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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.
61

A sustentabilidade da pesca da lagosta na visÃo do pescador artesanal: um estudo de caso / The sustainability of the lobster fishing in sight of the fisherman: a case study

MarcÃlia Marques Vieira 17 August 2007 (has links)
nÃo hà / A sustentabilidade dos recursos naturais, inclusive pesqueiros, tem sido pauta de discussÃo hà dÃcadas. A sensaÃÃo de infinito, que por vezes temos do mar, parece que se estende aos recursos ali encontrados. O saber cientÃfico e o saber popular convergem num sà alerta: sem medidas urgentes e realmente eficazes, a lagosta pode se acabar como atividade econÃmica. O Cearà ainda à o principal estado da federaÃÃo na exportaÃÃo do crustÃceo, mas o item, que por muito tempo esteve em primeiro lugar na pauta de exportaÃÃes do Estado, hoje està na quarta colocaÃÃo. Este estudo consiste em verificar junto aos pescadores artesanais da Praia das Frexeiras, BeberibeCe, a visÃo dos mesmos sobre a Sustentabilidade da pesca da Lagosta. Para alcanÃar esta finalidade, utilizou-se dados de origem primÃria, obtidos atravÃs de questionÃrios envolvendo as questÃes referentes aos aspectos pessoais e sociais da famÃlia, profissionais, bens de produÃÃo, defeso da lagosta e segurodesemprego,contemplando a populaÃÃo de 33 pescadores, todos beneficiÃrios do Programa de Seguro Desemprego ao Pescador Artesanal. Fez-se a gravaÃÃo de entrevistas, que relatavam o pensamento deles sobre o assunto e utilizou-se tambÃm a observaÃÃo cientÃfica. Conclui-se que os pescadores artesanais da Praia das Frexeiras em Beberibe-Ce, sÃo possuidores de um senso crÃtico formador de opiniÃo sobre a Sustentabilidade da pesca da Lagosta. Torna-se entÃo necessÃrio, que haja uma uniÃo de esforÃos para que num perÃodo de curto, mÃdio e longo prazo sejam definidas aÃÃes de cunho prÃtico, visando assim, a reestruturaÃÃo do setor lagosteiro e por conseqÃÃncia, a sustentabilidade da atividade
62

Neurolipofuscin is a Measure of Age in the Caribbean Spiny Lobster, Panulirus argus, in Florida

Maxwell, Kerry Elizabeth 03 August 2006 (has links)
Accurate age estimates for the commercially-important Caribbean spiny lobster, Panulirus argus, would greatly enhance analyses of life history and population dynamics. Previous estimates of their age based on size and growth may be inaccurate because of variable growth in the wild. An established technique for aging crustaceans – histologically-determined lipofuscin content in the nervous system – was used on lobsters reared in the laboratory for up to five years. We verified the presence of lipofuscin in eyestalk neural tissue and described its distribution in cell cluster A of the hemiellipsoid body. Neurolipofuscin content of both sexes increased linearly over the five-year age range, with seasonal oscillations. Growth of these animals, on the other hand, showed sex differences and began to asymptote after three years. Neurolipofuscin concentrations in the two eyestalks from the same animal were similar. These results suggest that the neurolipofuscin technique will be valuable for estimating age of wild-caught P.argus.
63

The effects of elevated temperature and pCO2 on the developmental eco-physiology of the European lobster, Homarus gammarus (L.)

Small, Daniel Peter January 2013 (has links)
The successful completion of the early developmental stages in organisms with complex life cycles is crucial to the persistence of a species both at the local and global scale. Thus changes in the abiotic environment experienced during larval and early benthic development can have profound effects on the development and ultimately dynamics of populations of marine invertebrates. The effects of elevated temperature and pCO2 in line with future predictions of anthropogenic climate change, ocean warming and ocean acidification (OA), on the survivorship and growth during early development of marine invertebrates is beginning to be understood, yet the underlying physiological ontogeny driving such changes, and the more subtle effects on physiological performance of climate change drivers, has yet to be distinguished. Therefore the aim of the present study is to investigate the effects of elevated temperature and pCO2 on the developmental eco-physiology of an economically and ecologically important species, the European lobster, Homarus gammarus, to characterise the underlying physiological responses of early development behind responses of survival and growth. The main findings relate to how changing optimal temperature conditions during larval development results in changes in metabolic performance and therefore aerobic scope, ultimately driving survival and growth. Larval stages which exhibit narrower aerobic scope were also sensitive to elevated pCO2 evident as reduced survival, changes to energetic demands and organic content, and reduced calcification. Furthermore, this is the first attempt to characterise the physiological response of early benthic juveniles to climate change drivers. Early benthic juveniles are quite different in underlying physiology to later juveniles and adults, cumulating in this stage being energy limited. Such limitations are expressed as a reduction in aerobic scope in relation to elevated temperature and pCO2, and associated sensitiveness to elevated pCO2 resulting in increased moult related mortalities and the breakdown of haemolymph buffering capacity under combinations of elevated temperature and pCO2. Throughout early development, elevated temperature and pCO2, through underlying physiological responses, may have dramatic effects on the geographic range and successful development of H. gammarus.
64

