Ecology of Endolithic Bivalve Mollusks from Ko ChangThailand

摘要

Theobjective of this study was to examine the ecology of coral boring bivalves from fourislands southeast of Ko Chang, Trat Province, Thailand. A total of 11 bivalve familiescontaining 18 species were recorded in the survey, including six reported for this firsttime in the region. Members of the Mytilidae comprised the highest bivalve diversity withfive species recorded. The five most abundant species were (Jousseaume in Lamy), (Philippi), (Gmelin), (Gmelin), and Spengler. Ecologicalanalysis showed that Ko Bai Dung had the highest density of boring bivalves, with 196.29 ±118.24 individual/ m . Density of coral boring bivalves was variable; thehighest density was recorded for (85.18 ±74.35 individual/m ) at Ko Bai Dung. The highest diversity of boring bivalveswas found on Ko Phrao Nok, and in dead coral. Multivariate analyses did not reveal a cleardifferences in the boring bivalve community composition between sites, or with coral age,or with coral species, however dead coral was well-grouped at 50% similarity. The numberof species and number of specimens of boring bivalves in this study was significantlypositively correlated with coral age. The maximum number of boring bivalve specimens wasfound in the oldest coral (11 years old) and in dead host corals.Following the same trend of all dominant boring bivalves, corals more than nine years oldshowed the highest frequency distribution and the largest shell length. The distributionof shell height frequency showed and had more variation in shell height than the other five dominant boringbivalve species. Endolithic bivalves are one of the main bioeroders in the coral biome.The ecologic data presented in this study can be used as one indicator of coral reefstatus, including bioerosion and nutrient recycling in coral ecosystems.