Keanekaragaman Siput Ordo Mesogastropoda dan Neogastropoda pada Zona Eulitoral di Kawasan Pesisir Pulau Sembilan, Kabupaten Kotabaru - Hery Fajeriadi; Muhammad Zaini; Dharmono Dharmono (Buletin Oseanografi Marina, 2019)
Gastropoda tersebar luas di kawasan pesisir, salah satunya pesisir Pulau Sembilan Kotabaru. Kawasan ini masih tergolong alami dan terdapat terumbu karang. Beberapa titik terumbu karang mulai mengalami kerusakan. Terumbu dan batu karang di zona eulitoral merupakan habitat alami gastropoda. Gastropoda terbagi menjadi tiga ordo, dua diantaranya adalah Ordo Mesogastropoda dan Ordo Neogastropoda belum didokumentasikan. Penelitian ini bertujuan untuk melanjutkan dokumentasi spesies gastropoda (Mesogastropoda dan Neogastropoda) dan menganalisis indeks keanekaragamannya. Data dikumpulkan dengan teknik purposive sampling dengan luas plot 1 m2, sebanyak 20 plot, di sepanjang seratus meter mengikuti garis pantai. Data yang dikumpulkan adalah nama spesies dan jumlah individu setiap spesies. Berdasarkan data tersebut ditentukan indeks keanekaragaman menggunakan persamaan Shannon-Wienner. Ditemukan lima spesies dari Ordo Mesogastropoda dan dua spesies dari Ordo Neogastropoda.Indeks keanekaragaman (H’) Mesogastropoda dan Neogastropoda adalah 1.620 dengan kategori sedang, artinya ekosistem di kawasan tersebut tergolong stabil. Gastropods are widespread in the coastal area, one of which is the coast of Pulau Sembilan Kotabaru. This area is still relatively natural, and there are coral reefs. Some points of coral reefs began to suffer damage. Reefs and rocks in the eulittoral zone are natural gastropod habitats. Gastropods are divided into three orders, two of which are mesogastropod orders, and the neogastropod order has not been documented. This study aims to continue the documentation of gastropod species (Mesogastropods and Neogastropods) and analyze their diversity index. Data were collected by purposive sampling technique with a plot area of 1 m2, as many as 20 plots, along a hundred meters following the coastline. The data collected is the name of the species and the number of individuals in each species. Based on these data the diversity index is determined using the Shannon-Wiener equation. Five species of the mesogastropod order and two species of the neogastropod order were found. The Mesogastropod and Neogastropod diversity index (H') is 1,620 in the medium category, meaning that the ecosystem in the region is classified as stable.