• Using the USDA wind erosion equation for comparative modeling of natural and anthropogenic sources of particulates measured at the Fort Greely PM₁₀ monitoring station, Alaska, a case study

      Becker, Steven R.; Perkins, Robert; Barnon, David; Whitaker, Keith; Aggarwal, Srijan (2015-05)
      In April of 2010, the Alaska Department of Environmental Conservation (ADEC) opened a compliance case against the U.S. Army Garrison Fort Greely, Alaska (FGA), for then repeated failure to comply with a permit condition requiring the collection of one year of Prevention of Significant Deterioration (PSD)-quality data on ambient levels of particulate matter less than 10 microns in effective aerodynamic diameter (PM₁₀). During the monitoring period of 2012-2013, background levels of PM₁₀ were more than 80% the Alaska Ambient Air Quality Standards (AAAQS) for a total of seven days in the winter of 2012-2013. On March 17, 2014, ADEC requested that FGA provide substantive documentation that PM₁₀ exceedances observed during the monitoring period were of natural provenance and not from anthropogenic sources. In response to this request, the author used Geographic Information System (GIS) technology to analyze basic meteorological data and outputs from the USDA Wind Erosion Equation (WEQ) to generate a simple back-trajectory model for determining the sources and relative contributions to PM₁₀ experienced at a given receptor. Using this model, the author was able to show that the vast majority of PM₁₀ at Fort Greely was natural rather than anthropogenic in nature. The ADEC Division of Air Quality determined that results of this study constituted substantive documentation that PM₁₀ exceedances observed during the monitoring period were of natural provenance and not from anthropogenic sources, and issued a compliance case closure letter on June 20, 2014. In addition to the direct results of the study, the project also serves to demonstrate a low-complexity model that can be used to assess the relative contribution of anthropogenic and natural sources of PM₁₀ at a given receptor. Additionally, it can be used in complex situations as a screening tool to focus data collection efforts on significant sources of PM₁₀ and facilitate the prioritization of PM₁₀ sources for more precise quantitative dispersion or receptor models when precise quantitative data are required.
    • Using work-based learning as a vehicle for student engagement and community investment

      Stickle, Stephanie; Gifford, Valerie; Dahl, Heather; Simpson, Joni (2017-05)
      Research indicates that rural communities with few labor market opportunities are at increased risk for social and economic unsustainability. As such, high-potential rural students often believe they must leave their homes for more populated areas with superior labor markets in order to obtain fulfilling employment, success, and life satisfaction. This out-migration trend places rural communities at risk for losing the youth that are most likely to contribute to their sustainability and growth. Rural education has been identified as a promising and central means to counter this risk. Effective work-based learning curriculums, which incorporate student engagement and talent development components, may facilitate school engagement, entrepreneurial interest, community involvement, intrinsic satisfaction, and extrinsic success among rural students, thus contributing to community investment.
    • Using WRF/Chem, in-situ observations, and Calipso data to simulate smoke plume signatures on high-latitude pixels

      Madden, James Michael; Mölders, Nicole; Sassen, Kenneth; Prakash, Anupma; Grell, Georg (2014-05)
      The transport of wildfire aerosols provides concerns to people at or near downwind propagation. Concerns include the health effects of inhalation by inhabitants of surrounding communities and fire crews, the environmental effects of the wet and dry deposition of acids and particles, and the effects on the atmosphere through the scattering and absorption of solar radiation. Therefore, as the population density increases in Arctic and sub-Arctic areas, improving wildfire detection increasingly becomes necessary. Efforts to improve wildfire detection and forecasting would be helped if additional focus was directed toward the distortion of pixel geometry that occurs near the boundaries of a geostationary satellite's field of view. At higher latitudes, resolution becomes coarse due to the curvature of the Earth, and pixels toward the boundaries of the field of view become difficult to analyze. To assess whether it is possible to detect smoke plumes in pixels at the edge of a geostationary satellite's field of view, several analyses were performed. First, a realistic, fourdimensional dataset was created from Weather Research and Forecasting model coupled with Chemistry (WRF/Chem) output. WRF/Chem output was statistically compared to ground observations through the use of skill scores. Output was also qualitatively compared to vertical backscatter and depolarization products from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. After the quantitative and qualitative examinations deemed the model output to be realistic, synthetic pixels were constructed, appropriately sized, and used with the realistic dataset to examine the characteristic signatures of a wildfire plume. After establishing a threshold value, the synthetic pixels could distinguish between clean and smoke-polluted areas. Thus, specialized retrieval algorithms could be developed for smoke detection in strongly distorted pixels at the edge of a geostationary satellite's field of view.
    • Utilizing animal assisted interventions in elementary schools

