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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.

The bacteriology of Atlantic halibut, Hippoglossus hippoglossus (L.) larval rearing

Verner-Jeffreys, David Willoughby January 2000 (has links)
No description available.

Studies on the effects of environmental factors and selected pathogens on morbidity and mortality of hatchery reared Oreochromis mossambicus (Peters) eggs and fry

Subasinghe, R. P. January 1986 (has links)
No description available.

Developing Hatchery and Growout Techniques for Bigeye Scad (Selar crumenophthalmus) Aquaculture

Welch, Aaron W. 01 January 2010 (has links)
The results of a two-year research project designed to develop techniques for closed cycle production of bigeye scad (Selar crumenophthalmus) are described. Broodstock fish were captured approximately 5 nautical miles east-southeast of Key Biscayne Florida in waters 100 to 400 feet deep. A 28-ton, eight tank, recirculating aquaculture system (RAS) was designed, built and used for broodstock maturation and growout. Between June and October of 2009, thirty-six volitional spawning events were recorded during a five-month spawning season. A larval rearing protocol focused on modified greenwater techniques using microalgae (Isochrysis galbana and Nannochlopsis oculata) at total concentrations of 400,000 cells ml-1 and rotifers (Brachionus plicatilis) at densities of 30 to 50 rotifers ml-1 was developed. A larval rearing trial using this protocol produced 1,940 fully weaned, 45 dph fingerling bigeye scad with an average length of 38.8 ml and average weight of 1.3 g. Growout trials conducted from 45 dph to four and a half months post hatch were conducted. During growout trials fish were fed ad libitum twice a day using commercially available feed with 44% crude protein and 18% crude fat. Growout trials resulted in an average survival rate of 88%, absolute growth rates (AGR) of 28.23 to 30.26 g, and feed conversion ratios (FCRs) between 1.17 and 1.38. Results from an informal survey of local recreational fishing interests indicate that there is a large potential live-bait market for bigeye scad. Overall results from these trials show that bigeye scad aquaculture is technically feasible and suggests that the species is strong candidate for commercialization.

Reproductive success of hatchery and wild steelhead, Oncorhynchus mykiss /

McLean, Jennifer Elizabeth. January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 98-111).

Effects of domestication on behavior in clonal lines of hatchery-reared rainbow trout, Oncorhynchus mykiss

Villagecenter, Sharon M., January 2008 (has links) (PDF)
Thesis (M.S. in zoology)--Washington State University, August 2008. / Includes bibliographical references (p. 41-44).

Long-term effects of alternative hatchery mating practices and size selective fishing on age and sex composition of Chinook salmon populations returning to hatcheries /

Chen, Yaming. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 76-81). Also available via Humboldt Digital Scholar.

Genetic variation within and among Ontario hatchery stocks of lake trout (salvelinus namaycush) as measured by three molecular marker systems : applications to rehabilitation and hatchery management /

Stott, Wendylee. January 1998 (has links)
Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references. Also available via World Wide Web.

Nearshore restoration associated with large dam removal andI implications for ecosystem recovery and conservation of northeast Pacific fish: lessons learned from the Elwha dam removal

