Geóloga / El presente estudio se centró en caracterizar el funcionamiento hidráulico de las cuencas endorreicas Salar de Aguas Calientes 2, Puntas Negras, Laguna Tuyajto, Pampa Colorada, Pampa Las Tecas y Salar El Laco, ubicadas en la II Región de Antofagasta. Estas son cuencas intra-volcánicas, que se forman al este de la Cordillera Occidental, donde se desarrolla el volcanismo de arco actual, y que se caracteriza por un clima semi-árido. Los depósitos volcánicos dan lugar a la morfología particular de esta zona, que consiste en un conjunto de pequeñas cuencas hidrológicas morfológicamente aisladas, que acumulan depósitos aluviales y/o salinos del Pleistoceno-Holoceno debido a la intensa aridez del área. La recarga se produce por la infiltración de las precipitaciones, las que infiltran o escurren dependiendo de las características geológicas y geomorfológicas del terreno. Las descargas se producen en mayor proporción por evaporación desde lagunas, salares, napas someras y evapo-transpiración a partir de la vegetación que allí existe. Las zonas acuíferas existentes están limitadas a la porosidad primaria de las rocas volcánicas, la porosidad secundaria asociada a procesos de fracturamiento en este tipo de formaciones, y horizontes erosionados y meteorizados encontrados en profundidad. El agua subterránea puede interceptar la superficie en las áreas de los salares y lagunas. El acuífero principal está compuesto por ignimbrita fracturada. Se deduce la existencia de continuidad hidráulica y flujo de aguas subterráneas profundas desde Puntas Negras a Salar de Aguas Calientes 2, desde Pampa Colorada a Pampa Las Tecas y Laguna Tuyajto; y desde Pampa Las Tecas a Laguna Tuyajto. Las interconexiones del flujo de aguas subterráneas son restringidas por zonas de baja permeabilidad, ubicadas en los márgenes de las cuencas, y horizontes permeables de potencia menor, ubicados en profundidad. El modelo conceptual que se presenta puede ser replicado para todas las cuencas de la Puna de Atacama de la II Región de Chile, aunque podrían haber variaciones mayores en la química de las aguas, lo que deberá ser revisado y analizado para cada caso particular, antes de replicar el modelo.

Les co-produits sont les parties non utilisées et récupérables lors des opérations de transformation du poisson, comme les têtes, les peaux, les os ou la pulpe. L’industrie de transformation du saumon Atlantique d’élevage (Salmo salar) génère environ 50% de co-produits qui constituent une source de protéines de haute qualité. Ce travail de thèse s’inscrit dans le cadre du projet Pesk&Co, qui réunit quatre partenaires industriels (Meralliance-Thai Union, Yslab, SPF-DIANA, AGH-Socofag) et un partenaire académique (LEMAR UMR 6539, UBO) dans le but d’extraire et de caractériser des ingrédients à haute valeur ajoutée issus des co-produits de saumon Atlantique d’élevage (Salmo salar). Le premier objectif de la thèse visait à développer un procédé d’extraction du collagène à partir des peaux de saumon par la mise en place d'un procédé non conventionnel au LEMAR, puis développé au stade pilote et enfin industriel. Le collagène obtenu a été caractérisé par différentes méthodes analytiques (SEC-FPLC, SDS-PAGE, FTIR, rhéologie, microscopie). Ensuite, des essais de réticulation du collagène par voie enzymatique avec une transglutaminase microbienne ont conduit à l’obtention d’un hydrogel. Le deuxième objectif de ce travail a porté sur l’hydrolyse en conditions contrôlées des têtes de saumon pour générer des peptides fonctionnels pour l’aquaculture. Deux protocoles d’hydrolyse enzymatique ont été développés et transposés à l’échelle pilote. Les hydrolysats ont été incorporés dans des aliments aquacoles afin d’être testés sur des larves de bar (Dicentrarchus labrax). Les deux ingrédients développés au cours de ce travail ont pour vocation future d'être commercialisés, et différents marchés et applications sont visés. / By-products are the not used parts and recoverable in the fish processing operations, such as heads, skins, bones or pulp. The processing industry of farmed Atlantic salmon (Salmo salar) generates about 50% of co-products, which are a source of high quality protein. This work is part of Pesk&Co project, which gather four industrial partners (Meralliance-Thai Union Yslab, SPF-DIANA, AGH-SOCOFAG) and one academic partner (LEMAR UMR 6539, UBO) in order to extract and characterize high value ingredients from farmed Atlantic salmon by-products (Salmo salar). The first aim of the thesis was to develop