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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

Développement d'une méthode méthodologie de PCR en temps réel pour l'identification et la quantification de trois espèces de thon (Thunnus obesus, Thunnus albacares et Katsuwonus pelamis) dans les produits appertisés / Development of a methodology of PCR in real time for identification and quantification of 3 species of tuna (Thunnus obesus, Thunnus albacares and Katsuwonus pelamis) in canned products

Bojolly, Daline 29 March 2017 (has links)
Le thon obèse (Thunnus obesus), le thon alabore (Thunnus albacares) et le listao (Katsuwonus pelamis) comptent parmi les espèces de thons les plus utilisées en conserve. Lors de la fabrication de conserves de thon, la substitution d'espèce et/ou le mélange de différentes espèces de thon sont interdits par la réglementation européenne. L'authentification des espèces de thon reste complexe à cause du degré de similitude élevé entre les espèces de thon, ou encore, lorsque les caractéristiques morphologiques externes sont éliminées au cours du filetage et lors de la mise en conserve. Par conséquent, des substitutions involontaires ou frauduleuses peuvent se produire. Dans cette étude, le marqueur mitochondrial du gène de la sous-unité 2 de la NADH déshydrogénase a été utilisé pour identifier le thon obèse et le gène de la sous-unité II de la cytochrome c oxydase a été utilisé pour identifier le thon albacore et le listao en utilisant la PCR en temps réel basée sur la technologie TaqMan. Deux méthodes différentes basées sur la qPCR ont été développées pour quantifier le pourcentage de chair de chaque espèce présente au sein d'une boîte de thon. La première a été basée sur la quantification absolue avec standard externe réalisée avec les deux marqueurs. La seconde a été basée sur la quantification relative avec standard externe avec le gène endogène de l'ARN 12S. Sur la base de ces résultats, nous pouvons conclure que notre méthode peut s'appliquer pour quantifier les deux espèces de thon albacore et obèse génétiquement très proches lorsqu'elles sont utilisées dans un mélange binaire en conserve. / Bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares) and skipjack tuna (Katsuwonus pelanis) are among the most widely used tuna species for canning purposes. Not only substitution but also mixing of tuna species is prohibited by the European regulation for canned tuna products. However, it can be difficult to authenticate the tuna species, due to their high degree of similarity or even when the external morphological characteristics are removed due to filleting before canning. Consequently, involuntary or fraudulent substitutions may occur during the canning process. In this study, the mitochondrial marker from NADH dehydrogenase subunit 2 gene was used to identify bigeye tuna and the mitochondrial marker cytochrome c oxidase subunit II gene was used to identify yellowfin tuna and skipjack tuna, utilizing TaqMan qPCR methodology. Two different qPCR-based methods were developed to quantify the percentage of flesh of each species used for can processing. The first one was based on absolute quantification using standard curves realized with these two markers ; the second one was founded on relative quantification with the universal 12S rRNA gene as the endogenous gene. On the basis of our results, we conclude that our methodology could be applied to authenticate the two closely related tuna species (bigeye tuna and yellowfin tuna) when used in a binary mix in tuna cans.
2

Historical Demography and Genetic Population Structure of the Blackfin Tuna (Thunnus atlanticus) from the Northwest Atlantic Ocean and the Gulf of Mexico

