concentrations of 10, 20, 30, 40 and 50 mg/L of clomazone for 96 h and the fish behavior was analyzed during this period. After exposure, we verified the activity of the enzyme acetylcholinesterase (AChE) in muscle and brain of the dead fish and the live carp. Secondly, fish were exposed to the herbicide for 7 days, both in field (rice crop) and laboratory conditions. The concentration used in the rice crop and the laboratory was 0.5 mg/L. After the experimental period of 7 days under laboratory conditions and 7, 30, and 90 days under rice crop conditions, brain, liver and muscle of fish were sampled to carry out the toxicological analysis. The parameters studied were enzymatic activity of AChE, catalase (CAT) and glutathione S-tranferase (GST) in different tissues of this species. Some markers of oxidative stress, such as protein carbonylation and thiobarbituric acid reactive substances (TBARS) levels in liver tissue were also analyzed. Some metabolic parameters such as glucose, glycogen, lactate, protein, and ammonia as well as amino acids in liver and muscle of carp were also measured. In plasma, we measured glucose, lactate, and protein. Thirdly, carp were exposed to approximately 15% of the LC50 (5.0 mg/L) for 7 days. We verified the formation of reactive oxygen species (ROS) and micronucleus, and the comet test was performed in order to investigate the presence of DNA damage. In the first study we observed that fish exposed to 20, 30, 40 and 50 mg/L showed behavioral changes and LC50 (96h) was 30.35 mg/L. In addition, it was found that the activity of the enzyme AChE showed no significant changes in the brain of the fish that died at the concentrations tested (30, 40 and 50 mg/L), and the muscle of dead fish had an increase in this enzyme when they were exposed to 50 mg/L of clomazone. The activity decreased significantly in the brain AChE of fish that remained alive after 96 h of exposure to 10, 20 and 30 mg/L, but increased in the muscle of the surviving fish exposed to all concentrations tested. In the second experiment results showed that fish exposed to 7 days had no changes in AChE under field conditions. However, a decrease in the activity of this enzyme in muscle was observed under laboratory conditions. During the same period of exposition, the parameters of oxidative stress conditions changed both under the field and in laboratory conditions. However, metabolic parameters were altered only under field conditions. After 30 and 90 days, AChE activity did not change under field conditions. Disturbances in oxidative stress parameters and metabolism in different tissues were evident in the tissues up to 90 days after treatment. The results showed that the activity of AChE changed only under laboratory conditions, and that oxidative stress associated with metabolic parameters can be good indicators of contamination for clomazone in C. Carpio in rice field conditions. In the third experiment, the results showed an increased formation of ROS and a significant micronucleus (MN) and DNA damage in erythrocytes after exposure to 5.0 mg/L of the herbicide clomazone. Given these results, we can conclude that the herbicide studied can be dangerous to Cyprinus carpio when exposed to it due to increased ROS, which in turn cause oxidative stress evidenced by changes in enzyme markers, metabolic, genotoxic and oxidative stress. However, further studies are needed in order to verify the safety of this herbicide is when associating rice and fish. / As formulações comerciais do herbicida clomazone têm sido amplamente utilizadas na agricultura e na piscicultura para controle de plantas daninhas. Os peixes podem ser afetados quando as águas de drenagem atingem os cursos d água, acarretando um desequilíbrio no ecossistema aquático. Para avaliar uma possível contaminação foi determinada a CL50 (96h) utilizando-se uma formulação comercial contendo clomazone (Gamit®) verficando-se parâmetros metabólicos, enzimáticos, genotóxicos e de estresse oxidativo em juvenis de carpas (Cyprinus carpio). Para o teste de toxicidade aguda, a fim de determinar a CL50, os peixes foram expostos às concentrações 10, 20, 30, 40 e 50 mg/L de clomazone em água durante 96 horas e o comportamento dos peixes foi analisado nesse período. Após a exposição, foi verificada a atividade da enzima acetilcolinesterase (AChE) no cérebro e músculo dos peixes mortos e das carpas que sobreviveram. No segundo experimento, os peixes foram expostos ao herbicida durante sete dias, tanto em condição de campo (lavoura de arroz irrigado) como de laboratório. A concentração utilizada na lavoura de arroz e no laboratório foi de 0,5 mg/L. Decorridos os períodos experimentais de 7 dias em condições de laboratório, e 7, 30 e 90 dias em condições de lavoura de arroz, foram retirados o cérebro, o fígado e o músculo dos peixes para realização das análises toxicológicas. Os parâmetros enzimáticos analisados foram a atividade da AChE, catalase (CAT) e glutationa S-transferase (GST). Também foram analisados alguns marcadores de estresse oxidativo, como a carbonilação de proteínas e níveis das substâncias reativas ao ácido tiobarbitúrico (TBARS) no tecido hepático. Por fim, foram avaliados alguns parâmetros metabólicos como: glicose, glicogênio, lactato, proteína, amônia e os aminoácidos em fígado e em músculo de carpas. No plasma, foram feitas as dosagens de glicose, de lactato e de proteína. Em um terceiro experimento, as carpas foram expostas a aproximadamente 15% do valor obtido para a CL50 (5,0mg/L) por 7 dias. Posteriormente, foi verificada a formação das espécies reativas de oxigênio (EROs) e foram realizados os testes do micronúcleo e cometa (expresso por índice de dano do DNA). No primeiro experimento, foi observado que os peixes expostos a 20, 30, 40 e 50 mg/L, mostraram mudanças comportamentais e a CL50 (96h) foi 30,35 mg/L. Além disso, foi verificado que a atividade da enzima AChE não apresentou alterações significativas no cérebro dos peixes que morreram nas concentrações testadas (30, 40 e 50mg/L), e no músculo dos peixes mortos houve uma elevação na atividade desta enzima, quando eles foram expostos a 50 mg/L de clomazone. Já a atividade AChE diminuiu significativamente no cérebro dos peixes que sobreviveram após 96h de exposição a 10, 20 e 30mg/L, no entanto, aumentou no músculo dos peixes sobreviventes expostos a todas as concentrações testadas. No segundo experimento, os resultados mostraram que os peixes expostos a 7 dias não apresentaram alterações na AChE em condições de campo. No entanto, uma diminuição da atividade desta enzima no músculo foi observada em condições de laboratório. Durante o mesmo período de exposição, os parâmetros de estresse oxidativo mudaram tanto em condições de campo quanto em laboratório. Entretanto, os parâmetros metabólicos foram alterados apenas em condições de campo. Após 30 e 90 dias, a atividade da AChE não se alterou em condições de campo. Distúrbios nos parâmetros de estresse oxidativo e metabolismo foram evidentes nos tecidos até 90 dias após a aplicação. Os resultados mostraram que a atividade da AChE alterou apenas em condições de laboratório, e que marcadores de estresse oxidativo associados aos parâmetros metabólicos podem ser bons indicadores de contaminação para o clomazone em C. carpio em condições de campo. No terceiro experimento, os resultados mostraram um aumento da formação das EROs e significativo aumento dos MN e de danos no DNA dos eritrócitos após a exposição a 5,0 mg/L do herbicida clomazone. De acordo com os resultados obtidos, conclui-se que o herbicida estudado pode ser perigoso para as carpas quando expostas, devido ao aumento das EROs que por sua vez causam estresse oxidativo, evidenciado por alterações em marcadores enzimáticos, metabólicos, genotóxicos e de estresse oxidativo. Contudo, mais estudos serão necessários para verificar a segurança desse herbicida para os cultivos associados utilizando-se arroz e peixes.

