No description available.

Patterns of genetic connectivity can help answer key questions about the evolutionary ecology of fishes. This knowledge is particularly useful when considering the management and conservation of species that are impacted by fisheries. Population connectivity in ocean habitats is heavily influenced by environmental and oceanographic factors. These factors can lead to strong genetic differences within populations, causing fragmentation into smaller subpopulations. The Red Sea exhibits pronounced oceanographic gradients in temperature, chlorophyll, and salinity, which have been assessed in various species’ populations and which have been found to have potential impacts on gene flow. The Red Sea also features strong cyclonic and anticyclonic eddies that may facilitate, or possibly inhibit, the transport of larvae throughout the Red Sea, potentially influencing gene flow themselves. The ability of oceanographic factors like eddies to structure wild fisheries populations in this region has yet to be fully determined. To address this, the genetic composition of two of the most highly fished species, (Plectropomus areolatus and Plectropomus pessuliferus marisrubri), in the Red Sea were evaluated utilizing genetic markers (polymorphic microsatellite loci). Samples from three geographically separate regions along the Saudi Arabian Red Sea coastline, as well as from Sudan, were analyzed to address latitudinal and cross-sea connectivity. I was able to determine that little genetic differentiation exists within Plectropomus species across all regions of the Red Sea, indicating high gene flow for these species throughout. These findings highlight the ability of currents and eddies to transport larvae along and across the Red Sea. The results from this study also indicate that a single population of P. areolatus and a single population of P. pessuliferus marisrubri occurs in the Red Sea. The high degree of genetic flow suggests that each species should be managed as individual units. This study presents a plausible avenue for buffering the effects of overfishing currently occurring in Saudi Arabia; Saudi Arabian fish subpopulations may be reseeded by the Sudanese subpopulations.

Orientador: Fernando Fernandes Mendonça / Resumo: Tubarões são organismos amplamente reconhecidos como predadores de topo de cadeia e sua distribuição geográfica associada à capacidade migratória em diversas espécies, principalmente pelágicas, tornam as avaliações e monitorias de suas populações uma tarefa complexa. O tubarão-azul, Prionace glauca, é uma espécie globalmente distribuída e altamente migradora, classificado como “Quase Ameaçado” na Lista Vermelha de Espécies Ameaçadas da IUCN. No entanto, ao longo de sua história, P. glauca vem sendo frequentemente associado a capturas da pesca industrial e, seus registros recentes, apontam declínios relevantes em suas populações em algumas localidades. Dentre o conhecimento necessário para a gestão adequada e conservação de espécies amplamente exploradas, podemos ressaltar que as informações sobre a variabilidade genética e dinâmica populacional são de grande valia, principalmente quando se trata de uma espécie de elevada capacidade de dispersão. Assim, este estudo é o primeiro a caracterizar a biodiversidade molecular e a estrutura populacional desta espécie globalmente, a partir de 534 indivíduos provenientes de diferentes localidades nos oceanos Atlântico, Índico e Pacífico. Utilizando a região controle de DNA mitocondrial (CR), encontramos 43 haplótipos com diversidade Hd=0,778, diversidade de nucleotídeos de π=0,005 e índice de estrutura populacional global de ΦST=0,054 (P=0,0001). Estes resultados indicam que P. glauca está entre as espécies de tubarões com os maiores ín... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sharks are organisms widely recognised as top-chain predators and their geographic distribution associated with migratory capacity in several species, mainly pelagic, make evaluations and monitoring of their populations a complex task. The blue shark (Prionace glauca) is a globally distributed and highly migratory species, classified as "Near Threatened" on the IUCN Red List of Threatened Species. However, throughout its history, P. glauca has been frequently associated with industrial fisheries catches, and its recent records indicate relative declines in their populations in some localities. Among the knowledge necessary for the proper management and conservation of widely exploited species, we can highlight the information about genetic variability and population dynamics are of great value, especially when it is a species of high dispersion capacity. Thus, this study is the first to characterise the molecular biodiversity and population structure of this species globally, from 534 individuals from different locations in the Atlantic, Indian and Pacific Oceans. Using the mitochondrial DNA control region (CR), we found 43 haplotypes with diversity Hd = 0.778, nucleotide diversity of π = 0.005 and a global population structure index of ΦST = 0.054 (P = 0.0001). These results indicate that P. glauca is among the species of sharks with the highest indexes of genetic variability and high gene flow among the oceans, with low geographic delimitation and moderate population struct... (Complete abstract click electronic access below) / Doutor

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-12T12:41:55Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Taciana Martins Barbosa Biblioteca Central.pdf: 2266957 bytes, checksum: c72479b848ff65eb617cd5065338256f (MD5) / Made available in DSpace on 2016-04-12T12:41:55Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Taciana Martins Barbosa Biblioteca Central.pdf: 2266957 bytes, checksum: c72479b848ff65eb617cd5065338256f (MD5) Previous issue date: 2015-08-31 / FACEPE / O octocoral Carijoa riisei é um cnidário colonial que possui ampla distribuição geográfica no Oceano Atlântico Sul, Caribe, Pacífico e Indo-Pacífico. Com intuito de conhecer a estrutura e a conectividade das populações da espécie, abordagens diferentes foram realizadas. Em pequena escala geográfica espacial (6-125 km) a partir de diferentes ambientes (recifes costeiros, naufrágios e estuários) da costa de Pernambuco (Brasil), análises do DNAmt, morfológicas e reprodutivas foram realizadas. Verificou-se que houve variação morfológica em 10 dos 11 caracteres morfológicos avaliados quando comparadas as localidades estudadas. No entanto, não há diferenciação genética entre as sete populações estudadas devido ao alto fluxo gênico, indicando que a espécie em Pernambuco consiste em uma população panmítica. Portanto, a alta variabilidade morfológica de C. riisei encontrada neste estudo é devido à plasticidade fenotípica em resposta às mudanças ambientais e não ao acúmulo de diferenças genéticas devido à interrupção do fluxo gênico entre as populações. Para análise em grande escala geográfica espacial (108-2781 km), o exame da conectividade genética por meio do DNAmt foi realizado em populações do Atlântico Sul/Brasil e comparado com resultados encontrados de outras regiões do Atlântico (Leste e Norte) e do mundo (Pacífico/Havaí e Indo-Pacífico). Estruturação genética foi observada em duas das seis populações estudadas no Atlântico Sul/Brasil. Contudo, foi verificado fluxo gênico suficiente para conectar todas as populações, tanto dentro do Atlântico Sul, como entre as populações desta região com as demais. O Atlântico Sul apresentou a maior diversidade genética entre todas as regiões do Atlântico estudadas. Quando a comparação é realizada entre as regiões geográficas do mundo, a maior diversidade genética foi encontrada no Indo-Pacífico e a menor no Atlântico Norte. De acordo com esses resultados e aliado com o que existe na literatura, encontra-se suporte à ideia de que C. riisei é nativa do Indo-Pacífico. A conectividade genética das populações em organismos sésseis é alcançada pela dispersão larval. Este estudo descreve pela primeira vez a embriogênese, desenvolvimento e assentamento larval de C. riisei. Foram recolhidas colônias na costa norte de São Paulo, Brasil e mantidos vivos em aquários. Através da observação direta, verificou-se que a liberação dos gametas predominantemente ocorreram entre 05h00-10h00. A fertilização é externa e os ovos fertilizados tem um diâmetro médio de 403 ± 6,0 μm, apresentando geralmente flutuabilidade