Saxton, Brandon L. 16 January 2010 (has links)
Little is known about the population structure and genetic variability of blackfin tuna despite catch increases over the past 25 years. In this thesis, levels of genetic variation contained in 323bp of the mitochondrial DNA (mtDNA) control region-I (CR-I) and in six microsatellite loci were characterized for two regions: the Gulf of Mexico (GoM) and the Northwest Atlantic. Large amounts of mtDNA diversity (h>0.99; =0.047) were observed in both regions. Mismatch distribution analysis of the CR-I sequence data, using a mutation rate of 1.6% Ma-1for scombroid fishes, indicate blackfin tuna underwent population expansion about 1.4 Ma, a timeline concordant with the expansion of other tunas and billfishes. Estimates of female effective population size were very large at 7.8 million and 12.8 million individuals for the NW Atlantic and the GoM, respectively. Both mtDNA and six microsatellite loci were used to determine blackfin tuna population structure. Microsatellite and mtDNA AMOVAs revealed significant differentiation (msat st=0.01, p=0.006 and mtDNA st=0.01, p=0.049) between the GoM and the NW Atlantic samples. Migration estimates using mtDNA data indicate that twice as many females enter the NW Atlantic from the GoM (346 individuals/generation) than the opposite direction (150 individuals/generation). Migration estimates using microsatellite data were substantially smaller, with the Gulf receiving 7 individuals/generation and the NW Atlantic 4 individuals/generation. Finally, low levels of genetic differentiation using microsatellite data have been reported in other highly abundant marine fishes, which have been attributed to homoplasy in allele size. To test this hypothesis, the allele frequency distributions of blackfin and yellowfin tuna at six microsatellite loci were compared. The distances between species were surprisingly small (Da=4.0%, (delta mu)squared=1.08), with a large degree of similarity in frequency distributions at four loci. The comparison of bigeye tuna at two microsatellite loci revealed additional inter-specific similarities. A mutation rate for these loci was estimated by modifying an equation used to estimate time since divergence. Microsatellites in tunas appear to evolve at a rate (4.3x10-7 Ma-1) that is two orders of magnitude slower than other fishes (1x10-5 Ma-1). Accordingly, microsatellite allele size similarities are plesiomorphic and not due to homoplasy.
3

The biology, ecology and exploitation of longtail tuna, Thunnus tonggol (Bleeker) in Oceania

Wilson, M. A. January 1982 (has links)
Thesis (M.Sc.)--Macquarie University, School of Biological Sciences, 1982. / "June 1981" Bibliography: leaves 176-185.
4

Variabilitat genètica i estructura poblacional en tres espècies de la família Scombridae, Sarda sarda, Thunnus alalunga i Thunnus thynnus, basada en la regió control del DNA mitocondrial

Viñas de Puig, Jordi 23 July 2001 (has links)
Aquest treball es centra en el coneixement de l'estructura poblacional de tres espècies piscícoles de la família Scombridae, el bonítol (Sarda sarda), la bacora (Thunnus alalunga) i la tonyina (Thunnus thynnus) en la seva distribució de l'atlàntic i el mediterrani. / This work focuses on understanding the population structure of three fish species of the family Scombridae, bonito (Sarda sarda), the figs (Thunnus alalunga) and bluefin tuna (Thunnus thynnus) distribution in the Atlantic and the Mediterranean.
5

A influência da temperatura da superfície do mar sobre a distribuição e abundância relativa da albacora bandolim (Thunnus obesus, Lowe 1839) no Atlântico Oeste Tropical

