The birds target continental
shelf and shelf break for foraging regardless of sea ice presence or absence
Date: July 20, 2016
Source: PLOS
Little auks forage in the same
areas off East Greenland -- the continental shelf and its edge -- regardless of
whether sea ice is present or absent, according to a study published July 20,
2016 in the open-access journal PLOS ONE by Françoise Amélineau, from
the University of Montpellier, France, and colleagues.
Little auks, which live only in
the Arctic, dive for copepods and other zooplankton in the "marginal ice
zone" that lies between pack ice and open water. To test the impact of sea
ice loss and underwater terrain on these seabirds, Amélineau and colleagues
compared their foraging habits during two breeding seasons on the east coast of
Greenland. Sea ice there varies naturally from year to year, and was present
during one of the study periods but nearly absent during the other. The
researchers temporarily fitted the auks with GPS and temperature-depth loggers
to track the birds' movements during foraging.
The researchers found that
whether sea ice was present or absent, little auks foraged in the same areas,
targeting the continental shelf and its edge where prey may be concentrated.
While the birds showed a preference for larger lipid-rich copepods, they also
targeted smaller species that were plentiful at the shelf break when ice was
absent. Importantly, the difference in diet had no impact on the body condition
of adult little auks or on the growth of their chicks. These findings
strengthen hypotheses from other recent work suggesting that little auks may
have more flexibility than expected as the Arctic warms, and identified
underwater terrain as a potential key factor for foraging.
No comments:
Post a Comment