Gastropod Community Structure as Environmental Change Signals for Tropical Status In Sedati Waters, Indonesia

Sedati is one of the Sidoarjo Regency's Coastal Areas, which has potential resources in capture fisheries. Many industries in Sedati have caused a decrease in aquatic productivity and aquatic organism conditions, including gastropods. Gastropods are easy to find in various habitats, but gastropods' distribution is highly dependent on habitat conditions such as physical, chemical and biological factors. Gastropods are sensitive to environmental changes and can withstand environmental changes that are not too wide to be used as indicators of environmental pollution. This study aims to determine the structure of the gastropod community in Sedati Waters. The research method used is an observation method. Gastropod samples were taken using a dredged net, while substrate samples using Ekmangrab. Gastropods found in Sedati Waters from October to December are nine species from 2 ordines and six families. The species most commonly found in R. venosa, while the least is C. ventricosa. The abundance index of gastropods every month shows a marked difference between stations but not the other main parameters. Diversity index value between 1.4846-2.0897.Evenness index value between 0.8284 and 0.9548. The dominance index ranges from 0.16 to 0.2299. The community structure of gastropods in Sedati Waters, Sidoarjo, East Java shows a significant difference (p