positiva. As clivagens são superficiais, o primeiro ciclo de divisão ocorre perto de 3h30-5 h após a liberação dos gametas. A divisão citoplasmática é rápida (15-20 min), facilmente visível nas fases de 16 e 32 células. As larvas plânulas são formadas entre 27-36 h após a liberação dos gametas; podem nadar por toda a coluna dágua e atingir 1,8 mm de comprimento. As plânulas assentam entre 10-18 dias após a liberação dos gametas. O pólipo primário é translúcido, e os tentáculos emergem como oito pequenos botões arredondados. Portanto, a espécie tende a ter um potencial de dispersão de longa distância, que aliado ao nível considerável de variação morfológica (que favorece a adaptação da espécie em condições ecológicas heterogêneas) e a conectividade ocorrendo entre populações em pequena e grande escala geográfica espacial, auxiliam a compreender a ampla distribuição deste octocoral. / The octocoral Carijoa riisei is widely spread in the South Atlantic Ocean, Caribbean, Pacific and Indo-Pacific. Seeking to know the structure and connectivity of populations of the species, different approaches have been undertaken. In small spatial geographic scale (6-125 km) from different environments (coastal reefs, shipwrecks and estuaries) from the coast of Pernambuco (Brazil), analysis of mtDNA, morphological and reproductive were held. It was found that there is morphological variation in 10 of 11 morphological characters evaluated when compared the locations studied. However, there is no genetic differentiation among the populations studied due to high gene flow, indicating that the species in Pernambuco consists of a panmitic population. Therefore, the high morphological variability of C. riisei found in this study is due to phenotypic plasticity in response to environmental changes and not the accumulation of genetic differences due to the interruption of gene flow between populations. For analysis in large spatial geographic scale (108-2781 km), examination of genetic connectivity through mtDNA was held in South Atlantic/Brazil populations and compared with results from other regions of the Atlantic (East and North) and the world (Pacific/Hawaii and Indo-Pacific). Genetic structure was observed in two of the six studied populations in the South Atlantic/Brazil. However, it was found sufficient gene flow to connect all populations, both within the South Atlantic, as among populations of this region with others. The South Atlantic showed the highest genetic diversity among all regions of the Atlantic studied. When a comparison is performed among the geographic regions of the world, the greatest genetic diversity was found in the Indo-Pacific and the smallest in the North Atlantic. According to these results and allied with what exists in the literature, it supports the idea that C. riisei is native to the Indo-Pacific. Genetic connectivity of populations in sessile organisms is achieved by larval dispersal. This study describes for the first time embryogenesis, development and larval settlement of this octocoral. Colonies were collected on the north coast of São Paulo, Brazil and kept alive in aquariums. Through direct observation, it was found that spawns predominantly occurred in the morning between 05h00-10h00. The fertilization is external and fertilized eggs have an average diameter of 403 ± 6.0 μm, usually presenting positive buoyancy. The cleavages are superficial, the first division cycle occurs near 3h30-5 h after spawning. The cytoplasmic division is rapid (15-20 min), easily visible in stages 16 and 32 cells. The larvae planula are formed 27-36 h after spawning; can swim throughout the water column and reach a length of 1.8 mm. Planulae settle 10-18 days after spawning. The primary polyp is translucent, and the tentacles emerge as eight small round buttons. Therefore, the species tends to have a potential for long-distance dispersal, that coupled with the considerable level of morphological variation (that favors the adaptation of the species in heterogeneous ecological conditions) and connectivity between populations occurring in small and large spatial geographic scale assists to understand the wide distribution of this octocoral.

No description available.

