Table Of ContentTHE
HONG KONG UNIVERSITY PRESS
THE CORALS OF HONG KONG
The Corals of Hong Kong
P.J.B. Scott
HONG KONG UNIVERSITY PRESS
© HONG KONG UNIVERSITY PRESS, 1984
ISBN 962-209-033-8
Printed by Kings Time Printing Press Ltd., 3 Tai Yip Street, Kwun Tong, Kowloon
Contents
Preface vii
1. Introduction 1
Flowers or Animals? 1
2. Coral Biology 3
What is Coral? 3
Structure 7
Feeding and Digestion 8
Growth — Asexual Reproduction 10
Reproduction 12
The Relationship between Coral and Zooxanthellae 13
3. Coral Reefs 17
Reef Formations 17
Hong Kong Coral Formations 18
Coral Communities in Hong Kong 21
4. Coral Conservation 41
5. A Species List of Hong Kong Corals 43
Glossary 95
Bibliography 99
Index 105
To Allan and Marilyn Barsky, with love
Preface
This book is intended for the growing generation of swimmers,
snorkellers and divers who escape from the horrors of the overcrowded
city into the quiet and calm of the aquatic world. Its aim is to provide
descriptions and clear colour illustrations of local coral species and the
common plants and animals found in association with them. An in
troduction for laymen to the biology of coral and the structure of coral
reefs provides a background for understanding the significance and
diversity of coral communities.
Identification of the marine life was kindly supplied by the following
people: Dr J.E.N. Veron, Australian Institute of Marine Science (her-
matypic corals); Dr Hans Moll, University of Amsterdam (aher-
matypic corals); Ms Ailsa Clark, British Museum (Natural History)
(echinoderms); Dr John Taylor, British Museum (Natural History)
(gastropods); Professor Brian Morton, University of Hong Kong
(bivalves); Dr William Chan, formerly Agriculture and Fisheries
Department, Hong Kong Government (fish); and Ms May Yipp,
University of Hong Kong (hermit crabs).
Divers of the YMCA SCUBA club were wonderfully patient and
helpful dive buddies and underwater photographers.
I would also like to thank Mrs M. Cope for reading and commen
ting on the manuscript and Professor Morton for much helpful advice
and support.
PJ.B.S.
Photograph credits:
Neil Harding (NH)
Issy Holland (IH)
Mike Holland (MH)
Chan Yuk-kwan (CYK)
Brian Morton (BM)
John Orr (JO)
Sara Wu (SW)
Tommy Yeung (TY)
All other photographs and drawings by the author.
nocturnal hunters, watching under a microscope as he tried to per
suade them to feed naturally. The difficulty was to provide enough
1. Introduction light to observe them, but not too much to make their polyps retract
to a daytime resting state.
Modern scientific techniques and equipment have further enlarged
our knowledge of the more specific aspects of nutrition and
For centuries Polynesians have lived in their tropical paradise, canoeing physiology. The symbiotic relationship with a simple plant was
over reefs, fishing and collecting crustaceans and edible shells which discovered and investigated using radioactive tracers and electron
live in coral crevices. The limestone skeletons have long been recogniz microscopy; this highly specialized technique was first adapted to coral
ed as useful building material and fertilizer. With understandable awe research by Thomas Goreau in the late 1950s.
of the spectacular beauty, early coastal peoples used the shells of rare Even today coral biology is still in its infancy. The development of
reef animals, such as cowries, for currency. Gradually, unquestioning the Self Contained Underwater Breathing Apparatus (SCUBA) by Jac
exploitation gave way to curiosity about the nature of the creators of ques Cousteau and Emile Gagnan now makes it possible for marine
such magnificent structures. Some 2,200 years ago the indefatigable in biologists to study reef animals in their natural environment.
tellectual, Aristotle; discussed the biology of Zoophytes (flower However, many parts of the tropical marine world have never been ex
animals) in De Incessu Animalium. plored. Lying on the northern fringe of the great Indo-Pacific
province, Hong Kong is just such a place. Indeed, so little informa
tion is available that virtually every dive can yield new records of
FLOWERS OR ANIMALS?
species in this area. Endless possibilities exist to study interactions be
Even such a fundamental question as to which kingdom coral belongs tween equatorial and temperate climate marine life unique to these
was not answered until the eighteenth century. Exploration of coral waters.
reefs was not undertaken in a systematic scientific fashion until the Sophisticated diving equipment is not a prerequisite to the pleasures
nineteenth century by Charles Darwin and the explorer/biologists of the coral world. The best communities are so shallow here that the
J.D. Dana and Alexander Agassiz during their round-the-world voyages. only requirements are a mask, snorkel and fins or even just a glass-
These men noted and named the animals and classified the reefs, with bottomed viewing cylinder and a low tide.
an eye to geology as much as to natural history.
The world had already turned the corner into the twentieth century
before we find any detailed examinations of coral biology. Just over
fifty years ago, Sir Maurice Yonge led an expedition to the Great Barrier
Reef of Australia (1928-9). The several volumes of the expedition
reports contain the first observations of scleractinian feeding and
behaviour. They are still valuable reference books today. Sir Maurice
describes the difficulty with which he carefully offered food to these
