Gastropoda dan bivalvia merupakan hewan intervetebrata dan anggotanya termasuk moluska bertubuh lunak. gastropoda dan bivalvia memiliki cangkang sebagai pelindung tubuh. penelitian ini dilakukan untuk mengetahui struktur komunitas mollusca di perairan tanjung buka kabupaten bulungan. penelitian ini dilakukan pada bulan februari 2021 - april 2021. pengambilan sampel dilakukan dengan cara clam trowl. terdapat 3 spesies bivalvia dan 7 spesies gastropoda. indeks keanekaragaman (h) sebesar 0,01, indeks evernnes (e) sebesar 0,01 dan indeks dominasi (c) sebesar 0,99. nilai ini menunjukkan bahwa semakin mendekati satu, maka ada organisme yang mendominasi ekosistem perairan. kata kunci: perairan tanjung buka, bivalvia, gastropoda, struktur komunitas

Gastropods and bivalves are intervetebrates and member include soft-bodied of mollusca. gastropods and bivalves have a shells as body armor. this rescarch was conducted to determine the structure of the mollusca community at tanjung buka waters, bulungan regency. this research was conducted in february 2021 - april 2021. samples was caugh by clam trowl. there was 3 species of bivalves and 7 species of gastropods. diversity index (h) was 0.01, evernnes index (e) was 0.01 and dominance index (c) was 0.99. this value indicates that the closer to one, the organisms that dominate the aquatic ecosystem. keywords: tanjung buka waters, bivalves, gastropods, community structure