Monitoring and investigation of coral reef ecological resources

Project Duration	2005-12-31 ~ 2006-12-30
Research Title	Monitoring and investigation of coral reef ecological resources
Contracted Organization	Coral Reef Society of the Republic of China
Principal Investigator	Cheng Ming-Hsiu
Co-Principal Investigators	Tai Chang-Feng, Chen Cheng-Ping, Meng Pei-Chieh
Project Personnel	Huang Hsing-Cho, Chen Deng-Song, Kuo Tao-Jen, Cheng An-Yi, Hung Sheng-Wen, Ho Min-Chieh, Chen Ching-Yi, Huang Chien-Hua, Yen Ching-Ya, Chang Chia-Ming, Huang Min-Yu, Chu Shu-Hui
Keywords	Fishes, corals, water sample analysis, echinoderms and crustaceans
Abstract	The objective of this project was to investigate and monitor coral reef ecological resources in Dongsha waters. The baseline data collected will serve as a foundation for future national park management. Major survey components included coral reef fishes, corals, large benthic invertebrates, and water quality analyses. From July to December 2006, diving surveys were completed at 17 stations. A total of 556 fish species, 264 coral species, 175 mollusk species, 28 echinoderm species, and 33 crustacean species were recorded. Species richness of fishes, corals, and large benthic invertebrates followed a consistent spatial pattern: outer reef stations > waters surrounding Dongsha Island > inner lagoon stations. A total of 556 fish species in 69 families have now been officially recorded in Dongsha waters. This study documented 335 species in 46 families, including 25 species not recorded in the previous year’s survey. Among the newly recorded species, the threadfin blenny and the double-banded goby represent first records for Taiwan. The outer reef area remains a species-rich and relatively healthy marine environment, while fish diversity around Dongsha Island is showing signs of recovery. Live stony coral cover in different outer reef sectors ranked as follows: east > south > west > north. Combined live cover of stony and soft corals ranked: east and north > south > west. The environmental factors responsible for spatial differences in coral assemblages require further study. Typhoon Pearl, which struck Dongsha in May 2006, mainly damaged coral reefs at depths of 10–15 meters along the southeastern, southern, and western outer reef. Soft corals within this depth range were particularly affected. Economically and aesthetically valuable large benthic invertebrates include giant clams, black-lipped pearl oysters, turban snails, spider conchs, cowries, abalones, and others, with giant clams and certain gastropods frequently harvested by fishermen. Among echinoderms, sea urchins are commonly collected. Prominent species such as crown-of-thorns starfish and blue sea stars play important ecological roles on coral reefs. Among crustaceans, ghost crabs, the terrestrial crab Cardisoma carnifex, and land hermit crabs are abundant and frequently interact with humans; any future terrestrial development must consider their habitat requirements. Lobsters are also vulnerable to harvesting and warrant enhanced protection. Water quality analyses from 14 stations indicated that Station L3, located within the lagoon, experiences limited water exchange with the open sea. Consequently, water quality parameters are more susceptible to external influences such as rainfall or freshwater input, occasionally resulting in anomalously low salinity. Temperature-salinity diagrams show that salinity generally increases with depth and decreasing temperature in outer reef stations, reflecting normal marine conditions.