The objectives of this study were to assess species diversity of benthic macrofauna on the
intertidal zone of seacoasts in Krabi, Trang and Satun provinces, Thailand. The survey included
30 sampling stations of 8 beaches. It was carried out in Nopparatthara, Ao-nang and Nam Mao
beaches along Krabi coast, Pak Meng, Chao Mai and Yong Ling beaches in Trang coast and
Pak Bara and Pak Bang beaches in Satun coast. Benthic macrofauna were collected by quadrate
sampling technique at the intertidal zones. The results showed that, overall, 116 species were
accounted belonging to 51 families, 20 orders, 5 classes of 4 phyla. The phyla were Polychaeta,
Mollusca, Arthropoda and Brachiopoda in order of species number. Of these, the numbers of
benthic macrofauna species found in Krabi, Trang and Satun provinces were 65, 72 and 64
species, respectively. Cluster analysis and multidimensional scaling (MDS) were used to
compare similarity of all sampling stations based on benthic macrofauna species. The results
exhibited moderate similarity at 21% and the sampling stations were separated into 3 groups at
35% similarity. The benthic macrofauna communities of sampling stations in Satun province
were homogeneity whereas in Krabi and Trang provinces were clustered into the same group.
All sampled stations from Yong Ling beach and a station from Pak Meng beach were separated
from those 2 groups. Sampling stations in Satun province had different types of species to
Krabi and Trang sampling stations. Satun province had 41 benthic macrofauna species that also
found in Krabi or Trang provinces whereas the species found in both Krabi and Trang
provinces were 58 species. The 26 species of benthic macrofauna were found in all three
provinces including 11 species of polychaetes, 9 species of mollusks and 6 species of
crustaceans.