Our knowledge of many aspects of food acquisition and
digestion in fish larvae has increased enormously during
the past few decades, but there are still many gaps that
require further research in order to improve the rearing of
marine fish larvae.
In relation to food detection we still need to develop an
overall picture of the sensory systems throughout development.
Not all types of sensory cell are present in individual
species, and those present in adult stages are often different
from those observed in larvae and juveniles. Furthermore,
some sense organs (e.g. solitary chemosensory cells) are
very poorly described and only in some species, and no or
few data on their physiological functions are available.
Broader and deeper knowledge of sense organs ontogenesis,
morphology and physiology in larvae, juveniles and adults
of reared species will greatly help us to optimize feeding
protocols and replace live prey with inert microdiets. This
will permit species-specific optimization of administration
of prey/food item sequences based on organoleptic properties,
dimensions, detectability (i.e. via mechanical or chemical
clues), the type and speed of movements or buoyancy.
Another issue that needs attention is the problem of
sense organ anomalies that has been described in some
reared fish (Mana & Kawamura 2002). If this situation is
confirmed in other reared species, it will have strong implications
for sampling for ontogenetic studies, including
reference material needing to be collected from wild populations
or fish having to be reared in extensive systems with
natural plankton in order to elucidate the normal pattern
of development. This would also imply that under