Western Alaska Research Articles

Estimating Demographic Parameters for Bearded Seals, Erignathus barbatus, in Alaska Using Close-Kin Mark-Recapture Methods.

Reliable estimates of population abundance and demographics are essential for managing harvested species. Ice-associated phocids, "ice seals," are a vital resource for subsistence-dependent coastal Native communities in western and northern Alaska, USA. In 2012, the Beringia distinct population segment of the bearded seal, Erignathus barbatus nauticus, was listed as "threatened" under the US Endangered Species Act requiring greater scrutiny for management assessments. We sought to estimate requisite population parameters from harvested seals by using close-kin mark-recapture (CKMR) methods, the first such application for marine mammals. Samples from 1758 bearded seals harvested by Bering, Chukchi, and Beaufort Sea communities during 1998-2020 were genotyped, genetically sexed, and aged by tooth annuli. After rigorous quality control, kin relationships were established for 1484 seals including two parent-offspring pairs (POPs) and 25 potential second-order kin pairs. Most of the second-order kin were half-sibling pairs (HSPs), but four were potential grandparent-grandchild pairs (GGPs). There were no full sibling pairs, suggesting a lack of mate fidelity. Mitochondrial DNA analysis identified 17 potential HSPs as paternally related, providing substantial evidence of persistent heterogeneity in reproductive success among adult males. The statistical CKMR model incorporates probabilities associated with POPs, HSPs, and GGPs and assumes known ages and a stable population. Our top model accommodates heterogeneity in adult male breeding success and yields an abundance estimate of ~409,000 with a coefficient of variation (CV) = 0.35, which is substantially greater than the "non-heterogeneity" model estimate of ~232,000 (CV = 0.21), an important difference for managing a harvested species. Using CKMR methods with harvested species provides estimates of abundance with the added opportunity to acquire information about adult survival, fecundity, and breeding success that could be applied to other species of concern, marine and terrestrial.

The lithosphere-asthenosphere boundary and lithosphere replacement as informed by mantle xenoliths and their host lavas

Alkaline lavas hosting mantle xenoliths occur in the hot back arc of the Cordillera of western Canada and Alaska and provide constraints on lithosphere thickness (within 5 to 10 km) and controls on the lithosphere-asthenosphere boundary (LAB). Such information is complementary to geophysical investigations of lithosphere strength and deformation in similar continental regions. Barometry of spinel lherzolite xenoliths and alkaline lavas from the Cordillera show LAB depths from 50 to 80 km, and marked thinning of the lithosphere at the Cordillera-craton transition coincident with the Rocky Mountain Trench-Tintina Fault. Similar barometric data globally for continental intraplate lavas show a relatively common lava equilibration depth of 65 to 80 km, that mostly coincide with LAB depths observed by seismology, and with the spinel- to garnet peridotite transition. The LAB is inferred as accumulated partial melt, modulated in depth by mantle solidus depression caused by varying H2O storage capacity across the garnet-spinel peridotite phase change. This mechanism does not explain cases where LAB depths are < 65 km, which instead require locally hotter asthenosphere. In many regions preserving a shallow LAB, foundering and wholesale replacement of mantle lithosphere is invoked. With the exception of North China, mantle xenoliths sampled from continental margins record cooling timescales that appear far longer than required for foundering and replacement in the past 50 Myr. Either cooling histories cannot be adequately modelled using closure/diffusion arguments or wholesale replacement of mantle lithosphere is a dubious process.

In-season monitoring of harvest and effort from a large-scale subsistence salmon fishery in western Alaska

In-season management of salmon harvest requires real-time data. Specifically, following a brief period of open fishing, knowledge of harvest outcomes is useful when deciding the nature of subsequent fishing periods. This in-season management strategy is relatively new to the lower Kuskokwim River of western Alaska, where depressed salmon runs have caused restrictions to the subsistence fishery. We have developed an in-season monitoring program to rapidly inform managers about fishery outcomes from short-duration (6-24 hours) fishery openings. Completed trip information and one or more aerial surveys are combined to estimate daily effort and harvest from drift gillnet fishers spanning 11 communities and ~130 river kilometers. We present a re-analysis of the 40 monitored openers in June-July 2016-2023, and validate harvest estimates of Chinook, chum, and sockeye salmon by comparing them to post-season estimates derived from an independent long-term monitoring program. Our results indicate that the program has produced estimates of sufficient quality to inform in-season managers, although it will likely need alterations to be successful in years with less restricted fishing.