a method for extracting collagen from salmon skins by the setting up of a non-conventional process at LEMAR and finally developed it at pilot and industrial scale. The collagen obtained was characterized by different analytical methods (FPLC-SEC, SDS-PAGE, FTIR, rheology, microscopy). Then, enzymatic cross-linking assays of collagen with a microbial transglutaminase led to obtain a collagen hydrogel. The second objective of this work was focused on the hydrolysis under controlled conditions of salmon heads to generate functional peptides for aquaculture. Two enzymatic hydrolysis protocols have been developed and transferred at pilot scale. The hydrolysates were incorporated into diets to be tested on bass larvae (Dicentrarchus labrax). Both ingredients developed during this work have for future use to be commercialized and different markets and applications are targeted.

Le salar est un dialecte turc dont la plupart des locuteurs habitent le comté de Xunhua (35°05’’nord - 102°03’’est), dans le sud-est de la province chinoise du Qinghai, où leur présence est attestée depuis la fin du XIVe siècle. Si ces dernières années ont vu une augmentation des études sur ce parler à bien des égards atypique, il n’en reste pas moins l’un des parents pauvres de la turcologie. Réalisée précisément dans le but de contribuer à mieux le faire connaître, en s’appuyant pour ce faire à la fois sur la documentation disponible et sur des données recueillies par l’auteur dans le cadre d’un travail sur le terrain, la présente thèse en propose non seulement une description phonologique, grammaticale et lexicale, mais aussi, semble-t-il pour la première fois, une étude détaillée de son système d’écriture traditionnel, aujourd’hui moribond, qui constitue une adaptation de l’alphabet arabe. Une attention particulière a également été portée à la question de la nature des liens du salar avec les autres dialectes, actuels ou anciens, composant le domaine turc (en particulier ceux du groupe oghouz, auquel il apparaît possible que cette variété appartienne), notamment à travers la comparaison avec le turc de Turquie que permet la traduction dans ce dernier dialecte des exemples illustrant les points de grammaire abordés. Considéré comme une langue en danger par l’UNESCO, qui le classe dans la catégorie « vulnérable », le salar traverse une période critique, et les problèmes que soulèvent son statut en Chine, la place qu’il occupe dans la société où il est pratiqué, et les représentations dont il fait l’objet n’ont pas non plus été négligés dans ce travail, dont une partie a été consacrée à la mise en évidence d’un début de situation diglossique dans le cadre de laquelle parmi les réponses que tentent d’apporter certains Salars à la question de l’avenir de leur idiome figure un projet de revitalisation linguistique particulier. / Salar is a Turkish dialect most speakers of which live in the county of Xunhua (35°05 north, 102°03 east) in the south-eastern part of the Chinese province of Qinghai where they have been present since the end of the fourteenth century. In spite of the fact that there has been lately an increase in the studies concerning this language, it is still a poor relative of turkology. Carried out with the aim of making it better known, with the support of the available documentation and data collected by the author in his investigation in the field, this thesis offers not only a phonological, grammatical and lexical description of Salar, but also, to the best of the author’s knowledge, for the first time, a detailed study of its nearly extinct traditional writing system that constitutes an adaptation of the Arabic alphabet. We have been particularly careful to take into account the links uniting Salar with other dialects, present and ancient, which form the Turkish domain (particularly with the Oghuz group to which this variety seems to belong) notably through the comparison with Turkey Turkish, based on the translations into the latter of the grammatical items dealt with. Classified as an endangered language by UNESCO, Salar is going through a critical period. The problems raised by its status in China, the position it occupies in the society where it is spoken and the representations to which it is subjected, have also been addressed in this work. A section has been devoted to the identification of a diglossic language situation in the context of which, among the concerns raised by some Salars about the future of their language, lies a project aiming at its revitalisation.

