Recent Submissions

  • Marine debris in the Bering Sea: combining historical records, toxicology, and local knowledge to assess impacts and identify solutions

    Padula, Veronica M.; Beaudreau, Anne; Causey, Douglas; McDonnell, Andrew; Konar, Brenda; Hollmen, Tuula (2022-05)
    Marine debris, particularly plastic marine debris, has numerous impacts on the environment, wildlife, and human communities. This research examines dimensions of marine debris in the Bering Sea and Aleutian Islands, Alaska, including impacts of marine debris pollution on wildlife and the environment; the history of marine debris research, monitoring, and cleanup activities; and community perspectives on local to global solutions. The first chapter of this dissertation is an integrative literature review to better understand the current status of marine debris knowledge in the Bering Sea region and identify critical knowledge gaps. We synthesized the depth and breadth of research, monitoring, and cleanup activities to better understand the sources, prevalence, and impacts of marine debris on wildlife and coastal communities. Our review revealed several knowledge gaps, including two that were a focus of the final chapters of the dissertation: measuring the extent of plastic-associated contaminants in the Bering Sea and capturing community perspectives and concerns about marine debris in the Bering Sea. The second chapter examined variation in phthalates, a class of plastic-associated chemicals, in Aleutian Islands seabirds, to refine hypotheses regarding ecological and environmental factors that affect phthalate exposure in marine wildlife. We quantified phthalates in seabirds collected across >1700 km of the Aleutian Islands, Alaska, and measured six phthalate congeners in seabirds representing ten species and four feeding guilds. Phthalates were detected in 100% of specimens (n = 115) but varied among individuals (range 3.64 - 539.64 ng/g). Total phthalates did not vary geographically, but differed among feeding guilds, with significantly higher concentrations in diving plankton-feeders compared to others. Our findings suggest feeding behavior could influence exposure risk for seabirds and lend further evidence to the ubiquity of plastic pollutants in marine ecosystems. The final chapter of the dissertation explored perspectives and concerns of St. Paul Island community members regarding marine debris and plastic pollution. This component of the research aimed to catalyze the inclusion of local knowledge in marine debris solutions for St. Paul Island, Alaska, by documenting community members' perceptions of marine debris, including its origin, impacts, and proposed solutions. We interviewed thirty-six St. Paul Island community members from 2017 to 2020 about the types, amount, distribution, and impacts of marine debris they have observed on the island and its surrounding waters over recent decades. Research participants reported increases in plastic debris since the 1980s, particularly plastic bottles. Nearly 80% expressed concern about impacts to subsistence resources, including entanglement and ingestion of plastic particles by marine mammals and fishes. St. Paul Island community members' experiences highlight that solving the problem of marine debris cannot rely on local efforts alone but requires broader policies and mitigation strategies to address the sources of debris and advance environmental justice for coastal communities. Overall, this dissertation contributes an improved understanding of the social and ecological impacts of plastic pollution in the Bering Sea region and the potential science and policy solutions that can stem the tide of marine debris.
  • Assessing the demographic and genetic contributions of precocial males in a naturally spawning population of coho salmon

    King, Erika M.; McPhee, Megan; Tallmon, David; Vulstek, Scott; Cunningham, Curry (2022-05)
    Despite the importance of alternative life history strategies to population productivity, little is known about the mating structure of precocial ('jack') males in Pacific salmon. The number of successful matings obtained by jacks in the wild is not well characterized and the impact of including or excluding jacks in the management of Pacific salmon populations is unknown. This study aims to fill knowledge gaps in the understanding of jack life history by 1) determining the typical contribution of jacks to the next generation in a natural mating population; and 2) estimating the impact of jacks on genetic diversity. The study capitalizes upon 11 years of demographic and genetic data from a naturally spawning population of Coho Salmon from Auke Creek, in Juneau, Alaska. Individuals returning over this time period (~8,000 individuals) were genotyped at ~250 single-nucleotide polymorphism (SNP) loci. Using these genotypes, we quantified the adult-to-adult reproductive success of different male types using parentage analysis for each of seven return years and compared genetic and demographic estimates of effective population size. We demonstrated that although jacks were less successful than full-size males on a per individual basis, they contributed substantially to the population and influenced population and evolutionary dynamics.
  • Spatial and temporal variability of fish and mussel distributions revealed through eDNA metabarcoding

