The ice entrapment of 11 killer whales last week generated
international media attention and raised concerns about the increasing
frequency of such events and how best to address them. It appears that a shift in wind and ice
enabled the whales to escape this time, changing what could have been a horrifying
story into a somewhat heartwarming one. But that is likely the exception to the
rule.
Photo by ABC News |
As I wrote last winter when dozens of beluga whales became entrapped by closing
ice in the Bering Sea near Russia, ice entrapments of large numbers of whales
has been infrequent through the years, though the Arctic is so thinly
populated that no one is around to observe or document entrapments in the vast
majority of the region. When
600 narwhals were entrapped off Baffin Island in Nunavut in 2008, local Inuit
hunters said the last entrapment they recalled occurred way back in 1943. But there are fears that climate change
is increasing its frequency.
Narwhal
biologist Kristin Laidre at the University of Washington told me that four ice
entrapments that resulted in the deaths of more than 700 narwhals occurred in
2008 and 2009 – the first one ever documented in East Greenland, as well as two
in northwest Greenland and the very large one near Pond inlet.
Laidre is beginning to examine the distribution and timing of known ice entrapments and look at the trends in
the breakup of sea ice on the narwhal’s summering grounds. She has found what
she calls “strongly significant trends” that suggest that the ice is forming
later and later. “Over a 30 year period there is a three to four week
difference in when the ice forms,” she said. “If ice formation is a clue
to the narwhals that it’s time to get out of their summering grounds, then the
trigger is changing, the pattern is changing.”
Is that change in the formation
of ice making narwhals more vulnerable to ice entrapments? Laidre
hypothesizes that it may be the case, though there is precious little data from
which to draw conclusions just yet. But the hints she has found so far
are another indication of the dangerous implications of global warming.