      France, Catherine E.; Cook, Christine; Morotti, Allan; Brashear, Dawn (2014)
      Animal Assisted Interventions in the elementary school counseling setting involves the school counselor choosing to bring in an animal, commonly a dog, to assist in counseling interventions with a student. The counselor uses the dog as a tool to build a secure and trusting rapport with the student. The counselor is the facilitator of the session; the dog is used in a variety of ways to increase and aide in the benefits of the counseling session. This project illustrates the positive impact of the human-animal bond, the steps necessary to bring animal assisted interventions into a school, and the theoretical base that supports animal assisted interventions. This information is also presented as a website to be easily accessible for counselors, parents, and educators.
    • Utilizing funds of knowledge to engage students in meaningful writing

      Webster, Bradley; Thorne, Steve; Shields, John; Siekmann, Sabine (2015-12)
    • Utilizing Multi-Source Abundance Estimation And Climate Variability To Forecast Pacific Salmon Populations

      Shotwell, Stacey Anne Kaleinauialoha; Adkison, Milo D. (2004)
      Data limitation is a common property of many fisheries. Some Pacific salmon populations are a typical example of this situation because the monitoring of numerous tributaries within an area becomes logistically intractable. Fishery management often responds to this scenario with qualitative stock assessments in the form of harvest projections In some cases, fishery data, although limited, exists in a variety of sources and may be integrated to develop quantitative population estimates. The first objective of this investigation is to generate a modeling process that combines multiple data sources to estimate abundance and escapement estimates for data-limited salmon populations. Second, we consider the reliability of these estimates by testing for robustness to various simulated levels of measurement error in the data. Finally, we perform rigorous development and selection on an age structured spawner-recruit model that incorporates abundance and escapement estimates and identifies potential environment-recruit relationships. We demonstrate our technique with a case study on summer chum salmon from the Kuskokwim and Yukon Rivers, Alaska. Recent declines of summer chum returns to this salmon-dependent region have created hardships for the local area residents. We developed a maximum likelihood statistical framework that synchronously combined all available data sources from this management region to estimate abundance and escapement. Successful estimation was dependent on an independent estimate of abundance for a least a few years. We provide error estimates of the modeling process through bootstrap methods. Simulations showed that measurement error had negligible effect on abundance estimates, whereas performance for escapement estimation was tied to the sequence of abundance years. High explanatory power was attained by including environmental variables in the spawner-recruit relationship developed from these population estimates. We used a three-stage modeling process to maintain biological realism in the predictor variables. Recent changes in variables chosen for the best model were consistent with poor environmental conditions and estimates of forecasting error were much lower than models using no environmental information. Based on our findings, we recommend that managers consider the utility of multiple source estimation and environmental variability with our modeling approach for future regulatory decisions of Pacific salmon fisheries in data-limited regions.
    • Utilizing pasture resources for sub-Arctic agriculture: sustainable livestock production in Alaska