Made available in DSpace on 2015-04-11T13:38:42Z (GMT). No. of bitstreams: 1 Tese Conceicao.pdf: 3479286 bytes, checksum: e423419bc970a5fbce6d4829446d589e (MD5) Previous issue date: 2010-09-24 / Fundação de Amparo à Pesquisa do Estado do Amazonas / The floodplain ecosystem shelters and supports most of the fish stocks of commercial importance, such as the tambaqui, Colossoma macropomum, which is considered a key species of this ecosystem. This fish is the largest characin of the Amazon and it is highly appreciated as food by the local population. Currently the tambaqui represents 70% of the regional pisciculture, but despite increasing aquiculture output, wild populations have been experiencing severe over-exploitation. To manage natural stocks of tambaqui it is necessary to access a range of information from diverse areas of knowledge, including genetics. It is thus of fundamental importance to access levels of genetic variability and how this variability is distributed throughout the Amazon region where the species occurs. This information is necessary to guide management strategies and conservation of this species. To obtain such information, mitochondrial (control region and ATPase gene) and nuclear (microsatellites) molecular markers were used. In this study 14 highly polymorphic microsatellite loci for the tambaqui were developed. These molecular markers were successfully transferred to other species of serrasalmids. For the genetic characterization of the tambaqui, 21 localities in the Amazon basin were sampled. We sequenced 1561pb (control region + ATPase gene) from 539 individuals finding 444 haplotypes, of which 440 were unique. The haplotype diversity was high and relatively homogeneous among all localities, however diversity was smallest in Porto Velho. Data from 12 microsatellite loci were collected from 604 individuals, showing an average of 21,4 alleles per locus. Total HE was 0,78 and heterozygosity levels were homogeneous among sampled localities. Porto Velho and Guaporé showed lower values of HE. These results suggest high levels of genetic variability in the tambaqui. AMOVA and other tests to detect population structure based on both markers indicated that within the Brazilian Amazon basin, the tambaqui comprises a single large population, supported by high gene flow between localities. These results indicate that species management in this area can be unified. Considering the entire sampling scheme, the data suggest a metapopulation scenario between the Brazilian and Bolivian basins, with low genetic differentiation between the basins and restricted gene flow due to isolation by distance. The rapids of the Tapajós and Madeira Rivers are not barriers to gene flow among population samples of tambaqui. A demographically stable population was detected in the Bolivian basin and a historical demographic expansion in the Amazon basin, supported by the large number of haplotypes and the presence of unique alleles in Brazilian localities. The migration rates were higher from white water tributaries to the main channel, while the opposite was true for the clear waters of Tapajós River. The effective population size (Ne) was greater in the channel, and in Jacareacanga and Boca do Acre. Genetic effects of over-exploitation were not detected in the tambaqui due to the high genetic diversity found. However, these findings are showing the historical status compatible with a large effective population size of the species in the past since the time of over-exploitation is still be short to be registered genetically. / O ecossistema de várzea amazônica abriga e sustenta a maior parte dos estoques de peixes de importância comercial, como o tambaqui Colossoma macropomum. Este peixe é o maior caracídeo da Amazônia e é muito apreciado como alimento pela população local. Atualmente corresponde com 70% da piscicultura regional, mas apesar da crescente produtividade cultivada, esta espécie na natureza vem experimentando uma intensa sobre-exploração. Para gerenciar os estoques naturais de tambaqui é necessário acessar um conjunto de informações de diversas áreas do conhecimento e, concernente à genética, é de fundamental importância acessar a variabilidade genética e a forma como esta variabilidade está distribuída ao longo da região Amazônica. Estas informações são importantes para direcionar estratégias de manejo e conservação para espécie. Para obter tais informações, foram utilizados marcadores moleculares mitocondriais (região controle e gene da ATPase) e nucleares (microssatélites). No presente estudo foram isolados 14 locos de microssatélites altamente polimórficos para tambaqui. Estes marcadores moleculares foram transferidos com sucesso para outras espécies de serrasalmídeos. Para a caracterização genética do tambaqui, 21 localidades foram amostradas na bacia Amazônica, e 1561 pb (região controle + gene da ATPase) foram seqüenciados em 539 indivíduos. Foram encontrados 444 haplótipos, sendo que 440 foram únicos. A diversidade haplotípica foi alta e relativamente homogênea para todas as localidades, mas foi menor em Porto Velho. Para dados de microssatélites foram utilizados 12 locos em 604 indivíduos, sendo encontrada uma média de 21,4 alelos por loco. A HE total foi de 0,78, sendo em geral, homogênea para as localidades amostrada. Para Porto Velho e Guaporé a HE apresentou os menores valores. Estes resultados sugerem altos níveis de variabilidade genética em tambaqui. AMOVA e as demais análises para detectar estrutura populacional, com base em ambos marcadores, indicaram que dentro da bacia Amazônica brasileira o tambaqui forma uma única e grande população, suportado por um intenso fluxo gênico entre as localidades. Estes resultados indicam que o manejo da espécie nesta área pode ser unificado. Considerando toda a amostragem do estudo, evidenciou-se um cenário de metapopulação entre as bacias hidrográficas brasileiras e bolivianas. As corredeiras presentes nos rios Tapajós e Madeira não representam uma barreira ao fluxo gênico entre as amostras populacionais de tambaqui. Uma estabilidade populacional foi detectada para a bacia Boliviana e uma expansão para a bacia Amazônica, suportado pelo grande número de haplótipos únicos e a presença de alelos exclusivos nas localidades brasileiras. As taxas de migração foram maiores das localidades dos tributários de água branca para a calha principal, e desta para o rio Tapajós. Os dados genéticos podem estar configurando a migração reprodutiva ou uma dinâmica nos movimentos da espécie. O tamanho efetivo populacional (Ne) foi maior na calha principal, no rio Tapajós e no rio Purus. Não foram detectados sinais de sobreexploração devido à alta diversidade genética encontrada. No entanto estes achados podem estar mostrando um status histórico da espécie compatível a um enorme tamanho efetivo populacional no passado ou que o tempo de sobreexploração pode ainda ser curto para um registro genético.

