17 research outputs found

    Bowhead Whale (Balaena mysticetus) Feeding near Point Barrow, Alaska, During the 1985 Spring Migration

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    Examination of stomach contents and behavioral observations showed conclusively that bowhead whales were feeding in the Point Barrow area during the spring of 1985. All three bowheads harvested near the village of Barrow had over five litres of pelagic zooplankton (calanoid copepods and euphausiids) in their stomachs. Over 60 whales were observed during the period 26 May through 6 June diving repeatedly under the landfast ice and feeding in an area 11.2 km southwest of Point Barrow. Observers recorded times for dive, surfacing and respiration intervals for these whales. The recorded times were significantly different from those of bowhead whales migrating past Point Barrow in the spring and from bowheads, whose major activity was feeding, recorded in the Canadian Beaufort Sea during the summer and fall.Key words: Balaena mysticetus, Point Barrow, feeding, bowhead whale, behavior, copepod,  euphausiid, respiration, springUn examen du contenu stomacal de baleines franches et des observations de leur comportement ont montré sans aucun doute qu’elles se nourrissaient dans la zone de Point Barrow pendant le printemps de1985. Les trois baleines franches pêchées près du village de Barrow avaient toutes dans l’estomac plus de cinq litres de zooplancton pélagique (copépodes calanoïdes et euphausiacés). Pendant la période allant du 26 mai au 6 juin, on a observé plus de 60 baleines qui plongeaient de façon répétée sous la banquise côtière pour se nourrir dans une zone située à 11,2 km au sud-ouest de Point Barrow. Les observateurs ont noté le moment de la plongée et celui du retour à la surface, et l’intervalle entre les souffles des baleines. Les durées enregistrées étaient nettement différentes de celles mesurées pour des baleines franches qui passaient à Point Barrow pendant leur migration au printemps, et de celles enregistrées dans la mer de Beaufort canadienne en été et en automne pour des baleines franches dont l’activité principale était de se nourrir.Mots clés: Balaena mysticetus, Point Barrow, se nourrir, baleine franche, comportement, copépode, euphausiacé, respiration, printemp

    Frequency of Killer Whale (Orcinus Orca) Attacks and Ship Collisions Based on Scarring on Bowhead Whales (Balaena Mysticetus) of the Bering-Chukchi-Beaufort Seas Stock

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    Bowhead whales of the Bering-Chukchi-Beaufort Seas stock harvested by Alaskan Eskimos were examined for scars from killer whale and ship-collision injuries. We estimated that the frequency of scars from killer whale attacks ranged from 4.1% to 7.9% (depending on our confidence that the whale was properly examined) while about 1% exhibited scars from ship collisions. The frequency of killer whale scars was considerably lower than for bowhead whales of the Davis Strait stock and for other baleen whales where data are available, and was significantly lower (P<0.05) for whales <13 m. Patterns of both types of scars were quite similar to those reported for other cretacean species. Spaces between rake marks were within the range of interdental measurements from four killer whale skulls. The occurrence of attempted killer whale predation and ship strikes inferred from scars has not prevented the BCBS stock from increasing.Key words: bowhead whale, killer whale, Alaskan Eskimos, whaling, scarring, ship/whale collision, propeller injuryOn a examiné des baleines boréales provenant du stock des mers de Béring, des Tchouktches et de Beaufort, prises par les Esquimaux de l'Alaska afin de voir si elles portaient des cicatrices résultant de morsures d'épaulards ou de blessures provoquées par des collisions avec des navires. On a estimé la gamme de fréquence des cicatrices venant d'attaques d'épaulards comme allant de 4,1 à 7,9 p. cent (compte tenu de notre niveau de certitude quant à la qualité de l'examen de la baleine), tandis qu'environ 1 p. cent des animaux montraient des cicatrices résultant de collisions avec des navires. La fréquence des cicatrices dues aux épaulards était bien inférieure à celle observée sur les baleines provenant du stock du détroit de Davis et d'autres cétacés à fanons pour lesquels on possédait des données. Les schémas des deux types de cicatrices étaient assez semblables à ceux rapportés pour d'autres espèces de cétacés. La fréquence des cicatrices dues aux épaulards était de beaucoup inférieure (P<0,05) pour les baleines mesurant moins de 13 m. Les espaces entre les éraflures se situaient dans la gamme d'écartement interdentaire mesuré sur le crâne de quatre épaulards. Les tentatives de prédation par les épaulards et les coups portés par les navires - déduits des cicatrices - n'ont pas empêché le stock des mers de Béring, des Tchouktches et de Beaufort d'augmenter.Mot clés: baleine boréale, épaulard, Esquimaux de l’Alaska, pêche à la baleine, cicatrices, collision navire/baleine, blessure infligée par une hélic

