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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.
21

The value of non-native fish species : a study of recreational angling in the Amathole district

Kinghorn, James Wolmarans January 2013 (has links)
Experience has shown that effective fisheries governance requires a sound understanding of fisheries as systems incorporating both ecological and human dimensions. The Ecosystem Approach to Fisheries requires that the human components of these systems be considered when developing management and governance frameworks. While the potential for inland fisheries to contribute towards societal welfare and the development of rural livelihoods is becoming increasingly apparent, developing South African inland fisheries requires a careful consideration of both their positive and negative impacts, given that they revolve mainly around five of the world‟s top 100 invasive species. This thesis aimed to explore the value of inland recreational fisheries to rural livelihoods in the Amathole District of South Africa, to the regional economy, and to anglers themselves. Three methods were used to isolate this value. Economic impact analysis was used to estimate the combined total economic impact of the 2011 Divisional Tournament (n=31) and the 2012 Amatola Bass Classic (n=100) on the regional economy of the Amathole District, estimated to be R106 625. The travel cost method was applied to data from the 2012 Amatola Bass Classic in order to estimate the social welfare generated by this tournament. The Negative Binomial model, corrected for truncation and endogenous stratification, estimated this value at R 1 960 090. The sustainable livelihoods framework was used to conduct a broad-based analysis of the value of Amatola Wild Trout, the firm which constitutes the fishery surrounding the rural village of Cata. It was found that the fishery had been responsible for a modest pecuniary impact on the community of Cata within its first two years of establishment, although significant improvements in human capital were found to have resulted from the development of the fishery. These results provide insights into the economic dimension of fisheries in the Amathole District, and will prove useful when weighing up the positive and negative impacts of non-native fish species, particularly when informing decisions regarding their potential eradication.
22

Sorgo em dietas para o Jundiá (Rhamdia quelen) / Sorghum in diets for Silver Catfish (Rhamdia quelen)

Rabelo, Pedro Carvalho 28 April 2014 (has links)
Made available in DSpace on 2017-07-10T18:13:15Z (GMT). No. of bitstreams: 1 Pedro Carvalho Rabelo.pdf: 606919 bytes, checksum: 4ef263560977f1837fef3b1443b68df0 (MD5) Previous issue date: 2014-04-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the effect of replacing corn by sorghum low tannins in diets for silver catfish (Rhamdia quelen) on growth performance and survival of the fish, the chemical composition of the carcass, in two hematological parameters - total protein and leukocytes - and size and density of micro villi of the fish. The experiment was conducted at the Instituto de Pesquisa em Aquicultura Ambiental - InPAA belonging to Universidade Estadual do Oeste do Paraná, Toledo campus. Six hundred fingerlings with initial average weight and length of 4.49 ± 0.8 grams and 3.42 ± 0.24 inches respectively were distributed in 24 tanks - network with capacity 1m3 of usable volume. Completely randomized design with six treatments and four replications was used with an experimental unit formed by tank with 25 fish. Treatments consisted of six diets with increasing levels of 0; 6; 12; 18; 24; 30% sorghum and decreasing 30; 24; 18; 12; 6; 0% corn.. For 114 days, the fingerlings were fed three times a day (8, 12 and 17h), ad libitum. Survival was lower in the lot of fish fed a diet containing 30% sorghum, differing significantly (p <0.05) diets with 0 and 6% sorghum. The values of the chemical composition of the carcass and total protein were normal for the species and may serve as a basis for comparison with studies involving different culture conditions of silver catfish. It was concluded that sorghum can replace corn by 80% in diets for silver catfish. / O objetivo desse trabalho foi avaliar o efeito da substituição do milho pelo sorgo de baixo tanino em dietas para jundiá (Rhamdia quelen) no desempenho produtivo, sobrevivência, composição centesimal da carcaça, em dois parâmetros hematológicos proteínas totais e leucócitos e no tamanho e densidade das micro vilosidades do peixe. O experimento foi realizado no Instituto de Pesquisa em Aquicultura Ambiental InPAA, pertencente a Universidade Estadual do Oeste do Paraná, Campus Toledo - PR . Foram utilizados 600 alevinos com peso e comprimento inicial médio de 4,49 ± 0,80g e 8,68 ± 0,62 cm respectivamente, distribuídos em 24 tanques rede com capacidade de 1m3 de volume útil. Utilizou-se delineamento experimental inteiramente casualizado com seis tratamentos e quatro repetições, sendo cada unidade experimental formada por um tanque com 25 peixes. Os tratamentos constituíram-se de seis dietas com níveis crescentes de 0; 6; 12; 18; 24 e 30% de sorgo e decrescentes de 30; 24; 18; 12; 6 e 0% de milho. Durante 114 dias os alevinos foram alimentados três vezes ao dia (8; 12 e 17h), ad libitum. A sobrevivência foi menor no lote de peixes alimentados com dieta contendo 30% de sorgo, diferindo estatisticamente (p<0,05) das dietas com 0 e 6 % de sorgo. Os valores da composição química da carcaça e proteínas totais foram normais para a espécie, podendo servir de base para comparação com trabalhos que envolvam situações diferentes de cultivo de Jundiá. Concluiu-se que o sorgo pode substituir o milho em até 80% em dietas para o Jundiá.

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