The Distribution of Sea Cucumbers in Pulau Aur, Johore, Malaysia

Abstract

Sea cucumbers have been harvested for centuries for human consumption. The high value of some species, the ease with which such shallow water organisms can be harvested, and their vulnerable nature due to their biology, population dynamics and habitat preferences have all contributed to overexploitation and the collapse of fisheries in some locations in Malaysia. Sea cucumbers are susceptible to overexploitation due to their late maturity, density-dependent reproduction, and low rates of recruitment. Although sea cucumbers are generally widely distributed, with some species occurring throughout entire ocean basins, most species have very specific zone within reef habitats. An investigation at the Pulau Aur group (about 65km east of mainland Mersing, Johore, Malaysia; in the Johor Marine Park) has been conducted using wandering transects to re-appraise the local holothuroid biodiversity pattern according to habitat and depth. Preliminary results show that three families, eight genera and 20 species of sea cucumbers were found in the 13 locations surveyed in Pulau Aur, Pulau Dayang, Pulau Lang and Pulau Pinang, during the survey from September 5~12, 2005. The dominant family found was Holothuriidae (12 species) followed by Stichopodidae (5 species). The most dominant species in the four islands were Holothuria edulis and Stichopus chloronotus, found abundantly on sand and rubble substrates from a wide range of depth (4-20m). Eleven of the species found were reported for the first time in the study sites. Pulau Aur, Pulau Dayang and Pulau Pinang islands exhibited a high diversity in sea cucumber population (12 species found in each island) while only 6 species of sea cucumbers were recorded in Pulau Lang. Detail of the coral reefs at the islands is given to provide a better understanding of the habitat preference of sea cucumbers in the main reef areas around the islands. Results of analysis combining habitat and sea cucumber populations show that some species can only be found in specific habitats and depths, for instance Thelenota anax (size: 30-40cm) can only be found in sandy areas at depths below 16m. The distribution patterns and results of data collected in the marine park where the sea cucumber fishery is prohibited and other marine resources are protected, is provided here to further the knowledge of the area and as a model for conservation purposes.