Western Alaska Research Articles

Ethnoarchaeological analysis of Arctic fish processing: chemical characterization of soils on Nelson Island, Alaska

Activity area analysis of archaeological soils using multi-element characterizations can illuminate how subsistence operations are organized and how subsistence behavior has changed over time, and is increasingly common at archaeological sites. However, in many regions it is impossible to examine the elemental signatures in known anthropogenic soil samples in order to compare them with unknown archaeological samples. This ethnoarchaeological study examines the chemical composition of the soils at known fish processing areas in the contemporary community of Tununak on Nelson Island, western Alaska. Using a quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS), the concentrations of the following elements in the soil extract were recorded in parts per million (ppm): aluminum (Al), barium (Ba), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), strontium (Sr), titanium (Ti), and zinc (Zn). Fish processing area features are elevated in various elements, including sodium, magnesium, phosphorus, potassium, and manganese, and Ba/Sr, Ba/Ca, and Sr/Ca are also useful in distinguishing between fish processing areas and offsite areas.

Genetic Diversity and Population Structure in the Kuskokwim River Drainage Support the Recurrent Evolution Hypothesis for Sockeye Salmon Life Histories

AbstractRiverine sockeye salmon Oncorhynchus nerka (those that do not use nursery lakes for juvenile rearing) tend to be characterized by greater genetic diversity and weaker population structure than lake‐type populations. These findings have led to the “recurrent evolution” hypothesis for sockeye salmon life histories, which proposes that riverine sockeye salmon are the principal colonizing form and play the dominant role in the long‐term persistence of sockeye salmon in a dynamic landscape. However, previous studies in Kamchatka (Russia) and Alaska have suggested that the general patterns of riverine sockeye salmon do not apply in all parts of the species' range. In this study, we examined genetic diversity and population structure in lake‐type and riverine sockeye salmon from the Kwethluk and Holitna rivers (Kuskokwim drainage, western Alaska), near the northern edge of the species' range in North America. As expected, lake‐type sockeye salmon exhibited lower genetic diversity and stronger genetic structure over short distances than did neighboring riverine populations, which is consistent with increased straying of the riverine form. In the Kwethluk River, allele identity and genetic evidence of population bottlenecks in lake‐type samples suggested that lake‐type sockeye salmon were derived from riverine ancestors. These findings further support the recurrent evolution hypothesis and are consistent with the dynamic nature of the floodplain habitats that support these riverine sockeye salmon.

Early childhood hemoglobin level is a strong predictor of hemoglobin levels during later childhood among low-income Alaska children

Objectives. For unknown reasons, Arctic Indigenous children have iron deficiency and anemia prevalences up to 10 times higher than national reference populations. The current study sought to identify the importance of Alaska Native status, residence and hemoglobin (Hb) level at age 10 to 23 months for predicting Hb levels at age 24 to 59 months when controlling for potential confounders.Study design. Retrospective cohort.Methods. A birth certificate database was linked to a database containing hemoglobin levels determined through the U.S. Supplemental Nutrition Program for Women, Infants and Children (WIC) among Alaskan children age 10 to 59 months evaluated from 1999–2006.Results. Of children with a birth certificate matched to WIC data, Alaska Native status and residence in western and northern Alaska were associated strongly with anemia at both ages. Nevertheless, of 5,796 children with Hb levels determined at both ages, the single strongest predictor of Hb level at age 24 to 59 months was Hb level at age 10 to 23 months. The community-level anemia prevalence among children age 10 to 23 months was predictive of community-level anemia prevalence among children age 24 to 59 months.Conclusions. The early onset of anemia and the strong association between earlier and later Hb levels or anemia at both the individual and community levels suggest a role for prenatal effects that remain until at least age 5 years. This is true particularly of Yupik and Inupiat children, who make up the primary residents of western and northern Alaska.