In Lake Vänern, Sweden, there is an endemic population of Atlantic salmon (Salmo salar L.) that lives its entire life in fresh water. The salmon is hindered from migrating to its natural spawning sites in the northern part of the River Klarälven by nine hydro-electric power plants. None of the hydro-electric power plants have fishways so that salmon migrating upstream or downstream may pass. In the current situation, the upward migrating salmon are caught in a fish trap at the most downstream located power plant in Forshaga. From there, the salmon are driven in a truck, past eight power plants and released a few kilometers upstream of the eighth power plant at Edsforsen. This study investigated the difference in the proportion of fallbacks between early (June-July) and late (August-September) migrating salmons in 2011-2013. The results showed that there was a significant difference in the proportion of fallbacks between the early and the late-migrating salmon. Fifty-one percent of the early salmon and 13% of the late salmon fell back during these 3 years. Further, there was no significant difference between males and females that became fallbacks. Nor was there any difference in the length of early and late-migrating salmon or fallbacks and non-fallbacks. / I sjön Vänern, Sverige, finns en endemisk population av Atlantlax (Salmo salar L.) som lever hela sitt liv i sötvatten. Laxen hindras från att migrera till sina naturliga lekplatser i norra delen av Klarälven av nio vattenkraftverk. Inget av vattenkraftverken har fiskvägar så att lax som migrerar uppströms eller nedströms kan passera. I dagsläget fångas lax som vandrar uppströms in i en fiskfälla vid det mest nedströms belägna kraftverket i Forshaga. Därifrån körs laxen i lastbil förbi åtta kraftverk och släpps ut några kilometer uppströms det åttonde kraftverket i Edsforsen. Den här studien undersökte skillnaden i andelen fallbacks mellan tidigt (juni-juli) och sent (augusti-september) migrerande laxar under åren 2011-2013. Resultaten visade att det fanns en signifikant skillnad i andelen fallbacks mellan den tidiga och den sent migrerande laxen. Femtioen procent av den tidiga laxen och 13% av den sena laxen föll tillbaka under dessa 3 år. Vidare fanns det ingen signifikant skillnad mellan hanar och honor som blev fallbacks. Det fanns inte heller någon skillnad i längden av tidigt och sent migrerande lax eller lax som föll tillbaka och lax som inte föll tillbaka.

Under hösten leker en inhemsk population av Atlantisk lax (Salmo salar) i Klarälven, Sverige, för att därefter vandra nedströms tillbaka till sjön Vänern. Vid älvens andra kraftverk sett från Vänerns mynning, Dejefors kraftverk, finns det planer på att ersätta ett av kraftverken mot ett nytt och det finns därför ett behov av att ta reda på hur laxens nedströmsvandring påverkas av det kraftverket som finns där i dag. Då alla kraftverk i Klarälven saknar fiskpassagelösningar är det extra viktigt att följa upp laxarnas passageöverlevnad under vandringen. Avsikten med denna studie var därför att ta reda på hur laxen rörde sig runt kraftverket, hur väl de klarade av att passera kraftverket beroende av vilken passageväg de tog och vilka faktorer som påverkade passageframgången. Under september 2020 fångades 40 laxindivider in när de var på väg uppströms inför leken. De mättes och märktes med telemetrisändare för att sedan transporteras uppströms och släppas ut nedanför kraftverket i Munkfors, varifrån deras nedströmsvandring förbi Dejefors kraftverk följdes och analyserades med hjälp av akustisk telemetri. Resultatet visade att det inte fanns någon signifikant skillnad mellan kön för när laxarna påbörjade sin nedströmsvandring. Kraftverket visade sig dock fördröja laxarnas nedströmsvandring då det tog längre tid för dem att passera kraftverket än vad det tagit dem att simma ner dit i den fritt strömmande delen av älven. Av de 31 laxar som anlände till Deje så passerade 27 av dem kraftverket, varav 13 individer överlevde (48 %). Överlevnaden var högre för individer som passerade via spillutskoven (10 av 12) än turbinerna (3 av 15). Det fanns en signifikant skillnad i mortalitet