SOUSA NETO, Aprigio Marques de 21 August 2009 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-08T11:57:22Z No. of bitstreams: 1 Aprigio Marques de Sousa Neto.pdf: 1174109 bytes, checksum: b0262e812fcb006c6f76782c56519e12 (MD5) / Made available in DSpace on 2017-02-08T11:57:22Z (GMT). No. of bitstreams: 1 Aprigio Marques de Sousa Neto.pdf: 1174109 bytes, checksum: b0262e812fcb006c6f76782c56519e12 (MD5) Previous issue date: 2009-08-21 / In recent years, with the advent of global climate change, several studies have been developed in order to better understand the changes in the pelagic ocean environment and its effects on the main fishing resources explored in the three oceans. This present study was to evaluate the influences of environmental variability on the CPUE of bigeye tuna (Thunnus obesus) caught by Brazilian longline fleet in the period from 1978 to 2008. For this, we analyzed the data on settings, seasonality, fishing areas, effort, catch, time of immersion, number of hooks / Basket and fishing time, and some environmental data such as sea surface temperature (SST), the depth of the layer of mixture (PCM) and the rate of illumination of the moon (IIL). We performed a cluster analysis with the aim of categorizing the fishing effort associated with the catches of different species, then an analysis with generalized additive models (GAMS) in order to assess the relationship between these factors and the CPUE from big eye tuna. The results showed that as regards the variable latitude, the higher values of CPUE occurred around the equator. The case of the month on the CPUE index, we observed the highest values between October and April. Already the level of lunar illumination on the CPUE showed an increasing trend of the new moon to crescent. The SST showed a positive trend with higher values occurring between 26 and 30° C on CPUE. The effect of PCM, highest CPUEs occurred in areas where the thermocline is closer to the surface, between 40 and 70 m. In relation to the variable year, positive effects were only observed from 2000. These results are probably related to the reproductive activity of the specie, which is focused off the Brazilian coast for spawning. / Nos últimos anos, com o advento das mudanças climáticas globais, diversos estudos vêm sendo desenvolvidos no intuito de melhor compreender às variações do ambiente pelágico oceânico e seus efeitos sobre os principais recursos pesqueiros explorados nos três oceanos.O presente estudo teve como objetivo avaliar as influências da variabilidade ambiental sobre a CPUE da albacora bandolim (Thunnus obesus) capturada pela frota espinheleira brasileira no período de 1978 à 2008. Para isto, foram analisados os dados referentes aos lançamentos, sazonalidade, área de pesca, esforço, captura, tempo de imersão, número de anzóis/samburá e turno de pesca, e alguns dados ambientais, como a Temperatura da Superfície do Mar (TSM), a Profundidade da Camada de Mistura (PCM) e o Índice de Iluminação da Lua (IIL). Foi realizada uma análise de cluster com o objetivo de categorizar o esforço de pesca associandoo as capturas de diferentes espécies e, em seguida, uma análise com Modelos Aditivos Generalizados (GAMs) com o intuito de avaliar a relação entre estes fatores e a CPUE da albacora bandolim. Os resultados obtidos mostraram que no que se refere a variável latitude, os maiores valores de CPUE ocorreram no entorno do equador. Se tratando do índice mês sobre a CPUE, observou-se os maiores valores entre outubro e abril. Já o índice de iluminação lunar sobre a CPUE apresentou uma tendência crescente de lua nova para quarto-crescente. A TSM mostrou uma tendência positiva com maiores valores ocorrendo entre 26° e 30°C sobre a CPUE. No efeito da PCM, as CPUEs mais elevadas ocorreram em áreas onde a termoclina encontra-se mais próxima da superfície, entre 40 e 70 m. Em relação à variável ano, efeitos positivos só foram observados a partir de 2000. Estes resultados estão provavelmente associados à atividade reprodutiva da espécie, que se concentra ao largo da costa brasileira para desova.
6

Efeitos da variabilidade ambiental na distribuição e abundância relativa da albacora branca (Thunnus alalunga, Bonaterre 1788) no Atlântico Sul

