Publication Date:
2016-08-30
Description:
The condition and survival of Antarctic krill (Euphausia superba) strongly depends on
sea ice conditions during winter. How krill utilize sea ice depends on several factors
such as region and developmental stage. A comprehensive understanding of sea ice
habitat use by krill, however, remains largely unknown. The aim of this study was to
improve the understanding of the krill's interaction with the sea ice habitat during
winter/early spring by conducting large-scale sampling of the ice-water interface (0-2
m) and comparing the size and developmental stage composition of krill with the
pelagic population (0-500 m). Results show that the population in the northern Weddell
Sea consisted mainly of krill that were less than one year old (age class 0; AC0), and
that it was comprised of multiple cohorts. Size per developmental stage differed
spatially, indicating that the krill likely were advected from various origins. The size
distribution of krill differed between the two depth strata sampled. Larval stages with a
relatively small size (mean 7 to 8 mm) dominated the upper two meter layer of the
water column, while larger larvae and AC0 juveniles (mean 14 to 15 mm) were
proportionally more abundant in the 0-500 m stratum. Our results show that, as krill
mature, their vertical distribution and utilization of the sea ice appears to change
gradually. This could be the result of changes in physiology and/or behaviour, as e.g.
the krill's energy demand and swimming capacity increase with size and age. The
degree of sea ice association will have an effect on large-scale spatial distribution
patterns of AC0 krill and on predictions of the consequences of sea ice decline on their
survival over winter.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
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isiRev
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