This study aims to determine the type and density of gastropods, the density of seagrass, seagrass closure. It also knows the association gastropods in seagrass ecosystem in the waters of the Senggarang Besar. The research was conducted by random sampling method using a point 31 transect squares measuring 1x1 meters for observation gastropods and seagrass. Results of the study were found 12 species of gastropods. Gastropod density values range between 0.35-2.94 individual/m². Results of research on the type of seagrass found 4 species of seagrass that is, Enhalus acoroides, Thalassia hemprichii, Halodule uninervis and Syringodium isoetifolium. A density value of seagrass species Enhalus acoides 14.32 individual/m², Thalassia hemprichii 86.39 individual/m², Halodule uninervis 21.58 individual/m² and Syringodium isoetifolium 3.87 individual/m². Total density of all seagrass 126.16 individual/m². The closure of the Seagrass Enhalus acoides 12,63%, Thalassia hemprichii 50,96%, Halodule unnerves 13,40%  and Syringodium isotifolium 0.29%. Total closure of all seagrass is 77,29%. The level of association between species of gastropods as many as 11 species have negative associations of which is Leavistrombus turturela, Strombus urceus, Planaxis sulcatus, Cerithium nesioticum, Cerithium Aluco, Cerithium zonatum, Pugilina cocholidium, Cronia margariticola, Muricodrupa fiscela, Pyrene epamella, Otopleura auriscati. While 1 species has a positive association level is kind of Rhinoclavis aspera.

This study aims to identify the habitat characteristics and distribution patterns of the antique ark Anadara antiquata in the waters of Senggarang Besar, Tanjungpinang City. The research was conducted from July to September 2024. The research process included site surveys, field data collection, sample analysis, data processing, data analysis, and preparation of the final report. Sampling points were determined using purposive sampling at three observation stations. Antique ark samples were collected using the sweep area method at each station, with an observed area of 10 x 10 meters. The results showed that antique ark in Senggarang Besar prefer habitats with high organic content, relatively lower water temperatures within the optimal range (around 29.83°C), stable salinity (around 30 ppt), and low but still safe levels of dissolved oxygen (around 5.17 mg/L), with these characteristics being most evident at Station I. The distribution pattern analysis showed that all stations had an index of dispersion (Ip) value greater than 0.5, indicating a clumped distribution pattern of the antique ark population in the study area.

The waters of Senggarang Besar are located in Senggarang Village, Tanjungpinang Kota District. The waters of Senggarang Besar have a fairly large mangrove ecosystem plus many mangrove seedling planting activities in the coastal waters of Senggarang Besar. Mangrove ecosystems have a variety of natural resources that are abundant and diverse. Mangroves are the most potential ecosystems because mangroves support the diversity of flora and fauna in aquatic communities and play a significant role in human survival based on economic, community and environmental perspectives. This study aims to determine the density, canopy cover, and status of mangrove ecosystems in the waters of Senggarang Besar. This research was conducted in September-December 2022 located in the waters of Senggarang Besar Tanjungpinang City, Riau Islands Province. Determination of observation stations using direct survey method in the field with 3 station points with 6 plots at each station, based on the presence of mangrove ecosystems. Determination of the retrieval point using purposive sampling method. Mangarove ecosystem species found in the waters of Senggarang Besar Tanjungpinang City Riau Islands Province there are 4 species including: Rhizophora apiculata, Bruguiera gymnorhiza, Xylocarpus granatum, and Avicenia marina. With density and cover values at station 1, 3900 ind/ha and 81.00%, at station 2, 1433.33 ind/ha and 69.98%, and station 3, 1446.7 ind/ha and 69.08%. The level of damage to the mangrove ecosystem in the waters of Senggarang Besar Tanjungpinang City, Riau Islands Province at station 1 includes good, very dense criteria based on KepMen LH No. 201 of 2004. While at stations 2 and 3 the level of damage includes good, moderate criteria based on KepMen LH No. 201 Year 2004.