    Use of satellite telemetry data, GIS, and HTML to create an interactive display of caribou movements

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    The use of animation clearly reveals the large annual variation in wintering areas and large differences in daily movement rates for this herd. This interactive display can be adapted for school groups, subsistence hunters, the general public, or scientists

    Distribution and Movements of the Teshekpuk Caribou Herd 1990–2005: Prior to Oil and Gas Development

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    Four caribou (Rangifer tarandus grantii) herds calve on the North Slope of Alaska, three of which have been exposed to little or no resource development. We present 15 years of baseline data on the distribution and movements of 72 satellite-collared and 10 GPS-collared caribou from the Teshekpuk caribou herd (TCH) that have had little to no exposure to oil and gas activities. Fixed-kernel home range analyses of collared caribou revealed that calving grounds were concentrated (i.e., 50% kernel utilization distribution) along the northeastern, eastern, and southeastern shores of Teshekpuk Lake. During the postcalving period, 51% and 35% of caribou moved through two constricted zones to the east and west of Teshekpuk Lake, respectively, and accessed insect-relief habitat along the Beaufort Sea coast. During late summer and early fall, TCH caribou were concentrated to the southeast and southwest of Teshekpuk Lake. Although 65% of the Teshekpuk caribou wintered in two areas on the central coastal plain around the village of Atqasuk and south of Teshekpuk Lake, other TCH animals wintered in a great variety of places, including the Seward Peninsula, the eastern and southern Brooks Range, and the Arctic National Wildlife Refuge. We detected an apparent emigration rate of 6.9%. One male and five female TCH caribou joined the breeding populations of the Western Arctic and Central Arctic herds. TCH caribou traveled an average distance of 2348 ± 190 km annually. Movement rates were at a maximum in midsummer, lowest in winter, and intermediate during spring and fall migrations. Restrictions on oil and gas leasing and surface occupancy have been in place to protect calving, migratory corridors, and insect-relief habitat for the TCH, but these protections are likely to be removed. These data will provide a good baseline that can be used to compare predevelopment distribution and movement patterns of TCH caribou to distribution and movement patterns during and after petroleum development.Quatre hardes de caribous (Rangifer tarandus grantii) vêlent sur la côte nord de l’Alaska, dont trois de ces hardes ont été exposées à peu ou pas d’aménagement des ressources. Nous présentons des données de base échelonnées sur 15 ans relativement à la répartition et aux déplacements de 72 caribous dotés d’un collier émetteur par satellite et de 10 caribous munis d’un collier émetteur GPS de la harde de caribous de Teshekpuk (HCT), caribous qui ont été peu ou pas du tout frottés aux activités pétrolières et gazières. L’analyse du noyau fixe des domaines vitaux des caribous à collier a révélé que les lieux de vêlage étaient concentrés (c’est-à-dire 50 % de la répartition de l’utilisation du noyau) le long des côtes nord-est, est et sud-est du lac Teshekpuk. Après la période de vêlage, 51 pour cent et 35 pour cent des caribous se déplaçaient au sein de deux zones de constriction à l’est et à l’ouest du lac Teshekpuk, respectivement, et accédaient un habitat où se trouvait moins d’insectes sur la côte de la mer de Beaufort. Vers la fin de l’été et le début de l’automne, les caribous de la HCT étaient concentrés au sud-est et au sud-ouest du lac Teshekpuk. Bien que 65 pour cent des caribous de Teshekpuk passaient l’hiver dans deux régions de la plaine côtière centrale autour du village d’Atqasuk et au sud du lac Teshekpuk, les autres bêtes de la HCT passaient l’hiver dans divers endroits, dont la péninsule de Seward, les versants est et sud des montagnes de Brooks et la Réserve faunique nationale de l’Arctique. Nous avons détecté un taux d’émigration apparent de 6,9 pour cent. Un caribou mâle et cinq caribous femelles de la HCT ont rejoint les populations de reproduction des hardes de l’ouest et du centre de l’Arctique. En moyenne, le caribou de la HCT parcourait une distance de 2348 ± 190 km annuellement. Les taux de déplacement étaient à leur point le plus élevé au milieu de l’été, tandis qu’ils étaient à leur niveau le plus bas l’hiver et à un niveau intermédiaire pendant les migrations du printemps et de l’automne. Il existe des restrictions en matière de location et d’occupation en surface pour le pétrole et le gaz afin de protéger le vêlage, les corridors de migration et les habitats à faible taux d’insectes pour la HCT, mais il est vraisemblable que ces restrictions soient éliminées. Ces données fourniront une bonne base pour comparer la répartition et les déplacements du caribou de la HCT avant la mise en valeur des ressources à la répartition et aux déplacements du caribou de la HCT pendant et après la mise en valeur pétrolière