vid kraftverkspassage beroende på laxens längd och passageväg; långa individer hade en högre mortalitet (73 %) än kortare (25 %) och passagevägen hade en signifikant effekt på mortaliteten. Resultatet visar tydligt på ett behov av åtgärder för att förbättra överlevnaden hos lax vid passage av Dejefors kraftverk. Lösningar för att få fisken att helt undvika turbinerna och istället välja en annan passageväg vore troligen den bästa och effektivaste lösningen för att öka laxens överlevnad under nedströmsvandringen. / During autumn, the endemic Atlantic salmon (Salmo salar) migrate upstream to spawn in the river Klarälven, Sweden, after which they migrate downstream back to Lake Vänern. There are plans to remove one of the power houses in Deje, and replace it with a new power house, and before that happens it is important to study the downstream passage conditions at the site. As all power plants in Klarälven lack fish passage solutions, it is important to follow up the salmon passage survival during the migration. The purpose of this study was therefore to study how downstream migrating salmon negotiate the power plant, the route-specific passage survival and what factors that could affect their passage success. In September 2020, 40 upstream migrating salmon individuals were caught, measured and tagged after which they were transported and released below the power plant in Munkfors. Their downstream migration past Dejefors power plant was studied and analyzed using acoustic telemetry. The results showed that there was no significant difference between sexes in regards of downstream migration timing. However, the power plant turned out to delay downstream migrating salmon as it took longer time for them to pass the power plant than it took them to swim down the free-flowing part of the river. Of the 31 salmon that arrived in Deje, 27 passed the power plant, of which 13 individuals survived (48%). The survival rate was higher for individuals passing via spillways (10 of 12) than turbines (3 of 15). There was a significant difference in mortality rate at power plant passage depending on the length and passage route of the salmon. Large individuals suffered a higher mortality (11 of 15) than short (3 of 12) and a larger proportion of the salmon died when passing through the turbines than through spill gates. Based on the results, there was a clear need for improved survival rates for salmon passing the Dejefors power plant. The design of the turbines could be changed for increased survival, but at the same time other solutions that will make it possible for fish to avoid the turbines and instead choose another passageway would probably be a better and more efficient solution to increase the survival of the salmon during their downstream migration.

Vattenkraften har en negativ miljöpåverkan på flera sätt, inte minst genom fragmentering av vattendrag. Därför är det viktigt att studera åtgärder som potentiellt minskar vattenkraftens inverkan. Här undersöktes experimentellt avledningseffektivitet och tidsåtgång för nedströmsvandrande atlantlaxsmolt hos låglutande avledare i en strömränna. Smolten startade uppströms om anläggningen och registrerades ifall de besökte flyktöppningarna i passagelösningen för nedströmsmigrerande fisk. Inom båda huvudtyperna, α- och β-avledare, testades tre olika avledare vardera där α-avledarna bestod av galler med spaltvidderna 15, 18 och 30mm. β-avledarna innefattade två galler med spaltvidderna 15 och 30 mm samt ett kevlarnät med entumsmaskor. Resultaten visade att hos α-avledare hade spaltvidden hos gallret betydelse för effektiviteten mellan största och minsta gallret. Mellan β-avledarna med 15 och 30 mm spaltvidd hade spaltvidden ingen betydelse varken för avledningseffektivitet eller tid till passage. Däremot var entumsnätet mindre effektivt. Resultaten indikerade att β-avledare var generellt mer effektiva än α-avledare med högre avledningseffektivitet, möjligen på grund av olikheter i konstruktionerna av flyktöppningarna i anslutning till avledarna. Resultatet pekar också på att β-galler kan ge upphov till en beteenderespons hos smolten som inte