Shaffer, J. Anne 04 May 2017 (has links)
This dissertation addresses the relationship between large-scale dam removal and the nearshore ecosystem function for fish. The work is based on almost a decade’s worth of collaborative field work in the nearshore of the largest dam removal in the world recently completed on the Elwha River. The data analyzed span seven years prior to, during, and throughout the first year of each dam removal (January 2008 to November 2015). As of September 2015, approximately 2.6 million m3 of sediment material increased the area of the Elwha delta to over 150 ha. Long term study of fish in the estuary reveals fish community response to dam removal, and indicates likely interactions in the nearshore between hatchery and wild fish, including chum salmon critical to watershed recovery. Continued hatchery releases may therefore further challenge chum salmon recovery, and this interaction should be considered when planning for future watershed recovery. Community analysis revealed that, while species richness and taxonomic diversity do not appear to have a significant response to dam removal, functional diversity in the nearshore does respond significantly to dam removal. Three main shifts occurred in the nearshore: large scale and rapid creation of estuary habitats; delivery of large amounts of sediment to the delta/estuary in a short period of time, and; a shift in original habitats from tidally influenced to non-tidally influenced habitats resulted in changes in estuary function. Changes in functional diversity occur disproportionately in the new sites, which have more unstable, and so less resilient, communities. Functional diversity in the original estuary sites appears to be more resilient than in the newly created sites due to the large-scale environmental disruption that, ironically, created the new sites. However, the functional diversity at the original sites may be defined in part by management activities, including hatcheries that could mute/mask/inhibit other community responses. Further, functional diversity at the newly formed nearshore areas is predicted to stabilize as the habitats are vegetated and mature. Principal components analysis of Elwha fish community over the course of this study reveals that the fish communities of the Elwha are predictably grouped, indicating that while a few new species are observed, dam removal has not resulted in observable disruptions in fish community assemblages. And finally, nearshore habitats are critical for many forage fish species, and an emerging topic for large-scale dam removals. Forage fish spawning response to dam removal appears to be complex and may be related to multiple factors including high interannual variability in physical habitat conditions, geographic factors and complex life histories of forage fish. Habitat suitability for forage fish spawning should increase as restored ecosystem processes and newly created habitats mature and stabilize, indicating that time may be an important factor in nearshore restoration for forage fish spawning. It is therefore important to implement long-term monitoring and incorporate nearshore ecosystem process and function for multiple life history stages of nearshore species, including forage fish, into large-scale dam removal restoration and management planning. / Graduate / 2019-04-12

Indicadores de sustentabilidade na larvicultura de camarão-da-amazônia, Macrobrachium amazonicum / Sustainability indicators of the Amazon River Prawn hatchery

Frota Filho, Josué Fernandes 19 April 2018 (has links)
Submitted by JOSUÉ FERNANDES FROTA FILHO (frotafilho.jf@outlook.com) on 2018-04-24T17:00:58Z No. of bitstreams: 1 Josue_Dissertação_24_04_FINAL.pdf: 705810 bytes, checksum: c7f70d2764da25e302dc2b38af6c84bd (MD5) / Rejected by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo: O arquivo pdf submetido ao repositório deve conter a ficha catalográfica e o certificado de aprovação (documentos obrigatórios). Favor inserir no arquivo pdf a ficha catalográfica e o certificado de aprovação (tudo em um arquivo só). Agradecemos a compreensão. on 2018-04-25T12:56:05Z (GMT) / Submitted by JOSUÉ FERNANDES FROTA FILHO (frotafilho.jf@outlook.com) on 2018-04-26T11:48:21Z No. of bitstreams: 1 Josue_Dissertação_24_04_FINAL corrigido.pdf: 927542 bytes, checksum: a658dd423a96120871bc91bfa99cbc9b (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-26T12:10:28Z (GMT) No. of bitstreams: 1 fotafilho_jf_me_jabo.pdf: 927542 bytes, checksum: a658dd423a96120871bc91bfa99cbc9b (MD5) / Made available in DSpace on 2018-04-26T12:10:28Z (GMT). No. of bitstreams: 1 fotafilho_jf_me_jabo.pdf: 927542 bytes, checksum: a658dd423a96120871bc91bfa99cbc9b (MD5) Previous issue date: 2018-04-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O crescimento acelerado da aquicultura vem sendo acompanhado pela crescente preocupação em se garantir a sustentabilidade das atividades aquícolas. A sustentabilidade neste trabalho é baseada principalmente em duas dimensões: ambiental, e econômica. O presente trabalho teve como objetivo avaliar a sustentabilidade ambiental e a viabilidade econômica em pequena escala de produção de pós-larvas do camarão de água doce da espécie Macrobrachium amazonicum, por meio de um conjunto indicadores de sustentabilidade. Foram considerados os ciclos de produção durante um ano de cultivo de pós-larvas do camarão-da-amazônia. A capacidade produtiva considerada foi de 290 milheiros de pós-larvas/mês. A sustentabilidade ambiental foi medida com base na utilização de recursos naturais, eficiência no uso destes recursos e poluição liberada ao ambiente pelo meio de cultivo. A sustentabilidade econômica foi medida com base nos aspectos sobre a eficiência no uso dos recursos financeiros e a capacidade de gerar recursos para reinvestimentos na atividade. Os resultados sugerem que há viabilidade econômica para o produtor que realiza larvicultura em sistemas de fundo de quintal (backyard hatchery). Além disso, os dados obtidos também mostraram que embora a larvicultura seja uma atividade bastante intensificada, há eficiência na utilização dos recursos naturais, sendo mais sustentável do que outras fases de produção, como o berçário e crescimento final da mesma espécie. Desse modo, o modelo utilizado é uma alternativa viável com sustentabilidade econômica e ambiental para produção de pós-larvas de M. amazonicum em sistemas familiares de produção. / The rapid growth of aquaculture has been accompanied by the increasing concern to ensure sustainability of aquatic activities. In this work, sustainability is based on environmental and economic dimensions. The objective of the study is to evaluate the environmental and economic sustainability of a small scale Macrobrachium amazonicum post-larvae production using a set of indicators for sustainability. Production cycles during one year of the Amazon Prawn hatchery was considered. The considered productive capacity was 290 thousand post larvae/month. Environmental sustainability measurements were based on the use of natural resources, efficiency in the use of resources and pollution released to environment from the production facility. Economic sustainability measurements were based on the aspects of efficiency in the use of financial resources and the capacity to generate resources for reinvestments in the activity. Results show that there is economic feasibility for the ‘backyard’ hatcheries system for freshwater prawn farmers. In addition, data indicate that in spite of hatchery being a highly intensified activity, there is efficiency in using natural resources, and it is more sustainable than other production phases, such as nursery and grow-out phase of the same species. To sum it up, the hatchery model studied is a feasible and sustainable alternative to produce M. amazonicum post-larvae with environmental and economic sustainability to be operated using either family labour production. / 88882.156917/2017-01