Gyrfalcon nest distribution in Alaska based on a predictive GIS model

The gyrfalcon (Falco rusticolus) is an uncommon, little studied circumpolar Arctic bird that faces conservation concerns. We used 455 historical nest locations, 12 environmental abiotic predictor layers, Geographic Information System (ArcGIS), and TreeNet modeling software to create a spatially explicit model predicting gyrfalcon breeding distribution and population size across Alaska. The model predicted that 75% of the state had a relative gyrfalcon nest occurrence index value of 60%. Areas of high predicted occurrence were in northern and western Alaska. The most important predictor variable was soil type, followed by sub-surface geology and vegetation type. Nine environmental factors were useful in predicting nest occurrence, indicating complex multivariate habitat relationships exist. We estimated the breeding gyrfalcon population in Alaska is 546 ± 180 pairs. The model was 67% accurate at predicting nest occurrence with an area under the curve score of 0.76 when assessed with independent data; this is a good result when considering its application to the entire state of Alaska. Prediction accuracy estimates were as high as 97% using 10-fold cross validation of the training data. The model helps guide science-based management efforts in times of increasing and global pressures for this species and Arctic landscapes.

Foraging behavior of adult female Steller sea lions during the breeding season in Southeast Alaska

AbstractDuring the 1990s, the Steller sea lion (Eumetopias jubatusSchreber) Western Alaska stock (WS) suffered steep population decline while the Eastern Alaska stock (ES) steadily increased. One bottom‐up forcing hypothesis explaining this decline predicted lactating adult female foraging behavior would be different between stocks. To investigate this effect, we monitored 11 ES females at two breeding rookeries using satellite dive recorders (SDR) during the early breeding seasons of 1992–1993, examined their behavior with respect to prey, physiological limitations, and habitat, and made limited comparisons to observations of WS female behavior reported in the literature. ES females were not operating at the extremes of ability, with most diving within the limits of aerobic metabolism, less than one‐quarter of possible foraging time during trips spent submerged and most foraging trips requiring less than one‐half the lipid store fasting ability of dependent pups. Thus, females may have some capacity to alter behavior to accommodate future changes in foraging conditions, but the extent of this plasticity is unknown. Because recent work suggests WS recovery is impeded by low natality, future studies should test differences between reproductive and non‐reproductive mature females in order to properly assess the contribution of foraging ecology to SSL population dynamics.

The Social Role of Technology in Coastal Alaska

Novel technologies linked to women and men through identity-demarcated tasks and knowledge sets can potentially have differential and even long-term effects on each group. This study follows the trajectory of two significant imports into the coastal western Alaskan system, the firearm and the metal cook pot. These imports had different implications for coastal Yup’ik women and men, young and old. Over time the gun became an integral piece of a man’s tool kit and one that had the potential to boost production and thus a man’s access to status-building. However, these same tools had the potential to undermine the apprenticeship system of male authority. Likewise, the metal cook pot replaced the productive oversight and skill set of elder women’s ceramic production but created paths of independence for younger Yup’ik women. These changes in technology destabilized relative balances of gender and age based status, security, and authority and fashioned new gender and age based social and economic opportunities and limitations.

Developing a validated Alaska Native food frequency questionnaire for western Alaska, 2002–2006

Objectives. The purpose of this study was to develop a dietary instrument (food frequency questionnaire [FFQ]) that measured total dietary intake over 1 year among Alaska Native people in 2 regions. Ways of assessing diet are needed in order to accurately evaluate how the diets of Alaska Natives relate to their health.Study design. Seasonal 24-hour (24-h) diet recalls were collected for developing an FFQ that described the average dietary foods and nutrients consumed. Alaska Native people living in 12 small communities in 2 regions of the state were eligible to participate.Methods. Each participant was to provide 4 24-h diet recalls, 1 per season. Recalls were used to develop an FFQ using regression techniques. The FFQ was administered to 58 of the 333 original participants. Responses to the FFQ were compared to the averages of their 24-h recalls using the Spearman Correlation Coefficient.Results. Energy-adjusted correlations ranged from 0.15 for protein to 0.49 for monounsaturated fatty acids. Fifteen of 26 nutrients examined were significantly correlated (total carbohydrates, sucrose, fructose, total fat, fatty acids [monounsaturated, polyunsaturated, omega 3, EPA, DHA], folate, vitamins A, C, D, potassium and selenium).Conclusions. The FFQ can be used to evaluate intakes of Alaska Natives in western Alaska for the correlated nutrients.