    Use of satellite telemetry to evaluate movements of caribou within subsistence hunting areas in northern Alaska

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    Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupiaq villages in northern Alaska. In recent years the use of satellite telemetry has increased the understanding of the herd's annual movements and interactions with other herds. Most caribou of the TH are within the National Petroleum Reserve—Alaska (NPRA) throughout the year. The northeastern portion of NPRA has undergone two lease sales for oil and gas exploration, and lease sales are tentatively scheduled for the central/northwest portion of the NPRA in 2004. During 1990—1999, the movements of 27 caribou from the TH were tracked using satellite collars. We evaluated the proportion of time caribou were available to Inupiaq hunters by incorporating maps depicting subsistence-use areas for each of seven Inupiaq villages, and then examining seasonal and annual movements of caribou relative to those areas. By combining caribou locations with subsistence hunting areas, we were able to explore spatial and temporal patterns in caribou availability to subsistence hunters. This information is useful for managers to set appropriate hunting regulations and for devising sensible alternatives and mitigation of likely petroleum development in NPRA

    Use of satellite telemetry to evaluate movements of caribou within subsistence hunting areas in northern Alaska

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    Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupiaq villages in northern Alaska. In recent years the use of satellite telemetry has increased the understanding of the herd's annual movements and interactions with other herds. Most caribou of the TH are within the National Petroleum Reserve—Alaska (NPRA) throughout the year. The northeastern portion of NPRA has undergone two lease sales for oil and gas exploration, and lease sales are tentatively scheduled for the central/northwest portion of the NPRA in 2004. During 1990—1999, the movements of 27 caribou from the TH were tracked using satellite collars. We evaluated the proportion of time caribou were available to Inupiaq hunters by incorporating maps depicting subsistence-use areas for each of seven Inupiaq villages, and then examining seasonal and annual movements of caribou relative to those areas. By combining caribou locations with subsistence hunting areas, we were able to explore spatial and temporal patterns in caribou availability to subsistence hunters. This information is useful for managers to set appropriate hunting regulations and for devising sensible alternatives and mitigation of likely petroleum development in NPRA

    Summer resource selection and identification of important habitat prior to industrial development for the Teshekpuk Caribou Herd in northern Alaska.

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    Many caribou (Rangifer tarandus) populations are declining worldwide in part due to disturbance from human development. Prior to human development, important areas of habitat should be identified to help managers minimize adverse effects. Resource selection functions can help identify these areas by providing a link between space use and landscape attributes. We estimated resource selection during five summer periods at two spatial scales for the Teshekpuk Caribou Herd in northern Alaska prior to industrial development to identify areas of high predicted use for the herd. Additionally, given the strong influence parturition and insect harassment have on space use, we determined how selection differed between parturient and non-parturient females, and between periods with and without insect harassment. We used location data acquired between 2004-2010 for 41 female caribou to estimate resource selection functions. Patterns of selection varied through summer but caribou consistently avoided patches of flooded vegetation and selected areas with a high density of sedge-grass meadow. Predicted use by parturient females during calving was almost entirely restricted to the area surrounding Teshekpuk Lake presumably due to high concentration of sedge-grass meadows, whereas selection for this area by non-parturient females was less strong. When insect harassment was low, caribou primarily selected the areas around Teshekpuk Lake but when it was high, caribou used areas having climates where insect abundance would be lower (i.e., coastal margins, gravel bars). Areas with a high probability of use were predominately restricted to the area surrounding Teshekpuk Lake except during late summer when high use areas were less aggregated because of more general patterns of resource selection. Planning is currently underway for establishing where oil and gas development can occur in the herd's range, so our results provide land managers with information that can help predict and minimize impacts of development on the herd

    Relative probability of use for parturient and non-parturient females during calving.

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    <p>Map of relative probability of use during the calving period for (A) parturient and (B) non-parturient females of the Teshekpuk Caribou Herd derived from landscape-scale resource selection function results on data from 2004–2010. Blue pixels represent areas with water where resource selection was not measured. The predicted map’s extent is defined by the range of the herd during the calving period.</p

    Relative probability of use during high and low insect harassment periods.

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    <p>Predicted maps derived from landscape-scale resource selection function results for the Teshekpuk Caribou Herd in Alaska based on data from 2004–2010: (A) high mosquito harassment, (B) low mosquito harassment, (C) high oestrid fly harassment, and (D) low oestrid fly harassment. Blue pixels represent areas with water where resource selection was not measured. The predicted map’s extent is defined by the range of the herd during the mosquito harassment period (A-B) and the oestrid fly harassment period (C-D).</p
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