    Dokai, William; McPhee, Megan; Larson, Wesley; Tallmon, David; Zanatta, David (2022-05)
    Unionid mussels (order Unionida) are freshwater bivalves distributed worldwide and are among the world's most endangered taxonomic groups. Unionid mussels utilize various fish species as obligate hosts for their parasitic larval stage, and as a result, native fish species are vital to unionid persistence. One of the primary conservation needs for both unionids and fishes is more complete distributional data. However, these data are labor and resource intensive to collect using traditional survey methods. Here, we utilized an eDNA metabarcoding approach to detect unionid mussels and fishes within a large portion of the lower peninsula of Michigan, USA, with the goal of validating this method for the paired detection of these two groups of taxa. We investigated whether communities of fishes and mussels varied between the tributaries of Lake Michigan and the Grand River watershed, between early- and late-summer sampling events, and between areas of high and low mussel diversity. We detected 21 unique mussel taxa and 46 unique fish taxa within the Grand River watershed and 20 Lake Michigan tributaries. We detected differences in fish and mussel communities across different sampling regions and between sampling events. We also found fish taxa associated with areas of high and low mussel diversity. Notably, we detected more mussel taxa within the Grand River watershed compared to Lake Michigan tributaries, more fish in the August sampling event compared to June, three fish taxa more frequently at areas of high mussel diversity, and four fish taxa more frequently at areas of low mussel diversity. This study demonstrates the utility of combining unionid and fish metabarcoding primers to efficiently describe the co-distribution of these interdependent taxa within the Great Lakes region.
  • The effect of sea otter predation and habitat structure on nearshore crab assemblages in Southeast Alaska

    Cates, Rebecca Jeanette; Eckert, Ginny L.; Cunningham, Curry; Siddon, Christopher (2022-05)
    Sea otter Enhydra lutris predation has resulted in conflict with humans for shared marine resources, as sea otters reduce the abundance and size of nearshore crabs. Several species of crab in Southeast Alaska are prey for sea otters including Cancer magister, a highly valued commercial and subsistence species, as well as Cancer gracilis, Cancer productus, and Telmessus cheiragonus, species that are abundant in the nearshore and of ecological and subsistence importance. Understanding the influence of sea otters and habitat structure on valuable crab species is of particular importance in Southeast Alaska as the abundance and range of sea otters expands across important crab nursery habitat. We 1) conducted breakpoint analyses to identify sea otter density thresholds that affect the abundance and biomass of nearshore crab species, 2) used a two-factor type III Analysis of Variance (ANOVA) to test the impact of sea otter presence and year on crab size, and 3) used general linearized models (GLM) to test the impacts of sea otter density and habitat structure on crab species abundance and size distribution. We found evidence of sea otters decreasing crab species' abundance, biomass, and size. C. magister, C. gracilis, and C. productus experienced a significant decline in size in the presence of sea otters, while T. cheiragonus size did not differ as a function of sea otter presence. We found a significant decrease in biomass in C. magister and in biomass and abundance in C. productus, associated with increasing sea otter density. Different responses across crab species are likely attributed to size distributions and sea otter foraging behavior. Habitat characteristics, such as eelgrass biomass and shoot density, had a small influence on crab abundance and size that depended on the species of crab. These results suggest that populations of large crabs do not persist in the presence of sea otters, small crabs may co-occur with sea otters, and eelgrass biomass and density marginally influence crab abundance and size.
  • The effects of ocean acidification and warming on the metabolic physiology of juvenile northern spot shrimp (Pandalus platyceros)