Role of Science, Policy, and Society in Adaptive Watershed Management: Planning for an Uncertain Future: Monitoring, Integration, and Adaptation; Estes Park, Colorado, 8–11 September 2008

Water managers around the world are being tasked to include potential effects of climate change in their future operations scenarios. One important water manager, the federal government, owns and manages 30% of all land in the United States, the vast majority of which is in western states and Alaska. On 9 March 2007, the Secretary of the Interior signed Order 3270, which states that adaptive management should be considered when (1) there are consequential decisions to be made; (2) there is an opportunity to apply learning; (3) the objectives of management are clear; (4) the value of reducing uncertainty is high; (5) uncertainty can be expressed as a set of competing, testable models; and (6) an experimental design and monitoring system can be put in place with a reasonable expectation of reducing uncertainty.

The Annual Migration Cycle of Emperor Geese in Western Alaska

Most emperor geese (Chen canagica) nest in a narrow coastal region of the Yukon-Kuskokwim Delta (YKD) in western Alaska, but their winter distribution extends more than 3000 km from Kodiak Island, Alaska, to the Commander Islands, Russia. We marked 53 adult female emperor geese with satellite transmitters on the YKD in 1999, 2002, and 2003 to examine whether chronology of migration or use of seasonal habitats differed among birds that wintered in different regions. Females that migrated relatively short distances (650–1010 km) between the YKD and winter sites on the south side of the Alaska Peninsula bypassed autumn staging areas on the Bering Sea coast of the Alaska Peninsula or used them for shorter periods (mean = 57 days) than birds that made longer migrations (1600–2640 km) to the western Aleutian Islands (mean = 97 days). Alaska Peninsula migrants spent more days at winter sites (mean = 172 days, 95% CI: 129–214 days) than western Aleutian Island migrants (mean = 91 days, 95% CI: 83–99 days). Birds that migrated 930–1610 km to the eastern Aleutian Islands spent intermediate intervals at fall staging (mean = 77 days) and wintering areas (mean = 108 days, 95% CI: 95–119 days). Return dates to the YKD did not differ among birds that wintered in different regions. Coastal staging areas on the Alaska Peninsula may be especially important in autumn to prepare Aleutian migrants physiologically for long-distance migration to winter sites, and in spring to enable emperor geese that migrate different distances to reach comparable levels of condition before nesting.

Late Quaternary paleoclimate of western Alaska inferred from fossil chironomids and its relation to vegetation histories

Fossil Chironomidae assemblages (with a few Chaoboridae and Ceratopogonidae) from Zagoskin and Burial Lakes in western Alaska provide quantitative reconstructions of mean July air temperatures for periods of the late-middle Wisconsin (∼39,000–34,000 cal yr B.P.) to the present. Inferred temperatures are compared with previously analyzed pollen data from each site summarized here by indirect ordination. Paleotemperature trends reveal substantial differences in the timing of climatic warming following the late Wisconsin at each site, although chronological uncertainty exists. Zagoskin Lake shows early warming beginning at about 21,000 cal yr B.P., whereas warming at Burial Lake begins ∼4000 years later. Summer climates during the last glacial maximum (LGM) were on average ∼3.5 °C below the modern temperatures at each site. Major shifts in vegetation occurred from ∼19,000 to 10,000 cal yr B.P. at Zagoskin Lake and from ∼17,000 to 10,000 cal yr B.P. at Burial Lake. Vegetation shifts followed climatic warming, when temperatures neared modern values. Both sites provide evidence of an early postglacial thermal maximum at ∼12,300 cal yr B.P. These chironomid records, combined with other insect-based climatic reconstructions from Beringia, indicate that during the LGM: (1) greater continentality likely influenced regions adjacent to the Bering Land Bridge and (2) summer climates were, at times, not dominated by severe cold.

Movements of Juvenile Gyrfalcons from Western and Interior Alaska Following Departure from Their Natal Areas

