A hidden getaway for bowhead whales in the Greenland Sea

Abstract

The critically endangered Spitsbergen stock of bowhead whale (Balaena mysticetus) seems to be increasing. However, research effort has also been increasing confounding a firm conclusion. A systematic aerial survey for walrus (Odobaenus rosmarus), applying distance sampling methodology in part of the Northeast Water Polynya (NEW), revealed a 'bycatch' of several observations of bowhead whales, which resulted in an estimated abundance of 102 (95 % CI 32-329) individuals. This is the largest abundance of bowhead whales reported from the Greenland Sea since the days of whaling in the sixteenth to seventeenth centuries. The NEW was inaccessible to vessels during the whaling period because of heavy pack ice, and it is only recently that researchers have visited this area; thus only a few sightings of bowhead whales within the NEW exist prior to the survey in 2009. The NEW may nevertheless be one of the most important summering grounds for the Spitsbergen stock, and the whales may benefit from advection of calanoid copepods from the productive deep basins along the coast of Svalbard east of the NEW. This discovery provides renewed hope for the Spitsbergen stock of bowhead whales that until now has shown only inconclusive signs of recovery despite more than 100 years of protection from whaling.

Late summer distribution and abundance of ice-associated whales in the Norwegian High Arctic

“…If part of the stock historically occupied an icecovered habitat, this fraction of the stock would not have been available to the hunters. Boertmann et al (2015) made similar conclusions regarding the animals surveyed in the Northeast Water Polynya in 2009; this area would not have been available for the early whalers because the polynya is surrounded by heavy pack ice. In addition, the most intense vocal behavior of bowhead whales from this stock has been recorded in heavy ice (Stafford et al 2012).…”

“…in contrast to the 15 sightings involving 27 individuals in this survey. This suggests that animals might have migrated into this area from other places over the past decade (Boertmann et al 2015), facilitated by the reduction in sea ice (see Heide-Jørgensen et al 2007) and increasing trends in some populations (Moore 2016), or alternatively, and most likely, this suggests a patchy, variable distribution of the animals in this stock. But, further studies are needed to confirm the degree of inter-and intra-annual variability in distribution.…”

“…However, during the last decade a few studies collectively suggest that some level of recovery is taking place. A survey conducted in northeast Greenland by Boertmann et al (2015) However, the line transect was the metho do logy employed to conduct this survey (with heavy observer focus on the 0-line), so the models were run accordingly, and a conservative distance sampling line-transect approach was used to calculate the estimates. Line methods are, all basically, quite conservative since they lead to higher confidence intervals.…”

Status of the world's baleen whales

“…Boertmann et al . () reported a corrected abundance estimate of 102 whales (95% CI 32–329) from an August 2009 aerial survey of the Northeast Water Polynya off the northeastern coast of Greenland.…”

“…: STATUS OF THE WORLD'S BALEEN WHALES 705 be increasing (Moore et al 2012b, IWC 2014. Boertmann et al (2015) reported a corrected abundance estimate of 102 whales (95% CI 32-329) from an August 2009 aerial survey of the Northeast Water Polynya off the northeastern coast of Greenland.…”