On Micropolitics: Climate adaptation and Indigenous governance in Western Alaska

Climate adaptation for Indigenous communities is not as simple as making good policy; it is equally about how policy is implemented and how collaboration unfolds between settler governments and Indigenous stakeholders. Rural Alaska Native villages are among the most environmentally threatened communities in the United States. Their ability to effectively manage environmental change and preserve sovereignty depends upon successful collaboration with a range of stakeholders, especially federal agencies. For more than two decades, academics and government agencies have documented a consistent pattern of failures, particularly by federal actors, to effectively manage adaptation challenges. These obstacles are sometimes misrepresented as policy failures. While poor policy is certainly involved in these poor outcomes, this paper highlights a set of barriers to successful collaboration that are not policy issues, per se, but rather micropolitical issues; that is, they pertain to the conduct of government in the context of Tribal relationships. Unaddressed, these micropolitical issues have created obstacles to Alaska Native communities’ self-determination as they adapt to a changing landscape. These barriers are explored in a case study drawn from Typhoon Merbok, which struck Western Alaska in 2022, and empirically grounded in a series of interviews and participant observation with experts, elders, elected officials, and Tribal staff. This article concludes with several concrete recommendations to improve the practice of domestic diplomacy between Indigenous communities and colonial governments.

Diversity of cross-pacific atmospheric river main routes

Atmospheric rivers distribute heterogeneously over the North Pacific. Here, we identify five cross-Pacific atmospheric river main routes (i.e., preferred migratory path) by Self-organizing map automatically. They originate from East Asia or the western North Pacific and terminate over western North America or Alaska. The cross-Pacific atmospheric river events are emphasized because they bring more long-lasting precipitation when landfalling over North America. In the synoptic scale, the presence and configurations of the intensive pressure dipole are the keys to cross-ocean ability and propagation direction of atmospheric rivers. In the interannual time scale, tropical oceanic forcing is found for the cross-Pacific atmospheric river from southeast China to the contiguous United States (i.e., in-phase Eastern Pacific El Niño-Southern Oscillation and the basin-wide mode of Indian Ocean) and the other two types of cross-Pacific atmospheric river events are more related to atmospheric internal variability (e.g., North Pacific Oscillation) with succeeding oceanic response.

Watershed features shape spatial patterns of fish tissue mercury in a boreal river network

Freshwater mercury (Hg) contamination is a widespread environmental concern but how proximate sources and downstream transport shape Hg spatial patterns in riverine food webs is poorly understood. We measured total Hg (THg) in slimy sculpin (Cottus cognatus) across the Kuskokwim River, a large boreal river in western Alaska and home to subsistence fishing communities which rely on fish for primary nutrition. We used spatial stream network models (SSNMs) to quantify watershed and instream conditions influencing sculpin THg. Spatial covariates for local watershed geology and slope accounted for 55 % of observed variation in sculpin THg and evidence for downstream transport of Hg in sculpins was weak. Empirical semivariograms indicated these spatial covariates accounted for most spatial autocorrelation in observed THg. Watershed geology and slope explained up to 70 % of sculpin THg variation when SSNMs accounted for instream spatial dependence. Our results provide network-wide predictions for fish tissue THg based largely on publicly available geospatial data and open-source software for SSNMs, and demonstrate how these emerging models can be used to understand contaminant behavior in spatially complex aquatic ecosystems.

Impact of Preseason Climate Factors on Vegetation Photosynthetic Phenology in Mid-High Latitudes of the Northern Hemisphere.

