Considerable increase in bowhead,blue,humpback and fin whales numbers in the Greenland Sea and Fram Strait between 1979 and 2014

更新时间:2023-08-14

【摘要】In the frame of our long-term study of cetacean abundance and distribution in polar marine ecosystems begun in1979,a drastic increase in the bowhead Balaena mysticetus North Atlantic "stock" was observed from 2005 on,by a factor 30 and more:from 0.0002 per count between 1979 and 2003(one individual,n=5430 counts) to 0.06 per count from 2005 to 2014(34 individuals,n=6000 counts);the most significant part of the increase occurred from 2007 on.Other large whale species(Mysticeti) showed a similar pattern,mainly blue Balaenoptera musculus,humpback Megaptera novaeangliae and fin whales Balaenoptera physalus.This large and abrupt increase cannot logically be due to population growth,nor to survival of a hidden "relic" population,nor to a changing geographical distribution within the European Arctic,taking into account the importance of the coverage during this study.Our interpretation is that individuals passed through the Northwest and/or Northeast Passages from the larger Pacific stock into the almost depleted North Atlantic populations coinciding with a period of very low ice coverage—at the time the lowest ever recorded.In contrast,no clear evolution was detected neither for sperm whale Physeter macrocephalus nor for Minke whale Balaenoptera acusrostrata.

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