Conserving and restoring anadromous fish populations is an important research and management priority. For conservation to be effective, researchers must understand the behavior of the fish they seek to restore. Telemetry has allowed researchers to understand the upstream migrations of these fish in freshwater, how migration patterns vary, and if there is a relationship between behavior and environmental variables. In the northeastern United States, alewife (Alosa pseudoharengus), one of two species collectively referred to as river herring, has historically been an important component of coastal rivers. However, populations of these fish have experienced recent declines, and a commonly used method to restore river herring is stocking. In this thesis, I summarize research that seeks to understand anadromous alewife behavior with the goal of providing insights that will help manage and conserve this species and the coastal systems in which they live. My thesis has a primary research chapter (Chapter 1), a second ancillary research chapter (Chapter 2), and four appendices that summarize related information as part of the funding proposal. First, to examine if fish origin (native or stocked) and fish release location (upstream or downstream) affected the pre-spawning movements of fecund alewives, I undertook a reciprocal experiment. In Chapter 1, for fish of both origins and release locations, I examined how long fish were in the river, where they spent their time, and how much and how fast they moved. For this, I gastrically tagged alewives with Lotek Nanotags NTC-6-1 radio tags and monitored movements in the lower 30 km of the Ipswich River (northeastern Massachusetts) using an array of 9 Lotek SRX_400 receivers. Based on these movement trajectories I concluded that in 2007, origin affected the total time fish spend in the river and release location affected where they spend their time. Downstream movements of upstream migrating fish have typically been viewed as a behavioral assay of adverse tag effects. For this reason, alosine telemetry studies rarely release tagged fish upstream of the capture site. However, fisheries managers often release fish upstream near spawning grounds during stocking. In Chapter 2, I re-evaluated whether downstream movements of upstream stocked fish were consistent with an adverse tag effect. By combining physiological experiments with select movement trajectories, I showed that pre-spawning migrations of alewife included an array of up and downstream directed movements with various interpretations. In my research, these downstream movements were unlikely to be related to tagging stress (Chapter 2), as the cortisol, glucose, and chlorides of tagged fish were not different from untagged fish (Appendix A, Physiology). Furthermore, I suggested metrics that should be recorded in telemetry studies to standardize how downstream fish movements are measured. In 2006, native fish were released at a downstream site (river km 6) and stocked fish were released upstream (rkm 25). I compared the behaviors of these same treatments across years. I showed that the behaviors of fish released in different years may differ based on temperature and discharge (Appendix B, Across Year Comparison). To determine the amount and location of potential spawning habitat, I undertook a habitat study that utilized a geographic information system (GIS) to maps the size and distribution of habitat types. I located multiple mainstem pools in the Ipswich River that may serve as suitable spawning grounds for alewife. Tagged fish were primarily located in these habitats (Appendix C, Habitat). To determine if juveniles were produced, I sampled various sites in the river for the presence of juveniles, using active and passive sampling techniques. Juveniles were not captured during these surveys (Appendix D, Juvenile Sampling). Before this research, little was known about the pre-spawning migrations of river herring. While river herring are assumed to be a generalist species, I found their behaviors to be complex. I have identified a number of gaps in the current knowledge of how these fish behave in the field. Restoration efforts must take into account the behavior of the fish, as well as the capacity of a system to accommodate those needs. Within the context of understanding fish behavior, protecting habitat, and providing regulatory restrictions on the fishery, stocking may contribute to broader management and restoration goals.

Over the last century anadromous alewife (Alosa psuedoharengus) and blueback herring (Alosa aestivalis), collectively called river herring, suffered drastic declines throughout their range from Newfoundland (Canada) to North Carolina (USA). A 2011 petition to include river herring in the Endangered Species Act (ESA) was rejected, partly due to inadequate information towards identifying coast-wide population status. Additionally, knowledge gaps were identified with basic ecology of the river herring life cycle in freshwater, including species reproductive strategies. In Chapter 2, I investigated how body size, spawning arrival time, and sex influence river herring reproductive success. I collaborated with the Massachusetts Division of Marine Fisheries to introduce adult river herring (421, 266, and 410 individuals in 2013, 2014, and 2015, respectively) into Pentucket Pond (Massachusetts, USA), which historically had river herring but is currently inaccessible to upstream migrants. Using fin clips from stocked adult fish and juveniles collected in the lake each summer, I genotyped individuals and constructed pedigrees with 15 microsatellites. River herring had small (mean =1.1) families and spawned multiple times with multiple mates from May to June. Females were more successful than males. Earlier arrival and larger body size were independent indicators of reproductive success. These results provide critical river herring life history information for the freshwater component of population models that will inform management of this at-risk species. Presently, most river herring populations are monitored using data from citizen counts of spawning adults entering freshwater. Involving citizen watershed groups in data collection and may provide ancillary benefits beyond collection of population-level count data. In Chapter 3, I used pre-and post-surveys to assess how involvement in one citizen monitoring program influenced participants’ environmental knowledge, attitudes, and behaviors. Participants began the program with high scores for broader scientific and pro-environmental attitudes and pro-environmental behaviors. After the program, participants reported increased connection to nature, citizen science involvement, river herring knowledge, and engagement in outdoor recreation. For participants, engagement with nature was the most important program benefit. These results provide an additional case study to the citizen science literature and demonstrate that citizen science programs can help participants connect with the environment.