      Starr, Laura Marie; Rowell, Janice; Greenberg, Joshua; Seefeldt, Steven; Zhang, Mingchu (2017-05)
      It is estimated that the globe must produce 100% more food in the next 50 years to meet growing demand while addressing the compounding challenge of climate change. One potential solution to this challenge is to produce more on existing agricultural lands and put more land into production. The extremely cold and dry climate that characterizes much of Alaska has all but removed the state from the state and national discussions of agricultural production and development. Yet despite this apparent incompatibility with traditional agricultural models, some of the largest wild herds of grazing ungulates are indigenous to Alaska - and thriving. This is both a testament to the resilience of grazing systems in general as well as a statement to the suitability of grazing systems specifically for Alaska. To shift the paradigm towards ecological and economic sustainability, we need to develop sustainable agricultural strategies that are specific to this unique ecosystem. A two-fold approach was used in this body of research: Is there an indigenous livestock species that could be economically feasible enterprise option? Is there a grazing management regime for subarctic Alaska that would improve ecosystem services and optimize pasture resources? I conducted an economic feasibility study of farming muskoxen (Ovibos moschatus), a uniquely adapted Arctic ungulate, to address the first question. An enterprise budget was used to estimate the fixed and variable costs and to model different revenue scenarios using six different combinations of qiviut, sold as raw fiber or value added yarn, and livestock sales to estimate the total economic potential of farming muskoxen at two scales, 36 and 72 muskoxen. Farming muskoxen was economically sustainable under several revenue scenarios. The most profitable scenario for either herd size was selling all the qiviut as value added yarn coupled with livestock sales. The enterprise was profitable at either scale assuming all the yarn sold at full retail price. If no livestock were sold, selling the total qiviut harvest as yarn was the only profitable option. When selling raw fiber alone, the break-even point was at a herd size of 124 muskoxen. Economies of scale accounted for a decrease in costs of approximately 21% overall, 30% in labor, and 23% in herd health, as the herd doubled in size. To address the need for grazing management strategies that are both environmentally and economically sustainable in Alaska, I conducted a study to evaluate the potential of intensively managed rotational grazing (IMRG) regimes on sub-arctic pasture. This regime is designed to mimic the short but intense grazing of wild, migratory ungulates that could enhance ecosystem function while optimizing pasture usage and forage growth. I conducted simulated grazing, applied using IMRG methodology, to evaluate above and below ground response to an IMRG regime and to gain insight on the role of grazing disturbance mechanisms on sub-arctic soil and plant health. A full factorial experiment of muskox dung/urine deposition (M), simulated trampling (T), and herbivory (H) (forage clipping), mimicking IMRG timing and intensity, was conducted at the Large Animal Research Station (LARS), UAF. I used a randomized block design with 96-1 m² plots in two established pastures with different soil types, over the 2014 and 2015 grazing seasons. I documented a treatment effect on soil parameters, forage growth, and percentage of bare soil (p<0.05). Soil nitrogen cycling and the Haney Soil Health Index both increased in plots that received a combination M and T or MT and H. The forage yield was consistently increased by MH, MTH, and H treatments. Although the MT and T treatments had a negative impact on forage yield, they had the largest reduction in the amount of bare ground. The data from this simulated study suggest that theories that underpin the IMRG method are potentially useful to producers, in the unique Alaskan subarctic environment.
    • Validating a GPS collar-based method to estimate parturition events and calving locations for two barren-ground caribou herds

