Keanekaragaman dan Distribusi Gastropoda dan Bivalvia (Moluska) di Muara Karang Tirta, Pangandaran

Abstract

Karang Tirta estuary is an estuarine zone located in Pangandaran, West Java. Substrate of the area was dominated by coarse sand and its salinity ranges from 10-25 ‰. The aim of the reaserch was to know the diversity and distribution of gastropod and bivalve in the estuary of Karang Tirta, Pangandaran and environmental factors affecting them. Samples of molluscs were collected from 3 stations choosen randomly by using quadrat method. Seventeen species were found in the study sties, 12 species belong to gastropod and 5 species of bivalve. The highest Importance Value Index (IVI) among the species was observed on Tellina radiata with 47.449 %. The lowest IVI was observed on four species belong to gastropod and bivalve with 1.949 %. The diversity index (H') ranged from 0.536 to 2.429, the evenness index (E) was from 0.189 to 0.857, and the dominant index (C) was from 0.001 to 0.037. The highest diversity index (H’ = 2.429) was found at station 2 and the lowest (H’ = 0.536) was at station 1. The similarity ranged from 0.235 to 0.522. The distribution patterns of molluscs occured mostly in clumps (Id > 1).