The relationships between watershed characteristics and stream use by spawning alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis) in the Rappahannock River drainage were identified. Trends in fish use of 72 tributaries were determined by consulting eighty-eight people from the Rappahannock River area through a questionnaire. These streams were each given an overall rank based on answers to the questionnaire. The watershed characteristics of these streams were determined from topographic maps, land use data, and digital line graphs. Trends in fish use of streams were associated with stream size, and proportions of forest, agriculture, and wetlands. No negative relationships between urbanization or presence of point-source pollution and fish use of streams were found. Forest was positively associated with stream rank, and agriculture was negatively associated with stream rank. Results indicate that, of the watershed characteristics in the Rappahannock River drainage, forest and agriculture have the strongest associations with stream use by spawning river herring. Three sites in a tributary of the Rappahannock River were studied to characterize the spawning habitat of river herring. The sites were sampled and their habitat variables were measured throughout the 1992 river herring spawning season. Densities of river herring adults, eggs, and yolk-sac larvae were highest at the upstream site. Densities of post-yolk sac larvae did not differ significantly among the sites. The upstream site differed from the downstream sites in size, vegetation, hydrology, photic zone depth, pH, and vegetation. At times, pH levels in the upstream site were within the range of lethality reported for blueback herring larvae. Relationships between habitat variables and occurrence of river herring life stages in the upstream site were identified. Effects of tidal condition, time of day, light intensity, and temperature on peaks in densities of river herring life stages in the upstream site were determined by plotting these variables with life stage densities. Trends in water temperature were positively related to peaks in densities of river herring life stages. Logistic regression was used to determine if temperature, light intensity, dissolved oxygen, velocity, depth, and secchi disc transparency predicted occurrence of river herring life stages in the upstream site. Occurrence of alewife early egg stages was positively related to dissolved oxygen and velocity. Occurrences of blueback herring adults and early eggs were positively related to water temperature. / Master of Science

The number of Swedish fishers has been in decline for many years. In 1930, there were almost 18000 fishing vessels in Sweden. The same number in 2022 was just under 1000. Along the Swedish northern Baltic coast, there are now 243 active vessels, compared to 1279 vessels in 1970. Apart from declining fish stocks, it is likely that other societal, cultural, economic, and ecological factors have affected the decline in the number of fishers. In particular, small-scale fishers in the area have expressed concerns about the result and goals of national and international fishing policy. The aim of this thesis is to investigate how national and international policy have contributed to the decline of small-scale fisheries along the Swedish northern Baltic coast between the 1970s and today. In the 1970s, Swedish fishing policy underwent a major change in focus, shifting towards an economic approach where efficiency and catch size played an important role. By comparing interviews conducted with small-scale fishers and families in Västernorrland during the 1970s to interviews conducted with active small-scale fishers today, the fisher’s perspective of what factors have been driving the development, the effects of policy for small-scale fisheries as well as the biggest differences between the past and current situation will be shown. The results highlight a strong decline in the number of fishers and vessels, a declining belief in the future, declining herring stocks and a declining trust in authorities among the fishers. This can in many ways be seen as a result of Sweden’s long history of capacity enhancing fishing policy, as well as the general development the Swedish northern Baltic region has undergone in the past 60 years. The results underline the importance of policy for the development of both small- and large-scale fisheries. The results of this thesis can be used to better understand the effects Swedish and European fishing policy have had on the development of Swedish northern Baltic small-scale fisheries from the fisher’s perspective. This can be useful to develop new policies that aim to preserve and strengthen the position of the small-scale fisheries.

