The macro-algae Nereocystis luetkeana or bull kelp is an important canopy-forming species in the rocky nearshore ecosystems of the Salish Sea. It provides structural habitat for many fish and invertebrates including juvenile salmon. In the Pacific Northwest, major declines in Chinook and Coho salmon populations have led to increased scientific efforts to determine the causes behind these losses. High mortality of juvenile salmon during their first months in the marine environment may be linked to loss of habitat such as kelp beds, which can provide shelter, concentration of prey and energetically favorable conditions. This work seeks to understand the role of kelp habitat in the early marine growth period of juvenile salmon. Initially, methods using satellite imagery were developed for mapping the location of kelp beds adjacent to a salmon bearing river in Cowichan Bay, on the West Coast of British Columbia. These methods were then applied to a time series of imagery from 2004 to 2017, to determine how kelp beds are changing over time and the possible drivers of those changes. The results found spatial and temporal variability in kelp beds with a decline from a high in 2015 to the lowest levels in 2017. The observed changes were over a short period considering the natural variability of Nereocystis and continued long term monitoring will help to determine if the declines are permanent. Spatial and temporal variability were found to relate to substrate type, current strengths and potential lag effects of declines due to warmer than average sea surface temperatures. Lastly, the maps created through satellite-based methods served to inform surveys investigating the importance of kelp habitat to the declining populations of Chinook and Coho salmon. To address this, remote underwater video and visual snorkel surveys were used to determine the presence and absence of juvenile salmon in paired kelp and no-kelp sites throughout the season when the fish are known to be present in the region. Higher densities of juvenile salmon were detected in kelp-associated areas; however, this effect was detected both before kelp growth in early spring and during kelp presence. Transects conducted on the inner edge of kelp beds, adjacent to rocky shorelines were determined to have the highest salmon densities indicating that physical factors such as substrate type and wave energy associated with these areas may be preferential to juvenile salmon. / Graduate

Hydropower production has advantages but also negative ecological consequences. Thisstudy analyzes the degree of flow variations downstream Viforsen's power plant to investigate how well the regulated flow is re-regulated towards a more natural flow pattern. The studyalso examine effects of the regulation on valuable salmon habitats in the section from Viforsen's power plant down to the sea and whether there is a downstream gradient in the presence of different fish species. Data on water level changes was obtained by installingthree pressure loggers in a gradient downstream of the Viforsen power plant. Collection of hourly flow-data in Viforsen and Vindelälven have been part of the data in the survey. The presence of different species of fish was determined by examination of the Swedish electrofishing registry. Results showed a strong correlation between flow and water level at all three sites in Ljungan and there is no ecologically significant dampening of water level fluctuations downstream Viforsen. The current requirement for a minimum discharge of 30 m3/s is too low as important salmon habitats risk being drained. The strong correlation between water levels and flow that this study shows make it possible to map in more detail the risks of valuable salmon habitats drying up. The results also showed that typically marine species” of fish are much more common in Viforsen than in Vindelälven. This study emphasizes that ecologically sustainable flows are complex and relevant field investigations at each watercourse are necessary when reconsidering and designing the new environmental conditions.

