Walrus feeding: a re-examination

Thesis (M.S.) University of Alaska Fairbanks, 1997A new approach for analyzing walrus (Odobenus rosmarus) diet was examined. Controlled gastric digestion experiments determined the relative rates at which different kinds of food items became unidentifiable. The ability to identify prey items varied within and among prey types. The laboratory experiments provided a new basis for examining diet data by characterizing the condition of stomach samples based on the rates at which different prey types were digested. Stomach content data acquired during 1952-1991 from 798 Pacific walruses were compiled, and interpretations about feeding habits were re-examined. Walruses regularly consumed a wider assortment of benthic prey than was previously thought. The diet of the Pacific walrus varied seasonally and regionally. Males and females consumed essentially the same food items when in the same location.Biological Resources Division of the U.S. Geological Survey, the Marine Mammals Management office of the U.S. Fish and Wildlife Servic

Bowhead whale distribution and feeding near Barrow, Alaska, in late summer 2005–06

Author Posting. © Arctic Institute of North America, 2010. This article is posted here by permission of Arctic Institute of North America for personal use, not for redistribution. The definitive version was published in Arctic 63 (2010): 195-205.Aerial surveys for bowhead whales were conducted in conjunction with oceanographic sampling near Barrow, Alaska, in late summer of 2005 and 2006. In 2005, 145 whales were seen, mostly in two distinct aggregations: one (ca. 40 whales) in deep water in Barrow Canyon and the other (ca. 70 whales) in very shallow (< 10 m) water just seaward of the barrier islands. Feeding behaviours observed in the latter group included whales lying on their sides with mouths agape and groups of 5–10 whales swimming synchronously in turbid water. In 2006, 78 bowheads were seen, with ca. 40 whales feeding in dispersed groups of 3–11 whales. Feeding behaviours observed included surface skimming, echelon swimming, and synchronous diving and surfacing. Surfacing behaviour included head lunges by single animals and groups of 2–4 whales. Of 29 whales harvested at Barrow, 24 had been feeding. Euphausiids were the dominant prey in 2006 (10 of 13 stomachs), but not in 2005 (4 of 11 stomachs). Copepods were the dominant prey in the stomachs of three whales harvested near Barrow Canyon in 2005. Mysiids were the dominant prey in four stomachs, isopods in two, and amphipods in one although these taxa were not routinely captured during plankton sampling conducted in the weeks prior to the autumn harvest.Much of the field portion of this work was supported by the NSF/SNACS program

The Potential for Using Little Diomede Island as a Platform for Observing Environmental Conditions in Bering Strait

