Gastropoda termasuk salah satu sumber daya hayati yang memiliki tingkat keanekaragaman tinggi di ekosistem mangrove yang memegang peranan penting dalam proses dekomposisi serasah dan mineralisasi materi organik terutama yang bersifat herbivor dan detrivor. Tujuan penelitian ini untuk menganalisis mengenai struktur komunitas gastropoda di Kawasan Konservasi Mangrove dan Kepiting Kelurahan Pamusian Kota Tarakan. Metode yang digunakan dalam penelitian ini yaitu metode deskriptif kuantitatif. Sampel gastropoda di ambil dari 3 titik stasiun yaitu daerah aliran Sungai Pamusian, daerah menara pengawas, dan daerah dekat pemukiman penduduk. Hasil identifikasi ditemukan 5 jenis gastropoda diantaranya yaitu Cerithidea cingulata, Cerithidea obtusa, Assiminea lutea, Cassidula aurisfelis, dan Alcyna lifunsis. Hasil kelimpahan gastropoda pada stasiun 1 berkisar 127-4.073 ind/m2, stasiun 2 berkisar 1.909-5.345 ind/m2, dan stasiun 3 berkisar 255-2.418 ind/m2. Hasil Indeks keanekaragaman (H’) gastropoda berkisar 0,28-0,44, Indeks keseragaman (E) gastropoda berkisar 0,59-0,93 dan Indeks dominansi (C) gastropoda berkisar 0,61-1,29. Gastropoda yang dominan ditemukan yaitu jenis Assiminea lutea.
Kata Kunci: Gastropoda, Kawasan konservasi, Mangrove, Struktur komunitas, Tarakan

Gastropods are one of the biological resources that have a high level of diversity in mangrove ecosystems that play an important role in the process of decomposition of litter and mineralization of organic matter, especially those that are herbivores and detrivores. The purpose of this study is to analyze the structure of the gastropod community in the Mangrove And Crab Conservation Area of Tarakan City Pamusian Village. The method used in this study is a quantitative descriptive method. Gastropod samples were taken from 3 stations, namely the Pamusian River watershed, the watchtower area, and areas near residential areas. The identification results found 5 types of gastropods including Cerithidea cingulata, Cerithidea obtusa, Assiminea lutea, Cassidula aurisfelis, and Alcyna lifunsis. The result of the abundance of gastropods at station 1 ranges from 127-4,073 ind/m2, station 2 ranges from 1,909-5,345 ind/m2, and station 3 ranges from 255-2,418 ind/m2. The results of the gastropod diversity Index (H') ranged from 0.28-0.44, the gastropod uniformity index (E) ranged from 0.59-0.93 and the dominance index (C) of the gastropod ranged from 0.61-1.29. The dominant gastropod is the assiminea lutea. Keywords: Gastropods, Conservation areas, Mangroves, Community structures, Tarakan