Long term ecological changes in the Gulf of Thailand

Abstract

The Gulf of Thailand is a tropical enclosed sea in the southwestern part of the South China Sea. The increasing deteriorating conditions in the coastal environment have raised concern among scientists and public. The frequency of occurrence of plankton bloom has markedly increased in some estuarine and mangrove areas corresponds to the increase in nutrients loading. Patterns of changes in biomass of phytoplankton are discussed in relationship to the increased nutrient discharge in the Inner Gulf. The changes in species composition of demersal fishes and benthic communities, disappeared species and species with strong change in population sizes are also discussed. Bivalves fishery had deteriorated as early as 1970 caused by organic pollutant discharged directly via the river to the sea. In regard to the decline of fishery production in the Gulf of Thailand, the principal cause is overfishing, however, discharges of organic pollutants from cities and industries have caused marine pollution in some estuarine and coastal areas that impacted the coastal aquaculture activities and bivalves fishery.