During the period preceding the vegetation growing season (GS), temperature emerges as the pivotal factor determining phenology in northern terrestrial ecosystems. Despite extensive research on the impact of daily mean temperature (Tmean) during the preseason period, the influence of diurnal temperature range (DTR) on vegetation photosynthetic phenology (i.e., the impact of the plant photosynthetic cycle on seasonal time scale) has largely been neglected. Using a long-term vegetation photosynthetic phenology dataset and historical climate data, we examine vegetation photosynthetic phenology dynamics and responses to climate change across the mid-high latitudes of the Northern Hemisphere from 2001 to 2020. Our data reveal an advancing trend in the start of the GS (SOS) by -0.15 days per year (days yr-1), affecting 72.1% of the studied area. This is particularly pronounced in western Canada, Alaska, eastern Asia, and latitudes north of 60°N. Conversely, the end of the GS (EOS) displays a delaying trend of 0.17 days yr-1, impacting 62.4% of the studied area, especially northern North America and northern Eurasia. The collective influence of an earlier SOS and a delayed EOS has resulted in the notably prolonged length of the GS (LOS) by 0.32 days yr-1 in the last two decades, affecting 70.9% of the studied area, with Eurasia and western North America being particularly noteworthy. Partial correlation coefficients of the SOS with preseason Tmean, DTR, and accumulated precipitation exhibited negative values in 98.4%, 93.0%, and 39.2% of the study area, respectively. However, there were distinct regional variations in the influence of climate factors on the EOS. The partial correlation coefficients of the EOS with preseason Tmean, DTR, and precipitation were positive in 58.6%, 50.1%, and 36.3% of the region, respectively. Our findings unveil the intricate mechanisms influencing vegetation photosynthetic phenology, holding crucial significance in understanding the dynamics of carbon sequestration within terrestrial ecosystems amidst climate change.

Abrupt warming and alpine glacial retreat through the last deglaciation in Alaska interrupted by modest Northern Hemisphere cooling

Abstract. Alpine glacier-based temperature reconstructions spanning the last deglaciation provide critical constraints on local to regional climate change and have been reported from several formerly glaciated regions around the world yet remain sparse from high-northern-latitude regions. Using newly and previously 10Be-dated moraines, we report paleo-glacier equilibrium line altitudes (ELAs) for 15 time slices spanning the Last Glacial Maximum (LGM) to the Little Ice Age (LIA) for a valley in the western Alaska Range. We translate our ELA reconstructions into a proxy for summer temperature by applying a dry adiabatic lapse rate at each reconstructed ELA relative to the outermost LIA moraine. We observe ∼4 °C warming through the last deglaciation at our site that took place in two steps following initial gradual warming: ∼1.5 °C abrupt warming at 16 ka, ∼2 kyr after the onset of global CO2 rise, and ∼2 °C warming at ∼15 ka, near the start of the Bølling. Moraine deposition and modest summer cooling during Heinrich Stadial 1 and the early Younger Dryas (YD) suggest that despite these events being expressed more strongly in wintertime, the classic blueprint of North Atlantic climate variability extends to the western Arctic region.

Space weather with an arc’s ∼2 h trip across the nightside polar cap

Flow channels can extend across the polar cap from the dayside to the nightside auroral oval, where they lead to localized reconnection and auroral oval disturbances. Such flow channels can persist within the polar cap >1½ hours, can move azimuthally with direction controlled by IMF By, and may affect time and location of auroral oval disturbances. We have followed a polar cap arc as it moved duskward from Canada to Alaska for ∼2 h while connected to the oval. Two-dimensional ionospheric flows show an adjacent flow channel that moved westward with the arc and was a distinct feature of polar cap convection that locally impinged upon the outer boundary of the auroral oval. The flow channel’s interaction with the oval appears to have triggered two separate substorms during its trip across western Canada and Alaska, controlling the onset location and contributing to subsequent development of substorm activity within the oval. The first substorm (over Canada) occurred during approximately equatorward polar cap flow, whereas the second substorm (over Alaska) occurred as the polar cap arc and flow channel bent strongly azimuthally and appeared to “lay down” along the poleward boundary. The oval became unusually thin, leading to near contact between the polar cap arc and the brightening onset auroral arc within the oval. These observations illustrate the crucial role of polar cap flow channels in the time, location, and duration of space weather activity, and the importance of the duration and azimuthal motion of flow channels within the nightside polar cap.

Critical periods in the marine life history of juvenile western Alaska chum salmon in a changing climate

Recent precipitous declines in western Alaska chum salmon Oncorhynchus keta returns followed unprecedented warming in the northern Bering Sea ecosystem. To better understand the role of anomalous events on the early marine ecology of juvenile chum salmon in the northern Bering Sea, we utilized time-series observations over a 17 yr period (2003-2019) of sea surface temperature (SST) and juvenile chum salmon size (length and weight), diet, energy density, and relative abundance. Particular attention was paid to more recent (2014-2019) years in which there was unprecedented loss of sea ice in the northern Being Sea in comparison to previous warm (2003-2005) and cold (2006-2013) periods. Our findings indicate significant correlations between SST and juvenile chum salmon relative biomass (positive) and energy density (negative). We found that juvenile chum salmon were larger during warm periods than during cold periods; however, there was no significant difference in their length and weight between the warm periods. Juvenile chum salmon fed on lower quality prey during warm periods than during cold periods, with an increase in the proportion of lower quality prey during the recent warm period. Consequently, the energy density of juvenile chum salmon was also lower during warm periods than during cold periods, with the lowest values occurring during the recent warm period (2014-2019). These results identify a shift in energy allocation and/or prey quality of juvenile chum salmon with temperature and illustrate how marine ecosystems have altered the nutritional condition of juvenile chum salmon prior to winter, when energy reserves are considered critical to survival.

