Bowhead whale (Balaena mysticetus)

Marine mammals 2013
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The bowhead whale is the only baleen whale that resides in the Arctic throughout its life. It is highly adapted to its ice-associated lifestyle, possessing a very thick layer of blubber (up to 30 cm), no dorsal fin, and a complex circulationcirculatory system (with numerous vascular retes) for conservingadaptations) to conserve heat. Moreover, their highly elevated blow-holesblowholes are thought to be an adaptation tofor breathing inwithin the cracks in sea ice.

Compared to the more streamlined species among theof baleen whales (e.g.., the rorqual group, Family Balaenopteridae),) the bowhead is a slow swimmer. They areIt is a loosely social species, travelling in small groups most of the time, without long-term associations, outside the period of mother-calf pair; but, communication. Communication among groups is thought to occur over very long distances, because general activity patterns of animals thatwhich are spread over a considerable area seem to be coordinated. Among the five recognised stocks of bowhead whales in the Arctic, the Spitsbergen stock occupies the area from the Greenland Sea to Svalbard and across the Barents Sea to Franz Josef Land, and perhaps beyond. Bowhead whales usually remain close to the southern boundary of winter ice; during winter they have been seen in the Kara Sea (Stas Belikov, pers. comm.). The whalesWhales in this stock appear to exhibit the same seasonal patterns that were followed in springduring springtime hundreds of years ago, when the population was numerous; at least. As such, they are still found in “Whalers Bay” in the Fram Strait in April (Wiig et al., 2007) and at least); some animals ininhabiting the Barents Sea migrate southward induring summer, and northmigrate northward again come fall, — unlike other populations of this species that dowhich exhibit the reverseopposite pattern (Lydersen et al., 2012b). Extreme

Extensive overharvesting in the Barents Region induring the 1600s-1700s came close to exterminating thisthe bowhead whale population. The number of bowheadsTheir abundance had dropped catastrophicallydramatically in the region by the mid-19th century (Shelden et al., 2001). After WWII, only lone animals or small groups of whales were occasionally seenobserved near the northeastern coast of Greenland, near Spitsbergen, Novaya Zemlya, and Severnaya Zemlya; sightings in Franz Josef Land were slightly more common (Belikov, 1985; Wiig, 1991; Christensen et al., 1992; Moore and Reeves, 1993; Kondakov and Zyryanov, 1994; De Korte and Belikov, 1995). The present number of bowheads belonging to the Svalbard stock is not known, but there is some evidence to suggest that they might be increasing (Wiig et al., 2010; Moore et al., 2012; Stafford et al., 2012; Falk-Petersen et al., 2015). In June 2015, a group that was estimated to number 85 animals ranging over a few kilometres was sighted by a tourist ship. Near future distributionDistribution and abundance of bowhead whales in the Barents Region dependsin the near future may depend largely on the impact of climate change impacts on the distribution and abundance of calanoid copepods, their primary prey. Their extreme longevity, slow maturity, and low reproductive capacity leave them vulnerable to negativeunfavourable aspects of environmental change (George et al., 1999; Kovacs and Lydersen, 2008), but). However, some populations of this species are known to be currently increasing currently in the Bering and Beaufort Seas. Increases in ocean noise are likely to pose a threat to this species that communicates acoustically over significant distances, which means; this suggests that special care needs toshould be taken when planning oil and gas exploration and development activities (Reeves et al., 2014).