Morphological
aspects of feeding and improvement in feeding ability in the early larval
stages of red sea bream Pagrus major
M. Moteki-2002
Fisheries Science, 68(5):
996-1003
Abstract:
The present study examined the appearance,
ossification and growth of the bones that form the oral cavity in early
larval stages of laboratory reared red sea bream (Pagrus major) for
380 h after hatching. The fundamental elements of the oral cavity
appeared 11 h after initial mouth opening (HAMO). Development in the
red sea bream, based on the osteological development of the feeding
apparatus, was divided into three phases following the first feeding (24 HAMO;
mean total body length 3.3 mm). The first phase was the early sucking
phase (24 to 80-100 HAMO; approximately 3.9 mm), during which the
head and bones increased in size. The intensified sucking phase (to 200-220 HAMO;
approximately 4.9 mm) was defined by the appearance of new structural
elements and a continued enlargement of the head and bones. Finally, during
the transition phase (beyond 300 HAMO; approximately 5.6 mm),
larvae used grasping as well as sucking to feed, new elements appeared,
ossification began, size increased and teeth were acquired. As the larvae
advanced through these three phases, the ability to feed by sucking was
enhanced by the appearance and growth of new bones. The developmental phases
appear to be linked to the transition from endogenous to exogenous nutrition
resources under laboratory rearing conditions and to diversification in the
size and components of wild food organisms.
(Department of Marine Biotechnology, Fukuyama
University, Innoshima, Hiroshima 722-2101, Japan, Tel:
81-3-5463-0527. Fax: 81-3-5463-0527. Email: masato@tokyo-u-fish.ac.jp)