Big Mantle Wedge and Intraplate Volcanism in Alaska: Insight From Anisotropic Tomography

AbstractWe determine high‐resolution tomographic models of isotropic P‐wave velocity (Vp) and tilting‐axis anisotropy of the Alaska subduction zone using a large number of local and teleseismic data recorded at many portable and permanent network stations in and around Alaska. We find a flat high‐Vp slab in the mantle transition zone (410–670 km depths) beneath western Alaska, which is connected with the subducting Pacific slab at 0–410 km depths, suggesting that a big mantle wedge has formed under western Alaska. Our tilting‐axis anisotropy model reveals complex mantle flows in the asthenosphere. Corner flow in the mantle wedge above the subducting Pacific slab and toroidal flow in the big mantle wedge are revealed, which may cause the Cenozoic intraplate volcanoes in western Alaska and the Bering Sea. In central Alaska, the mantle wedge beneath the Denali volcanic gap is characterized by high‐Vp and subhorizontal fast velocity directions normal to the volcanic arc, which may reflect a remnant of the subducted Yakutat slab. In SE Alaska, the shallow subduction of the Wrangell slab is visible above 150 km depth, and hot mantle upwelling through the Wrangell‐Yakutat slab gap may contribute to the Wrangell volcanic field.

Alaska’s climate sensitive Yukon–Kuskokwim Delta supports seven million Arctic-breeding shorebirds, including the majority of six North American populations

Abstract Baseline information about declining North American shorebird populations is essential to determine the effects of global warming at low-lying coastal areas of the Arctic and subarctic, where numerous taxa breed, and to assess population recovery throughout their range. We estimated population sizes on the Yukon–Kuskokwim Delta (YKD) in western Alaska on the eastern edge of the Bering Sea. We conducted ground-based surveys during 2015 and 2016 at 589 randomly selected plots from an area of 35,769 km2. We used stratified random sampling in 8 physiographic strata and corrected population estimates using detection ratios derived from double sampling on a subset of plots. We detected 11,110 breeding individuals of 21 taxa. Western Sandpiper (Calidris mauri), Red-necked Phalarope (Phalaropus lobatus), Dunlin (subspecies C. alpina pacifica), and Wilson’s Snipe (Gallinago delicata) were the most abundant taxa. We estimated that ~7 million individual shorebirds were breeding on the entire YKD in 2015 and 2016. Our surveys of this region provided robust population estimates (coefficient of variations ≤ 0.35) for 14 species. Our results indicate that the YKD supports a large proportion of North America’s breeding populations of the Pacific Golden-Plover (Pluvialis fulva), the western population of a Whimbrel subspecies (Numenius phaeopus hudsonicus), a Bar-tailed Godwit subspecies (Limosa lapponica baueri), Black Turnstone (Arenaria melanocephala), a Dunlin subspecies (C. alpina pacifica), and Western Sandpiper. Our study highlights the importance of breeding shorebirds of this relatively pristine but climatically sensitive deltaic system. Estuaries and deltaic systems worldwide are rapidly being degraded by anthropogenic activities. Our population estimates can be used to refine prior North American population estimates, determine the effects of global warming, and evaluate conservation success by measuring population change over time.

Environmental ethnography

This article discusses the theory and practice of environmental ethnography and how it joins with (and differs from) multispecies ethnography. In the context of geographical research, environmental ethnography attends to the irreducibility of context and the individuality of living and non-living entities. Moving beyond the universalizing ontology of species—which in some instances can be too narrow and in other instances too broad—facilitates a line of posthumanist inquiry that complements multispecies research even as it opens up new frontiers. In doing so, environmental ethnographies overcome the dualisms of “organism-environment” and “life-nonlife” that structure Western ontology and remain stubbornly (if partially) embedded in some academic theory and practice. I begin with a brief history of the decentering of the human in geographical research before mapping the still-in-progress development of environmental ethnography, highlighting examples from other scholars while drawing on my own experiences in remote Iñupiaq and Siberian Yupik communities in Western Alaska. Moving beyond the rigid ontologies of genetics and metabolism reveals the political horizon to be wider than we often imagine.