The Pacific waters that enter the Arctic via the Bering Strait exert a major influence on the Arctic Ocean’s stratification, ice cover, and ecosystem. We demonstrate the potential of a shore-based laboratory to monitor the water masses that flow predominantly northward past Little Diomede Island in the center of the Bering Strait into the Arctic Ocean. We determined near-surface water column salinity, inorganic nutrient concentrations, natural fluorescence associated with chlorophyll, and the oxygen isotope composition of seawater, both in summer during the open-water period and in late winter under ice-covered conditions, by pumping ashore water from shallow depths near the island. Additional surveys were undertaken within 5 km of the island to assess the influence of local sources of nutrients. Water mass variability was much greater during the open-water period than under ice-covered conditions, presumably because the relatively immobile ice cover attenuates wind forcing and the decrease in run-off reduces cross-shelf gradients. The mean oxygen isotope composition of the summer (?18O = -1.11‰) and late winter (?18O = -0.98) collections, however, was close to that which has been established for Bering Sea waters in the Pacific-dominated upper halocline of the Arctic Ocean (-1.1‰) particularly considering the higher seasonal flow of runoff in the summer. A comparison with data from shipboard sampling at various locations across the Bering Strait indicates that the oxygen isotope composition of near-surface water sampled at Diomede varies in response to wind-forcing. If the least saline (&lt; 30.5) water near the Alaska coast is excluded, the ?18O values of Diomede and shipboard samples cannot be distinguished statistically. This similarity suggests that the water sampled from the island also reasonably represents the ?18O value of Bering Sea waters that contribute to the upper halocline of the Arctic Ocean. Effects of benthic recycling, human activity, and seabird nesting on nutrient concentrations appeared to be concentrated within ~200 m of the island. Our results are discussed in the practical context of availability of electricity, interested local residents, and a geotechnical study indicating that it is feasible to construct and operate a more permanent undersea water intake system to improve environmental observation capabilities in the Bering Strait region.Les eaux du Pacifique qui entrent dans l’Arctique par le détroit de Béring ont une influence majeure sur la stratification, le couvert de glace et l’écosystème de l’océan Arctique. Dans ce rapport nous présentons des données qui démontrent le potentiel d’un laboratoire basé à terre dans le but de surveiller les masses d’eau qui circulent principalement vers le nord au-delà de l’île Little Diomede au centre du détroit de Béring jusqu’à l’océan Arctique. Nous avons déterminé la salinité de la colonne d’eau près de la surface, la concentration des nutriments inorganiques, la fluorescence naturelle associée avec la chlorophylle, ainsi que la composition en isotope d’oxygène de l’eau de mer. Ces données ont été recueillies pendant la période estivale en eaux ouvertes et à la fin de l’hiver sous des conditions de couvert de glace en pompant à terre l’eau provenant d’aires peu profondes près de l’île. Des études supplémentaires ont été entreprises à moins de 5 km de l’île afin d’évaluer l’influence des sources locales de nutriments. La variabilité des masses d’eaux était plus grande pendant la période sans couvert de glace que pendant les conditions de couvert de glace. Ceci était vraisemblablement dû à l’atténuation de la force exercée par le vent sous le couvert de glace relativement immobile et à une réduction des gradients à travers le plateau provenant d’une réduction du ruissellement. La composition moyenne en isotope d’oxygène des collections de l’été (?18O = -1.11‰) et de fin d’hiver (?18O = -0.98‰) étaient cependant près de celle qui a été établie pour les eaux de la mer de Béring dans l’halocline supérieure de l’océan Arctique dominée par les eaux du Pacifique (?18O = -1.1‰), particulièrement compte tenu du flux saisonnier de ruissellement plus élevé pendant l’été. Une comparaison avec des données recueillies par bateau à plusieurs locations à travers le détroit de Béring indique que la composition en isotope d’oxygène près de la surface des eaux mesurée à Diomede varie en réponse à la force du vent. Lorsque l’eau moins saline (&lt; 30.5) près de la côte de l’Alaska est exclue, les valeurs ?18O de Diomede et des échantillons recueillis par bateau ne peuvent être distingués statistiquement. Cette similarité suggère que l’eau échantillonnée à partir de l’île représente aussi raisonnablement les valeurs ?18O des eaux de la mer de Béring qui contribuent à l’halocline supérieure de l’océan Arctique. Les conséquences du recyclage benthique, des activités anthropogéniques et de la nidification des oiseaux de mer sur les concentrations de nutriments semblent être concentrées à moins de ~200m de l’île. Nos résultats sont interprétés dans le contexte pratique de la disponibilité de l’électricité, de l’intérêt des résidents locaux et d’une étude géotechnique qui indique qu’un système permanent de prise d’eau sous-marin peut être construit et opéré afin d’améliorer les capacités d’observation environnementale dans la région du détroit de Béring

Prevalence and Abundance of Cyamid “Whale Lice” (Cyamus ceti) on Subsistence Harvested Bowhead Whales (Balaena mysticetus)