Made available in DSpace on 2014-06-11T19:30:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-27Bitstream added on 2014-06-13T18:40:46Z : No. of bitstreams: 1 casaca_jm_dr_jabo.pdf: 10010578 bytes, checksum: 0a5d07e48907122164e78e3cf5a8e3f1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O estudo teve como objetivo desenvolver um novo sistema de cultivo de peixes, denominado de peixe verde. O princípio básico do sistema é alimentar a carpa capim, espécie principal do policultivo, com vegetais cultivados. O estudo analisou três intensidades de produção. Foi realizado no Oeste do Estado de Santa Catarina e abrangeu três segmentos: análise bioeconômica, análise do ciclo de vida e análise da fauna parasitária do sistema peixe verde. Os resultados do estudo indicam que o peixe verde é um sistema de baixa intensidade de produção. Demonstrou ser um sistema de baixo impacto ambiental. As intensidades de produção estudadas demonstraram ser economicamente viáveis, principalmente para piscicultores familiares. O peixe verde demonstrou ser mais dependente de mão-de-obra quando comparado com outros sistemas de produção. O estudo da análise do ciclo de vida (ACV) permitiu analisar os principais impactos ambientais do sistema peixe verde. O tratamento mais intensivo foi o que apresentou os maiores impactos nas categorias analisadas. Os alevinos foi o fator que mais contribuiu nas categorias de impactos. Com base nos resultados o sistema pode ser considerado como sistema de baixa intensidade parasitária. O tratamento com maior densidade mostrou ser o mais eficiente economicamente, enquanto o de menor densidade mostrou ser ambientalmente o mais eficiente. / The study had as objective to develop a new system of fish culture, called green fish. The basic principle of the system is to feed the grass carp, main species of the polyculture, with cultivated vegetables. The study analyzed three intensities of production. It was carried out in the West of Santa Catarina State and enclosed three segments: economic analysis, life cycle assessment and analysis of the parasitic fauna of the system green fish. Results of the study indicate that the green fish is a system of low production intensity. It demonstrated to be a system of low ambient impact. The studied intensities of production had economically demonstrated to be viable, mainly for family fish farmers. The green fish showed to be more dependent of man power when compared with other systems of production. The study of the life cycle assessement (LCA) allowed to analyze the main ambient impacts of the system green fish. The most intensive treatment presented higest impacts within the analyzed categories. Fry were the factor that more contributed in the categories of impacts. On the basis of the results the system can be considered as system of low parasitic intensity. The treatment with higher density showed to be more efficient economically, while the one of lesser density ishowed to be ambiently more efficient.