Piggott, April 01 January 2014 (has links)
The eastern oyster (Crassostrea virginica Gmelin 1791) has great ecological and economic importance but populations have declined, especially in Chesapeake Bay, to historically low numbers. Hatcheries strive to produce oysters with beneficial characteristics for supplementation and commercial purposes, both natural and stimulated mass spawning. Unequal contribution of parents in mass spawnings potentially can lead to high levels of inbreeding and a loss of beneficial characteristics in offspring. In this study, we determined microsatellite genotypes for parents (n^parents =24, 49, and 77 parents) and progeny (n=96 each) of three hatchery-produced families and used the data for parental assignment. We observed the presence of more than two alleles per locus for some offspring, yet because genetic analysis software only allows for a maximum of two alleles per locus, we chose the two alleles with the strongest signals. For the three parent “populations,” 71% of alleles had frequencies of <0.05 and observed heterozygosities were lower than expected by an average factor of 0.27. Inbreeding within the various parent populations was similar across the three families ranging from F^IS 0.26–0.43. In all three families, the offspring exhibited greater levels of genetic diversity and lower inbreeding levels than the parents (F^IS 0.14–0.21), and in some cases offspring exhibited alleles that were not present in the parents. Variance in the number of offspring produced per parent was observed for all families and in general, <10% of potential parents (generally 2-5 females and 1-3 males) produced >10% of the offspring. Reproductive success for spawning parents, N^b, determined by three methods, ranged from 0.07 to 0.27. As the number of parents per family increased, a higher proportion of parents failed to produce offspring. Across all three families, the average effective number of breeders was N^b = 7.1 and the level of reproductive success was inversely proportional to the number of potential parents. This finding implies that to maintain high levels of diversity and beneficial characteristics in the offspring (and to avoid the chance of unintentional inbreeding), hatcheries should perform more spawnings with fewer parents.

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