We present findings on the prevalence and abundance of cyamid ectoparasites (Cyamus ceti) or “whale lice” on bowhead whales (Balaena mysticetus) harvested for subsistence in the Bering, Chukchi, and Beaufort Seas from 1973 to 2015. Cyamids were present on 20% of the 673 whales that were examined for cyamid ectoparasites. Logistic regression was used to determine factors associated with cyamid prevalence. The probability of cyamid presence increased with age, length, and improving body condition, but decreased over the past 35 years. Cyamid presence was also more probable on whales harvested in the spring than on those harvested in the fall. When present, cyamid abundance was typically low(&lt; 10 per whale). Case histories provide ancillary information about the relationships between abundance of cyamids and their bowhead hosts. Environmental change and increasing anthropogenic disturbances are expected to occur in the Arctic regions inhabited by bowheads. We recommend continued monitoring of subsistence harvested whales for cyamids, as well as further investigations into the roles of environmental and anthropogenic variables in cyamid prevalence and abundance, as part of a comprehensive program of Arctic ecosystem assessment.Nous présentons nos constatations en matière de prévalence et d’abondance de l’ectoparasite cyamidae (Cyamus ceti) ou « pou des baleines » se trouvant sur la baleine boréale (Balaena mysticetus) capturée à des fins de subsistance dans la mer de Béring, la mer des Tchouktches et la mer de Beaufort entre 1973 et 2015. Les cyamidae étaient présents sur 20 % des 673 baleines qui ont été examinées dans le but d’y trouver des ectoparasites cyamidae. La régression logistique a servi à déterminer les facteurs liés à la prévalence de cyamidae. La probabilité de la présence de cyamidae augmentait en fonction de l’âge, de la longueur et de l’amélioration de l’état corporel, mais elle a diminué au cours des 35 dernières années. De plus, la présence de cyamidae était également plus probable chez les baleines capturées au printemps que chez les baleines capturées à l’automne. Lorsque présents, les cyamidae étaient généralement de faible abondance (&lt; 10 par baleine). Les cas types fournissent des renseignements supplémentaires sur les relations entre l’abondance de cyamidae et les baleines hôtes. Des changements environnementaux et de plus grandes perturbations anthropiques sont attendus dans les régions arctiques où évolue la baleine boréale. Nous recommandons la surveillance continue des baleines attrapées à des fins de subsistance pour en détecter les cyamidae. Nous recommandons également des études plus approfondies afin de déterminer le rôle des variables environnementales et anthropiques en matière de prévalence et d’abondance des cyamidae, dans le cadre d’un programme exhaustif d’évaluation de l’écosystème arctique

Frequency of Injuries from Line Entanglements, Killer Whales, and Ship Strikes on Bering-Chukchi-Beaufort Seas Bowhead Whales