      Hepler, Joelle D.; Griffith, Brad; Falke, Jeff; Roach, Jen (2019-12)
      In remote landscapes, it is difficult and expensive to document animal behaviors such as location and timing of parturition. When aerial surveys cannot be conducted as a result of weather, personnel or fiscal constraints, analyses of GPS collar movement data may provide an alternate way to estimate parturition rates and calving ground locations. I validated two methods (population-based method and individual-based method), developed to detect calving events of sedentary woodland caribou, on multiple years of data for two different migratory barren-ground caribou herds in Alaska, the Porcupine and Fortymile herds. I compared model estimates of population parturition rates, individual calving events, calving locations and calving dates to estimates from aerial survey data for both herds. For the Porcupine herd we also compared model estimates of annual calving ground sizes and locations of concentrated calving area centroids to those found with aerial survey. More years of data would be required for additional statistical power but for both the Porcupine and Fortymile herds, we found no significant difference between the population-based and individual-based method in: 1) individual classification rate accuracy (0.85 vs. 0.88, respectively; t = -7, P = 0.09, df = 1 and 0.85 vs. 0.83, respectively; t = 0.46, P = 0.69, df = 2) or 2) annual average distance from aerial survey calving locations (8.9 vs. 7.8 km, respectively; t = 0.16, P = 0.90, and 5.2 vs. 3.7 km, respectively; t = 1.03, P = 0.20). Median date of calving was estimated within 0-3 days of that estimated by aerial survey for both methods. Population parturition rate estimates from aerial survey, the population-based and individual-based methods were not significantly different for the PCH or FCH (0.91, 0.88 and 0.95, respectively; F = 0.67, P = 0.60, df = 2, and 0.83, 0.83 and 0.96, respectively; F = 3.85, P = 0.12, df = 2). Ultimately, more years of data would be required to support or reject the lack of significant differences between methods that we observed.
    • Validation and application of infrared thermography for the assessment of body condition in pinnipeds

      Nienaber, Jeanette (2009-08)
      Infrared thermography (IRT) was used to collect baseline information on skin surface temperatures of two species of pinnipeds, the harbor seal (Phoca vitulina; n = 6) and the Steller sea lion (Eumetopias jubatus; n = 2). The IRT technique was validated against objects of known temperature and through post-collection software manipulation of environmental parameters that influence IRT output (emissivity, distance, relative humidity, ambient temperature and reflected temperature). From February 2007 to February 2008, biweekly measurements were taken of skin surface temperature (FLIR P25 infrared camera) with subsequent measurements of blubber depth (SonoSite Vet 180 portable imaging ultrasound system) on captive individuals at the Alaska SeaLife Center, Seward, Alaska. Once validated, skin surface temperatures in 10 defined regions (whole body, torso, head, eye, muzzle, shoulder, axillae, hip, fore and hind flipper) were used to determine seasonal variability as well as consistent hot or cold spots, and of those spots, which may act as thermal windows (defined areas of active heat loss and/or retention). Concurrent measurements of blubber depth were compared to skin surface temperatures at eight body sites to assess: a) the impact of insulation level on skin surface temperature on a site-specific scale, and b) the potential use of IRT as an alternative method for the non-invasive measurement of body condition. Both species varied seasonally in skin surface temperature from winter to reproductive and molt to winter, however, harbor seals had greater regional variation. Similar hot and cold spots were consistently recognized in both species with shoulder, axillae, fore and hind flipper identified as likely thermal windows. While some site-specific significant relationships were found between skin surface temperature and blubber thickness, insulation level alone explained a very small portion of the variance. Future studies to determine the factors influencing the variance on skin surface temperature (i.e., blood flow to the skin) warrant further exploration.
    • A validity study of the reasons for life scale with emerging adult college students