    Musbach, Jamie Lee; Tamone, Sherry; Kelley, Amanda; Eckert, Ginny (2021-12)
    Northern spot shrimp (Pandalus platyceros) support important commercial, subsistence, sport, and personal use fisheries in Alaska. This species is currently experiencing population declines in Southeast Alaska, mandating fishery closures in previously productive regions. Northern spot shrimp are harvested as adults and declining populations may be a result of limited recruitment into the fishery. Very little is known about the physiology of P. platyceros early life history stages and no known data exists on how early life history stages may be affected by environmental stressors such as ocean acidification (OA) and ocean warming (OW). OA is a result of increased anthropogenic carbon dioxide (CO₂) input into the ocean. Increased pCO₂ affects both the physical and chemical properties of the ocean, which, in turn, affects the marine biota. In addition to OA, ocean warming (OW) is another environmental stressor associated with ocean change. The Intergovernmental Panel on Climate Change (IPCC) predicts an oceanic pH decrease of 0.2-0.4 units and an increase in ocean temperatures up to 5°C by the year 2100. The goal of this thesis is to characterize potential individual and interactive effects of increased pCO₂ and increased temperature on the metabolic rate (MO₂), gene expression of heat shock protein 70 (Hsp70), and gene expression of carbonic anhydrase (CA) in juvenile P. platyceros. In order to assess the individual and interactive effects of these environmental stressors on juvenile P. platyceros physiology, I built a low-cost open hardware OA and OW system in the seawater lab at the University of Alaska Southeast. This pH-stat system, based on open-source Arduino platform, allowed manipulation of pH and temperature in line with the IPCC's future predicted ocean conditions. Juvenile P. platyceros are a model organism for this type of research due to predictions that early developmental stages, the requirement of calcification for growth, and cold-water marine organisms may be most susceptible to OA and OW stressors. Understanding how this ecologically and economically important species may be affected by environmental stressors can highlight the capacity of P. platyceros to withstand ocean change.
  • Spawning site selection of coho salmon Oncorhynchus kisutch in Susitna River tributaries, Alaska

    McCracken, Betsy W.; Sutton, Trent; Falke, Jeffrey; Carey, Michael (2021-12)
    Coho Salmon Oncorhynchus kisutch are the most widely distributed Pacific salmon species across Alaska. The lack of knowledge surrounding the habitat requirements of this species results in challenges for conservation and management due to natural and anthropogenic pressures. Tributaries of the Susitna River drainage in Alaska support many small and distinct Coho Salmon populations. Heterogeneity of in-stream spawning habitat is an ecological concept known to promote resiliency of salmonid populations. The goal of this study was to investigate the best habitat predictors of spawning site selection and the scale by which spawning habitat should be evaluated for management insights. Scale is particularly important when measuring, assessing, and predicting potential impacts to species from development activities because habitat research at the stream rather than the reach scale can overestimate the amount of available spawning habitat. I investigated a suite of field-measured stream habitat variables paired with empirical Coho Salmon spawning survey data in five tributaries during 2013 and 2014. Physical data was defined as biotic and abiotic surroundings of an organism or population that have an influence on survival, development, and evolution. Mixed-effects modeling results indicated that Coho Salmon spawning-site selection was positively related to gravel substrate and the presence of groundwater flux, and that spawning Coho Salmon avoided cobble substrate. Physical data were analyzed at both the stream and reach scales, and mixed-effects modeling results further concluded that variation in spawning activity at the reach scale (variance = 1.34, SD = 1.16) accounted for more variability and was more predictive than at the stream scale(variance = 0.04, SD = 0.19). This is important because fish habitat-associations identified at the reach scale were not identified at the stream scale. These results highlight the need for multi-scale habitat data collections and analyses to identify the most meaningful fish-habitat associations.
  • Otolith derived hatch dates, growth rates, and microchemistry of Arctic cod (Boreogadus saida) support the existence of several spawning populations in Alaskan waters

