Holocene Bowhead Whale (<i>Balaena mysticetus</i>) Mortality Patterns in the Canadian Arctic Archipelago

Abstract

Changes according to elevation in frequencies of naturally stranded bowhead whale (Balaena mysticetus) remains on Holocene beaches in the Canadian Arctic Archipelago (CAA) closely parallel previously reported temporal changes in frequencies of independently radiocarbon-dated bowhead remains from these same beaches. Specifically, on the basis of emergence curves determined for 10 localities surveyed in the CAA, stranded whale remains tend to be relatively common in beaches dating to approximately 2500 -5500 B.P. and those older than 8000 B.P., but relatively rare in beaches dating to 0 -2500 B.P. and 5500 -8000 B.P. The former beaches apparently developed primarily during periods of relatively ice-free summer conditions, while the latter developed during periods of relatively pervasive summer sea ice that prevented bowheads from entering the region. Length-based mortality profiles of the stranded whale assemblages suggest that random processes, such as ice entrapment, were responsible for the death of most whales found on these beaches.RÉSUMÉ. Des changements en fonction de l'altitude dans la fréquence de restes de baleines boréales (Balaena mysticetus) sur les plages de l'holocène situées dans l'archipel Arctique canadien (AAC) correspondent de près aux changements temporels rapportés précédemment dans la fréquence des restes de baleine boréale datés indépendamment au radiocarbone trouvés sur ces mêmes plages. Plus précisément, en se fondant sur les courbes d'émersion déterminées pour dix localités étudiées dans l'AAC, les restes de baleine échouées ont tendance à être assez communs sur les plages qui datent d'environ 2500 à 5500 BP et sur celles qui remontent à plus de 8000 BP, tandis qu'ils sont relativement rares sur les plages qui datent de 0 à 2500 BP et de 5500 à 8000 BP. Les premières plages auraient été créées surtout durant des périodes où il n'y avait pratiquement pas de glace estivale, tandis que les dernières se seraient formées au cours de périodes où la glace d'été envahissante empêchait les baleines boréales de pénétrer dans cette zone. Les profils de mortalité des assemblages de baleines échouées, profils fondés sur la longueur, suggèrent que des processus aléatoires, tels que l'enfermement dans la glace, ont été responsables de la mort de la plupart des baleines trouvées sur ces plages.Mots clés: baleine boréale, changement climatique, holocène, profils de mortalité, glace marine Traduit pour la revue Arctic par Nésida Loyer.

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

“…If bowheads used this region commonly during the Holocene, they suffered no mortality while doing so. Mortality-free occupation for thousands of years is a great improbability, considering the fact that ice entrapment is the most probable significant cause of death (Savelle et al, 2000). The singular early Holocene find (Bednarski, 1990) must presently be seen, if the age determination is accurate, as the result of a brief exceptional condition, perhaps one warm summer, or perhaps as the stranding of a far-rafted carcass locked in sea ice, as suggested by Dyke et al (1996a).…”

“…al., 1996a; Savelle et al, 2000). Thus, there is a very sharp northward decline in bone abundance in the eastern CAA, with a particularly abrupt drop between Jones Sound and Norwegian Bay.…”

“…In many places, conspicuous raised shorelines, which formed during emergence, represent continuous Holocene sequences. Dyke and colleagues have located the remains of more than 1000 Holocene bowheads in the eastern, central, and southwestern CAA (Dyke and Morris, 1990;Dyke et al, 1996a;Savelle et al, 2000;Dyke and Savelle, 2001). They have surveyed bone abundance by elevation at the sites indicated on Figure 1 and have obtained radiocarbon dates on several hundred specimens.…”

Sealing, whaling and caribou revisited: additional insights from the skeletal isotope chemistry of eastern Arctic foragers

“…Prompted by long-standing debate regarding the economic importance of whaling (Krupnik, 1993;McCartney, 1980McCartney, , 1995Savelle, 1985, 1993;Sabo and Jacobs, 1980;Savelle and McCartney, 1988, 1994Savelle et al, 2000), we argued in Coltrain et al (2004) that if bowheads made a significant contribution to some or all Thule diets their role would be evident in the skeletal isotope chemistry of Thule foragers. In high latitude settings as elsewhere, the nitrogen isotope chemistry of bone collagen covaries with the trophic level of sampled diets (Kelly, 2000) and carbon isotope values distinguish marine from terrestrial intake (Chisholm et al, 1982).…”

Thule whaling at Point Barrow, Alaska: The Nuvuk cemetery stable isotope and radiocarbon record

“…Although whaling appears to define the Thule here and elsewhere (Coltrain et al, 2004;McCartney and Savelle, 1985;Sabo and Jacobs, 1980;Savelle et al, 2000), ice-adapted, ringed (Phoca hispida) and bearded seal (Erignathus barbatus) likely made a greater contribution to Nuvuk diets and the proximity of Elson Lagoon and other lagoon settings along the Beaufort Sea shelf may have increased intake of beluga whales. Jensen (2009a: 103) notes that whereas fast moving beluga are difficult to take, they tend to feed in bays and estuaries during summer months and are hunted more successfully in shallow waters.…”