      Curns, Daniel B.; Gonzalez, Vivian M.; Swift, Joshua K.; Skewes, Monica C.; Ashdown, Brien K. (2014-12)
      This study examined the validity of the Reasons for Life Scale (RFLS) with emerging adult college students. The RFLS measures "reasons for life." It was developed for use with Alaska Native youth as a way to assess potential risk of suicide without directly questioning about suicidal ideation or history of suicide attempts. This study sought to adapt the RFLS for use with emerging adult (age 18-25) college students, and to examine its factor structure and convergent validity with this population. First, a focus group was conducted to assist in rewording two Alaska Native-specific items from the RFLS for non-Natives. Then, with the additional items from the focus group, the revised version of the RFLS (RFLS-R) and other suicide-related measures were administered to a sample of 116 emerging adult college students. Exploratory factor analysis indicated a unidimensional factor structure for the RFLS-R with this sample. The RFLS-R showed a significant and strong correlation with the Reasons for Living Inventory (RLI; r = .70), which, like the RFLS-R, measures reasons for living but makes direct reference to suicide. There also were significant moderate negative correlations with the Suicidal Behavior Questionnaire - Revised (SBQ-R; r = -.36) and the Adult Suicidal Ideation Questionnaire (ASIQ; r = -.29). There was a significant moderate correlation between the RFLSR and a measure of socially desirable responding, the Balanced Inventory of Desirable Responding (BIDR; r = .31), with similar correlations found between the BIDR and other suicide-related measures included in this study. The results suggest that socially desirable responding did not strongly affect participants' responding or explain the associations found among the measures. The high correlation with the RLI suggests that the RFLS-R measures a similar construct, providing evidence of convergent validity; however, the RLI was more highly correlated with measures of suicidality than the RFLS-R -- suggesting that while the RFLS was moderately associated with measures of suicidality, it is a weaker predictor of suicide risk than the RLI. Although the RFLS-R was not as highly correlated with measures of suicidality as the RLI, which directly mentions suicide, the RFLS-R is the only known suicide measure that completely avoids items and instructions that mention suicide, therefore it may be useful in contexts where directly discussing suicide is not acceptable or appropriate.
    • Valuing residential energy efficiency in two Alaska real estate markets: a hedonic approach

      Pride, Dominique J.; Little, Joseph; Baek, Jungho; Lovecraft, Amy Lauren; Mueller-Stoffels, Marc (2017-05)
      Alaska households have high home energy consumption and expenditures. Improving the energy efficiency of the housing stock can reduce home energy consumption, thereby reducing home energy expenditures and CO₂ emissions. Improving the energy efficiency of a home may also increase its transaction price if the energy efficiency improvements are capitalized into the value of the home. The relationship between energy efficiency and transaction prices in the Fairbanks and Anchorage, Alaska residential real estate markets is examined. Using a hedonic pricing framework and difference-in-differences analysis, the impact of the Alaska Home Energy Rebate program on the transaction prices of single-family homes in the Fairbanks and Anchorage housing markets from 2008 through 2015 is examined. The results indicate that compared to homes that did not complete the program, homes that completed the program sell for a statistically significant price premium between 15.1% and 15.5% in the Fairbanks market and between 5% and 11% in the Anchorage market. A hedonic pricing framework is used to relate energy efficiency ratings and transaction prices of homes in the Fairbanks and Anchorage residential real estate markets from 2008 through 2015. The results indicate that homes with above-average energy efficiency ratings sell for a statistically significant price premium between 6.9% and 17.5% in the Fairbanks market and between 1.8% and 6.0% in the Anchorage market.
    • Variability in foraging by humpback whales (Megaptera novaenangliae) on the Kodiak, AK, feeding ground

