Canada's Most Northerly Postglacial Bowhead Whales (<i>Balaena mysticetus</i>) : Holocene Sea-ice Conditions and Polynya Development

Abstract

ABSTRACT. Rare remains of postglacial bowhead whales occur in the Norwegian Bay-Eureka Sound region. These are the northernmost remains known from the Canadian Arctic. The region is beyond the bowhead's current range because of persistent summer sea ice. We argue that the region has been beyond the bowhead's range for most of postglacial time for the same reason. With one exception, the 16 known subfossil bowheads from the region date to the last 4000 14 C years. Within the region, whale bones are most common adjacent to polynyas, which connect to more southerly channels extending from Baffin Bay. This distribution suggests that the polynyas, which here occupy areas of strong currents, developed as a result of shallowing of interisland channels due to postglacial uplift. The whale remains beyond the polynyas are seen as those of doomed strays that reached the polynyas from Baffin Bay and foraged farther along coastal leads before being trapped by freeze-up. This interpretation of Holocene sea-ice history agrees with the limited development of Holocene raised beaches in the region. However, it contradicts other interpretations of greatly ameliorated marine conditions in northernmost Canada at about 6000 14 C years B.P.Key words: Holocene bowhead whale, Arctic Ocean, sea-ice paleoclimate, Canadian Arctic Archipelago RÉSUMÉ. La région de la baie Norwegian et du détroit d'Eureka abrite un petit nombre de restes organiques de baleines boréales postglaciaires. Ce sont les restes trouvés le plus au nord de l'Arctique canadien. Cette zone est située en dehors du territoire actuel de la baleine boréale en raison de la présence constante de glace marine estivale. On soutient que la région s'est trouvée en dehors du territoire de la baleine boréale durant la plus grande partie de la période postglaciaire, et ce, pour la même raison. À une exception près, les 16 baleines boréales subfossiles qui ont été découvertes dans cette zone datent des 4000 dernières années (âge radiocarbone). Dans la région, les os de baleines se trouvent en plus grand nombre au voisinage immédiat de polynies, celles-ci étant reliées à des chenaux plus méridionaux qui sinuent depuis la baie de Baffin. Cette distribution suggère que les polynies, qui occupent ici des zones de courants forts, se sont formées à la suite d'une diminution de la profondeur des chenaux séparant les îles provoquée par un soulèvement postglaciaire. On pense que les restes de baleines qui se trouvent en dehors des polynies appartiennent à des baleines qui ont rejoint les polynies depuis la baie de Baffin et qui se sont égarées plus loin en quête de nourriture le long des passages côtiers avant d'être bloquées par les glaces. Cette interprétation de l'histoire de la glace marine de l'holocène concorde avec l'évolution restreinte des plages soulevées de la région, qui datent de l'holocène. Elle contredit toutefois d'autres interprétations de conditions marines nettement améliorées dans l'extrême nord du Canada il y a environ 6000 ans (âge radiocarbone) BP.Mots clés: baleine boré...

A 10 400-Year-Old Bowhead Whale (<i>Balaena mysticetus</i>) Skull from Ellef Ringnes Island, Nunavut: Implications for Sea-Ice Conditions in High Arctic Canada at the End of the Last Glaciation

“…this reconstruction supports the "meltwater drive" hypothesis proposed by Dyke and Morris (1990). Despite evidence that driftwood was received and transported by the Arctic Ocean during this interval, its near absence in the Norwegian Bay region between 8 and 7 ka BP indicates the presence of largely permanent and immobile landfast sea ice (Stewart and England, 1983;Dyke et al, 1996Dyke et al, , 1997Dyke and England, 2003;Atkinson and England, 2004;Figs. 2 and 5c).…”

“…5b and c). the archipelago remained beyond their range until ~4 ka BP, when stray whales occasionally reached polynyas from Baffin Bay, and foraged along coastal leads before being trapped during freeze-up (Dyke and England, 2003). to date, the only other early Holocene bowhead whale reported in the northern CAA occurs on northeast Axel Heiberg Island, adjacent to Nansen Sound, and dates to 7.5 ka BP (Bednarski, 1990; Fig.…”

Identification of Potential Foraging Areas for Bowhead Whales in Baffin Bay and Adjacent Waters

“…The present study indicates that bowhead whales in the North Atlantic use a wide range of habitats that extend far into the Canadian Arctic Archipelago, including large areas not considered in the predictions by Foote et al (2013). Fossils of bowhead whales dating back to the early Holocene (between 4000 and 7500 BP) have been located as far north as Axel Heiberg Island and Ellesmere Island, which suggests that bowhead whales were able to exploit a much larger area during the period of milder climate (and lack of sea ice) in the early Holocene (Bednarski, 1990;Dyke and England, 2003). Zooplankton are highly linked to the bloom of the phytoplankton community, and it has been suggested that reduced sea ice cover entails an early bloom of phytoplankton, thereby diminishing the foundation for the zooplankton community (Søreide et al, 2010).…”

New insights on Arctic Quaternary climate variability from palaeo-records and numerical modelling

“…Some of these use the distribution of fossils of the bowhead whale (Balaena mysticetus), which lives in the loose pack ice edge and follows the ice edge's seasonal migration. Therefore, the distribution of their fossils in beach deposits can be used as an added proxy for summer sea ice minima (Dyke et al, 1996;Dyke and England, 2003). The whales migrate both from the Pacific and Atlantic sides, but populations rarely met due to the persistent sea ice cover with few open leads in the central Canadian Arctic Archipelago.…”