We analyzed scarring data for Bering-Chukchi-Beaufort (BCB) Seas bowhead whales (Balaena mysticetus) harvested by Alaska Native hunters to quantify the frequency of line entanglement, ship strikes, and killer whale-inflicted injuries. We had 904 records in our database for whales landed between 1990 and 2012, and after data quality screening, we found 521 records containing information on scarring. Logistic regression was used to evaluate different combinations of explanatory variables (i.e., body length, sex, year, year-group) to develop a prediction model for each scar type. We also list bowhead whales that were harvested, found dead, or observed alive entangled in commercial line/fishing gear. Our findings suggest that about 12% of harvested bowheads show entanglement scars. Their frequency is highly correlated with body length and sex: about 50% of very large bowheads (&gt; 17 m) show such scars, while whales under 9 m rarely do, and males show a significantly higher rate than females. Scars associated with ship strikes are infrequent and occur on ~2% of all harvested whales; body length, sex, and year were not significant factors. Scarring from attempted killer whale predation was evident on ~8% of landed whales. As with entanglement injuries, the frequency of killer whale scars was much higher (&gt; 40%) on whales more than 16 m in length and statistically more frequent in the second half of the study (2002 – 12). Increased killer whale injuries in the recent decade are consistent with studies conducted on bowheads of the Eastern Canada-West Greenland population. The findings presented here reflect the most thorough analysis of injury rates from entanglement, ships, and killer whales for the BCB bowheads conducted to date. They indicate that (1) entanglement rates primarily from pot fishing gear (crab or cod or both) are relatively high for very large and presumably older bowheads, (2) collisions with ships are infrequent at present, and (3) scarring from killer whales is frequent on very large adult whales (&gt; 17 m). Considering that bowhead habitat is changing rapidly (e.g., sea ice reduction), industrial ship traffic in the Arctic is increasing, and commercial fishing operations are expanding to the north, we strongly recommend that monitoring of scarring and injuries on harvested bowheads continue into the future as a means of documenting change.Nous avons analysé les données sur les cicatrices que portent les baleines boréales (Balaena mysticetus) des mers de Béring, des Tchouktches et de Beaufort capturées par des chasseurs autochtones de l’Alaska afin de quantifier la fréquence d’emmêlements dans des filets de pêche, de collisions avec des navires et de blessures infligées par des épaulards. Notre base de données contenait 904 enregistrements portant sur des baleines prises entre 1990 et 2012 et, après une sélection des données selon leur qualité, nous avons trouvé 521 enregistrements comptant de l’information sur des cicatrices. Une méthode de régression logistique a été utilisée pour évaluer différentes combinaisons de variables explicatives (longueur corporelle, sexe, année et année-groupe, par exemple) afin de concevoir un modèle prédictif pour chaque type de cicatrice. Nous énumérons également les baleines boréales retrouvées emmêlées dans des engins ou des filets de pêche commerciale qui ont été capturées, trouvées mortes ou observées vivantes. Nos découvertes suggèrent qu’environ 12 % des baleines boréales capturées portent des cicatrices causées par l’emmêlement. La fréquence des cicatrices est étroitement liée à la longueur corporelle et au sexe : environ 50 % des baleines boréales de très grande taille (&gt; 17 m) montrent de telles cicatrices, tandis que les baleines mesurant moins de 9 m portent rarement de telles cicatrices. Par ailleurs, les mâles affichent beaucoup plus de cicatrices que les femelles. Les cicatrices reliées à des collisions avec des navires sont rares et n’apparaissent que sur environ 2 % de toutes les baleines capturées; la longueur corporelle, le sexe et l’année n’étaient pas des facteurs importants. Les cicatrices causées par des tentatives de prédation par les épaulards étaient apparentes sur environ 8 % des baleines prises. Comme pour les blessures causées par l’emmêlement, la fréquence des cicatrices causées par des épaulards était beaucoup plus élevée(&gt; 40 %) sur les baleines mesurant plus de 16 m de longueur et statistiquement plus fréquente dans la deuxième partie de l’étude (2002–2012). L’augmentation des blessures causées par des épaulards au cours de la dernière décennie concorde avec les études réalisées sur la population des baleines boréales de l’est du Canada et de l’ouest du Groenland. Les résultats présentés dans cette étude reflètent l’analyse la plus profonde du taux de blessures causées par l’emmêlement, les navires et les épaulards sur les baleines boréales des mers de Béring, des Tchouktches et de Beaufort à avoir été réalisée jusqu’à présent. Les observations indiquent que : 1) le taux d’emmêlement découlant principalement des engins ou casiers de pêche (crabe ou morue ou les deux) est relativement élevé chez les baleines boréales de très grande taille et probablement plus vieilles, 2) les collisions avec les navires sont rares en ce moment, et 3) les cicatrices causées par des épaulards sont fréquentes chez les baleines adultes de très grande taille (&gt; 17 m). Étant donné le changement rapide de l’habitat de la baleine boréale (diminution des glaces marines, par exemple), l’augmentation de la circulation maritime industrielle dans l’Arctique et l’intensification des opérations de pêche commerciale au nord, nous recommandons fortement de continuer de surveiller les cicatrices et les blessures des baleines boréales capturées afin de documenter les changements