      Wright, Dana Louise; Witteveen, Briana; Quinn, Terrance II; Wynne, Kate; Horstmann-Dehn, Lara (2014-12)
      The North Pacific humpback whale (Megaptera novaeangliae) population has been growing rapidly following a moratorium on commercial whaling in 1986. Knowledge of humpback whale foraging on feeding grounds is becoming increasingly important as the growing population consumes more prey, including economically important commercial fishes. The goal of this thesis is to better understand how marine resources are shared among the growing humpback whale population and sympatric apex predators, including western Steller sea lions (SSLs; Eumetopias jubatus), on the Kodiak, AK, feeding ground. To address this, we explored spatial and temporal (inter-annual and within-feeding season) variability in summer foraging by humpback whales along the eastern side of the Kodiak Archipelago as described by stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios of humpback whale skin (n = 118; 2004-2013). We found evidence for the existence of two sub-aggregations of humpback whales ('North', 'South') on the feeding ground that fed at different trophic levels (TLs) throughout the study period. Bayesian stable isotopic mixing models were applied to describe the proportional contribution of prey species to the diet of humpback whales for the two regions. The 'North' region humpback whale sub-aggregation consumed a mixed diet of euphausiids and forage fishes, whereas the 'South' region sub-aggregation foraged predominantly on euphausiids. Results from these analyses were compared to diet composition of Kodiak SSLs of the recovering western SSL population estimated from fecal samples (n = 656; 2000-2005), to explore spatial differences in the degree of overlap in trophic niche between these predators. Western SSLs underwent a marked population decline starting in the late 1970's and have shown slow and variable signs of recovery. Regional variability in SSL and humpback whale diets resulted in a higher degree of overlap in trophic niche, although not biologically significant (Ojk < 0.60), for individuals in the 'North' region compared with the 'South'. However, humpback whale consumption appears to overlap considerably with multiple piscivorous fishes that are prominent prey for SSLs, and thus, consumption by humpback whales may indirectly impact the prey resources of SSLs. Therefore, this study highlights the complexity of the Kodiak ecosystem and suggests consumption by an increasing population of humpback whales has the potential to indirectly impact the recovery of SSLs on a regional scale depending on the biomass of prey species and diet composition of humpback whales in the region.
    • Variability In Population Trends, Life History Characteristics, Amd Milk Composition Of Northern Fur Seals In Alaska

      Hayden, Alison Banks; Springer, Alan; Iverson, Sara; Castellini, Michael (2012)
      The northern fur seal population on the Pribilof Islands has been declining since the 1960s and is now less than 30% of its former size. Chapter 1 examines factors that might cause a population to decrease to such an extent and concludes that only nutritional limitation caused by climate change or commercial fisheries, predation by killer whales, or a combination of factors that includes conditions in the North Pacific during the winter were possible explanations. Chapter 2 reports the seasonal patterns in proximate composition of fur seal milk between St. Paul Island (one of the Pribilof Islands) and Bogoslof Island (an increasing population) to understand the energy requirements of lactation and the energetics of pup growth and body condition at weaning. Factors that caused variability in milk composition included days postpartum, time ashore, individual phenotype, island and preceding trip duration. Average milk lipid increased from 45.5+/-0.7% to 53.8+/-1.0% at St. Paul and from 45.8+/-0.7% to 57.3+/-0.8% at Bogoslof between July and October, while average milk protein remained relatively stable ranging between 10.0% and 10.5%. The lipid content of northern fur seal milk near peak lactation is the highest reported among otariid seals and among the highest known for all mammals.
    • Variability in Steller sea lion (Eumetopias jubatus) prey quality in Southeastern Alaska

      Vollenweider, Johanna Jill; Kelly, Brendan; Adkison, Milo; Stekoll, Michael (2005-05)
    • Variability In The Circulation, Temperature, And Salinity Fields Of The Eastern Bering Sea Shelf In Response To Atomospheric Forcing