registrerades hos α-galler. / Hydropower has a negative environmental impact in several ways, not least through fragmentation of watercourses. This makes it important to study measures that potentially reduce the impact of hydropower. Here, diversion efficiency (passage) and time spent migrating by Atlantic salmon smolts was tested experimentally in a flume equipped with low-slope diverters, simulating passage of a hydropower plant. The smolt were released upstream of the facility and were registered if they visited the entrance to the flume’s passage solution for downstream migrating fish. In both main types, α- and β-diverters, three different diverters were tested each, where the α-diverters consisted of bar racks with gap widths of 15, 18 and 30mm. The β-diverters included two bar racks with gap widths of 15 and 30 mm and a kevlar net with 25 mm meshes. The results showed that in α-diverters, the gap width of the racks was important for the efficiency between the largest and smallest gap widths. Between the β-diverters with 15- and 30 mm gap width, the gap width had no significance either for efficiency or time to passage. However, the one-inch net was less efficient. The results indicated that β-racks were generally more efficient than α-racks with higher diverting efficiency, possibly due to differences in the constructions of the escape openings adjacent to the diverters. The result also suggests that β-racks may give rise to behavioral responses in the smolt that was not registered in α-racks.

Daily demands for electrical power are met through sub-daily release of turbined water in the form of hydropeaking. Hydropeaking’s changes to stream flow are listed as a threat to biodiversity in river ecosystems as it causes rapid habitat alteration such as increased depth and velocity, affecting the species living downstream. The brown trout and landlocked salmon populations in Gullspång River, Sweden, are threatened and subjects to the hydropeaking regime. This study investigated the effects of hydropeaking in summertime (summer peaks) in Gullspång River on growth and survival of age 0 (fry) and age 1 (parr) brown trout and Atlantic salmon. The study used an individual-based model (inSTREAM 7.2-SD) to predict how different peak scenarios would affect the different species and age groups. A previous study’s parameters and model calibration for the study area were used, and I manipulated the flow time-series to create new flow time-series including three single peaking scenarios on different dates during summer, one multiple summer peak scenario as well as a no-peak (steady flow) scenario. The analysis focused on qualitative patterns in how the populations responded to the various flow scenarios. Age 0 salmon’s growth and survival were negatively affected by all peaking scenarios in comparison to the steady flow scenario, with the combined peaking scenario having the worst effect. Age 0 trout survival was either unaffected by single peaking (Scenario 1 & 2) or negatively affected (Scenario 3) and was also worst affected by the combined peaks compared to steady flow. Age 1 survival of both species was positively affected by the combined peaking but either unaffected (Scenario 1 & 2) or negatively (Scenario 3) affected by single peaks compared to the steady flow scenario. Age 1 growth followed a similar trend with highest growth rate in the combined peaks scenario and the lowest in the steady flow for both species. Results of the study may contribute to river management decisions regarding choice of peaking period depending on management goals regarding target species and life cycle stage. / Dagliga efterfrågan av elektricitet tillgodoses genom daglig korttidsreglering avvattenkraftverk där vatten flödar genom turbinerna. Korttidsreglering är listat somett av de större hoten mot den biologiska mångfalden i floders ekosystem då det ledertill snabba habitatförändringar som ökat djup och flödeshastighet, vilket påverkararterna som lever nedströms. Gullspångsälvens bestånd av öring och lax är hotadeoch utsätts för korttidsreglering som nyttjas i älven. Den här studien undersöktekorttidsregleringens