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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

study on the devdlopment of net-cage fish-farming in Taiwan

Yang, Bo-ren 26 July 2002 (has links)
There are many approach for The study of marine resources and now in Taiwan is a lot of express , but the damage to net-cage by typhoon is cost much money . The most important study in Taiwan is to use new teconology to update the traditional business and get advanture in international.
2

Monitoramento de características físico-químicas da água e taxas de sedimentação de tripton no Córrego da Arribada (Baixo Tietê-SP) relacionadas à piscicultura em tanques-rede

Alves, Rachel Cristina Prehl [UNESP] 24 July 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-07-24Bitstream added on 2014-06-13T19:48:40Z : No. of bitstreams: 1 alves_rcp_me_jabo.pdf: 2216450 bytes, checksum: 3a9202bb2a67f1b43fa4f21f4c14b6ea (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A água é usada para os mais variados fins: abastecimento, irrigação, geração de energia elétrica, lazer, aqüicultura, local de despejo de efluentes domésticos e industriais, etc. No caso da aqüicultura, a criação em tanques-rede introduz diretamente no corpo d’água uma grande quantidade de matéria orgânica. Essa atividade pode contribuir para acelerar os processos de eutrofização do meio devido aos aportes de nutrientes e material em suspensão provenientes, principalmente, do excedente de alimento, fezes e excretas dos peixes. Estudos sobre os impactos causados por essa atividade podem fornecer dados para uma gestão ambiental que permita otimizar o uso múltiplo dos recursos hídricos sem que haja maiores danos ao ambiente aquático. Este trabalho procurou fazer uma caracterização limnológica e uma avaliação do impacto da criação em tanques-rede de tilápia (Orechromis sp.) no córrego da Arribada (Bacia do Baixo-Tietê), que é represado pelo reservatório da Usina Hidrelétrica de Nova Avanhandava, no Rio Tietê, SP. A área destinada à piscicultura é de 4ha de espelho d’água e foi projetada para 200 tanques-rede com volume de 18m3 cada. Em sete pontos distribuídos estrategicamente na região onde foi instalado o sistema de cultivo foram analisados as seguintes variáveis: temperatura, concentração e saturação de oxigênio dissolvido, pH, transparência, e taxas de sedimentação de fósforo total, ortofosfato, nitrogênio amoniacal, nitrito, nitrato e material em suspensão por meio de câmaras de sedimentação. Os resultados mostraram mais padrões temporais que espaciais, com queda acentuada na concentração e saturação de oxigênio dissolvido e aumento nas taxas de sedimentação de fósforo total e nitrato. Apesar do impacto causado apresentar tendências preocupantes, concluiu-se que neste estudo de caso, a produção em tanques-rede é viável... / Water is used to multiple uses: water supply, irrigation, power generation, leisure, aquaculture, place of discharge of home and industrial wastes, etc. In aquaculture, cage fish farming releases a great amount of organic matter directly into the water body. This activity can accelerate the water eutrophication process due to the input of dissolved nutrients and suspended matter, mainly by diet wastes, feces and fish excreta. Studies about environmental impacts caused by this activity can provide a support for a better environmental management that allows the use of water resources without over degradation of the ecosystem. This work aimed to make a limnological characterization and evaluation of the environmental impact of cage culture of Tilapia (Oreochromis sp.) in the stream of Arribada (Tietê river basin - Brazil). This stream is partially impounded by the reservoir of the hydroelectric power station of Nova Avanhandava. The culture is placed in an area of 4ha and it is planned the installation of 200 cages of 18 m3 each one. Till December 2004, there were 180 cages, each one with 1500 to 1800kg of fish production per harvest period. Seven sampling points were strategic placed in the area where was installed the cage fish farming to analise temperature, concentration and saturation of dissolved oxigen, pH, depth and total phosphorus, ortophosfate, ammoniacal nitrogen, nitrite, nitrate and susppended matter sedimentation ratios. The results have shown more temporal then spacial patterns, with drops in concentration and saturation of dissolved oxigen in water and increase of total phosphorus and nitrate sedimentation ratios. Despite of the warning tendences, we concluded that in this study of case, the impact caused by the activity, the cage fish farming is possible, since some precautions shall be taken to avoid degradation of the water body.
3

Monitoramento de características físico-químicas da água e taxas de sedimentação de tripton no Córrego da Arribada (Baixo Tietê-SP) relacionadas à piscicultura em tanques-rede /