      Danielson, Seth Lombard; Weingartner, Thomas; Aagaard, Knut; Coyle, Kenneth; Hedstrom, Katherine; Kowalik, Zygmunt (2012)
      Although the Bering Sea shelf plays a critical role in mediating the global climate and supports one of the world's largest fisheries, fundamental questions remain about the role of advection on its salt, fresh water, heat and nutrient budgets. I quantify seasonal and inter-annual variability in the temperature, salinity and circulation fields. Shipboard survey temperature and salinity data from summer's end reveal that advection affects the inter-annual variability of fresh water and heat content: heat content anomalies are set by along-shelf summer Ekman transport anomalies whereas fresh water content anomalies are determined by wind direction anomalies averaged over the previous fall, winter and early spring. The latter is consistent with an inverse relationship between coastal and mid-shelf salinity anomalies and late summer -- winter cross-shelf motion of satellite-tracked drifters. These advection anomalies result from the position and strength of the Aleutian Low pressure system. Mooring data applied to the vertically integrated equations of motion show that the momentum balance is primarily geostrophic within at least one external deformation radius of the coast. Local accelerations, wind stress and bottom friction account for < 20% (up to 40%) of the along- (cross-) isobath momentum balance, depending on location and season. Wind-forced surface Ekman divergence is primarily responsible for flow variations. The shelf changes abruptly from strong coastal convergence conditions to strong coastal divergence conditions for winds directed to the south and for winds directed to the west, respectively, and substantial portions of the shelf's currents reorganize between these two modes of wind forcing. Based on the above observations and supporting numerical model integrations, I propose a simple framework for considering the shelf-wide circulation response to variations in wind forcing. Under southeasterly winds, northward transport increases and onshore cross-isobath transport is relatively large. Under northwesterly winds, onshore transport decreases or reverses and nutrient-rich waters flow toward the central shelf from the north and northwest, replacing dilute coastal waters that are carried south and west. These results have implications for the advection of heat, salt, fresh water, nutrients, plankton, eggs and larvae across the entire shelf.
    • Variability Of Pink Salmon Family Size Has Implications For Conservation And Management Models

      Geiger, Harold Joseph, Iii; Gharrett, A. J. (2002)
      In several populations of pink salmon, the short-term dynamics population size was related to both the mean and variance of individual family sizes, because not all families were equally productive. In the marine lifestage, population increases came disproportionately from the most productive families, especially in populations with the highest average marine survival. Moreover, the trait of marine survival itself had a statistically detectable genetic component. This implies that the most favored phenotypes change from generation to generation, and that the marine environment is unpredictable and changing. These results, together with laboratory studies of freshwater survival and measurements of wild pink salmon in Prince William Sound, Alaska, seemed to indicate that family-specific variation in marine survival and variation in egg retention within the redd were the most important potential influences on variation of pink salmon family size in the studied populations, when density was controlled to intermediate levels. These results provide more justification for maintaining stock sizes at intermediate or high levels, and for protecting metapopulation structure. These results also show the importance of variation and instability in the recruitment process of Pacific salmon, and highlight the inadequacy of current models of salmon recruitment, which emphasize stability and long-term averages.
    • A variable-boundary numerical tidal model

      Mungall, J. C. H. (1970-05)
      A numerical tidal model using equations developed by Hansen (1952) and Yuen (1967) is automated to the point where a potential user need not undertake extensive reprogramming. The user adds to the program only those cards needed to specify tides at input points as a function of time; the application of the relevant calculations at each grid point being controlled by an integer matrix that corresponds to the inlet boundary. A sample problem is covered in detail and applications of the model to the M₂ tide of the Gulf of California, and to a hypothetical mean tide in Cook Inlet are shown.
    • Variation in abundance and physiological status of juvenile chum salmon (Oncorhynchus keta) in relation to marine factors in Southeast Alaska