OLIVEIRA, Bruno de 31 August 2010 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-08T16:07:31Z No. of bitstreams: 1 Bruno de Oliveira.pdf: 2373684 bytes, checksum: 5f89aaf529fed3c21f21b9c51546d9b8 (MD5) / Made available in DSpace on 2017-02-08T16:07:31Z (GMT). No. of bitstreams: 1 Bruno de Oliveira.pdf: 2373684 bytes, checksum: 5f89aaf529fed3c21f21b9c51546d9b8 (MD5) Previous issue date: 2010-08-31 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Analysis between the environmental variability in the pelagic ocean environment, distribution and abundance of the main oceanic fishing resources, have been evaluated in several studies, mainly with the intensification of global climate changes in the recent decades. The main objective of this study was to evaluate the relations between the catches (CPUE) of albacore(Thunnus alalunga) and some environmental parameters, together with spatio temporal data of fishing activities during the period between 1980 and 2007. The fishing data used, including the spatio temporal distribution of effort and catches are referred of long line fleet operations of Brazil (BNDA) and China Taipei (ICCAT). The environmental parameters (SST– Sea Surface Temperature and DML – Depth Mixed Layer) were obtained in international oceanographic data banks. Generalized Additive Models (GAM’s) were used for analyses between CPUE (dependent variable) and the environmental variability. Furthermore, spatio temporal aspect(latitude, longitude, month and year) of fish activity were included, in order to evidence the seasonality in catches. The results obtained show that the environmental variability on oceanographic conditions have a strong influence in the distribution and abundance of albacore, and, consequently, in its catch rate (CPUE). The SST (positive correlation with latitude, for the area of this study) was the most important environmental parameter in catch rates (CPUE). Besides that, we inferred that catches received a positive influence in areas where the thermocline is more superficial and there is a seasonal pattern in the distribution and abundance characteristic. These aspects seem to be in relation with the migratory movements of this specie in the South Atlantic Ocean, including the concentration along the Brazilian coast for spawn in austral summer. / Relações entre a variabilidade ambiental do ambiente pelágico oceânico e a distribuição e abundância relativa dos principais recursos pesqueiros oceânicos, vêm sendo avaliadas em diversos estudos, principalmente com a intensificação dos processos de mudanças climáticas, ocorridos em décadas recentes. O objetivo principal deste estudo foi avaliar a relação entre a captura (CPUE) da albacora branca (Thunnus alalunga) e algumas variáveis ambientais, juntamente com dados espaço-temporais da atividade pesqueira, referentes ao período compreendido entre 1980 e 2007. Os dados de pesca utilizados, incluindo a distribuição espaço-temporal do esforço de pesca e das capturas, são referentes à operação da frota espinheleira do Brasil (Banco Nacional da Pesca de Atuns e Afins) e de China Taipei (International Comission for Conservation of Atlantic Tunas, em inglês). Os dados ambientais (TSM – Temperatura da Superfície do Mar e PCM – Profundidade da Camada Mistura) foram obtidos de bancos internacionais de dados oceanográficos. Modelos Aditivos Generalizados (GAM’s) foram utilizados para averiguar as relações entre o rendimento pesqueiro, expresso através da CPUE (variável dependente), e à variabilidade ambiental. Além disto, aspectos espaço-temporais (latitude, longitude, mês e ano) foram incorporados, de modo a evidenciar a sazonalidade das capturas na área do estudo. Os resultados obtidos mostram que à variabilidade ambiental do ambiente oceanográfico influencia fortemente à distribuição e abundância da espécie e, consequentemente, das capturas. A TSM (correlação positiva com a latitude, para a área de estudo) foi o fator ambiental que mais influenciou a CPUE. Além disto, podemos inferir que as capturas sofrem influência positiva em áreas com a termoclina mais próxima da superfície aquática e que existe um padrão sazonal de distribuição e abundância bem marcado. Estes aspectos parecem estar relacionados com o padrão migratório da espécie no Atlântico sul, incluindo a concentração da mesma ao largo da costa brasileira para fins reprodutivos, durante o verão austral.
7

Biologia reprodutiva da albacora Bandolim (Thunnus Obesus) no oceano Atlântico Oeste Tropical

