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Sammanfattning Dammutrivningar blir alltmer vanligt på grund av att många är föråldrade och kostar mer att driva och underhålla än vinsten de ger i energi. Effekten av utrivningar på halten miljögifter i fiskar är relativt okänd, men det finns observationer som indikerar att det dammutrivningar kan minska kvicksilverhalten i fiskar. Syftet med min studie var att undersöka skillnaderna i kvicksilverhalten hos gädda (Esox lucius), mellan sjöar som har fått dammen i sjöutloppet utriven respektive dammen intakt. Jag undersökte 66 provtagningar från 18 oligotrofa svenska skogssjöar. I sjöar där dammutrivning skett innehöll en medelstor gädda 500 ng/g kvicksilver, medan motsvarande värde i sjöar med dammen intakt var 740 ng/g kvicksilver. Det fanns ingen signifikant effekt av vare sig antal år efter utrivning eller provtagningsår. Kvicksilverhalten var nära förknippad med gäddans längd och varierade mellan sjöar, och i fyra av sjöarna, översteg mätningarna 1000n ng/g (gränsvärdet för konsumtion inom EU) medan gäddor från de andra sjöarna hade värden som mestadels under detta gränsvärde. / Abstract Dam removals are becoming increasingly common because many are outdated and cost more to operate and maintain than the value of that they provide in energy. The effect of dam removal on the level of environmental toxins in fish is relatively unknown, but there are observations that indicate that dam removal can reduce mercury concentrations in fish. The aim of my study was to investigate differences in the mercury concentration of pike (Esox lucius) between lakes that have had their outlet dams removed and those that have their dams intact. I examined 66 samples from 18 oligotrophic Swedish forest lakes.n lakes where the dam had been removed, a pike of average length contained 500 ng/g mercury, whereas the corresponding value for lakes with the dam intact was 740 ng/g of mercury. There was no significant effect of the number of years after removal or sampling year. The mercury concentration was closely associated to pike length and varied between the lakes, and in four of the lakes, all measurements exceeded 1000 ng/g (the limit value for consumption in EU), whereas most pike from the other lakes had values below this limit value.

The diploma thesis deals with the analysis of particular detective and Gothic elements in Christopher Pike's adventurous series Remember Me. The main aim of the thesis is to analyse themes and motifs of Pike's work with respect to the Gothic tradition and the development of detective prose. The thesis is formally divided into theoretical and practical parts. The theoretical chapter is devoted to the genre of the detective and Gothic literature, as well as metaphysical detective story. The theoretical part is followed by the practical analysis of selected Pike's works. The practical analysis involves the characteristics of the main protagonists and the influence of horror and metaphysical detective elements on the search of individual identity.

Genetic variation is essential for biological evolution, for maintaining viability of populations, and to ensure ecosystem resilience. Increased human exploitation and environmental change result in rapid loss of biological variation, including genetic diversity. Measures to halt this trend require that biological diversity is assessed and monitored. Assessment of biodiversity includes identifying patterns of distribution of genetic variation within individual species. This thesis focuses on spatial genetic structure and assessment of units for conservation in continuous environments without apparent migration barriers. Empirical data refer to Scandinavia and the model species are northern pike (Esox lucius), brown trout (Salmo trutta), and harbour porpoise (Phocoena phocoena). Questions regarding monitoring genetic diversity and releases of alien populations are also addressed.  The spatial genetic structure of the northern pike in the Baltic Sea is characterized by isolation by distance and continuous genetic change. Positive genetic correlation was found among pike within geographical distances of less than 150 km. This distance may be used to suggest management units in this area. For the brown trout, genetic monitoring identified two sympatric populations within a small mountain lake system. The situation is characterized by a clear genetic but no apparent phenotypic dichotomy. Scientific support for a genetically distinct Baltic harbour porpoise population is limited, and the spatial genetic structure of the harbour porpoise in Swedish waters needs to be clarified. Data for launching conservation genetic monitoring programs is available for only a few Swedish species. Millions of forest trees, fish, and birds are released annually in Sweden and the documentation on these releases is poor. To meet responsibilities of safeguarding biodiversity and surveying biological effects of releases, there is an urgent need for studies aimed at evaluating genetic diversity. / At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.

This study determines opinions of two Indiana communities concerning the proposed Patoka River National Wildlife Refuge. Surveys were mailed to residents of Pike County and Noblesville, Indiana. The response rate was 38%. Differences in attitudes were measured between residents of the two areas regarding ten issues of concern. The issues respondents were most concerned with were those focusing on the loss of county tax base, road closings and access, and a possible increase in the mosquito population. Surprisingly, the issues concerning avian diseases and land acquisition/ condemnation were not major concerns. It was originally thought that these issues of employment and property would have been of primary concern to respondents. Residents of Pike County in the affected refuge area were more aware of the refuge and the issues of concern. However, of the respondents who were aware of the refuge in both Pike county and Noblesville, few differences in their perceptions of the issues were noted. / Department of Natural Resources and Environmental Management