      Kohan, Michael L.; McPhee, Megan V.; Mundy, Phillip R.; Orsi, Joseph A.; Mueter, Franz J. (2015-08)
      Little is known about the mechanisms influencing the critical early life stages of juvenile chum salmon (Oncorhynchus keta) from coastal to offshore marine waters. There is mounting evidence to suggest that fluctuations in early marine conditions affect juvenile salmon physiological status and year class strength. We investigated relationships of a suite of marine factors at local, regional, and basin scales to the physiological status and abundance of juvenile chum salmon in northern Southeast Alaska (SEAK) from 1997-2013. Correlation analyses were used to identify potential mechanisms influencing year class strength. Marine factors at the local scale were correlated to the observed physiological status of juvenile chum salmon: average June/July wind speed was negatively correlated to weight-at-length residuals, sea surface temperatures in July were positively correlated with length, and the June mixed-layer depth was positively correlated to the energy density of juvenile chum salmon in July. Marine factors at the regional scale influenced juvenile chum salmon abundance: freshwater discharge was positively correlated whereas upwelling was negatively correlated with abundance, linking high abundance to characteristics of strong Aleutian Low (AL) climatic conditions. Comparisons of juvenile chum salmon physiological status were also made between: 1) SEAK habitats (Icy Strait and the Eastern Gulf of Alaska, EGOA), 2) stock groups (hatchery and wild), and 3) years 2010 and 2011 possible mechanisms influencing productivity of chum salmon. Between habitats, length of juvenile chum salmon did not differ. However, both weight-at-length residuals and energy density values were significantly higher in the EGOA, irrespective of year, indicating juvenile salmon allocate energy to somatic growth in Icy Strait, while the EGOA may serve as a habitat for juvenile chum salmon to store energy as lipids. Between chum salmon stocks, wild stocks were shorter and had higher weight-at-length residuals than hatchery stocks. Between years, the 2010 ocean year was associated with a strong AL that coincided with higher physiological status of juvenile chum salmon and relatively higher returning adult commercial harvests and ocean survival of hatchery fish compared to the 2011 ocean year. Our results suggest differences in juvenile chum salmon physiological status in 2010 and 2011 coincided with positive and negative anomalies of the coupled ocean-atmosphere system, which were linked to previous winter environmental conditions, and have the potential to be used as a predictive salmon management tool to forecast year class strength in SEAK.
    • Variation in age and size at maturity of Lake Clark, Alaska sockeye salmon

      Benolkin, Elizabeth B.; Margraf, Joseph; Woody, Carol Ann; Adkison, Milo (2009-12)
      Salmon returning to Lake Clark, Alaska are a valuable subsistence, commercial and ecological resource, and are an important component of the larger Kvichak River escapement. Average escapement to the Kvichak River declined sharply during 1996-2005, prompting studies to investigate age and size at maturity, key life history traits of salmon linked to reproductive success and survival. We examined potential factors which may influence sockeye salmon Oncorhynchus nerka age and size at maturity: spawning habitat and ocean environment, and examined variation in both traits over time. Sockeye salmon age and length at maturity differed among spawning locations and between brood years, but no consistent patterns were observed among habitat types. Age and length at maturity differed over time; the proportion of older marine age 3 fish was larger in recent brood years, while fish were smaller during 1997-2001 compared to 1976-1980. Sea surface temperatures and coastal upwelling appeared to be important indicators of fish length, highlighting the importance of the ocean environment in salmon growth. These results demonstrate the complexity and importance of both the freshwater and ocean ecosystems in variation in age and size at maturity, and indicate that trends may not necessarily be similar among systems or years.
    • Variation of agonistic behavior and morphology among juvenile chinook salmon (Oncorhynchus tshawytscha) of hatchery, wild, and hybrid origin under common rearing conditions

      Lang Wessel, Maria Elena (2004-05)
      Hatcheries play an important role in the enhancement of Pacific salmon (genus Oncorhynchus) as a resource, but genetic and phenotypic divergence trom wild populations may occur as a result of founder effects, genetic drift and/or domestication. In this study, agonistic behavior, ability to establish dominance, and morphology were compared among juveniles of chinook salmon (Oncorhynchus tshawytscha) that have experienced five generations of hatchery ranching culture, juveniles derived trom the wild founding stock, and second generation hybrids of the two lines. The parent generation of all lines was cultured in the same hatchery environment as the juveniles tested. Behavioral observations were conducted in replicate artificial stream tanks; hatchery and hybrid fish were significantly more aggressive than wild derived fish. No difference was detected in the ability of fish lines to win dyadic dominance contests. Thin-plate spline analysis was used to characterize morphometric variation; hatchery and wild derived juveniles differed significantly. Canonical discriminant analysis correctly classified 88% of hatchery fish and 90% of wild derived fish. Morphologically, hybrid fish were significantly different trom both hatchery and wild derived fish. These results suggest that the differences observed between lines are genetic in origin although the sources of the divergence were not conclusively identified.