FIGUEIREDO, Marina Bezerra 23 February 2007 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-16T14:56:11Z No. of bitstreams: 1 Marina Bezerra Figueiredo.pdf: 4281028 bytes, checksum: 769a66f89e02f5c1359899b741605fea (MD5) / Made available in DSpace on 2017-02-16T14:56:11Z (GMT). No. of bitstreams: 1 Marina Bezerra Figueiredo.pdf: 4281028 bytes, checksum: 769a66f89e02f5c1359899b741605fea (MD5) Previous issue date: 2007-02-23 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The study presents information about the reproductive characterísticas of bigeye tuna (Thunnus Obesus0. Were obtained 1082 samples of this species in the tropical Western Atlantic between July of 2004 and June of 2006. Were realized 873 (522 females and 351 males) histological cuts and observations of the present oocytes, analyzed with microscopy to determine the stage of gonadal development. For the females were determined 5 maturational stages: immature, initial and advanced maturation, spawning and resting. The fork length of the samples varied from 62 to 210 cm, and the sexual ratio was 1.46:1 (female:male). The females of bigeye tuna with high values of Gonadossomatic Index associated with advanced maturation were found during the first trimester, suggesting that this species has bigger reproductive activity in this period.The L for females was 92.8 cm and the males 82.1 cm. The estimate mean fecundity through hydrated oocytes counting for this species was 3,971,328 oocytes. / O presente estudo fez um levantamento sobre as características reprodutivas da albacora bandolim (Thunnus Obesus). Para isso, foi obtido um total de 1082 amostras de gônadas da presente espécie no Atlântico oeste Tropical entre julho de 2004 e junho de 2006. foram realizados 873 (522 fêmeas r 351 machos) cortes histológicos e observações dos ovócitos presentes, analisados microscopicamente para determinação das fases de desenvolvimento gonadal. Para as fêmeas foram determinados 5 estágios maturacionais: maturo, maturação inicial e avançada, desovado e em repouso. O comprimento zoológico dos exemplares variou de 62 210 cm, e a proporção sexual foi de 1,46 fêmeas para um macho. A relação entre o Índice Gonadal e exemplares em maturação avançada mostrou que a albacora bamdolim parece possuir maior atividade reprodutiva no primeiro trimestre do ano. O tamanho de primeira maturação sexual para as fêmeas foi de 92,8 cm, já para os machos esse valor foi menos, 82,1 cm. A fecundidade média estimada através da contagem de ovócitos hidratados para a presente espécie foi de 3.971.328,13 ovócitos.
8

The biology, ecology and exploitation of longtail tuna, Thunnus tonggol (Bleeker) in Oceania

Wilson, M. A (Marc A.) January 1982 (has links)
"June 1981" / Thesis (M.Sc.)--Macquarie University, School of Biological Sciences, 1982. / Bibliography: leaves 176-185. / This study was undertaken at the behest of the Papua New Guinea Government in 1973 and extended to 1978. It aimed at elucidating the various aspects of the life history of longtail tuna Thunnus tonggol with a consideration of the factors influencing distribution, relative abundance and exploitation. During this period, 414 tagged fish were released with an overall recapture rate of 8.6% being recorded. Age at first maturity was established at approximately 60 cm for both sexes with a spring-summer spawning being postulated on the basis of gonadal development as evidenced by increasing gonadal indices. No significant departure from the 1:1 sex ratio was observed. -- Von Bertalanffy growth eguations were derived from the reading of increments on sagittal otoliths and modal progression analysis, and yielded respectively:- Lt = 131.8 [1-e⁻·³⁹⁵ ⁽t⁻·⁰³⁵⁾] and Lt = 122.91 [1-e⁻·⁴¹ ⁽t⁻·⁰³²⁾] Both curves were consistent with growth indications from tag recoveries. The predictive length-weight relationship was determined to be ln(Wt) = -9.67+2.656 ln(L.C.F.) and no significant differences existed between the sexes. -- Longtail were shown to be opportunistic feeders: fish constituted the major portion of the diet and increased in accord with longtail size. It is postulated that longtail undergo longshore migrations due to thermal requirements and that these allowed for a hypothetical spawning site around the Aru Island region - an acknowledged nutrient rich area during spring. Both morphometric and biochemical analyses failed to establish the existence of an eastern and western Australian longtail tuna population although there is strong evidence to suggest that sub-specific differences occur between Malaysian and Australian-P.N.G. stocks. -- The exploitation of longtail at three levels; artisanal, amateur and commercial are reported. Concern is expressed as to the lack of data collection and collation of the Taiwanese gillnet fleet operating in the Australian Fishing Zone and about the exploitation of pre-adult longtail tuna. Accordingly, recommendations are made to alleviate the statistical problems and that consideration be given to a detailed study of the fishing parameters which affect the population dynamics of longtail tuna. The latter recommendation in particular should examine the impact that the foreign operated fishery has had on the stocks in Oceania. / Mode of access: World Wide Web. / ix, 195 leaves ill., maps
9

Determinação da origem e conectividade da população da albacora laje, Thunnus albacares (Bonnaterre, 1788) no atlântico equatorial

