Pola sebaran spesies-spesies moluska di hutan mangrove menunjukkan adanya suatu zonasi. Moluska mangrove dapat dibagi ke dalam tiga kelompok, yaitu: moluska pengunjung, fakultatif dan asli. Tujuan penelitian ini adalah mengkaji distribusi vertikal moluska dan keanekaragaman jenis, dominansi jenis, kemerataan jenis dan kesaman komunitas moluska hutan mangrove di Gugusan Pulau Sidangoli Kabupaten Halmahera Barat. Pengambilan moluska  menggunakan metode transek kuadrat. Transek ditarik secara horizontal sejajar garis pantai berdasarkan zonasi hutan mangrove yaitu zona bagian depan (ZBD), zona bagian tengah (ZBT) dan zona bagian belakang (ZBB). Hasil penelitian diperoleh distribusi vertikal moluska pada Zonasi Bagian Depan (ZBD) memiliki keanekaragaman jenis moluska lebih tinggi dan terendah di Zona Bagian Belakang (ZBB). Struktur komunitas moluska untuk semua stasiun penelitian memiliki keanekaragaman jenis tergolong sedang, tidak ada jenis yang dominasi dan penyebaran jenis moluska sangat merata.

Seagrass Ecotourism is a tourism activities based on the ecosystem of seagrass. Component of seagrass consist of vegetation and biota that associated with the seagrass. The purpose of this research is to understand the condition biophysics of seagrass (Types of seagrass, Cover of seagrass, fish, makrozoobenthos, types of substrat, water brightness, the depth of the seagrass) and to establish the suitability of seagrass to support nautical ecotourism. This research have been done in Sibu island, Guraping village, north oba district, Tidore city for 6 month from April – September 2020. The method that used is a survey method consist of direct measuring of types seagrass, cover of seagrass, fish, makrozoobenthos, types of substrat, water brightness, the depth of the seagrass. The data analysis includes percentage of cover seagrass and the suitability index of seagrass ecotourism. The result of the biophysical study were obtained are 8 types of seagrass, cover of seagrass (51,04- 92,71%), fish (12 types), makrozoobenthos (17 types), brightness (77-100%), substart (sand, muddy sand, mud) flow speed (0,01- 0,06 m/dt) and the depth of the seagrass (1-2,5 m). Sibu island could be developed as a region of Seagrass Ecotourism with index suitability tourism (IKW) station 1,3,4 and for the whole are located in category S1 (very suitable) and station 2 is in the suitable category.

The mangrove ecosystem is one of the main ecosystems in the coastal area which is very productive, but is very vulnerable to changes or external influences. As a vulnerable ecosystem, mangrove ecosystem management has to concern the integration of the community's ecological, economic and socio-cultural aspects so that optimal and sustainable management is achieved. The research objectives were to know the composition of mangrove species, to determine the structure of the mangrove forest community (species diversity, species dominance, uniformity, species density, species cover) and to determine the condition of mangrove forests on Tarnana Island, Jailolo Selatan District. This research was conducted on Tarnana Island, Jailolo Selatan District, and West Halmahera Regency in January - February 2021. The sampling method was carried out using the spot check method. Sampling was carried out at the lowest tide by using 5 line transects and each line transect placed 5 plots. Data analysis included species diversity, species dominance, uniformity, species density and species cover. The composition of mangrove species on Tarnana Island was obtained as many as 8 species, namely Rhizophora apiculata, R. stylosa, Bruguirea gymnorrhiza, Ceriops decandra, Ceriops tagal, Sonneratia alba, Xylocarpus granatum and Avicennia alba. The structure of the mangrove community has moderate species diversity, no dominant species and moderate uniformity. The condition of the mangrove forest on Tarnana Island is in the damaged category with rare density.