Physiological responses of coral boring bivalves to changes in suspended sediment and salinity at Sichang Islands, the Gulf of Thailand
Nittharatana Paphavasit1), Piyawan Maila-jad2) and Padermsak Jarayabhand1)
1) Department of Marine Science, Faculty of Science. Chulalongkom University, Bangkok 10330, Thailand. 2) Marine Fisheries Division, Department of Fisheries, Ministry of Agriculture and Cooperatives, Bangkok I 0900, Thailand
Physiological responses to changes, in suspended sediment and salinity were carried out in three coral boring bivalves found at the Sichang Islands., the Gulf of Thailand namely Lithophaga malaccana, Splengleria mytiloides and Gastrochaena cuneiformis. L. malaccana was the most dominant species found in many species of living corals and dead corals. S. mytiloides and G. cuneiformis were found only in the dead coral or dead part of coral.
The physiological responses of boring bivalves to suspended sediment demonstrated two different patterns. The first pattern was the increases in respiration while the clearance rate decreased as found in G. cuneiformis and S, mytiloides. The second pattern was increases in respiration but the clearance rate unchanged as in L. Malaccana. The responses to salinity changes at three levels i.e. 16 PSU, 24 PSU and 32 PSU sho wed the same trends in the three boring bivalves with low scope for growth at low salinity.
It can be concluded from the physiological responses of, coral boring bivalves to environmental changes that L. malaccana was the most tolerant species While G. cuneiformis was the most sensitive species. They can be used as indicator species in the monitoring on the changes in coral reefs.