ROQUE, Pollyana Christine Gomes 15 May 2015 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-11-06T13:42:40Z No. of bitstreams: 1 Pollyana Christine Gomes Roque.pdf: 583107 bytes, checksum: e0225cd4330d9aa9481ff4809d92f859 (MD5) / Made available in DSpace on 2017-11-06T13:42:40Z (GMT). No. of bitstreams: 1 Pollyana Christine Gomes Roque.pdf: 583107 bytes, checksum: e0225cd4330d9aa9481ff4809d92f859 (MD5) Previous issue date: 2015-05-15 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The yellowfin tuna, Thunnus albacares (Bonnaterre, 1788), is a pelagic species of the Scombridae family that is distributed throughout the tropical and subtropical waters of the three oceans. Characterized by the yellow coloration of its fins and finlets, it is usually found close to the surface, in waters with high productivity and warm temperatures, being mainly targeted by pelagic longliners and purse seiners. The yellowfin tuna displays a marked migratory behavior, which hinders the understanding of their movements between spawning, nursery and feeding areas. In order to ensure the conservation of exploited populations, it is fundamental to determine the size distribution and length at age of the individuals caught. The use of trace elements in the analysis of the stock structure can assist in reconstructing the life history, origin and connectivity of various species. In the present study, in order to assess the degree of connectivity between the specimens caught in the eastern and western sides of the West and Central Equatorial Atlantic, the otoliths of 20 specimens with fork lengths (FL) ranging between 37 cm and 57 cm were analyzed. For this purpose, an ablation laser system coupled to a mass spectrometer through plasma induction (LA ICPMS) was used to measure the concentration of various trace elements: 7Li, 24Mg , 55Mn, 88Sr, 137Ba, 44Ca- from an average of five ablation points to the core of each randomly chosen otolith. A Multivariate Analysis of Variance (MANOVA) and a Quadratic Discriminant Function Analysis (QDFA), along with univariate tests, were performed with the SYSTAT 13 software. The catch sites, which included the Saint Peter and Saint Paul Archipelago- SPSPA (10), the Gulf of Guinea (5) and Cape Verde (5), were discriminated with high accuracy, with a rate of 85% being correctly classified. The spatial comparison of trace elements suggests a significant variation between regions (p ≤ 0.05), with canonical scores equal to 0.172 in Brazil and 0.758 for Africa. The Wilk's Lambda test (0.386) was significant indicating that the concentration of the elements differed between the two regions showing that the individuals examined must have originated from chemically and/ or geographically distinct areas. / A albacora laje Thunnus albacares (BONNATERRE, 1788) é uma espécie pelágica da família Scombridae que se distribui em águas tropicais e subtropicais dos três oceanos. Caracterizada pela coloração amarelada de suas nadadeiras e pínulas, é normalmente encontrada na camada superficial, em águas com alta produtividade e elevada temperatura. Um dos principais alvos da frota pesqueira de espinhel pelágico e de rede de cerco, a espécie apresenta um comportamento altamente migratório o que dificulta a compreensão de seus movimentos entre áreas de desova, berçário e alimentação. Um aspecto fundamental para a conservação de populações explotadas pela pesca, contudo, é a determinação da distribuição de tamanhos e a variação dos comprimentos individuais em função da idade. A utilização de elementos traço na análise de estrutura dos estoques explotados pode auxiliar na reconstrução da história de vida, origem e conectividade de diversas espécies. No presente trabalho, foram analisados os otólitos de 20 indivíduos, com comprimento zoológico (CZ) variando entre 37 cm e 57 cm, para se avaliar o grau de conectividade entre os exemplares capturados no Atlântico Equatorial Oeste e Central. Para este fim, um sistema de ablação a laser ligado a um espectrômetro de massa por indução de plasma (LA ICPMS) foi utilizado para se medir à concentração dos elementos traços: 7Li, 24Mg, 55Mn, 88Sr, 137Ba, e 44Ca, a partir de uma média de cinco pontos de ablação para o núcleo de cada otólito escolhido aleatoriamente. Uma Análise Multivariada de Variância (MANOVA) e uma Análise Discriminante da Função Quadrática (QDFA), além de testes de univariância, foram efetuadas para determinar os locais de captura, que incluíram o Arquipélago de São Pedro e São Paulo- ASPSP (10), o Golfo da Guiné (5) e Cabo Verde (5). A acurácia da classificação foi de 85% e a comparação espacial dos elementos traços sugeriu uma variação significante entre as regiões (p ≤ 0,05), com escores canônicos iguais a 0,172 para região do Brasil e de 0,758 para a da África. O teste Wilk’s Lambda (0,386) foi significativo indicando que a concentração dos elementos difere entre as duas regiões evidenciando que os indivíduos analisados devem ter se originado de áreas quimicamente e/ ou geograficamente distintas.
10

