One of the biota that utilizes the mangrove ecosystem as its habitat is a group of Bivalvia belonging to the Phylum Mollusca Class Pelecypoda (Bivalvia). Shellfish have relatively high economic and nutritional value, so that the collection of shellfish in Aceh Jaya District continues. The research was conducted to study the biological components, analyze the habitat preferences, and management patterns of shellfish in the mangrove area of Aceh Jaya Regency. The research was conducted by using purposive sampling method, by determining 12 stations in 6 districts. Shellfish samples were taken three times with an interval of 15 days. The results found 5 species of shellfish with a dominance index of 0.002 to 0.255 with a low dominance level. The frequency of the presence of shellfish species is very rare (accidental) to rare (constant). The lowest presence level was Centrocardita rosulenta with a value of 8.33% and the highest was Sinanodonta woodiana with a value of 58.33. Habitat preference Sinanodonta woodiana has a salinity range between 3-7ppt and clay soil texture class, while Geloina habitat preference likes salinity with a range of 12 to 25 ppt with sand, loamy sand and sandy loam soil texture classes.

Bivalves Infauna is a Bivalve that lives in the bottom of the waters, including in the waters of the Rigaih mangrove ecosystem in Setia Bakti District, Aceh Jaya Regency, Aceh Province. The aim of the study was to analyze the population of Bivalve Infauna, analyze the dominance of the Bivalvia Infauna population and analyze the bottom substrate of each Bivalvia Infauna population in the waters of the Mangrove Ecosystem in Setia Bakti District, Aceh Jaya Regency, Aceh Province. The research activity was carried out in April and May 2019. The population of Bivalves Infauna used a destructive sampling method. Bivalves infauna dominance data were analyzed by dominance index, while population and environmental conditions were analyzed descriptively. The results of the study indicated that the population of Bivalves infauna in the waters of the mangrove ecosystem in the study area was Anadaragranosa, Geloinaerosa, and Dosinia sp. The dominance index of the population of Anadaragranosa.67, Geloinaerosa is 0.22, and the index of dominance of Dosiniasp is 0.11. The results also show that the environmental conditions of the substrate are sand, mud and clay. Correspondingly, the study shows that there are three populations of Bivalve Infauna that dominate the ecosystem, namely Anadara granosa and found three bottom substrates in the ecosystem studied.

Biota dasar perairan merupakan fauna yang hidup di dasar perairan, baik di kawasan tawar, payau, maupun di perairan asin terutama di perairan  ekosistem mangrove. Tujuan penelitian adalah (1) Mengkaji jumlah  spesies biota dasar perairan masing-masing ekosistem mangrove yang terdapat pada masing-masing  perairan ekosistem mangrove di Kabupaten Aceh Jaya, dan (2) Menganalisis ekosistem mangrove yang paling dominan ditempati oleh spesies biota dasar perairan di Kabupaten Aceh Jaya. Penelitian dilakukan di ekosistem mangrove di Kabupaten Aceh Jaya, dan dilaksanakan  pada Bulan April dan Bulan Mei 2019. Penetapan kawasan penelitian dilakukan dengan metode purposive sampling, dan pengambilan data menggunakan metode destruktif sampling. Jumlah spesies biota dasar perairan dianalisis secara deskriptif, sedangkan ekosistem mangrove yang didominansi oleh biota dasar perairan yang terdapat di Kabupaten Aceh Jaya  dianalisis dengan rumus indek dominansi. Hasil penelitian menunjukkan bahwa (1) Jumlah spesies biota dasar perairan di masing-masing ekosistem mangrove Kabupaten Aceh Jaya berkisar antara 3 spesies sampai 10 spesies, dan (2) Indek dominansi ekosistem mangrove yang ditempati oleh biota dasar perairan berkisar antara 0,23 sampai 0,77,  yang tertinggi adalah  ekosistem mangrove Kecamatan Setia Bakti. dengan indek dominansi 0,77, dan  terendah adalah ekosistem mangrove Kecamatan Krueng Sabe dan Kecamatan Teunom dengan indek dominansi rata-rata 0,23.  Kesimpulan penelitian adalah (1) Jumlah spesies biota dasar perairan di ekosistem mangrove Kabupaten Aceh Jaya bervariasi, dan (2) Ekosistem mangrove yang paling dominan ditempat oleh biota dasar perairan di Kabupaten Aceh Jaya Provinasi Aceh adalah ekosistem mangrove dalam Kecamatan Setia Bakti.

Mollusca are soft-bodied animals that are generally protected by shells, and have a variety of species richness in habitat, especially in Lanaga Waters, Mereubo Subdistrict, Aceh Barat Regency and need to be studied through research. The research objectives were (1) to assess the number of species of each class, and (2) to analyse the level of species richness of each class of molluscs, which are found in Lanaga Waters, Meureubo Sub-district, Aceh Barat district, Aceh Province. The research was carried out from January to March 2021, in Lanaga Waters. The research area was divided into three locations, each location was divided into five stations, and each station was assigned five sampling plots. Data were taken by using the purposive sampling technique. Data analysis of species richness level was analysed by richness formula, and analysis of data about the number of each species in each class was carried out descriptively. The results showed that (1) the species of Molluscs belonging to the Gastropod class were 9 species with a richness index, the Bivalvia class contained 2 species with a species richness index of 0.13 to 0.90 indicating that the level of species richness was low to high, in the Lanaga Waters area. Mereubo Subdistrict, Aceh Barat Regency, Aceh Province.