The Sacramento River watershed provides important rearing habitat for key aquatic species, including juvenile Chinook salmon (Oncorhynchus tshawytscha). Salmon rearing in the watershed may inhabit the mainstem river channel or a corresponding floodplain, the Yolo Bypass, before migrating to the ocean. Studies of juvenile salmon have indicated that floodplain rearing may be beneficial in terms of growth and survival, likely related to different trophic pathways of the river and floodplain. However, fish also encounter many anthropogenic stressors in these habitats, such as pesticides, which have well-documented use and environmental presence in the region. Rearing individuals are potentially exposed to pesticides via trophic transfer, which may vary based on utilized food webs due to hydrophobic pesticide fate and transport. To examine the food web structure of each system and the potential for pesticide exposure through dietary routes, a two-year field study was completed. First, to characterize dietary contributions, a three-tiered approach incorporating stable isotopes (δ13C, δ15N and δ34S), essential fatty acids and gut content analyses was employed. Subsequently, pesticides were extracted from prey items and salmon and analyzed to determine contaminant residues. Stable isotope analyses indicated that critically important components of juvenile Chinook diet were amphipoda and adult diptera in 2019 and 2020, respectively. Amphipoda groups had higher concentrations of the fatty acid docosahexaenoic acid (DHA), an important component for fish development, than juvenile diptera or oligochaeta. Diptera (larvae and adults) were frequently found in juvenile Chinook stomachs from both areas and years. Throughout the pesticide examination, organochlorines including the DDT group (p,p’-DDT, p,p’-DDD and p,p’-DDE) were prevalent in all examined biota. There were a significantly greater number of pyrethroid and phenylpyrazole detections and concentrations in zooplankton as compared to macroinvertebrates (Poisson regression, p < 0.05) across regions and years. Additionally, significantly higher concentrations of organochlorines were exhibited in floodplain rearing fish as compared to the Sacramento River (ANOVA, p < 0.05). These findings suggest that juvenile Chinook feeding primarily on zooplankton may be exposed to a greater range of pesticides than those exhibiting benthic feeding, but these pelagic prey were not demonstrated as a major dietary item during the two-year study. Additionally, the previously inferred benefits of floodplain rearing may come at a cost of increased organochlorine exposure. This research has allowed for a robust assessment of potential trophic transfer of pesticides to juvenile salmon, which may help inform future floodplain restoration efforts.

Environmental citizenship is positioned as a platform where the rights of social and environmental justice converge with civic engagement and responsibility. As industrialized economies continue to exhaust the limits of finite natural resources and exacerbate conditions of global climate change, scholars have questioned if environmental citizenship models offer a method for deepening obligations to a sustainable movement. In the material culture enjoyed by Western civilizations, existing research supports that an individual’s purchases are seen as an indicator of their values and identities. Consequently the commitment to responsible buying behavior or sustainable consumption is in a sense an expression of eco-citizenship. My thesis offers a critical perspective of Andrew Dobson’s ecological citizenship theory, by asking how sustainable consumption can be conceptualized in the existing political and economic infrastructures. Using a thorough case study of globally traded fish provisions, I investigate the existing barriers for eco-citizens attempting to realize their obligations to sustainable consumption. This analysis allows me to draw conclusions on how these barriers may inhibit ecocitizenship theories and ultimately a sustainable social movement. The structure of this thesis is broken into three parts. First, I define existing theories of ecological citizenship and sustainable consumption, including the theoretical propositions, requirements, and limitations. Secondly, I rely on Dobson’s conception of ecological citizenship and an instrumental case study of Pacific Salmon provisions to illustrate the barriers eco-citizens encounter in the current market and regulatory system. Finally, this paper concludes by proposing individual and institutional changes that will assist in fostering an eco-citizen community and the contribution my findings may have on existing green citizenship research.

Growth plays a key role in regulating ecological and population dynamics. Life history characteristics such as age at maturity, fecundity and age and size at migration are tightly linked to growth rate. In addition, size can often determine survival and individual breeding success. To fully understand the process of growth it is important to understand the mechanisms that drive growth rates. In Atlantic salmon, growth is critical in determining life history pathways. Models to estimate growth could be useful in the broader context of predicting population dynamics. In this dissertation I investigate the growth process in juvenile Atlantic salmon (Salmo salar). I first used basic modeling approaches and data on individually tagged salmon to investigate the assumptions of different growth metrics. I demonstrate the size-dependency in certain growth metrics when assumptions are violated. Next, I assessed the efficacy of linear mixed effects models in modeling length-weight relationships from longitudinal data. I show that combining a random effects approach with third order polynomials can be an effective way to model length-weight relationships with mark-recapture data. I extend this hierarchical modeling approach to develop a Bayesian growth model. With limited assumptions, I derive a relatively simple discrete time model from von Bertalanffy growth that includes a nonparametric seasonal growth function. The linear dynamics of this model allow for efficient estimation of parameters in a Bayesian framework. Finally, I investigated the role of life history in driving compensatory growth patterns in immature Atlantic salmon. This analysis demonstrates the importance of considering life history as a mechanism in compensatory growth. Information provided in this dissertation will help provide ecologists with statistical tools to estimate growth rates, estimate length-weight relationships, and forecast growth from mark-recapture data. In addition, comparisons of seasonal growth within and among life history groups and within and among tributaries should make a valuable contribution to the important literature on growth in Atlantic salmon.