Les téléostes, le clade possédant le plus d’espèces parmi les vertébrés, emploient une saisissante diversité de mécanismes de détermination du sexe, incluant des mécanismes génétiques et environnementaux. Des études récentes ont identifié de nombreux nouveaux régulateurs génétiquesdu développement sexual des poissons et ont introduit la notion de “terrain de jeux évolutif”. Le but de ce projet de thèse est de donner une vue complète des dynamiques évolutives des déterminants du sexe dans un ordre de téléostes, les Esociformes. Dans notre espèce focale, Esox lucius, nous avons identifié une duplication d’un membre de la famille des TgfB – une famille qui a émergé en tant que fondamentale dans la régulation du sexe chez les téléostes – comme MSD (gène controlant la détermination du sexe). Nous avons obtenu des preuves fonctionnelles du rôle de ce gène en tant que MSD, de son interaction avec des facteurs environnementaux, ainsi que des nouvelles informations sur les processus évolutifsCe gène est perdu dans une population de la même espèce en Amérique du Nord, mais il est conservé parmi les autres Esociformes. En parallèle, d’autres systèmes de détermination du sexe ont été identifiés dans des espèces proches. De plus, dans des clades plus distants comme Umbra et Dallia, le MSD d’Esox n’est pas présent, et d’autres mécanismes implicants de nouveaux MSD ont été identifiés, complefixiant l’histoire évolutive des MSD dans ce groupe, qui reflète la plasticité génétique observée dans les téléostes en général. / Teleost fishes, the most species-rich clade among vertebrates, employs an astonishing diversity of sex-determining (SD) mechanisms, including environmental and genetic systems. Recent studies identified many new genetic regulators in fish sexual development that lead to the notion of an 'evolutionary playground'.This thesis project aims to provide a complete picture of the evolutionary dynamic of SD systems within a small order of teleost, Esociformes. In our focal species Esox lucius, we idenWhile the gene is lost in another population of the same species rapidly possibly during post-glacial recolonization process, it is well conserved among different species. Meanwhile, additional transition of SD system have also been identified in a sister Esox species. Moreover, in the most distant genera Dallia and Umbra, the Esox master SD gene is not present and we found different SD mechanisms with novel SD genes that adds additional layers of complexity to this group, which mirrors the observed high genetic plasticity in teleost SD

The main objective of this thesis is to describe and experimentally evaluate the possibility of adaptation of pike (Esox lucius L.) in controlled housing conditions and income artificial pelleted feed. The thesis is mainly based on the effect of an initial larval density of pike for adaptation and survival and the growth of larvae reared in the rearing tanks. The experiment consisted of four different densities of larvae (10, 20, 40, 80 pc of the larvae l??, which were always repeated three times. Two experiments were performed (M, H), with a length of rearing of five days. Rearing itself was conducted in twelve circular tanks with a capacity of 180 l??, the recirculation system connected to the experimental rearing facility in Vodňany FROV JU. The temperature during rearing was constant. For the first experiment the temperature was 22.3 ? 03 °C. For the second one, the average temperature was 21.5 ? 0.6 °C. The frequency of feeding was continuous (24 h) with a combination of hand feeding and feeders with a timer (at night). The illumination of the aquarium tanks was provided by fluorescent lamps, for each tank individually. The light intensity was high (210 lux) and constant during the rearing. Both experiments showed the optimal density at the initial feeding from 20 to 40 units . l??. Also, we have implemented made out performed- the basic biometric analysis of W (g) and TL (mm), the body length, size of eyes, head, jaw length, prenatal length.

Top predators in aquatic ecosystems often have strong top-down effects on the ecosystem. Northern pike (Esox lucius) has been documented to cause whitefish (Coregonus lavaretus) populations to diverge into different ecomorphs. This can facilitate piscivory in other predators as a novel resource becomes available to them in the form of dwarf whitefish. The aim of this study is to examine whether the presence of pike causes Eurasian perch (Perca fluviatilis) to shift their diet from insectivory to piscivory, and whether this is directly driven by whitefish polymorphism. Stomach contents of 147 perch from lakes with and without pikes were analyzed. The results show that the presence of pike has a clear influence on the diet of the perch. In lakes without pike, perch are mostly insectivorous, and in lakes with pike, they are mostly piscivorous. This diet shift appears to be driven by whitefish availability, as a majority of the diet of perch in pike lakes consisted of whitefish, while none of the fish eaten by perch in non-pike lakes was whitefish. In addition, the results showed that perch undergo the diet shift from insectivory to piscivory at a smaller size when coexisting with pike. This study can be added to the growing body of evidence for the ecological significance of pike.

The population size of the horned grebe, Podiceps auritus, is declining in most of the world due to loss of wetlands, deteriorating water quality and establishment of predatory fish such as pike, Esox lucius, in former fish free wetlands. The horned grebe is now globally classified as vulnerable. In this study, data on population dynamics of the horned grebe in six created wetlands in Linköpings kommun was examined together with field work carried out in three of the wetlands. The results indicate that the number of pairs and juveniles of horned grebe crash six to eight years after the wetland is created and does not recover if there is fish present. The pairs and juveniles of horned grebe decreased significantly with the increasing age of the wetland if there was pike present in the wetland. Reduction fishing and drainage of the water in two of the wetlands inhabited pike showed a small improvement in population size of the horned grebe, but the numbers ultimately declined after a few years. Reduction fishing of common roach in one wetland showed a continuing improvement in the population size of horned grebe. Other factors that affected the horned grebe negatively, was an abundance of macrophytes such as Canadian pondweed, Elodea canadensis, that makes foraging harder.

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