KELIMPAHAN BIVALVIA PADA EKOSISTEM MANGROVE DI DESA PINOTU KECAMATAN TORIBULU KABUPATEN PARIGI MOUTONG

Bivalves are one of the molluscan groups that play an important role in maintaining the ecological balance of mangrove ecosystems. Their
presence and abundance are influenced by environmental conditions, making them useful indicators of habitat quality. This study aimed
to determine the abundance of bivalves in the mangrove ecosystem of Pinotu Village, Toribulu District, Parigi Moutong Regency, Central
Sulawesi, Indonesia. A quantitative descriptive approach was employed in this study. The research sites were selected using a purposive
sampling technique based on the presence of suitable bivalve habitats. Sampling was conducted using the belt transect method at two
observation stations, each covering an area of 500 m². Field sampling was carried out during low tide on 17–18 December 2025.
Collected bivalve specimens were identified using taxonomic identification keys. In addition, environmental parameters, including water
temperature, salinity, and pH, were measured. The collected data were analyzed using the species abundance index (R) and the Relative
Abundance Index (RAI). The results revealed the presence of four bivalve species belonging to two orders and two families, namely
Polymesoda erosa (39 individuals), Polymesoda expansa (19 individuals), Polymesoda bengalensis (38 individuals), and Anadara
granosa (9 individuals), with a total of 105 individuals recorded. The species abundance index (R) value of 0.64 indicated a low level of
bivalve abundance. The highest Relative Abundance Index values were observed for Polymesoda erosa (37.14%) and Polymesoda
bengalensis (36.19%), both classified as highly abundant. In contrast, Anadara granosa exhibited the lowest relative abundance value
(8.57%) and was categorized as having low abundance.