påverkan under sommartid (sommartoppar) i Gullspångsälvenpå tillväxt och överlevnad hos ålder 0 (yngel) och ålder 1 (parr) öring och atlantlax.Studien använde en individbaserad modell (inSTREAM 7.2-SD) för att förutspå hurscenarion med olika toppar påverkar de olika arterna samt åldersgrupperna. Entidigare studies parametrar och kalibrering av modellen för studieområdet användesoch jag ändrade flödestidsserierna för att skapa nya flödestidsserier vilket1inkluderade tre enstaka sommartoppar vid olika datum under sommaren, ettkombinerat sommartoppscenario samt ett scenario utan topp (stadigt flöde).Analysen fokuserade på kvalitativa mönster bland populationernas respons till deolika flödestoppscenarion. 0-laxens tillväxt och överlevnad var negativt påverkad avalla flödestoppscenarion i jämförelse med det stadiga flödesscenariot, där detkombinerade flödesscenariot resulterade i en värsta påverkan. 0-öringens överlevnadvar antingen opåverkad (Scenario 1 & 2) eller negativt påverkad (Scenario 3) avenstaka flödestoppar samt också värst påverkad av det kombinerade flödesscenariot ijämförelse med det stadiga flödet. Överlevnaden hos ålder 1 av båda arter blevpositivt påverkad av det kombinerade flödescenariot men var antingen opåverkad(Scenario 1 & 2) eller negativt påverkad (Scenario 3) av de enstaka flödestopparnajämfört med det stadiga flödet. Tillväxten hos ålder 1 av båda arter följde ett liknandemönster där störst tillväxt uppmättes i det kombinerade scenariot och den lägstatillväxten i det stadiga flödesscenariot. Studiens resultat kan bidra tillförvaltningsbeslut gällande älvar när det kommer till utformningen av flödestoppar,beroende på vilka förvaltningsmål som finns för arter och dess livscykelstadium.

Salar de Atacama (SdA) located in Northern Chile is home to one of the planet’s largest salar systems and lithium resources. Managing groundwater resources in salars is not obvious due to the lack of scientific understanding on the connectivity between the freshwater and brine systems. Using heat as a tracer in SdA provides a cost-effective method to further investigate groundwater flow in salars. This study employs 372 temperature-depth profiles from 90 boreholes between 2013-18 to understand the distinct thermal zones and flow between them in SdA. Three thermal zones exist within the southern margin of SdA’s thermal regime, at higher elevations alluvial fans containing freshwater have a temperature range between 23-28 °C. Down-gradient 2.5 km into the salar transition zone, characterized by freshwater lagoons and newly formed carbonates, the temperature range decreases to 12-17 °C. The transition zone, adjacent to the mature halite crust which hosts a lithium bearing brine and ranges in temperature from 18-22 °C. A 2D numerical groundwater and heat flow model was created to test three hydrologic scenarios to determine how the currently observed thermal regime exists and what the role of groundwater flow is between the different thermal zones. Results demonstrate that a focused flow concept matches current thermal observations with warm inflowing water discharging into the transition zone, cooling due to evaporation, reinfiltrating and preferentially flowing near the surface and discharging again at lagoons near the halite nucleus. Initial focused flow models had the halite nucleus and transition zone hydraulically connected, but results displayed advective flow between the two zones and the halite nucleus carried too much heat from current observations. Indicating the halite nucleus and transition zone has minimal connection, otherwise advective flow would result in thermal equilibrium and a lack of distinct zones as observed. Proper interpretation of temperature-depth profiles along with 2D models place critical constraints on the connectivity between the brine and freshwater systems, providing insight into salar surface energy budgets and a more comprehensive understanding of groundwater flow in the southern margin of SdA. This work gives a new perspective on the groundwater system in SdA while also contributing a novel case study to using heat as a tracer in salar systems.

