In lieu of an abstract, here is a brief excerpt of the content:

Perspectives on Marine Environment Change in Hong Kong and Southern China, 1977-2001 (ed . B. Morton). Proceedings o f a n Internationa l Worksho p Reunio n Conference, Hon g Kon g 21-26 Octobe r 2001. Hong Kong: Hong Kon g University Press , 2003. HISTOLOGICAL DESCRIPTIO N O F EMBRYONI C DEVELOPMENT I N THE CHOCOLATE HIND, CEPHALOPHOLIS BOENAK (BLOCH , 1790 ) (SERRANIDAE: EPINEPHELINAE ) M. Li u an d Y . Sadov y Department o f Ecology an d Biodiversit y The University o f Hong Kong, Hong Kong ABSTRACT Histological technique s wer e applie d t o stud y th e embryoni c developmen t o f Cephalopholis boenak. Th e blastodis c underwen t si x synchronou s mitoti c division s before entering blastulation. The optic vesicles began to invaginate at the 8-somite stage. The heart fold wa s evident at the 10-somit e stage and started beating a t the 14-somit e stage. The oti c vesicles invaginate d a t the 15-somit e stage ; Kupffer's vesicl e reache d its maximu m siz e and disappeare d a t the 18-somit e stage . The haemocoel, th e neura l cord and the gut, with a single layer of columnar cells, were evident prior to hatching. INTRODUCTION Cephalopholis boenak (Bloch, 1790) is a relatively small Indo-Pacific grouper (Heemstra and Randall 1993 ) and pair spawning has been observed at Horseshoe Reef, Papua New Guinea (Donaldso n 1989) . C. boenak i s the last grouper stil l abundan t i n Hong Kon g waters (Sadovy and Cornish 2000). However, little research has been conducted on this species locall y unti l recently , whe n embryo s an d earl y larva l morpholog y (Li u an d Sadovy 2001), reproductive biology, age and growth (Chan and Sadovy 2002) have been studied. Othe r studie s o n C . boenak hav e been carrie d out , e.g., habitat choice , socia l structure, behaviour, gonad development, an d the experimental manipulation o f sexua l differentiation an d sex change (Liu in preparation). In this paper, we used histologica l techniques to describe, for the first time, the embryonic development and newly hatched larvae o f C. boenak, an d compare d thes e wit h description s o f livin g individual s (Li u and Sadovy 2001). 476 M. LIU & Y. SADOVY MATERIALS AN D METHOD S Floating fertilize d embryo s o f Cephalopholis boenak wer e collecte d fro m natura l spawning event s i n captivit y an d incubate d i n 10-litr e glas s container s wit h gentl e aeration. Differen t embryoni c stage s (700-75 0 pm ) an d newl y hatche d larva e (1.30 1 .52 mm) , les s tha n si x hour s ol d (Li u an d Sadov y 2001) , wer e fixe d i n Dietrich' s solution for five days. Histological preparations included dehydrating in an ethanol series (70-100%), embedding in paraffin wax , serial sectioning at 6-7 pm, mounting on slides and staining with Ehrlich's haematoxylin and eosin. Slides were examined under a light microscope an d photographs wer e taken a t x 10 0 magnification . RESULTS After fertilization, the cytoplasm streamed towards the animal pole of the embryo leaving an optically clea r vegetal one . A cap-like blastodisc wa s formed o n the upper surfac e of the yolk mass and this was defined a s the 1-celled stage (Plate 1A) . During cleavage, the blastodis c underwen t si x synchronou s mitoti c divisions . However , n o cleavag e occurred in the yolk mass. The first cleavag e went medially and vertically to form tw o cells (Plate IB) . Eight cells were arranged as two rows of four cell s (Plate 1C ) and the sixteen cell s a s fou r row s o f fou r cell s (Plat e ID) . Th e sixt h divisio n wa s th e firs t horizontal division and turned the blastodisc into two layers and each had 32 cells (Plate IE). After th e 64-celled stage, the embryo entered blastulation. Cell division continue d but with a loss of synchrony so that constituent cells were in different phase s of mitosis and different size s (Plate IF). The surface layer, consisting of thin cells attached firmly , became the epidermal...

Share