In many cases in the past fish bones recovered during archaeological excavations at Upper Palaeolithic sites were often assumed to result from human activity without any consideration for alternate accumulation processes. Many of these assemblages had not been analysed in a scientifically rigorous manner, with some receiving no consideration at all. A review of current evidence and results of new analyses indicate that salmonids (salmon and trout) are the most frequently recorded fish at the European Palaeolithic cave sites. Two potential accumulation agents for fish remains were explored: brown bears (Ursus arctos) and eagle owls (Bubo bubo). Controlled feeding experiments integrated with ecological studies indicate that salmonid remains survive the digestive systems of both species and result in distinctive patterning in assemblage characteristics. Post-depositional taphonomic processes, such as trampling, also produce distinct taphonomic signatures and are an agent of differential inter-species preservation. A thorough consideration of depositional and post-depositional processes of archaeological assemblages in central Italy (Grotta di Pozzo, Maritza, La Punta and Ortucchio) and Spain (El Juyo, Altamira, Salitre, Castillo and Rascaño) shows that the fish remains from these sites result from human activity. The overrepresentation of cranial elements at the Italian sites suggest that fish were processed by removing the head to perhaps smoke or dry before transportation to other locations for consumption. This research lead to improved methods of analysis, and thus enhanced understanding of the role of fishing and fish consumption in Upper Palaeolithic hunter-gatherer societies.

Thesis advisor: Noah P. Snyder / Thesis advisor: Mathias J. Collins / Large wood (used interchangeably with the term “instream wood”), which refers to trees, logs and other wood within a channel, is beneficial to river ecosystems and is being used more frequently as a component of river restoration projects. The process of large wood becoming stable within a river channel, inducing floodplain formation, and eventually providing large wood back to the system is known as the ‘floodplain large-wood cycle’ hypothesis (Collins et al., 2012). In a stream restoration context, this process can be viewed as an indicator of a self-sustaining cycle. The ‘floodplain large-wood cycle’ hypothesis was formulated in the Pacific Northwest. To investigate this process in other regions, I used the Merrimack Village Dam (MVD) study site in southern New Hampshire. The study site provided a location where instream wood was recruited to the river from an adjacent terrace as a consequence of erosion associated with a dam removal. Assessment of wood in this scenario was used to evaluate the ‘floodplain large-wood cycle’ (Collins et al., 2012), and to compare MVD to “passive” large wood restoration and deliberate, and potentially engineered, large wood restoration sites throughout New England. To assess multiple sites, I identified metrics to evaluate the effectiveness of large wood to promote ecological and geomorphic complexity within channels. The metrics were quantified at the MVD site and several other sites in New England with natural or placed large wood. I also collected additional data at the MVD site using methods implemented during previous studies, including cross section surveys and repeat photographs (Collins et al., 2017; Pearson et al., 2011). The study assessed habitat and geomorphic effects of large wood within river systems in the northeastern U.S. and provided information to evaluate the use of large wood during river restoration. Overall, only 33%, 33%, and 20% of surveyed sites are consistent with hypotheses formulated regarding significant differences in depth variability, velocity variability, and median velocity between test and reference reaches, respectively. With evidence for and against each hypothesis at both passive and active sites, large wood structures did not cause the geomorphic and hydraulic changes I expected to see. The availability of sand in a channel and the stream slope influencing sediment transport seem to be important factors in determining whether or not large wood has the ability to impact the geomorphic and hydraulic characteristics of a channel. At the MVD site, where sand is available, up to 0.90 m of sediment deposition is seen on top of the surface eroded by a March 2010 flood, surrounding recruited trees. Evaluation of historical aerial imagery further indicates that evidence of the ‘floodplain large-wood cycle’ hypothesis is present at the MVD06 cross section on the Souhegan River in New Hampshire. / Thesis (MS) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