    Chapman, Zane M.; Mueter, Franz; Norcross, Brenda; Oxman, Dion (2021-12)
    The changing climate in the Arctic is resulting in increased air and water temperatures as well as a reduction in sea ice, affecting native species that evolved to live in the unique habitats of the Arctic Ocean. One species of significant importance to Arctic marine ecosystems is the Arctic Cod (Boreogadus saida), a keystone species that serves as vital prey for many marine mammals, seabirds, and fishes. Arctic Cod have a strong association with sea ice for spawning and for much of their early life history. In the Pacific Arctic, little is known about their early life history, especially with regards to hatch timing and locations. To address these gaps, I estimated the hatch timing and growth rates of Arctic Cod during their first year by examining incremental growth patterns in their otoliths. Specifically, I counted daily growth increments to estimate age, and used those estimates to describe the relationship between length and age. Using this relationship, length measurements of age-0 Arctic Cod were converted to estimated daily ages and subtracted from the day of capture to estimate hatch date distributions for multiple sampling regions. Results suggest that fish caught during spring in the northern Bering Sea and southern Chukchi Sea hatched near their capture location over a relatively short period that coincided with the timing of local sea ice recession. Hatch dates from summer samples over multiple sampling regions indicated a prolonged hatching event that lasted from early winter (December) through early summer (July). Summer aggregations in the northeast Chukchi Sea likely represented a mix of different hatching populations that had been transported from the south and retained in the northern regions. Within each sampling region, mean hatch dates differed between pelagic and demersal caught Arctic Cod, which supports the existence of multiple hatching populations mixing within each region during the summer. In general, hatching occurred earlier the further south they were captured for summer captured fish, whereas their growth rate declined as one moved northward, possibly due to the higher average temperatures during the larval stage in southern hatching locations. By analyzing the elemental composition of otoliths, I was able to infer environmental conditions such as salinity near the time of hatching of age-0 Arctic Cod. Regional differences in elemental concentrations at the time of hatching suggest a stronger freshwater influence in the eastern Beaufort Sea compared to the Chukchi Sea and western Beaufort Sea and support the existence of separate hatching populations. This study expands the understanding of the early life history of Arctic Cod and informs managers and policy makers to better protect critical life stages of this key species in a changing environment.
  • Habitat analysis of major fishing grounds on the continental shelf off Kodiak, Alaska

    Rooney, Sean Charles; Reynolds, Jennifer; Norcross, Brenda; Heifetz, Jonathan; Kruse, Gordon (2008-12)
    "The continental shelf and upper slope of the Gulf of Alaska support diverse and commercially important communities of demersal fishes. Twenty-eight video-strip transects conducted from a research submersible, together with habitat maps based on interpreted multibeam sonar data, were used to classify distribution and abundance patterns of fishes relative to seafloor substrate type and water depth on Albatross and Portlock Banks on the Kodiak Shelf in the Gulf of Alaska. These associations were examined across spatial scales: ranging from tens of kilometer centimeters in size. A total of 5,778 fishes were recorded from 33 taxa. Fish community distribution patterns were largely correlated with depth and to a lesser extent with substrate type. Individual fish species habitat associations were also influenced by depth and substrate type; however, the spatial scale at which these factors were relevant varied by fish species. There was strong regional concordance among observed fish species habitat associations and those previously documented in studies from central California to the northern Gulf of Alaska. Although integrating substrates classified at different scales was challenging, the resulting information of scale specific habitat associations provides a more comprehensive understanding of how demersal fishes utilize benthic habitats"--Leaf iii
  • Age, growth and productivity of juvenile sockeye salmon in two high latitude lakes, Alaska

    Wilson, Lorna I.; Smoker, William W.; Adkison, Milo D.; Zimmerman, Christian E.; Volk, Eric C. (2009-12)
    "The growth of Seward Peninsula sockeye salmon (Oncorhynchus nerka) from Salmon and Glacial lakes is related to their physical environment. Dermal scales collected over many years were measured to document the annual age specific growth of smolts and adults. The effect of fertilization on fry growth was examined using the first year of growth. The growth histories of Salmon Lake sockeye salmon were compared to Glacial Lake sockeye salmon through smolting and in the marine environment. Annual age specific fry growth had no direct relationship to fertilization; however, there were interactions between biomass of salmon prey and fertilization, and between prey biomass and age of smolting. Glacial Lake age-1 smolts are the same size as Salmon Lake age-1 smolts, but age-1.3 Salmon Lake juveniles after their first year in the ocean are smaller than age-1.3 Glacial Lake juveniles suggesting lower size based mortality. The differences in growth histories show each population's response to lake production and mortality experienced by smolt between the rearing lake and the ocean"--Leaf iii
  • Analysis of adult sport fishing lesson choices and their application to post-secondary curriculum development

