Physiological recovery from
prolonged ‘starvation’ in larvae of the Pacific oyster Crassostrea
gigas
A.L. Moran, D.T. Manahan-2004
Journal of Experimental Marine Biology and Ecology,
306(1): 17-36
Abstract:
Previous studies of energy metabolism in larvae have
described a developmental "point of no return" (PNR), a time by
which larvae of planktotrophic marine species must feed in order to survive
and grow. This study investigated the effects of long-term food deprivation
on developing larvae of the oyster Crassostrea gigas with the goal of
providing a biochemical and metabolic description of larvae at the PNR in
this species. Mortality of unfed larvae was low for the first 14 days
without the addition of phytoplankton foods. Even after 33 days without
food, larvae were still swimming. Unfed larvae did not lose their ability to
capture and digest algal cells when provided with food after 33 days.
Growth, metabolic rate and biochemical constituents all increased at the
same or greater rates in larvae whose feeding was delayed for 5, 8, 11, 14
or 17 days compared to larvae fed at 2 days old, when feeding was possible.
These results show that larvae of C. gigas can survive long
feeding delays while maintaining a constant rate of metabolism. These
results suggest that oyster larvae have the capacity to survive
‘starvation’ using alternative sources of energy. If there is a
"point of no return" beyond which larvae of C. gigas
must feed on microalgae to survive, our findings suggest this point may be
set by the availability of detrital material or dissolved organic carbon
that can fuel maintenance metabolism for extended periods equivalent to over
four times the predicted lifespan.
(Department of Biological Sciences, University of
Southern California, Los Angeles, CA 90089-0371, USA, e-mail: amoran@unc.edu)