INTRODUCTION
Coral
reefs and their associated corals have always aroused an interest
among scientists, especially geologists, biologists and natural
historians, for a number of reasons. Early in the study
of coral reefs geologists focused much of their interest on the
problem of how small atolls, composed entirely of shallow-water
coral reef deposits with no evidence of a nonreef foundation,
could have formed in the open oceans at depths of 3000 or more
meters. Charles Darwin correctly speculated on their origin
by subsidence of the ocean floor, but the mechanism for such a
phenomenon, through plate tectonics, has only been recently provided.
As world commerce developed, geographers and navigators
were very interested in knowing the location of coral reefs because
of their ability to develop shallow wave-resistant structures
that were hazardous to ships at sea. Biologists have long
been intrigued by coral reefs because, in terms of numbers of
species, they are one of the most diverse ecosystems on earth
and also one of the most productive, yet they develop in, and
for the most part are restricted to relatively nutrient-poor tropical
seas.
To the
early residents of Guam, the coral reef has always been a valuable
natural resource because of its role in providing a large part
of their subsistence. Although present-day residents of
Guam are possibly less directly dependent upon the coral reefs
around them, especially as they become more enmeshed in the modern
world of technology, there is a growing awareness of the importance
of this natural resource.
To the
potential nontropical visitor, coral reefs conjure exotic visions
of blue lagoon waters teaming with brilliantly colored fishes
and bizarrely shaped corals, bordered at the shore by white sand
beaches, which in turn are clothed in a backdrop of lush green
tropical vegetation.
There
are also those whose interest in coral reefs lie in their intrinsic
inquisitiveness in the natural world around them or who are drawn
to them by their natural beauty. Some reefs offer a recreational
outlet in the form of snorkeling, diving, spear fishing, reef
walking, photography, or collecting.
In view
of the diverse interest in coral reefs, the principal objective
of this book is to nurture an awareness and appreciation of the
natural marine world by describing, principally through the medium
of photography, some of the general features of the coral reefs
that encircle our island and one of its fundamental groups of
organisms—the corals.
This book
illustrates and provides an annotated key for 233 species of corals
found in various reef habitats around Guam. The illustrations
include 141 in situ color photographs, 342 black and white photographs,
4 aerial views of reefs, and 13 text figures. The 233 species
represent 95 percent of the shallow-water (surface to 30 meter
depths) corals known from Guam and other Mariana Islands, and
about 80 percent of the shallow-water corals known from all of
Micronesia. Nearly all the species figured are also widespread
in the large Indo-Pacific faunal region.
The corals illustrated in the color plates of the
guidebook were photographed, except where otherwise credited,
by Robert F. Myers and the black and white photography was done
by Richard H. Randall.