This dissertation argues that the significance and extent of American animal “acclimatization”—the nineteenth-century term for the purposeful introduction of non-native wild animals—has been drastically underestimated in previous historiography. Far from a negligible “fad” that only briefly interested a small number of hunters and wildlife enthusiasts, American acclimatization was in fact a large-scale and enduring exercise in bioengineering that introduced dozens of new species to the nation over the course of more than a century. At first led by private individuals and organizations, American acclimatizers introduced several new birds and fish into the country from the mid-nineteenth century, including modern-day mainstays like the English sparrow, ring-necked pheasant, and German carp. While private organizations devoted to animal acclimatization mostly dissipated by the late nineteenth century, the federal government’s biologist-bureaucrats made the acclimatization of new animals a central component of vast efforts to supply America’s hunters and fishers deep into the twentieth century, a persistence that has been heretofore overlooked. In composing the first dedicated study of American animal acclimatization, I visited a dozen different archives and have brought hundreds of previously unexamined sources to bear. These revealed the enduring popularity of animal acclimatization and its persistence as a wildlife rejuvenation tool. These sources also laid bare the ideological motivations for animal acclimatization. Far from salving a nostalgic yearning for the fauna of Europe, Euro-Americans often saw animal acclimatization projects as progressive techniques of environmental management instead. Animal acclimatization projects, moreover, were intertwined with the Euro-American colonization of the American West. Settler-colonial ideology, that fusion of Euro-American racial supremacy with grandiose notions of national identity and expansion, runs through the rhetoric of many acclimatizers. More concretely, the United States Fish Commission effected the violent dispossession and subordination of the Winnemem Wintu People on California’s McCloud River in order to set up the nation’s first chinook salmon hatchery. The USFC used the hatchery to artificially spawn tens of millions of salmon to replenish American waters as well as establish chinook salmon in American and international watersheds where the fish had never existed before. Finally, I argue that the story of American acclimatization—what I call the American “acclimatization exchange”—offers important nuance and modification to the two most famous paradigms in environmental history: the conservation movement and Alfred Crosby’s “Columbian Exchange.” Massive parallel efforts in animal acclimatization indicate that the conservation era featured far more interventionist environmental management than usually appreciated. The early adoption of “fish culture” in 1860s American also suggests that the conservation era’s periodization should be significantly backdated. Furthermore, the sheer popularity and endurance of foreign species acclimatization in the nineteenth and twentieth centuries, plus the fact that Americans often obtained and exchanged species from Asia, India, and the broader Pacific World, temporally and geographically expands on Crosby’s notion of an Atlantic World “Columbian Exchange” in the wake of initial European discovery and colonization.

We have performed experimental infections of Atlantic salmon (Salmo salar) from the Baltic Sea region with the protozoan parasite Spironucleus salmonicida. By this infection trial we have been able to show that the life cycle may use an alternative route of transmission. Instead of the commonly used faecal-oral route, the parasites can also be excreted directly into the surrounding water from the mucous layer of the skin or from an ulcerated skin lesion. Three different stages of the infection were identified: one intestinal, one blood stage and one tissue stage. New putative life-cycle forms of S. salmonicida cells detected by ex-vivo cell-cultures. Similar cells were also observed in imprints from skin lesions sampled during the experimental infection trials. The cells differed morphologically, from normal trophozoite cells and indicate an alternative cell-cycle when exposed to salmonid host cells.

Bei dem architektonischen Entwurf 'Begehungen' handelt es sich um die thematische Auseinandersetzung mit der Planung einer Gedenkstätte gegen den Einsatz und die Testung von Atomwaffen. Dies geschieht auf dem Gelände des 'Salmon Site' im Osten der USA. Dieses Gebiet war Schauplatz zweier unterirdischer nuklearer Testungen, die Teil des amerikanischen 'Vela Projekts' waren. Die Explosionen erfolgten im Jahr 1964 und 1966. Bis heute ist das Gebiet eingezäunt und unbewohnt. Der Entwurf soll eine Heranführung an die Thematik sein. Er behandelt den Ort als Erinnerung und setzt sich mit dieser Erinnerung auseinander. Es wurden landschaftliche Parameter aufgestellt, die den Ort erfahrbar machen sollen.