Reprodução da albacora branca Thunns alalunga (Bonnaterre, 1788) capturada pela frota brasileira Espinheleira no Oceano Atlântico Sudoeste

PEDROSA, Vanessa Baptista 28 June 2011 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-22T16:09:14Z No. of bitstreams: 1 Vanessa Baptista Pedrosa.pdf: 733342 bytes, checksum: 553e5fd04a4d2eccb1338f8210bc81ba (MD5) / Made available in DSpace on 2017-02-22T16:09:14Z (GMT). No. of bitstreams: 1 Vanessa Baptista Pedrosa.pdf: 733342 bytes, checksum: 553e5fd04a4d2eccb1338f8210bc81ba (MD5) Previous issue date: 2011-06-28 / Albacore is one of the main species of tuna caught in the South Atlantic for tuna Brazilian fishing vessel. Moreover, it has a little knownledge available about albacore biology in this portion of Atlantic Ocean, mainly regard to reproduction, aim of this study. Histological analysis of 735 gonads (370 males and 365 females)captured in the southwest atlantic were conducted during 2005 to 2010. Fork length of specimens ranged from 89 cm to 138 cm. Gonad index was determined monthly and observed the spawning activity from September to March. also, females exhibiting hydrated oocytes and post ovulatory follicles indicating an imminent spawning stage and post spawning, respectively.The sex ratio prior the reproductive period was 1:1 (males:females) with males mainly in the larger length classes (> 114 cm FL). At the first sexual maturity the length was 92 cm for females and 100 cm for males. The batch fecundity ranged from 0.5 to 1.2 million oocytes with approximately 3.700 oocytes/g. The oocyte diameter frequency showed a parceled spawning due to the occurrence of successives modes of unyolked oocytes, yolked and hydrated. These results contribute with information about the reproduction of the species in the South Atlantic both these life history parameters will allow to assess the albacore stock from this region. / A albacora branca é uma das principais espécies de atuns capturadas no Atlântico sul pela frota atuneira brasileira. Entretanto, pouco é conhecido sobre a biologia da espécie nesta parte do Atlântico, principalmente no que se refere à reprodução, objetivo do presente estudo. Análises histológicas das gônadas de 735 indivíduos de Thunnus alalunga (370 machos e 365 fêmeas) capturados no Atlântico Sudoeste foram realizadas no período de 2005 a 2010. O comprimento dos espécimes variou de 89 cm a 138 cm. Através do acompanhamento mensal do índice gonadal foi observada atividade de desova entre os meses de outubro a março, com fêmeas apresentando ovócitos hidratados e folículos pós-ovulatórios, indicando iminente estado de desova e pós-desova, respectivamente. A proporção sexual anterior ao período reprodutivo entre machos e fêmeas foi de 1:1, com os machos predominando nas maiores classes de comprimento (> 114 cm CF). O tamanho de primeira maturidade sexual determinado para as fêmeas foi de 92 cm e para os machos de 100 cm. A fecundidade variou de 0,5 a 1,2 milhões de ovócitos com cerca de 3.700 ovócitos/g. Pela freqüência do diâmetro dos ovócitos de fêmeas (37 - 1200 μm) foi verificada a desova do tipo parcelada devido a ocorrência de modas sucessivas de ovócitos avitelogênicos, vitelogênicos e hidratados. Esses resultados contribuem com informações sobre a reprodução da espécie no Atlântico Sul que junto com outros parâmetros do seu clico de vida permitirá avaliar o estoque dessa região.

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