    Jones, Shann Paul; Hebert, Michele; Wipfli, Mark; Bomar, Charles R.; Johnson, Terry L.; Carlson, John (2009-12)
    "Post-secondary angler education offerings have increased nationally, but little is known about what sport fishing skills anglers desire. I noticed variations in such curricula while developing the University of Alaska Fairbanks course, Fundamentals of Fly Fishing. My study objectives were to 1) determine what fly-fishing skills potential students desire so they invest both time and money attending my education events; 2) refine my offerings; and, 3) determine if students gained angling-related knowledge. I developed a questionnaire gauging the public's fly-fishing educational desires and requirements, and distributed it from 2003 to 2005. After analyzing the results, I revised my class to include more science-based angler knowledge and practical skills. The target audience for my classes is people under 55 years of age with less than three years angling experience who fish less than twice monthly. They want preparatory topics that allow them to continue with the sport once they complete the educational event. After incorporating the results into my offerings, enrollments more than doubled from 2003 to 2008. Students made measurable advances in understanding the sciences behind sport fishing. By surveying potential participants' educational desires and needs, adult educators should be able to build sustainable personal enrichment programs as demonstrated here"--Leaf iii
  • Environmental gradients and prey availability relative to glacial features in Kittlitz's murrelet foraging habitat

    Arimitsu, Mayumi L.; Hillgruber, Nicola; Piatt, John; Weingartner, Thomas; Mueter, Franz (2009-12)
    "The goal of this study was to characterize Kittlitz's murrelet (Brachyramphus brevirostris) foraging habitat relative to prey availability and oceanography in Kenai Fjords National Park, a glacial-marine system. I conducted oceanographic, hydroacoustic, trawl, beach seine, and marine bird surveys monthly from June-August in 2007 and 2008. High sediment load from glacial river runoff shaped the marine ecosystem, and this appeared critically important to Kittlitz's murrelets at sea. Submerged moraines influenced inner fjord habitat that was characterized by cool, fresh, stratified, and silt-laden waters. This silty glacial runoff limited light availability to chlorophyll near tidewater glaciers, but zooplankton abundance was enhanced in the surface waters, perhaps due to the absence of a photic cue for vertical migration. Zooplankton community structure was influenced by glacial features and varied along an increasing temperature gradient over the summer. Acoustic measurements suggested that low density aggregations of fish and zooplankton were available in the surface waters near glacial river outflows where murrelets typically forage. Dense fish aggregations moved into the fjords by August. Kittlitz's murrelets were more likely to occur in areas with higher acoustic biomass near glaciers, making these birds more susceptible to climate change than the congeneric marbled murrelet (B. marmoratus), which was most associated with shallow, ice-free areas"--Leaf iii
  • Balancing biological sustainability with the economic needs of Alaska's sockeye salmon fisheries