Made available in DSpace on 2015-03-03T14:00:59Z (GMT). No. of bitstreams: 1 AllysonSS_DISSERT.pdf: 3119890 bytes, checksum: 5de05e8e42f3274421226e677a37e4ea (MD5) Previous issue date: 2011-04-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Brazil has about 8,500 km of coastline and on this scale, fishing is a historically important source of animal protein for human consumption. The national fishing background shows a growth of marine fishery production until 1985 and within this period it was recorded a steady decline. From the year 2003 fishing statistics aim to some "recovery" of the total fisheries production, which probably is related to a change in industry practice. The target of commercial fishing became smaller species with low commercial value, but very abundants. The coney, Cephalopholis fulva (Serranidae), is one of these species that have been suffering a greater fishing pressure in recent years. In order to provide data about the current situation of the genetic diversity of these populations, several molecular markers have been being used for this purpose. The prior knowledge of genetic variability is crucial for management and biodiversity conservation. To this end, the control region sequences (dloop) of mtDNA from Cephalopholis fulva (Serranidae) from five geographical points of the coast of Brazil (Cear?, Rio Grande do Norte, Bahia and Esp?rito Santo) and the Archipelago of Fernando de Noronha (FN) were sequenced and their genetic diversity analyzed. The FST values were very low (0.0246 to 0.000), indicating high gene flow between the sampled spots. The indices h and indicate a secondary contact between previously allopatric lineages differentiated or large and stable populations with long evolutionary history. Tests of Tajima and Fu showed expansion for all populations. In contrast, the mismatch distribution and SSD indicated expansion just for coastal populations. Unlike other species of the Atlantic which have been deeply affected by events on later Pleistocene, the population-genetic patterns of C. fulva may be related to recent events occurred approximately 130,000 years ago. Moreover, the data presented by geographical samples of the specie C. fulva showed high genetic diversity, also indicating the absence of deleterious effects of over-exploitation on this specie, as well as evidence of complete panmixia between all sampled populations / Brasil possui cerca de 8.500 km de litoral e diante desta dimens?o, a pesca historicamente constitui uma importante fonte de prote?na animal para consumo humano. O hist?rico nacional na pesca mostra um crescimento da produ??o pesqueira marinha at? 1985 e a partir deste per?odo registrou-se um cont?nuo decr?scimo. A partir do ano de 2003 as estat?sticas pesqueiras apontam para certa ?recupera??o? da produ??o pesqueira total, o que provavelmente esta relacionada a uma mudan?a nas pr?ticas do setor. O alvo da pesca comercial passou a ser esp?cies menores e de baixo valor comercial, por?m muito abundantes. A pira?na, Cephalopholis fulva (Serranidae) ? uma destas esp?cies alvo que vem sofrendo uma maior press?o pesqueira nos ?ltimos anos. A fim de fornecer dados sobre a real situa??o da diversidade gen?tica destas popula??es, diversos marcadores moleculares v?m sendo utilizados para esta finalidade. O pr?vio conhecimento da variabilidade gen?tica ? crucial para o manejo e conserva??o da biodiversidade. Neste intuito, sequ?ncias da regi?o controle (d-loop) do DNAmt de Cephalopholis fulva (Serranidae) de cinco pontos geogr?ficos da costa brasileira (Cear?, Rio Grande do Norte, Bahia e Esp?rito Santo) e o Arquip?lago de Fernando de Noronha (FN) foram sequenciadas e sua diversidade gen?tica analisada. Os valores de FST se revelaram muito baixos (0.0246 a 0.000), indicando intenso fluxo g?nico entre os pontos amostrados. Os ?ndices h e indicam um contato secund?rio entre linhagens alop?tricas previamente diferenciadas ou a grandes e est?veis popula??es com longa hist?ria evolutiva; Os testes de Fu e Tajima indicaram expans?o para todas as popula??es. J? as diferen?as par-a-par e o SSD indicaram expans?o apenas para as popula??es costeiras. Diferentemente de outras esp?cies do Atl?ntico que foram profundamente afetadas por eventos Pleistoc?nicos mais tardios, os padr?es gen?tico-populacionais presentes em C. fulva parecem estar relacionados a eventos mais recentes ocorridos a cerca de 130.000 anos. Al?m disso, os dados apresentados pelas amostras geogr?ficas da esp?cie C. fulva demonstram elevada diversidade gen?tica, indicando ainda a aus?ncia de efeitos delet?rios da sobrepesca da esp?cie, bem como evid?ncias de panmixia plena tanto entre as ?reas continentais, como entre estas e o regi?es insulares

