Between September 1996 and March 1999, a total of 135 fish species in 43 families
were recorded from the mangrove estuary of Sikao Creek, Trang Province, Thailand, using two sizes
of beach seine and a bag net. A checklist of the species is given, with preliminary descriptions of
their assemblage structure. In terms of the number of species per family, Gobiidae was the most
diverse (28 species), followed by Leiognathidae (11 species) and Engraulidae (10 species). In terms
of individual numbers, Engraulidae, Leiognathidae and Ambassidae were the most dominant,
whereby the 20 most abundant species comprised 88.5% of the total number of individuals collected.
The fish assemblage structure was compared with published accounts of other tropical Indo-West
Pacific mangrove estuaries, and found to be similar to those of tropical Australia. Although a grater
number of species were recorded from Sikao Creek than in comparable studies in other geographic
regions, all of the studies were similar in that they have relatively few species that are clearly
dominant in abundance.