Molecular detection and characterization of highly pathogenic H5N1 clade 2.3.4.4b avian influenza viruses among hunter-harvested wild birds provides evidence for three independent introductions into Alaska

We detected and characterized highly pathogenic avian influenza viruses among hunter-harvested wild waterfowl inhabiting western Alaska during September–October 2022 using a molecular sequencing pipeline applied to RNA extracts derived directly from original swab samples. Genomic characterization of 10 H5 clade 2.3.4.4b avian influenza viruses detected with high confidence provided evidence for three independent viral introductions into Alaska. Our results highlight the utility and some potential limits of applying molecular processing approaches directly to RNA extracts from original swab samples for viral research and monitoring.

Hillslope‐Channel Transitions and the Role of Water Tracks in a Changing Permafrost Landscape

AbstractThe Arctic is experiencing rapid climate change, and the effect on hydrologic processes and resulting geomorphic changes to hillslopes and channels is unclear because we lack quantitative models and theory for rapid changes resulting from thawing permafrost. The presence of permafrost modulates water flow and the stability of soil‐mantled slopes, implying that there should be a signature of permafrost processes, including warming‐driven disturbance, in channel network extent. To inform understanding of hillslope‐channel dynamics under changing climates, we examined soil‐mantled hillslopes within a ∼300 km2 area of the Seward Peninsula, western Alaska, where discontinuous permafrost is particularly susceptible to thaw and rapid landscape change. In this study, we pair high‐resolution topographic and satellite data to multi‐annual observations of InSAR‐derived surface displacement over a 5‐year period to quantify spatial variations in topographic change across an upland landscape. We find that neither the basin slope nor the presence of knickzones controls the magnitude of recent surface displacements within the study basin, as may be expected under conceptual models of temperate hillslope evolution. Rather, the highest displacement magnitudes tended to occur at the broad hillslope‐channel transition zone. In this study area, this zone is occupied by water tracks, which are zero‐order ecogeomorphic features that concentrate surface and subsurface flow paths. Our results suggest that water tracks, which appear to occupy hillslope positions between saturation and incision thresholds, are vulnerable to warming‐induced subsidence and incision. We hypothesize that gullying within water tracks will outpace infilling by hillslope processes, resulting in the growth of the channel network under future warming.

Building resilience to extreme weather and climate events in the rural water and wastewater sectors

AbstractExtreme weather and climate events pose significant risks to rural water and wastewater systems. We examine the vulnerability of the water sector to weather and climate extremes in rural, predominantly Indigenous and underserved coastal areas and analyze how networks support resilience. Drawing on the analysis of 39 web‐based questionnaire responses and 19 interviews with rural water and wastewater managers and service providers in southern Louisiana and western Alaska, this article reports a range of interrelated historical, environmental, and social factors that influence vulnerability to extreme weather events. Formal and informal social networks serve multiple roles in building resilience. These roles include building technical and financial capacities, supporting emergency response and operational‐ to long‐term planning, fostering data collection and monitoring, supporting information sharing and innovative research, and providing institutional support. Results from this research enrich our understanding of the social, relational, and networking processes that condition community resilience to extreme weather events.

Sharing, social norms, and social distance: Experimental evidence from Russia and Western Alaska

This paper investigates how dictator giving varies by social context and worthiness of the recipient. We conduct lab-in-the-field experiments in Kamchatka, Russia, and Western Alaska, as well as a lab experiment with university students, in which we vary social distance and recipient characteristics across treatments. We ask what motivates individuals to share and whether offers from a dictator game, where dictators give from own-earnings, can tell us something more fundamental about social norms and sharing. Results indicate that subjects living in rural Indigenous communities, in both Russia and Alaska, who depend heavily on wild food harvests and possess strong sharing norms, are significantly more likely to give positive amounts compared to university students. We also find that in Indigenous communities, family relations and financial needs are prioritized in giving decisions. We suggest that treatment differences correspond to social norm differences in our study areas.

Report of two distinct ribotypes in ITS sequences of Phalarisarundinacea (Poaceae) in western Canada and Alaska.