The topic of this diploma thesis is the Commemorative Book of Prague Nydrlak, whose origins date back to the 17th century in the Prague New Town. The records in the book were written mainly by the merchants who travelled to Prague to trade. Most of those merchants were most likely involved in the international trade with marine fish that were imported from the North Sea and the Baltic Sea. Due to the representative role of commemorative books, the majority of the merchants received their illuminations from professional artists. The introductory chapters of the thesis describe contemporary practice of business of the given period, specifics of Nydrlak in the context of the practice, the commemorative book culture of the 16th and 17th century, but also the fortunes of Nydrlak before its depositing into the Prague City Archives. A pivotal part of the paper is dedicated to the merchants themselves who would left some information about their lives in the book. Based on this source and several other archival documents, the thesis assesses the confessional, societal, regional, and proprietary stratification of the community that was assembled around Prague Nydrlak.

Detta examensarbete syftade till att ta fram ett underlag för en regional åtgärdsplan avseende dibenso-p-dioxiner och dibensofuraner, gemensamt benämnda som PCDD/F eller dioxiner, i Gävleborgs län. Länet har historiskt varit ett av de mest utsatta områdena i Sverige beträffande dessa föroreningar och höga koncentrationer i bland annat strömming har medfört att denna inte får saluföras i övriga EU.   I arbetet har resultaten från den rådande forskningen på området studerats för att få kunskap om nuvarande källor och möjliga förklaringar till de fortsatt förhöjda koncentrationerna av dioxiner. Därefter har data från tidigare undersökningar av dioxinkoncentrationer i Gävleborgs län samlats in, sammanställts och använts för att studera hur koncentrationerna varierar geografiskt inom länet. Principalkomponentanalys (PCA) av specifika dioxinkongeners koncentrationer har sedan använts för att försöka identifiera verksamhetstyper som potentiellt kan ha bidragit till föroreningarna på olika platser - en analys som dock är behäftad med stora osäkerheter. De insamlade provresultaten har även använts för att genom massbalansmodellering undersöka återhämtningen i två känt förorenade fjärdar i länet; Norrsundet och Gårdsfjärden. Utifrån resultaten av ovanstående analyser diskuterades även nyttan av att genomföra eventuella åtgärder för att reducera halterna i kraftigt förorenade områden.   Proverna som sammanställts visade klara geografiska skillnader i sedimentkoncentration, och till viss del även i koncentration i muskel från abborre, vilket visar på en stark betydelse av lokala källor i vissa områden. Bland strömmingsproverna kunde inget liknande samband ses. Detta kan förklaras av att det migrerande beteendet hos strömming gör att fisken under sin livstid exponeras för varierande föroreningsnivåer i olika områden, medan abborren är mer stationär även som vuxen. Principalkomponentanalysen gav, för vissa prover, indikationer kring vilken typ av verksamhet som bidragit till de uppmätta koncentrationerna. Dessa resultat är dock mycket osäkra och bör inte på egen hand användas som underlag för att fastställa föroreningskällor. Massbalansmodelleringen visade att PCDD/F-koncentrationen i sediment inte har någon betydelse för koncentrationen i vattenmassan utan att inflödet från omgivande hav dominerar även i avgränsade fjärdar. De modellerade jämviktskoncentrationerna mellan sediment och vattenmassa indikerade även att koncentrationerna i sediment kommer fortsätta överskrida somliga gränsvärden tills koncentrationen i vattenmassan reducerats, vilket även stöds av att dessa gränsvärden överskreds i majoriteten av de sammanställda proverna.   Baserat på samtliga ovannämnda resultat drogs slutsatsen att lokala saneringsåtgärder sannolikt inte ger någon effekt på PCDD/F-koncentrationerna i strömming, samt att de inte är tillräckliga för att erhålla sedimentkoncentrationer under samtliga gränsvärden. De kan däremot effektivt minska den exponering som mer stationära organismer som abborre utsätts för i områden med kraftigt förorenade sediment, och kan även ha positiva effekter på förekomsten av andra miljöfarliga ämnen i området. För- och nackdelar måste således övervägas i varje enskilt fall. / The aim of this Master’s Thesis was to provide a basis for a regional plan of action regarding dibenzo-p-dioxins and dibenzofurans, commonly referred to as PCDD/F or dioxins, in Gävle-borg County. This region has historically been one of the Swedish areas most affected by these pollutants, and high concentrations in for example Atlantic herring (Clupea harengus) have resulted in restrictions where some fish species cannot be sold in other EU countries.   In this work, results of current research on the subject were studied in order to gain knowledge about current sources and possible explanations to the continued high concentrations of dioxins. Thereafter, data from earlier investigations of dioxin levels in Gävleborg County have been gathered, compiled and used to study the regional geographic variation of the concentrations. Principal component analysis (PCA) was then used on the concentrations of specific congeners in an attempt to identify source types that might have contributed to the contamination in various sites; this analysis is however marred by uncertainties. The gathered data have also been used to investigate the recovery in two bays with known contaminations, Norrsundet and Gårdsfjärden, using mass balance modelling. The benefits of implementing measures to reduce the PCDD/F-concentrations in highly polluted areas were then discussed based on the results of the above-mentioned analyses.   The measured sediment concentrations, and partly also the concentrations in European perch (Perca fluviatilis), of the compiled samples showed distinct geographic differences, which indicates a strong influence from local sources in some areas. Among the herring samples, no such connection could be seen. This could be explained by the migrating behaviour of adult herring, resulting in an exposure to various levels of contamination in different areas as they migrate, while adult perch has a more stationary behaviour. For some samples, the principal component analysis gave indications on source types that might have contributed to the local contamination levels. These results are however very uncertain and they should not be used as the sole basis when determining emission sources. The mass balance modelling showed that the PCDD/F-concentrations in sediments have no influence on the concentrations in the water body; the inflow from the surrounding sea is predominant also in enclosed bays. The modelled equilibrium concentrations between sediments and water body also indicated that the sediment concentrations will continue to exceed the guideline values until the water concentrations have decreased. This is also supported by the fact that the majority of the samples showed concentrations exceeding these guideline values.   Based on all of the abovementioned results it was concluded that local remediation measures would most likely not affect the PCDD/F-concentrations in herring. It was also concluded that such measures would not suffice to obtain sediment concentrations that fall below all guideline values. They can however be used to lessen the exposure that stationary organisms are subjected to in areas with highly contaminated sediments, and can also have positive effects on the levels of other hazardous substances in the area. Thus, the benefits and disadvantages need to be considered in each specific case.

