TITLE:   Ecological physiology of larval euphausiids, Euphausia 
	 superba (Euphausiacea).  
JOURNAL: Memoirs of the Queensland Museum 31: 321-33.  Brisbane.
AUTHORS: Robin M Ross, Langdon B Quetin
Palmer LTER Contribution #58

Keywords: Larval euphausiids, reproductive strategy, recruitment, 
	  physiological condition, critical period

Abstract:
Studies of the effects of environmental variability on the physiology of
the early life history of the Antarctic krill, Euphausia superba, suggest
that there are several critical periods during the first year of life that
will affect survival, and thus recruitment of young krill into the adult
population.  The first critical period occurs during development of the
non-feeding stages.  Results of a collaborative modelling study suggest
that release of embryos over warm deep water (250-400 m) is advantageous
for these early larval stages.  The geographical distribution of spawning
populations combined with the observed pattern in sinking rates in embryos
during development form a reproductive strategy that maximises survival of
the early non-feeding stages.  The first winter is the second critical
period.  Physiological condition (condition factor, lipid content, and
growth rate) of larvae and juveniles is an index of their nutritional
history and ability to survive and enter the adult population the following
summer.  Significant differences were found in the physiological condition
of larvae collected during two winters which differed primarily in the
degree of ice cover.  Larvae in the heavy ice winter had higher growth
rates, higher condition factor and more lipid.  Although phytoplankton in
the water column were scarce in both winters, ice biota were an additional
possible source of food during the heavy ice winter.