Juvenile raptors often travel thousands of kilometers from the time they leave their natal areas to the time they enter a breeding population. Documenting movements and identifying areas used by raptors before they enter a breeding population is important for understanding the factors that influence their survival. In North America, juvenile Gyrfalcons (Falco rusticolus) are routinely observed outside the species' breeding range during the nonbreeding season, but the natal origins of these birds are rarely known. We used satellite telemetry to track the movements of juvenile Gyrfalcons during their first months of independence. We instrumented nestlings with lightweight satellite transmitters within 10 d of estimated fledging dates on the Seward Peninsula in western Alaska and in Denali National Park (Denali) in interior Alaska. Gyrfalcons spent an average of 41.4 ± 6.1 d (range = 30–50 d) in their natal areas after fledging. The mean departure date from natal areas was 27 August ± 6.4 d. We tracked 15 individuals for an average of 70.5 ± 28.1 d post-departure; Gyrfalcons moved from 105 to 4299 km during this period and tended to move greater distances earlier in the tracking period than later in the tracking period. Gyrfalcons did not establish temporary winter ranges within the tracking period. We identified several movement patterns among Gyrfalcons, including unidirectional long-distance movements, multidirectional long- and short-distance movements, and shorter movements within a local region. Gyrfalcons from the Seward Peninsula remained in western Alaska or flew to eastern Russia with no movements into interior Alaska. In contrast, Gyrfalcons from Denali remained in interior Alaska, flew to northern and western Alaska, or flew to northern Alberta. Gyrfalcons from both study areas tended to move to coastal, riparian, and wetland areas during autumn and early winter. Because juvenile Gyrfalcons dispersed over a large geographic area and across three international boundaries, conservation efforts should focus on both regional and international scales.

Plasma Biochemistry Values in Emperor Geese (Chen canagica) in Alaska: Comparisons Among Age, Sex, Incubation, and Molt

Reduced populations of emperor geese (Chen canagica), a Bering Sea endemic, provided the need to assess plasma biochemistry values as indicators of population health. A precursory step to such an investigation was to evaluate patterns of variability in plasma biochemistry values among age, sex, and reproductive period. Plasma from 63 emperor geese was collected on their breeding grounds on the Yukon-Kuskokwim Delta in western Alaska, USA. The geese sampled included 18 incubating adult females captured, in mid June, on their nests by using bow nets, and 30 adults and 15 goslings captured in corral traps in late July and early August, when the adults were molting their wing feathers and the goslings were 5-6 weeks old. Plasma was evaluated for 15 biochemical parameters, by comparing results among age, sex, and sampling period (incubation versus wing-feather molt). Ten of the 15 biochemical parameters assayed differed among adults during incubation, the adults during molt, and the goslings at molt, whereas sex differences were noted in few parameters.

Post-Fledging Movements of Juvenile Common Mergansers(Mergus merganser)in Alaska as Inferred by Satellite Telemetry

Abstract We implanted satellite transmitters into eight juvenile Common Mergansers to investigate post-fledging movements from their natal river in southcentral Alaska. Subsequently, they moved widely throughout portions of western and southcentral Alaska up to 750 km from their natal areas during fall and winter months. Transmitters of two birds (one male and one female) continued to send location data into their second year and allowed us to determine the location and timing of the flightless molt period for each bird. Overall, our data suggest that juvenile Common Mergansers range widely immediately after fledging, that second year males and females may differ in their movement patterns, and that these movements have implications for population genetic structure of this species.

Metabolic Syndrome: Prevalence among American Indian and Alaska Native People Living in the Southwestern United States and in Alaska

Metabolic syndrome occurs commonly in the United States. The purpose of this study was to measure the prevalence of metabolic syndrome among American Indian and Alaska Native people. We measured the prevalence rates of metabolic syndrome, as defined by the National Cholesterol Education Program, among four groups of American Indian and Alaska Native people aged 20 years and older. One group was from the southwestern United States (Navajo Nation), and three groups resided within Alaska. Prevalence rates were age-adjusted to the U.S. adult 2000 population and compared to rates for U.S. whites (National Health and Nutrition Examination Survey [NHANES] 1988-1994). Among participants from the southwestern United States, metabolic syndrome was found among 43.2% of men and 47.3% of women. Among Alaska Native people, metabolic syndrome was found among 26.5% of men and 31.2% of women. In Alaska, the prevalence rate varied by region, ranging among men from 18.9% (western Alaska) to 35.1% (southeast), and among women from 22.0% (western Alaska) to 38.4 % (southeast). Compared to U.S. whites, American Indian/Alaska Native men and women from all regions except western Alaska were more likely to have metabolic syndrome; men in western Alaska were less likely to have metabolic syndrome than U.S. whites, and the prevalence among women in western Alaska was similar to that of U.S. whites. The prevalence rate of metabolic syndrome varies widely among different American Indian and Alaska Native populations. Differences paralleled differences in the prevalence rates of diabetes.