Many previous studies in evolutionary genetics have been based on few model organisms that can be reared at ease in the laboratory. In contrast, genetic studies of non-model, natural populations are desirable as they provide a wider range of adaptive phenotypes throughout evolutionary timescales and allow a more realistic understanding of how natural selection drives adaptive evolution. This thesis represents an example of how modern genomic tools can be effectively used to study adaptation in natural populations. Atlantic herring is one of the world’s most numerous fish having multiple populations with phenotypic differences adapted to strikingly different environments. Our study demonstrated insignificant level of genetic drift in herring that resulted in minute genetic differences in the majority of the genome among these populations. In contrast, a small percentage of the loci showed striking genetic differentiation that were potentially under natural selection. We identified loci associated with adaptation to the Baltic Sea and with seasonal reproduction (spring- and autumn-spawning) and demonstrated that ecological adaptation in Atlantic herring is highly polygenic but controlled by a finite number of loci. The study of Darwin’s finches constitutes a breakthrough in characterizing their evolution. We identified two loci, ALX1 and HMGA2, which most likely are the two most prominent loci that contributed to beak diversification and thereby to expanded food utilization. These loci have played a key role in adaptive evolution of Darwin’s finches. Our study also demonstrated that interspecies gene flow played a significant role in the radiation of Darwin’s finches and some species have a mixed ancestry. This thesis also explored the genetic basis for the remarkable phenotypic differences between three male morphs in the ruff. Identification of two different versions of a 4.5 MB inversion in Satellites and Faeders that occurred about 4 million years ago revealed clues about the genetic foundation of male mating strategies in ruff. We highlighted two genes in the inverted region; HSD17B2 that affects metabolism of testosterone and MC1R that has a key role in regulating pigmentation, as the major loci associated with this adaptation.

