Russian Journal of Marine Biology, Vol. 29, Suppl. 1, 2003, pp. S22–S33.
Original Russian Text Copyright © 2003 by Biologiya Morya, Latypov.
1063-0740/03/2901-S $25.00 © 2003
Bordering on the Indochina Peninsula in the west
and with the Malacca Peninsula in the East, the Gulf of
Thailand is the largest gulf of the South China Sea. As
distinct from the rest of the Vietnam shelf, which is
formed on the submerged periphery of a lithospheric
plate, the Gulf of Thailand was formed in the place of a
vast depression spreading over 400 km northward and
ﬁlled with Quaternary deposits over 2500 m thick .
The central depression, 60–80 m thick, and the major
part of the bottom consist of loose ﬁne-grained deposits
underlain with ﬂuvial valleys and smaller alluvial
forms of bed facies .
At the time of the winter monsoon, the gulf is
entered by one of the branches of the southwestern cur-
rent, bearing water from the East China and Philippine
seas. Uda and Nakao reported that the branch reaches
the central part of the gulf , while Sudara  states
that it declines slightly westward, reaches the Malacca
coast, and runs along it ﬁnally ﬂowing into the Kari-
mata strait. In this period, circular cyclonic currents and
upwelling may arise in the bay, registered via observa-
tions of plankton distribution [22, 49].
At the time of the summer monsoon, the waters of
the Java Sea moving through the Karimata Strait form
the currents of the South China Sea . One of the
branches of these currents enters the Gulf of Thailand
to give rise to cyclonic and anticyclonic circular cur-
rents. These run at a speed of some 0.3 knots  and
involve all the water of the gulf (Fig. 1). The southwest-
ern monsoon forces the currents clockwise, while the
northwestern, counterclockwise .
The tidal cycle in the gulf is comprised of irregular
daily and daily tides with an average amplitude of
2.7 m. On the eastern coast of the gulf, regular daily
tides are observed, with the amplitude increasing from
Reef-Building Corals and Reefs of Vietnam:
1. The Gulf of Thailand
Yu. Ya. Latypov
Institute of Marine Biology FEB RAS, Vladivostok, 690041 Russia
Received December 12, 2002
—This paper deals with the history and investigations of the reefs and coral communities of the Gulf
of Thailand based on published and unpublished materials, including the author’s. The state of the art in the
study of reef-building scleractinian corals and reefs of this region is presented. Characterized by remarkable
distinctive features, the coral fauna and reefs of the Gulf of Thailand exhibit high similarity in coral species
composition to other regions of Vietnam and form a single complex of species of the equatorial Indo-Paciﬁc.
Gulf of Thailand, reefs, reef-building corals, species composition.
Schematized map of the summer (a) and winter (b) currents in the southern South China Sea and in the Gulf of Thailand