Enhancing value of lobster waste by enzymatic methods

Dauphin, Laurie January 1991 (has links)
In processing lobster, approximately 70% of the body weight is discarded as waste. The solid waste consists of shell, viscera and a small amount of meat. Lobster waste is an excellent source of protein (26.6%) crude fat (2.7%) and pigment (98 $ mu$g/g) on a dry weight basis which could be processed into a stable complex known as carotenoprotein. / Procedures for extraction of carotenoprotein from lobster waste have been developed, along with investigation of its distinctive physicochemical properties. The main factors were: demineralization agents (EDTA, HCl or heat) and precipitation agents ((NH$ sb4$)$ sb2$SO$ sb4$ or HCl). Lobster carotenoprotein recovered under different extraction procedures showed significant differences in terms of quantity and quality of the product recovered. However the procedures did not appear to affect the physical properties and amino acid profiles of carotenoprotein. / Optimal recovery involved treatment with EDTA as demineralization agent and precipitation with (NH$ sb4$)$ sb2$SO$ sb4$. Proximate and amino acid analyses indicated the potential of the recovered lyophilized protein as feed ingredient for cultured salmonids.
65

Chitin nanofibers, networks and composites : Preparation, structure and mechanical properties

Mushi, Ngesa Ezekiel January 2014 (has links)
Chitin is an important reinforcing component in load-bearing structures in many organisms such as insects and crustaceans (i.e. shrimps, lobsters, crabs etc.). It is of increasing interest for use in packaging materials as well as in biomedical applications. Furthermore, biological materials may inspire the development of new man-made material concepts. Chitinmolecules are crystallized in extended chain conformations to form nanoscale fibrils of about 3 nm in diameter. In the present study, novel materialshave been developed based on a new type of chitin nanofibers prepared from the lobster exoskeleton. Improved understanding about effects of chitin from crustaceans and chitin material preparation on structure is provided through Atomic Force Microscopy(AFM) (paper I&amp;II), Scanning Transmission Electron Microscopy(STEM) (paper I&amp;II), X-Ray Diffraction (XRD), Intrinsic Viscosity, solid state 13C Nuclear Magnetic Resonance (NMR) (paper II), Field Emission Scanning Electron Microscopy(FE-SEM) (paper I, II, III, IV &amp; V), Ultraviolet-Visible Spectrophotometryand Dynamic Light Scattering (DLS) (paper III). The presence of protein was confirmed through colorimetric method(paper I &amp; II). An interesting result from the thesis is the new features of chitin nanofiber including small diameter, high molar mass or nanofiber length,and high purity. The structure and composition of the nanofibers confirms this (paper I &amp; II). Furthermore, the structure and properties of the corresponding materials confirm the uniqueness of the present nanofibers: chitin membrane (I &amp; II), polymer matrix composites (III),and hydrogels (paper IV). Improved mechanical properties compared with typical data from the literature were confirmed for chitin nanofiber membranes in paper II, chitin-chitosan polymer matrix composites in paper III, and chitin hydrogel in paper IV. Mechanical tests included dynamic mechanical analysis and uniaxial tensile tests. Mechanical properties of chitin hydrogels were evaluated based onrheological and compression properties (paper IV). The values were the highest reported for this kind of chitin material. Furthermore, the relationships between materials structure and properties were analyzed. For membranes and polymer matrix nanocomposites, the degree of dispersion is an important parameter. For the hydrogels, the preparation procedure is very simple and has interesting practical potential. Chitin-binding characteristics of cuticular proteins areinteresting fornovel bio-inspired material development. In the present work(paper V), chitin nanofibers with newfeaturesincluding high surface area and low protein content were combined with resilin-like protein possessing the chitin-binding characteristics. Hydrated chitin-resilin nanocomposites with similar composition as in rubber-like insect cuticles were prepared. The main objective was to improve understanding on the role of chitin-binding domain on mechanical properties. Resilin is a rubber-like protein present in insects. The exon I (comprising 18 N-terminal elastic repeat units) together with or without the exon II (a typical cuticular chitin-binding domain) from the resilin gene CG15920 found in Drosophila melanogasterwere cloned and the encoded proteins were expressed as soluble products in Escherichia coli.Resilin-like protein with chitin-binding domain (designated as ResChBD) adsorbedin significant amount to chitin nanofiber surface andprotein-bound cuticle-like soft nanocomposites were formed. Although chitin bindingwas taking place only in proteinswith chitin-binding domain, the global mechanical behavior of the hydrated chitin-resilin nanocomposites was not so sensitive to this chitin-resilin interaction. In summary, chitin is an interesting material component with high potential as mechanical reinforcement in a variety of nanomaterials. The present study reports the genesisof novel chitin nanofibers and outlines the basic relationships between structure and properties for materials based on chitin. Future work should be directed towards both bio-inspired studies of the nanocomposite chitin structures in organisms, as well as the industrial applications of chitin waste from the food industry. Chitin nanofibers can strengthen the properties of materials, andprovide optical transparency as well as biological activities such as antimicrobial properties. / <p>QC 20141110</p>
66

