The community structure of Gastropods as bioindicators of water quality in Krueng Aceh, Banda Aceh

. Gastropods have an important role in an ecosystem that is directly involved in the food chain system and can be used as a bioindicator of water quality because it is sensitive to water pollution. This study was conducted to analyze the quality of the waters of Krueng Aceh by identifying the diversity of the Gastropod community and analyzing the COD and BOD content in the waters. The study used a purposive sampling method by applying 5 sampling stations along the study area. Gastropod samples are taken using Ponal Grab, which is 23cm x 23cm and sieved from the substrate using a mesh filter. The results showed that the highest abundance index was obtained at station 1, which is 15 ind/m 2 . The results of identification in the study area are 15 Gastropod Species. Furthermore, the most widely found Gastropod species is Snail tiger , while the least is Margarites . This result informs that the highest diversity index is found at station 1, which is 2.51 categorized as moderate pollution and on the other hand the dominance index level is less than 0.50 or no one dominates at each station.