<p>Although the practice of releasing fish into the wild is common in the management and conservation of fish populations, the success of release programmes and the potential harmful genetic and ecological effects that may follow are rarely considered. This thesis focuses on genetic and ecological consequences of fish releases, exemplified by supportive breeding of brown trout (<i>Salmo trutta</i>) and translocation of European eel (<i>Anguilla anguilla</i>). Specific questions addressed include: What is the relative performance of hatchery produced fish released to support wild populations, and do released hatchery fish contribute to the natural productivity? What is the variation in reproductive success in the wild, and how does it affect the genetic consequences of a supportive breeding programme? Is there a spatial genetic structure in the European eel that must be considered in the management of this rapidly declining species?</p><p>Experiments conducted under natural and near-natural conditions in the River Dalälven, Sweden, suggest that hatchery produced trout can reproduce in the wild. In fact, when the pronounced variation between individual breeders was accounted for, there were no detectable differences between hatchery produced and wild born trout in reproductive success or offspring survival. These results were supported by molecular genetic data suggesting a pronounced gene flow from hatchery to wild trout in the river. Hatchery reared trout were, however, found to exhibit reduced survival rates immediately following release into the wild, an effect that was most likely due to phenotypic responses to the hatchery environment during ontogeny and a lack of experience of the wild.</p><p>In sharp contrast to recently published studies, the present genetic analyses of European eels sampled across the whole distribution range suggest no spatial genetic structure but a subtle temporal genetic heterogeneity within sampled locations. These results emphasise the need to consider temporal replication when assessing population structure of marine species.</p><p>The results obtained have general implications for the management and conservation of fish populations. First, supportive breeding of threatened salmonid populations might be successful, not only for boosting the census size and thereby reducing the short-term probability of extinction, but also for reducing the risks of inbreeding depression and loss of adaptive potential in future generations. However, the results also highlight the need to restore the natural productivity of a population under supportive breeding to avoid a potential reduction in fitness due to hatchery selection. Further, the lack of a detectable spatial genetic structure in the European eel suggests that the management strategy of translocating juvenile eels from locations were they are overabundant to other suitable freshwater habitats does not necessarily have to include genetic considerations with respect to the geographical origin of the translocated eels.</p>

