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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 the aquatic productivity and aquatic organism conditions, including gastropods. Gastropods are easy to find in various habitats, but their distribution is highly dependent on the habitat conditions such as physical, chemical and biological factors. Gastropods are sensitive to environmental changes and can withstand the 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 the Sedati Waters. The research was performed using an observation method. The gastropod samples were taken using a dredge net, while the substrate samples were collected using Ekman grab. The gastropods found in Sedati Waters from October to December are nine species from 2 orders 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. The diversity index value was between 1.4846-2.0897. The evenness index value reached between 0.8284 and 0.9548. The dominance index ranged from 0.16 to 0.2299. The community structure of gastropods in the Sedati Waters, Sidoarjo, East Java shows a significant difference (p<0.05) between stations and belongs to the medium category.

Cantang grouper (Epinephelus fuscoguttatus × lanceolatus) is an Indonesian fisheries commodity that seeded and has high economic value. Cantang grouper is also had excellence because it has fast growth and tolerance to disease, so these fish are widely cultured. The purpose of this study was to analyze the hatching rate, growth monitoring, and survival rate of cantang grouper. This research was conducted at UPT PBL Situbondo, East Java Province on December 2018 until January 2019. Spawning of the cantang grouper was done artificially. The hatching rate of cantang grouper eggs was 53.3 %, growth rate ranging from 0.0009-0.7900 gr/day and specific growth rate ranging from 10.34-29.84 %. Larvae maintenance includes feeding, measurement of water quality, and change of water. Feeding is in the form of Chlorella sp., Rotifer, Artemia sp., Acetes sp., and artificial feed. The survival rate of cantang grouper was 26.9%. The measured water quality was a temperature ranging from 29-30 °C, pH with a range of 7.9-8, and dissolved oxygen (DO) was 7 mg/L.

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