Phalarisarundinacea L. (reed canary grass) is a widely occurring grass throughout the Northern Hemisphere. In North America, it is thought to consist of introduced agricultural forms from Europe as well as native populations. During a survey of Phalarisarundinacea in western Canada, we discovered two distinct ribotypes in the sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA: one full length (ITS-long) and one with a seven base pair deletion (ITS-short). In addition, ITS-long plants have fixed heterozygosity indicating possible polyploidy. Phylogenetic analysis reveals that ITS-short is a unique ribotype that characterises an intraspecific clade. We designed an efficient PCR-based assay that allows sizing of a 238/245 base pair fragment in a capillary sequencer. This approach provides a novel marker that could be useful in future surveys of Phalarisarundinacea.

Patterns and rates of soil movement and shallow failures across several small watersheds on the Seward Peninsula, Alaska

Abstract. Thawing permafrost can alter topography, ecosystems, and sediment and carbon fluxes, but predicting landscape evolution of permafrost-influenced watersheds in response to warming and/or hydrological changes remains an unsolved challenge. Sediment flux and slope instability in sloping saturated soils have been commonly predicted from topographic metrics (e.g., slope, drainage area). In addition to topographic factors, cohesion imparted by soil and vegetation and melting ground ice may also control spatial trends in slope stability, but the distribution of ground ice is poorly constrained and hard to predict. To address whether slope stability and surface displacements follow topographic-based predictions, we document recent drivers of permafrost sediment flux present on a landscape in western Alaska that include creep, solifluction, gullying, and catastrophic hillslope failures ranging in size from a few meters to tens of meters, and we find evidence of rapid and substantial landscape change on an annual timescale. We quantify the timing and rate of surface movements using a multi-pronged, multi-scalar dataset including aerial surveys, interannual GPS surveys, synthetic aperture radar interferometry (InSAR), and climate data. Despite clear visual evidence of downslope soil transport of solifluction lobes, we find that the interannual downslope surface displacement of these features does not outpace downslope displacement of soil in locations where lobes are absent (downslope movement means: 7 cm yr−1 for lobes over 2 years vs. 10 cm yr−1 in landscape positions without lobes over 1 year). Annual displacements do not appear related to slope, drainage area, or modeled total solar radiation but are likely related to soil thickness, and volumetric sediment fluxes are high compared to temperate landscapes of comparable bedrock lithology. Time series of InSAR displacements show accelerated movement in late summer, associated with intense rainfall and/or deep thaw. While mapped slope failures do cluster at slope–area thresholds, a simple slope stability model driven with hydraulic conductivities representative of throughflow in mineral and organic soil drastically overpredicts the occurrence of slope failures. This mismatch implies permafrost hillslopes have unaccounted-for cohesion and/or throughflow pathways, perhaps modulated by vegetation, which stabilize slopes against high rainfall. Our results highlight the breadth and complexity of soil transport processes in Arctic landscapes and demonstrate the utility of using a range of synergistic data collection methods to observe multiple scales of landscape change, which can aid in predicting periglacial landscape evolution.

Bowhead whale feeding in the Alaskan Beaufort Sea, based on stomach contents analyses

This study examined feeding of bowhead whales (Balaena mysticetus) taken by Alaska Natives at Barrow (western Beaufort Sea), Nuiqsut (central Alaskan Beaufort Sea) and Kaktovik (eastern Alaskan Beaufort Sea) during 1969-2000. The objectives were to: (1) identify the proportion of harvested whales that had been feeding; and (2) describe the diet based on stomach contents. Data used were field records for 242 whales whose stomachs were examined and laboratory analysis of samples from 123 animals. There were no significant differences in the proportions of animals that had been feeding during the autumn at Kaktovik (83%) and Barrow (75%), or in sub-adults (78%) versus adults (73%). Copepods occurred significantly more frequently in animals from Kaktovik, while euphausiids and hyperiid amphipods occurred more frequently at Barrow. During the autumn, the percent copepods by volume was greater in animals taken at Kaktovik than at Barrow, while the percent euphausiids by volume was greater in whales taken at Barrow. At Barrow, a larger proportion of animals was feeding in the autumn (76%) than the spring (34%), and copepods occurred more often in the spring. Examination of five whales taken at Nuiqsut in the autumn suggests a feeding pattern similar to that seen at Kaktovik. There were no significant differences in diets of males versus females or of sub-adults versus adults. It is concluded that in the autumn, bowheads feed regularly in the eastern, central and western Alaskan Beaufort Sea, and that feeding during the spring migration is more common than previously thought.