Harmful algal blooms in the Alaskan Arctic: an emerging threat as the ocean warms

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Anderson, D., Fachon, E., Hubbard, K., Lefebvre, K., Lin, P., Pickart, R., Richlen, M., Sheffield, G., & Van Hemert, C. Harmful algal blooms in the Alaskan Arctic: an emerging threat as the ocean warms. Oceanography, 35(2), (2022), https://doi.org/10.5670/oceanog.2022.121.Harmful algal blooms (HABs) present an emerging threat to human and ecosystem health in the Alaskan Arctic. Two HAB toxins are of concern in the region: saxitoxins (STXs), a family of compounds produced by the dinoflagellate Alexandrium catenella, and domoic acid (DA), produced by multiple species in the diatom genus Pseudo-nitzschia. These potent neurotoxins cause paralytic and amnesic shellfish poisoning, respectively, in humans, and can accumulate in marine organisms through food web transfer, causing illness and mortality among a suite of wildlife species. With pronounced warming in the Arctic, along with enhanced transport of cells from southern waters, there is significant potential for more frequent and larger HABs of both types. STXs and DA have been detected in the tissues of a range of marine organisms in the region, many of which are important food resources for local residents. The unique nature of the Alaskan Arctic, including difficult logistical access, lack of response infrastructure, and reliance of coastal populations on the noncommercial acquisition of marine resources for nutritional, cultural, and economic well-being, poses urgent and significant challenges as this region warms and the potential for impacts from HABs expands.The authors acknowledge that the Alaskan Arctic as described here includes the lands and waters of the Inupiaq, Saint Lawrence Island Yupik, and Central Yupik peoples. Funding for DMA, RSP, EF, PL, and MLR was provided by grants from NSF Office of Polar Programs (OPP-1823002 and OPP-1733564) and NOAA’s Arctic Research program (through the Cooperative Institute for the North Atlantic Region [CINAR]; NA14OAR4320158 and NA19OAR4320074), and for DMA, KH, and KAL through NOAA’s Center for Coastal and Ocean Studies ECOHAB Program (NA20NOS4780195). Additional support was provided for DMA, MLR, and EF by the US National Park Service Shared Beringian Heritage Program (P21AC12214-00). We also thank Natalie Renier (WHOI Graphic Services) and Emily Bowers (Northwest Fisheries Science Center) for creating figures. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government. This is ECOHAB Contribution number 1007

Application of a Novel Method for Assessing Cumulative Risk Burden by County

The purpose of this study is to apply the Human Security Index (HSI) as a tool to detect social and economic cumulative risk burden at a county-level in the state of Texas. The HSI is an index comprising a network of three sub-components or “fabrics”; the Economic, Environmental, and Social Fabrics. We hypothesized that the HSI will be a useful instrument for identifying and analyzing socioeconomic conditions that contribute to cumulative risk burden in vulnerable counties. We expected to identify statistical associations between cumulative risk burden and (a) ethnic concentration and (b) geographic proximity to the Texas-Mexico border. Findings from this study indicate that the Texas-Mexico border region did not have consistently higher total or individual fabric scores as would be suggested by the high disease burden and low income in this region. While the Economic, Environmental, Social Fabrics (including the Health subfabric) were highly associated with Hispanic ethnic concentration, the overall HSI and the Crime subfabric were not. In addition, the Education, Health and Crime subfabrics were associated with African American racial composition, while Environment, Economic and Social Fabrics were not. Application of the HSI to Texas counties provides a fuller and more nuanced understanding of socioeconomic and environmental conditions, and increases awareness of the role played by environmental, economic, and social factors in observed health disparities by race/ethnicity and geographic region

Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV

Peer reviewe

Search for the production of dark matter in association with top-quark pairs in the single-lepton final state in proton-proton collisions at √s=8 TeV

Peer reviewe

Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

Peer reviewe