La condition des larves de hareng des Downs durant la période critique a été caractérisée entre 2008 et 2015, en Manche orientale et dans la Baie sud de la Mer du Nord à partir des données collectées, durant la campagne International Bottom Trawl Surveys (IBTS). Tout d'abord, l'étude de la stratégie alimentaire, à partie de l'observation des proies dans les contenus digestifs par deux méthodes complémentaires (microscopie électronique et mesure de la fluorescence) a montré un changement de régime en fonction de la taille. Les larves inférieures à 13 mm avaient un régime omnivore très diversifié et composé de protistes et de petites proies zooplanctoniques, tandis que les larves plus grandes avaient un régime moins diversifié et composé principalement de plus grandes proies zooplanctoniques. En parallèle du changement de régime alimentaire, la combinaison de quatre indices de condition (taux d'ingestion, rapports ARN/ADN et ADN/C et otolithes) à l'échelle individuelle a également révélé un changement de l'état nutritionnel et de la croissance de ces larves. Les larves inférieures à 13 mm avaient une nutrition et une croissance soutenues, tandis que la croissance des larves plus grandes était faible. Ceci peut traduire un changement dans la stratégie d'allocation de l'énergie à partir de 13 mm, qui serait plus orientée vers du stockage que vers de la croissance. Ces changements ontogéniques dans la condition larvaire suggèrent que le changement de régime alimentaire qui s'opère à partir de 13 mm, pourrait constituer le coeur de la période critique pour les larves de hareng des Downs. / The larval condition of Downs herring during the critical period was investigated between 2008 and 2015 in the eastern English Channel and Southern Bight of North Sea from data collected during the International Bottom Trawl Survey (IBTS). First, the study of the feeding strategy from gut contents analysis using two complementary approaches (electronical microscopy and measure of fluorescence) revealed a shift in the feeding diet occuring at a larval size of 13 mm. Smaller larvae had an omnivorous and a more diversified diet composed of numerous protists and small zooplanktonic preys whereas bigger larvae had a less diversified diet composed mainly of bigger zooplanktonic prey. Along with the diet shift, combination of four condition indices (ingestion rate, RNA/DNA and DNA/C ratios and otoliths) also revealed important changes in the nutritional status and growth of these larvae. Larvae smaller than 13 mm had a sustainable nutrition and growth whereas larger larvae depicted low growth rate. This could reflect a change in the energy-allocation strategy from a growth-oriented strategy towards a more storage-oriented strategy. These ontogenetic changes in the larval condition suggest that the diet shift occurring at 13 mm could constitute the core of the critical period for Downs herring larvae.

This study was initiated to determine the effects of Herring Gulls (Larus argentatus) on the vegetation and soils of their nesting sites within the Mingan Island National Park Reserve. Both vegetation (species composition, cover, density, growth) and soil characteristics (pH, N, P, K, Ca, Mg) were monitored throughout the 1995 breeding season. Exclosures were installed within the colonies as control sites to prevent gull activity and these were compared to "treatment plots" or areas where gulls were present. All plants located at the study sites were native perennials with the exception of Stellaria, a native annual. Ledum groenlandicum was the only plant species significantly affected by gull activities. Both % cover and shoot growth for Ledum were greater in the exclosures than in the treatment plots over the breeding season. The gulls were also found to significantly increase pH and phosphorous levels in the soil through the deposition of faeces. Gull roosting sites were found to have higher nutrient levels than the nesting areas (treatment plots). The gulls appear to have minor effects over the short term, however the increases in soil nutrients may lead to significant changes over the long term. It is therefore imperative the exclosures remain in place to monitor for any long term changes which may occur.

This thesis focuses on toxicity and occurrence of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in Baltic Sea biota. The aims were to assess OH-PBDEs potency for disruption of oxidative phosphorylation (OXPHOS) and determine their and related compounds exposure in Baltic blue mussel, herring and long-tailed duck. A method for analysis of OH-PBDEs in herring and long-tailed duck plasma was also evaluated. Relevant OH-PBDEs were tested in vitro for OXPHOS disruption, using a classic rat mitochondrial respiration assay and a cell mitochondrial membrane potential assay. All compounds were found to disrupt OXPHOS either by protonophoric uncoupling and/or via inhibition of the electron transport chain. 6-OH-BDE47 and 6-OH-BDE85, were identified as particularly potent OXPHOS disruptors. Strong synergism was observed when OH-PBDEs were tested as a mixture corresponding to what is present in Baltic blue mussels. Baltic blue mussel is main feed for several species of mussel feeding sea ducks which have decreased dramatically in numbers. To assess long-tailed ducks exposure to brominated substances, liver tissue from long-tailed ducks wintering in the Baltic Sea and blue mussels were analysed. The result confirms that long-tailed duck are exposed to OH-PBDEs via their diet. However, low concentrations were found in the duck livers, which suggest low retention of these compounds despite daily intake. How the nutritional value of blue mussels as feed for sea ducks are affected by OH-PBDE exposure still needs further studies. Other species of sea ducks foraging on Baltic blue mussels during summer months can also be more exposed due to seasonal variation in primary production. Herring sampled in the Baltic Proper and Bothnian Sea, were found to contain OH-PBDEs and high levels of their methylated counterpart, MeO-PBDEs. As demethylation of MeO-PBDEs is known to occur in fish, MeO-PBDEs may pose as additional source for more toxic OH-PBDEs in herring and their roe. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.</p>