    Steiner, Erin M.; Criddle, Keith R.; Adkison, Milo D.; Kruse, Gordon H. (2009-05)
    "The total revenue of the Bristol Bay, Alaska sockeye salmon, Oncorhynchus nerka, fishery has continued to decline despite strong run sizes. This decline is primarily attributed to increases in production of farmed Chilean rainbow trout O. mykiss and coho salmon, O. kisutch. Although wild salmon managers have less control over production than salmon farmers, there may be some opportunity to regain value to the fishery by altering management strategies. To explore this potential, we first simulated three management strategies for sockeye salmon: a fixed escapement range strategy, a fixed harvest strategy and a fixed harvest rate strategy. Yields from these simulations were then combined with a forecast of farmed Chilean trout and salmon production and a model of international trade flows for Alaskan sockeye and Chilean coho salmon and rainbow trout to generate forecasts of exvessel price and total revenue for 2010. All three management strategies were able to achieve a run size equilibrium indicating biological sustainability. The highest median yield resulted from the fixed escapement strategy and the lowest median yield was generated by the fixed harvest strategy. Exvessel prices and total revenue were highest under the fixed harvest strategy. These results demonstrate a switch to an inelastic market environment and reveal the need to modify current management strategies to improve the economic health of the fishery"--Leaf iii
  • Ontogenetic considerations in the trophic level of commercial groundfish species in the Gulf of Alaska

    Marsh, Jennifer Marie; Hillgruber, Nicola; Foy, Robert; Kruse, Gordon; Wooller, Matthew (2010-12)
    "Trends in trophic level (TL) estimates of commercial fishery catches are used as ecosystem-based indicators for sustainability, but these estimates often do not incorporate species-specific interannual and ontogenetic feeding patterns. This study provides a finer resolution of ontogenetic and temporal variations in the trophic position of four groundfish species in the central Gulf of Alaska (GOA), walleye pollock (Theragra chaleogramma), Pacific cod (Gadus macrocephalus), arrowtooth flounder (Atheresthes stomias), and Pacific halibut (Hippoglossus stenolepis), using stable isotope analysis to assess TL and diet source. Samples were collected from the northeastern side of Kodiak Island, Alaska, from 2000-2004. Several Analysis of Covariance models were tested, allowing TL to co-vary with length, to detect possible variation among years and seasons and to estimate TL of catch for each study species. For each species, TL increased with length. Significant annual differences in [delta]¹³C and [delta]¹⁵N were detected for all groundfish, indicating a lower TL, pelagic diet in 2003 and a higher TL, benthic diet in 2001. Overall, TL of GOA commercial catches appeared to remain stable over 1990-2009, with the exception of walleye Pollack after 1999. This study shows that including length data could lead to an earlier detection of decline in TL estimates"--Leaf iii
  • Variation in the trophic position of spiny dogfish (Squalus acanthias) in the Northeastern Pacific Ocean: an approach using carbon and nitrogen stable isotopes

    Andrews, Alexander George III; Foy, Robert J.; Hillgruber, Nicola; Kruse, Gordon H.; Wooller, Matthew J. (2010-12)
    "Spiny dogfish (Squalus acanthias) are among the most abundant shark species in the Gulf of Alaska (GOA). An increase in relative biomass of spiny dogfish in 2003 and 2007 inspired interest in this species as a commercial resource. However, very little was known about the ecology of this species in the GOA. This study investigated the trophic role of spiny dogfish in the GOA, British Columbia (BC), and Washington using stable isotope analysis of carbon and nitrogen. Specifically, we examined the trophic position (TP) of spiny dogfish in relation to length, sex, and geographic region. Weathervane scallops (Patinopecten caurinus) were used as a stable isotopic baseline organism. Spiny dogfish between 52 to 113 cm length had [delta]¹⁵N values that ranged geographically from 10.8°/₀₀ to 15.6°/₀₀; [delta]¹⁵N was linearly related to length. In contrast, lipid-normalized [delta]¹³C, values ranged from -21.28°/₀₀ to -16.88°/₀₀ and were not linearly related to length. In the GOA, TP of spiny dogfish ranged from 3.3 to over 4.1, with Kodiak having the highest TPs for spiny dogfish of a given length. Our results indicated that size-based ontogenetic changes in TP of spiny dogfish are important and should be incorporated into mass-balance, food-web models such as Ecopath"--Leaf iii.
  • Life history and spawning movements of broad whitefish in the middle Yukon River

