Coastal aquaculture in Thailand has expanded rapidly in both area and production in the last decade. The important cultured species are the shrimps (Penaeus monodon and P. merguiensis), sea bass Lates calcarifer, groupers Epinephelus malabaricus and E. tauvina, green mussel Perna viridis, horse mussel Modiolus senhausenii, blood cockles Anadara granosa and A. nodifera and the oysters Crassostrea belcheri, C. lugubris and Saccostrea commercialis. The total production from coastal aquaculture in 1991 was 230,444 tons, consisting of 70.3% shrimp, 28.8% mollusks, and 0.9% fishes. The seaweeds Gracilaria spp., pearl oysters, scallops, and abalones are cultured on a pilot scale in some places. Hatchery technologies have recently been developed for groupers, oysters, scallops, and abalones. Expanded aquaculture has had some adverse effects on the environment and has also suffered from the environmental changes and conflicts due to other sectors using the same water and other resources.