Atlantic salmon (Salmo salar) are found in a range of locations along Sweden's coastline, but Sweden's largest lake, Vänern, also harbors a population of salmon; the rare freshwater migratory form. The majority of the salmon in Lake Vänern migrate upstream in River Klarälven in order to spawn, where they are assisted by humans through the "trap and transport" method to get past Klarälven's eight hydropower dams, which otherwise constitute definite obstacles to upstream migration. When the salmon later migrate downstream to Lake Vänern they receive no assistance and experience a high mortality rate as they are partially forced to swim through the turbines. The wild salmon population today includes over 1000 spawners annually, an increase from <200 in the 196os, but far below historic records of over 10,000 spawners.  This report therefore aimed to investigate the population growth rate and extinction risk for the salmon in Klarälven, both in the current situation and with passages installed past the hydropower plants, and in doing so answer the questions 1) How large is the population growth rate and risk of extinction for today’s population of salmon in Klarälven over the course of 100 years? and 2) How would passage solutions past the hydropower plants in Klarälven affect the population growth rate and risk of extinction for today’s population of salmon in Klarälven over the course of 100 years? These questions were answered by running a population viability analysis in the program Extinction Vortex, which allows the programming of model populations and the manipulation of parameters to test different scenarios. The scenarios that were tested were 1) Scenario 1: Today's method with trap and transport and total lack of passages, 2) Scenario 2: Trap and transport continues, and downstream passages are installed past all eight power plants, and 3) Scenario 3: Upstream and downstream passages are installed past all eight power plants and trap and transport ceases. The results of the vulnerability analysis did not show any risk of extinction for the next 100 years, but a long-term negative trend for the salmon in Klarälven using today's method was seen. However, the development became significantly more positive for the salmon in Klarälven when the installation of downstream passages was simulated, but after that not significantly more positive when the installation of upstream passages was simulated as well. This result provided answers to the research questions and based on them it could be concluded that even though the salmon in Klarälven are not under any acute threat at the moment, and that there may be other fish populations in other regulated streams and rivers that would benefit more from environmental adaptation, measures need to be taken also in Klarälven, to ensure the long-term conservation of the unique freshwater migrating salmon that inhabit the area. / Laxen (Salmo salar) förekommer på flera håll längst Sveriges havskuster, men även Sveriges största insjö Vänern hyser en population av lax; den sällsynta sötvattensvandrande formen. Majoriteten av Vänerlaxarna migrerar upp för att leka i Klarälven, där de assisteras av människan genom metoden ”trap and transport” som tar dem förbi Klarälvens åtta vattenkraftverk vilka annars utgör definitiva vandringshinder. När laxen sedan ska ta sig tillbaka ner till Vänern får de ingen assistans, i stället tvingas de delvis simma genom turbinerna med stor dödlighet som följd. Laxpopulationen idag består av över 1000 lekande fiskar varje år, en ökning från <200 individer på 1960-talet, men långt under historiska siffror på över 10 000 lekande laxar. Detta arbete syftade därför till att undersöka populationsutvecklingen och utdöenderisken för Klarälvslaxen, såväl i nuläget som vid en installation av passager förbi kraftverken, och genom detta besvara frågeställningarna 1) Hur stor är populationsutvecklingen och utdöenderisken för dagens population av Klarälvslax över kommande 100 år? och 2) Hur skulle passagelösningar förbi vattenkraftverken i Klarälven påverka populationsutvecklingen och utdöenderisken för dagens population av Klarälvslax över kommande 100 år? Dessa frågeställningar besvarades med hjälp av en sårbarhetsanalys i programmet Extinction Vortex, som tillåter uppbyggandet av modellpopulationer och manipulation av parametrar för att testa olika scenarier. Scenarierna som testades var 1) Scenario 1: Dagens metod med trap and transport och total avsaknad av passager, 2) Scenario 2: Trap and transport fortsätter samt nedströmspassager installeras förbi alla åtta kraftverk, och 3) Scenario 3: Upp- och nedströmspassager installeras förbi alla åtta kraftverk och trap and transport upphör. Resultatet av sårbarhetsanalysen visade inte på någon utdöenderisk kommande 100 år, men en negativ trend för Klarälvslaxens långsiktiga populationsutveckling med dagens metod. Utvecklingen blev dock signifikant mer positiv för Klarälvslaxen vid den simulerade installationen av nedströmspassager, och ännu något stabilare när även uppströmspassager installerades. Detta resultat gav svar på frågeställningarna, och utifrån detta kunde slutsatsen dras att trots att Klarälvslaxen inte befinner sig under något akut hot för närvarande, och att det kan finnas andra fiskpopulationer i andra vattendrag som är i mer akut behov av miljöanpassning, så behöver åtgärder komma på plats även i Klarälven, för att säkerställa det långsiktiga bevarandet av den unika sötvattensvandrande Klarälvslaxen.