    Carter, William K. III; Sutton, Trent; Brown, Randy; Lopez, Andres; Margraf, Joseph (2010-05)
    "Broad whitefish Coregonus nasus have long been an important subsistence resource across its Arctic and sub-Arctic range. Despite its regional importance, little is known about the life history and ecology of this species. This research illuminates fundamental life-history information through the use of catch-per-unit-effort (CPUE) run timing, gonadosomatic index (GSI), radio telemetry, and aging and microchemical analysis of otoliths. From 2001 to 2006, fishwheels were used to capture individuals 1,200 km upstream from the mouth of the Yukon River. CPUE data indicated a consistent increase in daily fish numbers through mid-September. The GSI showed an increasing gonad weight over the sampling period, indicating preparation for spawning. Thirty-one of 41 radio-tagged fish were tracked to a 260 km long spawning area centered 350 km upstream of the tagging site. Thirteen of 17 fish found in the spawning area in 2003 overwintered nearby. Ages of 79 individuals ranged from 5 to 16 years (mean age = 10; median age = 9). Microchemical analysis showed amphidromy in 10 of 12 individuals by examining otolith strontium (Sr) concentrations. This information indicates that the broad whitefish captured in this study were mature, migrating to a spawning/overwintering area, and have a complex amphidromous life history"--Leaf iii
  • A review of the species status of the Angayukaksurak charr (Salvelinus anaktuvukensis) of northern Alaska: perspectives from molecular and morphological data

    Ayers, Scott David; Rosenberger, Amanda; Hillgruber, Nicola; Larsen, Amy; Taylor, Eric (2010-05)
    "The Arctic, known for its dynamic past, is a significant place to examine drivers of and spatial variation in diversity of life history strategies in fishes. Diversity in heritable life history traits can lead to speciation, as may be the case for the putative Angayukaksurak chair (Salvelinus anaktuvukensis). The goal of this study was to determine the species status of this fish, the only described freshwater species endemic to Alaska. I examined and compared the morphology and genetics of Angayukaksurak charr and its most closely related species, the Dolly Varden (Salvelinus malma). Meristic characters divided the specimens into three forms by major river drainage. Morphological analysis divided the specimens into two forms along nominal species lines based on differences that could also be attributed to differences between life history forms. Sequences from a 550 bp section of mitochondrial d-loop failed to segregate the putative Angayukaksurak charr into a separate lineage, rather placing specimens into two previously resolved lineages of holarctic Arctic chair. In addition, analysis of microsatellite loci showed no clear differentiation between species. Based on these results, I concluded that the Angayukaksurak charr is not a separate species, but rather a resident life history form of the Dolly Varden"--Leaf iii
  • A remote sensing-GIS based approach to identify and model spawning habitat for fall chum salmon in a sub-arctic, glacially-fed river

    South, Lisa; Rosenberger, Amanda; Margraf, F. Joseph; Prakash, Anupma (2010-08)
    "At northern extremes, fish habitat requirements are often linked to thermal preferences and the presence of overwintering habitat. The goal of this study was to identify spawning habitat for fall chum salmon Oncorhynchus keta and model habitat selection from spatial distributions of tagged individuals in the mainstem Tanana River, Alaska. I hypothesized that the presence of groundwater, which provides thermal refugia for overwinter incubation, would be most important for fall chum salmon. Models included braiding, sinuosity, open water surface area (indicating significant groundwater influence), and open water persistence (consistent presence of open water for a 12 year period according to satellite imagery). Candidate models containing open water persistence were selected as most likely. Persistent open water areas were further examined using forward-looking infrared (FLIR) imagery; marked differences between sites were observed in the extent of thermal influence by groundwater. Persistent open water sites with strong groundwater influence appear to serve as core areas for spawning salmon; the importance of stability through time suggests the legacy of successful reproductive effort in these areas for this homing species. This study indicates that not only the presence of groundwater is important for spawning chum, but its persistence and extent of groundwater influence"--Leaf iii
  • The relationship between rainbow trout stocking success and habitat variables in Interior Alaska Lakes