Although the practice of releasing fish into the wild is common in the management and conservation of fish populations, the success of release programmes and the potential harmful genetic and ecological effects that may follow are rarely considered. This thesis focuses on genetic and ecological consequences of fish releases, exemplified by supportive breeding of brown trout (Salmo trutta) and translocation of European eel (Anguilla anguilla). Specific questions addressed include: What is the relative performance of hatchery produced fish released to support wild populations, and do released hatchery fish contribute to the natural productivity? What is the variation in reproductive success in the wild, and how does it affect the genetic consequences of a supportive breeding programme? Is there a spatial genetic structure in the European eel that must be considered in the management of this rapidly declining species? Experiments conducted under natural and near-natural conditions in the River Dalälven, Sweden, suggest that hatchery produced trout can reproduce in the wild. In fact, when the pronounced variation between individual breeders was accounted for, there were no detectable differences between hatchery produced and wild born trout in reproductive success or offspring survival. These results were supported by molecular genetic data suggesting a pronounced gene flow from hatchery to wild trout in the river. Hatchery reared trout were, however, found to exhibit reduced survival rates immediately following release into the wild, an effect that was most likely due to phenotypic responses to the hatchery environment during ontogeny and a lack of experience of the wild. In sharp contrast to recently published studies, the present genetic analyses of European eels sampled across the whole distribution range suggest no spatial genetic structure but a subtle temporal genetic heterogeneity within sampled locations. These results emphasise the need to consider temporal replication when assessing population structure of marine species. The results obtained have general implications for the management and conservation of fish populations. First, supportive breeding of threatened salmonid populations might be successful, not only for boosting the census size and thereby reducing the short-term probability of extinction, but also for reducing the risks of inbreeding depression and loss of adaptive potential in future generations. However, the results also highlight the need to restore the natural productivity of a population under supportive breeding to avoid a potential reduction in fitness due to hatchery selection. Further, the lack of a detectable spatial genetic structure in the European eel suggests that the management strategy of translocating juvenile eels from locations were they are overabundant to other suitable freshwater habitats does not necessarily have to include genetic considerations with respect to the geographical origin of the translocated eels.

Šio darbo metu naudojant 5 mikrosatelitinius DNR žymenis buvo bandoma išsiaiškinti, ar į Lietuvą natūraliai atplaukiantys upiniai unguriai skiriasi nuo į Lietuvą introdukuotų upinių ungurių genetiškai. Vietines Anguilla anguilla populiacijas atstovavo Baltijos jūros ir Kuršių marių imtys, o introdukuotas – Dringio ir Siesarčio ežerų imtys. Tikrinama buvo, tiek izoliacijos dėl atstumo (IBD), tiek laikinės izoliacijos (IBT), įtaka A. anguilla genetinei diferenciacijai. Nors genetinė diferenciacija tarp didžiosios dalies lyginamų imčių buvo maža (FST = 0,0042) ir nepatikima (p > 0,05), tačiau remdamiesi gautais tyrimo rezultatais negalime patvirtinti panmiksinės hipotezės A. anguilla rūšyje, kadangi mažos (FST = 0,0143) ir patikimos (p = 0,0018) genetinės diferenciacijos nustatymas tarp Siesarčio ežero introdukuotų upinių ungurių leidžia teigti, kad genetinė diferenciacija Anguilla anguilla rūšyje egzistuoja. / In order to find out whether native and introduced Anguilla anguilla populations differ one from another genetically I have used 5 microsatellite markers and compared 2 native between 2 introduced European eel samples. Native A. anguilla samples were taken from Baltic sea and Curonian lagoon, while introduced samples were taken from Dringis and Siesartis lakes. During this work I tried to find out not only IBD, but also IBT impact to A. anguilla genetic differentiation. Experiment results do not reject panmixia hypothesis in European eel, because there are small (FST = 0,0042) and not significant (p > 0,05) genetic differentiation among all samples used in this experiment. However, there is no enough data to say that A. anguilla genetic differentiation does not exist at all, because there is small (FST = 0,0143) and significant (p = 0,0018) genetic differentiation among lake Siesartis samples.