The Krabi Bay and Estuary

The Krabi River estuary Ramsar site, located adjacent to and including the municipality of Krabi City, represents a fine example of the need for co-existence of urban environments and natural wetland environments. The Krabi River estuary covers an area of 21,300 hectares that comprise mudflats, sandy beaches and canals in front of Krabi Town and mangrove forests and extensive seagrass beds in Koh Sri Boya. It is formed where a complex of several rivers discharge into southern Thailand’s Phang-Nga Bay, and is dominated by in excess of 10,000 hectares of mangrove forest. At low tides, an additional 1,200 hectares of tidal mudflat are revealed. Krabi River estuary is a fine example of co-existence between urban and natural areas. The mangrove forests, seagrass beds and coral reefs provide important sources of food for fishes, spawning grounds and nurseries. While included in the Ramsar list as a wetland of international importance in 2001, a recent assessment of the ecology of Krabi estuary found that the it can be identified as a wetland of international importance. The area is divided into the following sections: 5% of endemic mangrove forests, 73% of all Thai mangrove tree species, 5% of seagrass and one of only 2 fossilised gastropod pavements in the world and Krabi supports 27 globally threatened or near threatened species. Mangroves, seagrass (they provide the critical habitat for Dugong, which feed exclusively on these) and coral vegetation support a high diversity both of migratory and resident birds and inshore fish. Of 280 fish species, 60% were found in immature and juvenile stages of their lives, showing the importance of the area in terms of fish spawning and nursery. The site also includes 221 species of visiting birds and shorebirds. INTERNATIONALLY IMPORTANT BIRD SITE Krabi Estuary and Bay supports a high diversity of avifauna and the area’s mudflats form one of the most important sites for migratory birds in southern Thailand with a total of 221 bird species having been recorded at the area. Of migrant bird species, 23 are shorebirds which feed here during their annual migrations between North Asia, Southeast Asia and Australasia. In addition, the inter-tidal flats provide feeding areas for significant numbers of near threatened Malaysian and Asian birds. As one of the most easily accessible areas of species-rich mangroves in Southern Thailand, the site has great recreational and educational potential – especially for bird watching. MARINE MAMMALS AND REPTILES Krabi Estuary and Bay is of surprisingly high significance for marine mammals, with up to 20 species possibly occurring in the area, including globally threatened species such as Byde’s whale, sperm whale and false killer whale. Other smaller animals including various species of dolphin and porpoise are also recorded although the scarce sightings suggest that these are migrations to feed on seasonal fish movements. Seagrass beds around Koh Si boya Island also provide critical feeding habitats for small local populations of Dugong, which are entirely dependent on seagrass habitats, while at least 3 species of marine turtle – including the critically endangered Hawksbill turtle, are regularly observed within the Krabi Estuary and Bay. FISH It is estimated that of the 280 fish species utilising the Krabi Estuary, 232 species utilise the area’s mangrove forests, 149 feed in seagrass beds and 233 species can be found off coral reefs in Krabi Bay. Of these known species, 60% have been found. Krabi Estuary’s wetlands play a critical role in supporting local fisheries. As a result of the rich diversity of fish species, including the many mangrove dependant, seagrass dependant and coral dependant species, local people have access to a wide range of fish resources. The future of Krabi Estuary is dependant on its proximity with the Krabi Town municipality. The greatest threat to Krabi Estuary is the continuing discharge of urban wastewater into the estuary, which threatens the rich benthic biomass to be found in the extensive inter-tidal mudflats, while solid and organic waste is also adding to the pollution burden. Like most mangrove areas in Thailand, remaining mangroves at the Krabi site are under pressure from illegal encroachment, in particular from increasing industry and the expansion and migration of shrimp aquaculture. RAMSAR CONVENTION The Convention on Wetlands, signed in Ramsar, Iran, in 1971, is an intergovernmental treaty which provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources. There are presently 158 Contracting Parties to the Convention, with 1747 wetland sites, totaling 161 million hectares, designated for inclusion in the Ramsar List of Wetlands of International Importance.