    Mansfield, Kelly A.; Skaugstad, Calvin; Rosenberger, Amanda; Sutton, Trent (2010-08)
    "Fish are stocked for a variety of reasons, including the providence of diverse angling opportunities. Rainbow trout Oncorhynchus mykiss are the most widely stocked sport fish species in North America. In Interior Alaska, over 90 of the 137 lakes chosen for stocking are stocked with rainbow trout. To optimize fish stocking programs, managers require a better understanding of the lake characteristics associated with success in meeting program objectives, for assessment of potential lakes proposed for stocking, and to address angler inquiries. For my project, I used a model-selection process with lake morphometric and biotic data from 36 stocked lakes in interior Alaska to develop a predictive model for rainbow trout stocking success defined by pre-set mean length-at-age standards. Average stocking density, lake surface area, and shoreline development explained 46% of the variation in rainbow trout lengths. Model cross-validation, however, called into question the predictive capabilities of the model. In addition, limnological data collected from 10 lakes in 2009 identified water temperature as a correlate with rainbow trout length. This study provided an approach that can be used by managers to evaluate rainbow trout length in stocked lakes, and serves the basis for improving stocking programs while providing satisfactory fishing experiences"--Leaf iii
  • Reproductive biology and movement patterns of humpback whitefish and least cisco in the Minto Flats-Chatanika River complex, Alaska

    Dupuis, Aaron Wayne; Sutton, Trent; Wuttig, Klaus; Seitz, Andrew (2010-08)
    "Humpback whitefish Coregonus pidschian and least cisco C. sardinella are two species of coregonids common to the interior of Alaska and are a food resource for rural and urban communities. These fishes exhibit variation in life-history characteristics throughout their range, and many basic life-history questions remain unanswered. My objectives were to describe the spawning movements and identify the current distribution of putative spawning areas for humpback whitefish, and to assess the reproductive biology of humpback whitefish and least cisco in the Minto Flats-Chatanika River complex. Observed movement patterns indicated that humpback whitefish exhibited complex dispersals to putative spawning areas. Two putative spawning areas were identified: one in the Chatanika River downstream of the Elliot Highway Bridge and the other in the Tanana River near Fairbanks. Mean absolute fecundity was 45,000 eggs female⁻¹ for humpback whitefish and 41,780 eggs · female⁻¹ for least cisco. This examination of reproductive biology suggested that larger-bodied females associated with higher gonadosomatic index values produce more and larger eggs per unit body weight than smaller females. This study increased our understanding of the life history and biology of whitefishes in Alaska and can assist managers with developing appropriate management strategies for these fishes in the future"--Leaf iii
  • Examination of gear type efficacy, tagging methodology, and population structure for establishing a directed Enteroctopus dofleini fishery

    Barry, Patrick D.; Tallmon, David; Tamone, Sherry; Adkison, Milo (2010-08)
    "In recent years, there has been a renewed interest in a directed fishery for North Pacific giant octopus, Enteroctopus dofleini. This species continues to be managed as a bycatch only species through the use of commisioner's permits primarily due to the lack of information on the basic ecology of E. dofleini and the logisitics of management. In the summer of 2007, we completed a survey in Kachemak Bay, Alaska, to determine the efficiency of different gear types for targeting E. dofleini, compared different methods of tagging individuals for movement and abundance estimates, and collected tissue samples for use in a genetic analysis of population structure. If a directed fishery develops in Alaska, our data suggest that unbaited lair pots may be the most effective means of capture while minimizing bycatch of other commercially important species. Most regions in Alaska lack sufficient data to estimate abundance and often estimates using catch-per unit of effort can be inaccurate. If mark-recapture methods are used to estimate abundance of octopus populations, then results from our tagging indicate that visible implant elastomer may be the most effective means of marking individuals. Genetic analysis of E. dofleini populations revealed an enigmatic pattern of population structure with two haplotype lineages. The large amount of sequence divergence at the COI locus may indicate the presence of a cryptic species within the E. dofleini complex. It appears that North Pacific giant octopus will continue to be managed as a bycatch-only species for the near-term future. It is essential that management agencies resolve both the phylogenetic and population structure, as well as confidently estimate abundances of the stocks identified before a directed fishery is opened"--Leaf iii

View more