The flooded forest of Prek Toal has been designated as a core area (21,000 ha) of the Tonle Sap Biosphere Reserve based on its botanical diversity and its nesting colonies of threatened waterbirds.The biggest Flooded forest, and so many fresh water birds and fishes. The core area (boundaries in black on the map) is in theory dedicated to biodiversity conservation but in reality, it was intensely exploited as a commercial fishing concession until 2011. The fishing lot covered no less than 50,000 ha (area delineated in red on the map) and was the most productive and lucrative area of the lake with a value in fish estimated at 3 million dollars per year. However, the recent abolishment of fishing lots by the Prime Minister Hun Sen creates a new challenge for ensuring protection of the waterbird colonies and their unique habitat.
Phalacrocoracidae is a family of some 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed. There is no consistent distinction between "cormorants" and "shags", and these appellations have been assigned to different species randomly. Cormorants and shags are medium-to-large birds, with body weight in the range of 0.35–5 kilograms (0.77–11.02 lb) and wing span of 45–100 centimetres (18–39 in). The majority of species have dark feather. The bill is long, thin and hooked. Their feet have webbing between all four toes. All species are fish-eaters, catching the prey by diving from the surface. They are excellent divers, and under water they propel themselves with their feet with help from their wings; some cormorant species have been found to dive as deep as 45 metres. They have relatively short wings due to their need for economical movement underwater, and consequently have the highest flight costs of any bird. Cormorants nest in colonies around the shore, on trees, islets or cliffs. They are coastal rather than oceanic birds, and some have colonised inland waters – indeed, the original ancestor of cormorants seems to have been a fresh-water bird. They range around the world, except for the central Pacific islands.