Recovery, drying and characterization of carotenoproteins from industrial lobster waste

Tu, Ya. January 1991 (has links)
Lobster waste (including the head and hard carapace, viscera, mandibles and gills) contains approximately 98 $ mu$g/g total astaxanthin, 23% protein, 20% chitin, 34% ash, and 2.2% crude fat on dry weight basis. Carotenoprotein, amounting to 16% of the dry matter was effectively recovered from lobster waste by a trypsin aided process. Air-dried carotenoproteins were enriched in protein by about 108-115%, in crude fat by 540-594% and in carotenoid pigment by about 147-329% as compared with the waste material. Furthermore, the ash and chitin levels in the products were considerably lower than those of the raw material. / Drying characteristics of carotenoprotein was evaluated in a modified air-drier using air temperature (45$ sp circ$C, 55$ sp circ$C or 65$ sp circ$C) and relative humidity (5% and 15%) as main factors. The study indicated that higher temperatures achieved faster drying rates of the product but adversely affected its nutritional composition and/or quality. The proximate compositions of carotenoprotein dried at 45$ sp circ$C and relative humidity of 5% or 15% were comparable with that obtained by freeze drying. / Thus, the process achieved a substantial reduction in the levels of anti-nutrients associated with lobster waste (i.e., ash and chitin) while elevating the levels of carotenoid pigments and essential nutrients such as protein and fat in the recovered product. These characteristics of the tray-dried carotenoprotein suggest that it could be used as an inexpensive source of pigment and protein in diets of cultured salmonid species.
67

Comparative Physiology of Calcium Transport in Crustacean (Homarus Americanus) and Echinoderm (Helianthoides Pycnopodia) Gastrointestinal Epithelia

Zhuang, Zhenpeng 05 1900 (has links)
Thesis (Ph. D.)--University of Hawaii at Manoa, 1996. Includes bibliographical references (leaves 113-115). / ix, 143 leaves, bound : ill. ; 29 cm.
68

Feeding and digestion in the phyllosoma larvae of ornate spiny lobster, Panulirus ornatus (Fabricius) and the implications for their culture /

Johnston, Matthew D. January 2006 (has links)
Thesis (Ph.D.)--University of Western Australia, 2007.
69

Advancing the nutrition of juvenile spiny lobster, jasus edwardsii, in aquaculture /

Simon, Cédric Johan. January 2009 (has links)
Thesis (PhD--Marine Science)--University of Auckland, 2009. / Includes bibliographical references.
70

Lobstermen, Lines, and Endangered Whales: Risk Reduction Measures for Coastal Maine

Brooke, Samantha January 2005 (has links) (PDF)
No description available.

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