MULTIPLE HYPOTHESIS TESTING AND THE DECLINING‐POPULATION PARADIGM IN STELLER SEA LIONS

We describe a novel spatially and temporally detailed approach for determining the cause or causes of a population decline, using the western Alaskan population of Steller sea lions (Eumetopias jubatus) as an example. Existing methods are mostly based on regression, which limits their utility when there are multiple hypotheses to consider and the data are sparse and noisy. Our likelihood-based approach is unbiased with regard to sample size, and its posterior probability landscape allows for the separate consideration of magnitude and certainty for multiple factors simultaneously. As applied to Steller sea lions, the approach uses a stochastic population model in which the vital rates (fecundity, pup survival, non-pup survival) at a particular rookery in each year are functions of one or more local conditions (total prey availability, species composition of available prey, fisheries activity, predation risk indices). Three vital rates and four scaling functions produce twelve nonexclusive hypotheses, of which we considered 10; we assumed a priori that fecundity would not be affected by fishery activities or predation. The likelihood of all the rookery- and year-specific census data was calculated by averaging across sample paths, using backward iteration and a beta-binomial structure for observation error. We computed the joint maximum likelihood estimates (MLE) of parameters associated with each hypothesis and constructed marginal likelihood curves to examine the support for each effect. We found strong support for a positive effect of total prey availability on pup recruitment, negative effects of prey species composition (pollock fraction) on fecundity and pup survival, and a positive effect of harbor seal density (our inverse proxy for predation risk) on non-pup survival. These results suggest a natural framework for adaptive management; for example, the areas around some of the rookeries could be designated as experimental zones where fishery quotas are contingent upon the results of pre-fishing season survey trawls. We contrast our results with those of previous studies, demonstrating the importance of testing multiple hypotheses simultaneously and quantitatively when investigating the causes of a population decline.

Effects of within-lake gradients on the distribution of fossil chironomids from maar lakes in western Alaska: implications for environmental reconstructions

We examined fossil chironomids (Diptera: Chironomidae) in the surface sediments of four maar lakes in western Alaska to determine chironomid distribution patterns with respect to within-lake gradients of water depth, LOI (loss-on-ignition), and bottom-water temperature. Linear and non-linear regressions were undertaken to test whether the within-lake distributions of fossil chironomids were uniform. Additionally, water depths where abrupt changes or breakpoints in the assemblages occur were identified using piecewise regression. Direct gradient analysis was then used to examine variation in the assemblages explained by the environmental data. For the shallowest lake, chironomid abundances of individual taxa and inferred temperatures varied little within the lake. For the three deep lakes, seven of the sixteen commonest fossil taxa varied significantly with water depth, although some lake-specific patterns were evident. Water depth was generally identified as the principal environmental variable in explaining variation in the assemblages, although sediment organic matter content and bottom-water temperature were also important. Abrupt changes in assemblages occurred at different water depths in each lake, and at only one lake did the breakpoint occur within the range of water depths defining the thermocline. Chironomid-inferred temperature trends from the lakes also showed depth-related patterns: the warmest inferred temperatures were generally from both the shallowest and deepest water depths, whereas intermediate depths yielded temperature inferences about 0.5 to 1.0°C cooler than the average within-lake value. Nevertheless, we conclude that these patterns had only a slight impact on temperature reconstructions relative to the prediction error of the model. A greater understanding of taphonomic processes is needed to determine their influence on environmental reconstructions based on chironomids.

Predicting synergistic effects of resources and predators on foraging decisions by juvenile Steller sea lions

