Ao Bandon (Bandon Bay)
9°11'-9°24'N, 99°13'-99°41'E; extending between Chaiya and Don Sak Districts of Surat Thani Province, on the east coast of peninsular Thailand. The site covers all the coast in the immediate vicinity of the provincial capital, Surat Thani.
Approximately 102 km of shoreline.
Sea level.
Biogeographical Province:
Wetland type:
02, 06, 07 & 10.
Description of site:
The largest estuarine and mangrove inlet on the east coast of the Malay Peninsula. A huge area of intertidal mudflats, extending 1-2 km offshore, encompasses the delta of the Tapi River and at least nine other smaller rivers. The area is backed up inland to a distance of two km by shrimp ponds and degraded mangrove, including large areas of dead and dying trees. Most of the mangrove has been cleared leaving a narrow fringe of tallish trees (10-15m high) along the seaward edge. The bay is very shallow with extensive areas less than one metre deep at mean low water. In areas of shrimp ponds, the salinity ranges from 15 p.p.t. in the rainy season to 33 p.p.t. in the dry season. The mean tidal range is l.10m; the amplitude at spring tides is l.90m (occasionally as much as 2.2m), and that at neap tides, 0.7m. Tidal influences are modified by freshwater run-off from the Tapi River catchment.
Climatic conditions:
Tropical monsoonal climate with an average annual rainfall of 1,755.3 mm, the heaviest rain usually falling in November (346.2 mm). February is the driest months, receiving an average of 13.2 mm. Most rain falls during the southwest monsoon (May to October), but the season is extended into December by the onset of the northeast monsoon. The prevailing winds are northeast from November to April and southwest from May to October. The mean annual temperature is 26.3°C (range 22.2-32.1°C). The relative humidity varies from 76% in March to 88% in November.
Principal vegetation:
Sonneratia is dominant in the mangrove on the seaward edge, and is fringed behind with Rhizophora. In only a few areas is this belt of mangroves more than l00m wide, and along much of the coastline it is much less. There are extensive areas of dead mangrove among the shrimp ponds. Adjacent land is mainly under cultivation with rubber plantations, rice paddies and field crops. There is some secondary evergreen forest on the nearby hills.
Land tenure:
The wetland is state owned, though many areas have been settled illegally; surrounding areas are mainly in private ownership.
Conservation measures taken:
Some small-scale replanting of mangrove has been undertaken. Bandon Bay is a designated site under the ASEAN/USAID Coastal Resources Management Project (CRMP), which aims to develop site-specific coastal resource management plans.
Conservation measures proposed:

The following recommendations have been made by Swennen et al. (1986):

  • that surveys be made of roosting Sites and possible breeding sites of Egretta spp in relict stands of mangrove;
  • that such roosting and breeding sites be protected from human disturbance;
  • that more detailed studies be made of the feeding habits of shorebirds using the area;
  • that the level of research at the Surat Thani Fisheries Station be increased, especially as concerns the relationship between aquaculture and the amount and type of mangrove vegetation.
It is also recommended that better protection be given to the remaining patches of mangrove, and that this be combined with increased replanting. The area might be considered for possible establishment as a Non-Hunting Area.
Land use:
Fishing, and aquaculture for penaeid shrimps including the Jumbo Tiger Prawn Penaeus monodon. The offshore mudflats are used for the culture of oysters Crassostrea spp and Green Mussel Perna viridis. Cockles Anadara granosa are seeded. There are some small areas of salt pans. Most of the adjacent land is used for the cultivation of rice (one crop of wet-season rice per year), but there are also some orange and coconut orchards and small areas of rubber plantation.
Possible changes in land use:
Increasing areas are being given over to human habitation, and there is further clearance of mangroves for aquaculture. There is also the likelihood of further industrialization of the areas immediately adjacent to the town of Surat Thani. Increased destruction of the forests of the uplands in the water catchment area may lead to increased amounts of silt entering the estuarine ecosystem.
Disturbances and threats: Continued clearance of mangroves for aquaculture may eventually threaten the site with irreparable damage due to erosion of the seaward bunds. Most clearance has taken place in the past five years as a result in part to an influx of settlers from elsewhere.

Industrial effluents and the release of deoxygenated water from the Chiew Nam hydro-electric dam (situated upstream on a major tributary of the Tapi River) are already causing severe pollution.
Economic and social values: The fishery is of immense importance and the remaining mangroves are probably essential in maintaining its productivity.
Fauna: Information on fish species at the site may be obtained from the Director of the Surat Thani Brackish Water Fisheries Station at Ban Changoe.

The site is believed to be a major wintering and/or staging area for migratory shorebirds. At least 2,840 shorebirds of 22 species were recorded along 17 km of shoreline during a five day survey in late October 1986. These included:
1,290 Charadrius mongolus 380 Pluvialis dominica
310 Calidris ferruginea 200 Tringa stagnatilis
140 Calidris subminuta 125 C. ruficollis
About 500 herons of seven species were also counted, of which over 80% appeared to be Egretta garzetta. There were also small numbers of Ardea cinerea and A. purpurea (Swennen et al., 1986). The area was found to support an extremely high density of wintering Halcyon pileata, and the scarce Copper-throated Sunbird Nectarinia calcostetha, a species restricted to mangrove habitats in Thailand, was also recorded.
Small numbers of the Estuarine Crocodile Crocodylus porosus may still be present (Ngampongsai & Nabhitabhata, 1987).

Some collection of mudflat benthos has been undertaken by Interwader. Although the full results are not yet available, initial examination showed the biomass of invertebrates to be relatively high, with polychaetes, especially nereids, dominating numerically.
Special floral values: The remaining mangrove areas are of considerable regional importance.
Research and facilities: The Surat Thani Brackish Water Fisheries Station is situated at Ban Changoe on the shores of the bay. This provides a convenient base for shorebird research. Interwader carried out an aerial survey in autumn 1984 and a partial ground-based survey in autumn 1985. Dr Anant Saraya, Chief of the Coastal Investigation Unit in the Brackish Water Fisheries Division of the Department of Fisheries, has detailed information concerning the development of aquaculture at the site.
References: Ngampongsai & Nabhitabhata (1987); Swennen et al. (1986).
Criteria for inclusion: 1b, 1e, 2b, 3b.
Jira Jintanugool, Philip D. Round and Interwader.