Sampling surveys to study the diversity of mollusks in the Lam Ta Khong reservoir,
Nakhon Ratchasima Province, northeast Thailand, were carried out in the hot, rainy and cold
seasons. The study area was divided into: Area I-the upper part where the Lam Ta Khong river
drains; Area II-the mid-section of the reservoir; Area III-behind the dam. Mollusks were collected
from four locations on each bank (to the right and left) of each area. Each location was sampled
to include 6 cross-sectional stations; in total, 144 stations were sampled. In the deep water, an
Ekman dredge was used to collect samples; the scoop or manual method was used at the water’s
edge. Ten species of snails and four species of clams were found. The dominant species of snails
were: Clea helena, Bithynia siamensis goniomphalos and Melanoides tuberculata; clams were
dominated by Corbicula sp. The intermediate host of the human blood fluke was not found. The
population of most mollusk species increased during the cold season while that of clams and that
of some species of snails increased during the rainy season. Clams and operculate snails predominated
in Areas II and III. Pulmonate snails were mostly found close to the bank and on aquatic
plants especially in Areas I and II. Operculate snails and clams mainly inhabited water 1 to 10
m deep. Two species of edible mollusks were found: Filopaludina martensi martensi and large
numbers of Corbicula. Neither shedding light nor digestion with pepsin A revealed any human
parasites in the mollusks sampled.