Many theoretical and experimental studies suggest that synergistic interactions between resources and predators influence foraging decisions and their fitness consequences. This framework, however, has been ignored almost completely by hypotheses on causes of the population decline of Steller sea lions (SSLs) (Eumetopias jubatus) in western Alaska. By comparing predictions from a dynamic state variable model to empirical data on the behaviour of individuals instrumented with satellite-linked time-at-depth recorders, we develop and find preliminary support for the hypothesis that, during winter in Prince William Sound, juvenile SSLs (a) underutilise walleye pollock, a predictable resource in deep strata, due to predation risk from Pacific sleeper sharks, and (b) underutilise the potential energy bonanza of inshore aggregations of Pacific herring due to risk from either killer whales, larger conspecifics, or both. Further, under conditions of resource scarcity-induced by overfishing, long-term oceanographic cycles, or their combination-trade-offs between mortality risk and energy gain may influence demographic parameters. Accordingly, computer simulations illustrated the theoretical plausibility that a decline of Pacific herring in shallow strata would greatly increase the number of deep foraging dives, thereby increasing exposure to sleeper sharks and mortality rates. These results suggest that hypotheses on the decline of SSLs should consider synergistic effects of predators and resources on behaviour and mortality rates. Empirical support for our model, however, is limited and we outline tasks for empirical research that emerge from these limitations. More generally, in the context of today's conservation crises, our work illustrates that the greater the dearth of system-specific data, the greater the need to apply principles of behavioural ecology toward the understanding and management of large-scale marine systems.

Genetic analysis of sympatric char populations in western Alaska: Arctic char (Salvelinus alpinus) and Dolly Varden (Salvelinus malma) are not two sides of the same coin

The North Pacific Ocean has been of great significance to understanding biogeography and speciation in temperate faunas, including for two species of char (Salmonidae: Salvelinus) whose evolutionary relationship has been controversial. We examined the morphology and genetics (microsatellite and mitochondrial DNA) of Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) in lake systems in western Alaska, the eastern and western Arctic, and south of the Alaskan Peninsula. Morphologically, each lake system contained two forms: one (Arctic char) largely confined to lake habitats and characterized by greater numbers of pyloric caeca, gill rakers, and shallower bodies, and another (Dolly Varden) predominated in adjacent stream habitats and was characterized by fewer pyloric caeca, gill rakers, and deeper bodies. MtDNA partial (550 bp) d-loop sequences of both taxa were interspersed with each other within a single 'Bering' clade and demographic inferences suggested historical gene flow from Dolly Varden to Arctic char had occurred. By contrast, the taxa were strongly differentiated in sympatry across nine microsatellite loci in both lakes. Our data show that the two taxa are highly genetically distinct in sympatry, supporting their status as valid biological species, despite occasional hybridization. The interaction between these species highlights the importance of the North Pacific, and Beringia in particular, as an evolutionary wellspring of biodiversity.

Correction to “Evidence for and implications of a Bering Plate based on geodetic measurements from the Aleutians and western Alaska”

[1] In the paper ‘‘Evidence for and implications of a Bering Plate based on geodetic measurements from the Aleutians and western Alaska’’ by Ryan S. Cross and Jeffrey T. Freymueller (Journal of Geophysical Research, 113, B07405, doi:10.1029/2007JB005136, 2008), the magnitudes of the estimated angular velocities for the Bering plate were off by two orders of magnitude (or by a factor of 100) because of a unit conversion error. The same error affected all forward and inverse calculations, so only the Bering plate rotation rate was incorrect; the pole location and all other calculations in the paper are correct. The correct angular speed for the best model is 0.064 ± 0.033 degrees/ Ma. An updated Table 3 is given below, with the correct rates for all models tested.

Preliminary Studies on the Etiology of Keratoconjunctivitis in Reindeer (Rangifer tarandus tarandus) Calves in Alaska

Keratoconjunctivitis outbreaks occur each summer in reindeer (Rangifer tarandus tarandus) herds in western Alaska, USA. This condition has not been well characterized nor has a definitive primary etiologic agent been identified. We evaluated the eyes of 660 calves near Nome, Alaska, between 29 June and 14 July 2005. Clinical signs of keratoconjunctivitis were observed in 26/660 calves (3.9%). Samples were collected from the conjunctival sac of both affected (n=22) and unaffected (n=24) animals for bacterial culture, enzyme-linked immunosorbent assay testing for Chlamydophila psittaci, and for polymerase chain reaction assays for Mycoplasma and Moraxella spp. No primary bacterial or viral etiologic agent(s) were isolated or identified. The cause of keratoconjunctivitis among reindeer calves was not determined, but it could involve an anaerobic bacteria, a difficult-to-isolate viral agent, stress associated with repeated handling, ocular foreign bodies, exposure to corral dust or arthropods, or a combination.