The aim of this study was to examine the production efficiency of processed triticale and compared to unmodified triticale during 135 day feeding experiment on ponds in the system Naděj. Dosing of feed, feeding technique and condition of the market carp in experimental ponds, the quality and quantity of natural food were observed. At the end of the experiment the main production indicators were evaluated and data were statistically evaluated. Higher production efficiency of mechanical and thermally processed cereals was not proved. The highest production efficiency was observed in variant with triticale supplementary feeding without processing (FCR ? 1.4; SGR ? 0.97 %.d-1; PER ? 6.74) and in variant with thermally processed triticale (FCR ? 1.63; SGR ? 0.88 %.d-1; PER ? 5.79). The lowest effective production was reached using grinded triticale (FCR ? 1.68; SGR ? 0.86 %.d-1; PER ? 5.62). Results were affected by different levels of quantity of zooplankton in the monitored ponds.

The optimalization way of hormonal induction ovulation females European catfish Silurus glanis was the aim of experiment with the help of hormonal preparate on the base functional of the analogue GnRH. Fish with females were fish out in the ponds early in june and injected by hormonal preparates CPE, Dagin and Ovopel. Was monitoring latency time in dependency of water temperature, percent of ovulated females, relative weight of ovulated eggs, fertilization eggs and hatching performance.

In the present study, we examined several cryoextenders previously used by several authors and various freezing protocols to determine the relative importance of each parameter on sperm freezing. The effects of controlled seeding and changes in cooling rate at different stages of freezing were also examined. Sperm samples from seven individual carp males were frozen in 0.5 ml straws by conventional freezing. Cooling rates were determined by monitoring the sample's internal temperature. We compared four freezing protocols, which involved placing sperm samples at various levels (1, 3, 6, and 9 cm) above the liquid nitrogen (LN) surface (corresponding to -190, -150, -110, and -70 °C, respectively) for 20 min followed by transferring the samples into LN. Freezing at 3 cm above the LN surface resulted in the highest motility (33 ? 8 %) and velocity (118 ? 9 ?m/s) of spermatozoa after thawing and diluting in swimming medium. We determined that -90 °C is an optimal temperature at which immersing the samples in LN does not affect sperm motility after thawing. The sperm motility of samples immersed in LN before or immediately after the crystallisation point (-16 °C) was 0 %. Motility of spermatozoa cryopreserved with or without a seeding procedure was not significantly different after thawing. Therefore, we hypothesise that supercooling the sample during the conventional freezing procedure is not the main damaging factor during carp spermatozoa cryopreservation.

The study compared survival and growth rate in grass carp (Ctenopharyngodon idella) juveniles in pond and recirculation aquaculture system (RAS) during winter time. The juveniles of grass carp were stocked to 5 tanks and three ponds during 2013 and 2014. In the RAS, the fish were fed by dry pellets and rearing was in constant temperature. In the pond, the temperature and feeding were only natural. In the RAS, the survival rate was significantly higher 97.79 % 0.52 % compared to 10.94 % 11.42 % in the pond. At the end of experiment, the weight of fish, Specific growth rate (SGR) and Fulton coefficient (FK) was significantly higher in RAS in comparison with the pond. The results showed that the rearing of grass carp is more effective in RAS in comparison with pond during winter time.