In this study, full coding sequences of Atlantic salmon (Salmo salar L.) muscle genes were cloned, including myogenic regulatory factors (MRFs) (myod1c, myog, mrf4, myf5), inhibitors of Myostatin (fst, decorin), markers of myogenic progenitor cell (MPC) proliferation (sox8) and fusion (calpastatin), a marker of slow muscle fibre differentiation (smlc1) and a novel eukaryotic gene involved in regulating growth (cee). Several of these genes were then characterised using a range of experimental and computational analyses with the aim to better understand their role in myogenesis and their evolution in teleosts. A series of experiments supported previous findings that teleosts have extra copies of many genes relative to tetrapods as a result of a whole genome duplication (WGD) event that occurred some 320-350 Mya. For example, it was shown that genes for myod and fst have duplicated in a common teleost ancestor, but were then specifically lost or retained in different lineages. Furthermore, several characterised Atlantic salmon genes were conserved as paralogues, likely from a later WGD event specific to the salmonid lineage. Phylogenetic reconstruction and comparative genomic approaches were used to characterise the evolution of teleost paralogues within a framework of vertebrate evolution. As a consequence of one experiment, a revised nomenclature for myod genes was proposed that is relevant to all diploid and polyploid vertebrates. The expression patterns of multiple myogenic genes were also established in Atlantic salmon embryos using specific complementary RNA probes and in situ hybridization. For example, co-ordinated embryonic expression patterns were revealed for six salmon MRFs (myod1a, myod1b, myod1c, myog, mrf4, myf5), as well as markers of distinct MPC populations (pax7, smlc1), providing insight into the regulatory networks governing myogenesis in a tetraploid teleost. Furthermore, it was shown that Atlantic salmon fst1 was expressed concurrently to pax7 in a recently characterised MPC population originating from the anterior domain of the epithelial somite, which is functionally analogous to the amniote dermomyotome. In another experiment, the individual expression domains of three Atlantic salmon myod1 paralogues were shown to together recapitulate the expression of the single myod1 gene in zebrafish, consistent with the partitioning of ancestral cis-acting regulatory elements among salmonid myod1 duplicates. Additionally, the in situ expression of cee a novel and highly conserved eukaryotic gene was revealed for the first time in a vertebrate and was consistent with an important role in development including myogenesis. Additionally, Atlantic salmon were reared at 2, 5, 8 or 10 ºC solely to a defined embryonic stage, which was just subsequent to the complete pigmentation of the eye. After this time, animals were provided an equal growth opportunity. Remarkably, changing temperature during this short developmental window programmed the growth trajectory throughout larval and adult stages. While 10 and 8 ºC fish were larger than those reared at 2 and 5 ºC at the point of smoltification, strong compensatory growth was subsequently observed. Consequently, after 18 months of on growing, size differences among 5, 8 and 10 ºC fish were not significant, although each group was heavier than 2 ºC fish. Furthermore, significant embryonic-temperature induced differences were observed in the final muscle fibre phenotype, including the number, size distribution and myonuclear density of muscle fibres. A clear optimum for the final muscle fibre number was observed in 5 ºC fish, which was up to 17% greater than other treatments. In a sub-sample of embryos, temperature induced heterochonies were recorded in the expression of some MRFs (myf5, mrf4) but not others (myod1a, myog). These results allowed the proposition of a potential mechanism explaining how temperature can program the muscle phenotype of adult teleosts through modification of the somitic external cell layer, a source of MPCs throughout teleost ontogeny.