Alves, Rachel Cristina Prehl. January 2006 (has links)
Orientador: Ana Eliza Baccarin Leonardo / Banca: Abílio Lopes de Oliveira Neto / Banca: Antonio Fernando Monteiro Camargo / Resumo: A água é usada para os mais variados fins: abastecimento, irrigação, geração de energia elétrica, lazer, aqüicultura, local de despejo de efluentes domésticos e industriais, etc. No caso da aqüicultura, a criação em tanques-rede introduz diretamente no corpo d'água uma grande quantidade de matéria orgânica. Essa atividade pode contribuir para acelerar os processos de eutrofização do meio devido aos aportes de nutrientes e material em suspensão provenientes, principalmente, do excedente de alimento, fezes e excretas dos peixes. Estudos sobre os impactos causados por essa atividade podem fornecer dados para uma gestão ambiental que permita otimizar o uso múltiplo dos recursos hídricos sem que haja maiores danos ao ambiente aquático. Este trabalho procurou fazer uma caracterização limnológica e uma avaliação do impacto da criação em tanques-rede de tilápia (Orechromis sp.) no córrego da Arribada (Bacia do Baixo-Tietê), que é represado pelo reservatório da Usina Hidrelétrica de Nova Avanhandava, no Rio Tietê, SP. A área destinada à piscicultura é de 4ha de espelho d'água e foi projetada para 200 tanques-rede com volume de 18m3 cada. Em sete pontos distribuídos estrategicamente na região onde foi instalado o sistema de cultivo foram analisados as seguintes variáveis: temperatura, concentração e saturação de oxigênio dissolvido, pH, transparência, e taxas de sedimentação de fósforo total, ortofosfato, nitrogênio amoniacal, nitrito, nitrato e material em suspensão por meio de câmaras de sedimentação. Os resultados mostraram mais padrões temporais que espaciais, com queda acentuada na concentração e saturação de oxigênio dissolvido e aumento nas taxas de sedimentação de fósforo total e nitrato. Apesar do impacto causado apresentar tendências preocupantes, concluiu-se que neste estudo de caso, a produção em tanques-rede é viável ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Water is used to multiple uses: water supply, irrigation, power generation, leisure, aquaculture, place of discharge of home and industrial wastes, etc. In aquaculture, cage fish farming releases a great amount of organic matter directly into the water body. This activity can accelerate the water eutrophication process due to the input of dissolved nutrients and suspended matter, mainly by diet wastes, feces and fish excreta. Studies about environmental impacts caused by this activity can provide a support for a better environmental management that allows the use of water resources without over degradation of the ecosystem. This work aimed to make a limnological characterization and evaluation of the environmental impact of cage culture of Tilapia (Oreochromis sp.) in the stream of Arribada (Tietê river basin - Brazil). This stream is partially impounded by the reservoir of the hydroelectric power station of Nova Avanhandava. The culture is placed in an area of 4ha and it is planned the installation of 200 cages of 18 m3 each one. Till December 2004, there were 180 cages, each one with 1500 to 1800kg of fish production per harvest period. Seven sampling points were strategic placed in the area where was installed the cage fish farming to analise temperature, concentration and saturation of dissolved oxigen, pH, depth and total phosphorus, ortophosfate, ammoniacal nitrogen, nitrite, nitrate and susppended matter sedimentation ratios. The results have shown more temporal then spacial patterns, with drops in concentration and saturation of dissolved oxigen in water and increase of total phosphorus and nitrate sedimentation ratios. Despite of the warning tendences, we concluded that in this study of case, the impact caused by the activity, the cage fish farming is possible, since some precautions shall be taken to avoid degradation of the water body. / Mestre
4

Direct and indirect ecological interactions between aquaculture activities and marine fish communities in Scotland

Ghanawi, Joly Karim January 2018 (has links)
Presence of coastal aquaculture activities in marine landscapes is growing. However, there is insufficient knowledge on the subsequent ecological interactions between these activities and marine fish communities. The overall aim of this thesis was to evaluate the direct and indirect ecological effects of aquaculture activities on marine fish communities in Scotland. A combination of empirical and modelling approaches was employed to collect evidence of how aquaculture activities affect marine fish communities at the individual, population and ecosystem levels around coastal sea cages. The two fish farms evaluated in this research provided the wild fish sampled near the sea cages with a habitat rich in food resources which is reflected in an overall better biological condition. Results of the stomach content analysis indicated that mackerel (Scomber scombrus), whiting (Merlangius merlangus) and saithe (Pollachius virens) sampled near sea cages consumed wasted feed which was also reflected in their modified FA profiles. The overall effects of the two fish farms were more pronounced in young whiting and saithe than in mixed aged mackerel sampled near the sea cages. The phase space modelling approach indicated that the overall potential for fish farms to act at the extremes as either population sources (a habitat that is rich in resources and leads to an overall improved fitness) or ecological traps (a habitat that appears to be rich in resources but is not and leads to an overall poor fitness) are higher for juvenile whiting than for mackerel. Based on the empirical evidence and literature the two fish farms are more likely to be a population source for wild fishes. Using an ecosystem modelling approach indicated that fish farming impacts the food web in a sea loch via nutrient loading. Mussel farming relies on the natural food resources and has the potential to affect the food web in a sea loch via competing with zooplankton for resources which can affect higher trophic levels. The presence of both activities can balance the overall impact in a sea loch as compared to the impact induced if each of these activities were present on their own. Both activities have the potential do induce direct and indirect effects on the wild fish and the entire sea loch system. The results of this PhD identified several gaps in data and thus could be used to improve future sampling designs. It is important to evaluate the cumulative effect of the presence of aquaculture activities in terms of nutrient loading and physical structure in the environment. Using a combination of empirical and modelling approaches is recommended to gain further insight into the ecological impacts of aquaculture activities on wild fish communities. Results of this PhD study could lead to more informed decisions in managing the coastal aquaculture activities. Establishing coastal fish farms as aquatic sanctuaries can be of an advantage to increase fish production and conserve species that are endangered provided that no commercial and recreational fishing is allowed nearby. It would be useful to have long term monitoring of the fish stocks around the cages and if there is any production at the regional level. Additionally, information on behaviour, migration patterns should be collected to understand the impacts of aquaculture activities on fish stocks. From an aquaculture perspective, ecologically engineered fish farms in addition to careful site selection in new aquaculture developments may improve nutrient loading into the ecosystem.

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