Habitat Preference of Ophiuroidea in the Intertidal Zone of Pancur Coastal Area, Alas Purwo National Park.

Abstract

Class Ophiuroidea is a member of Echinodermata. Ophiuroidea generally has five whip shaped arms, maximum length can reach 60 cm. Ophiuroidea has 16 families with 276 genera and 2064 species spread throughout the world. Ophiuroidea is found mostly in coral reefs, seaweed, and seagrass area in the intertidal zone. Species Ophiuroidea use the area as feeding ground and hiding place. Intertidal zone has coral reefs and bed rock which can be used by Ophiuroidea as a shelter. The characteristics of intertidal zone was found in Pancur Coastal Alas Purwo National Park. Alas Purwo National Park is a conservation area situated in Banyuwangi District, East Java Province. Intertidal zone in Pancur Coastal comprises of sand and sandy rock substrate. Many organisms were found in sandy rock substrate, including species of Ophiuroidea. Until now, there were no research publication about habitat preferencies of Ophiuroidea in intertidal zone, especially in Indonesia. The lack of the information underlied the research of habitat preferencies of Ophiuroidea in intertidal zone, Pancur Coastal, Alas Purwo National Park. Pancur Coastal is one of the natural coastal in the Alas Purwo National Park. Generally, Pancur Coastal has two type of substrates, which are sand dan rock (coral and vulcanic). Habitat observation in Pancur Coastal used GPS data coordinate to map Pancur Coastal topography area. Coordinate data were used to examine characteristic of habitat type based on topography area. The research on Pancur Coastal were conducted at three sampling sites i.e. sampling line T1, sampling line T2, and sampling line T3. The method used in this study was road sampling method, by walking along the coast from coast line toward ravine in all area of Pancur Coastal. Mapping of Ophiuroidea were recorded with road sampling method. Environmental factors measured were physics and chemical factors. Seaweed, seagrass, and Ophiuroidea were identified up to species level. Coordinat data of Pancur Coastal topography were transferred in to ArcGIS 9.3 programme. Coordinat data of Ophiuroidea, seaweed, and seagrass habitats area were mapped with ArcGIS 9.3 programme. Environmental factors and habitat type of Ophiuroidea were described. Spatial distribution coordinate were mapped and species density were analyzed per habitat size. Ophiuroidea distribution map was overlayed with seaweed and seagrass distribution map. Patch was examined and described based on substrat type, seaweed, seagrass, and Ophiuroidea coordinate. Pancur coastal has various of topography, substrate type, and species diversity. Habitat type of Pancur Coastal is rocky shore dominated by bed rock. The other type of habitat, such as sandy substrate, bed rock, sandy rock, seaweed, seagrass, and boulders. Site T1 of Pancur Coastal was dominated by bed rock and sandy rock substrate. Site T2 was dominated by sandy rock substrate with abundant of seaweed and seagrass. Site T3 was dominated by bed rock and boulders substrate. Average temperature in the study sites was 29.7˚C. Average of salinity was 32.3‰. This study found 9 species of seaweed i.e Sargassum duplicatum, Turbinaria ornata, Padina australis, Ulva fasciata, Caulerpa sertularioides, Halimeda sp., Codium intricatum, Gelidium sp., and Gracillaria salcornia and 2 species of seagrass i.e Thalassia hemprichii and Syringodium isoetifolium. The research found 2 families, 3 genera, and 6 species of Ophiuroidea in Pancur Coastal. The Ophiuroids species were Ophiocoma scolopendrina, Ophiocoma erinaceus, Ophiocoma dentata, Ophiocoma brevipes, Ophiomastix annulosa, and Macrophiothrix longipeda. Ophiuroidea in Pancur Coastal were not evenly distributed and more prone to group in the area with more sandy rock, seaweed, and seagrass substrate. Ophiocoma scolopendrina was dominant species and inhabit in the larger area than other species of Ophiuroidea. Macrophiothrix longipeda was less dominant species and inhabit on smallest area. Overall, density of Ophiuroidea species was less than 1 individual per m2. Ophiuroidea inhabit in the sandy rock substrate with seaweed and seagrass. Ophiocoma Scolopendrina was found in the sandy rock substrate area and Sargassum duplicatum habitat. Ophiocoma erinaceus and O. dentata were found in the sandy rock substrate with seaweed and seagrass. Ophiocoma brevipes inhabit in bed rock covered with thin sand, O. annulosa inhabit in bed rock with water basin, and M. longipeda inhabit in bed rock and rock clave.