Biological Richness Of The Asian Tidal Flats And Its Crisis By Human Impacts

The great biological richness of the Asian coastal shallow waters including estuaries and intertidal flats seems to be underestimated probably due to its simple and colourless appearance and the delay of the basic studies. Human impacts such as water pollution have damaged the coastal environments. For example, species number and biomass of benthic invertebrates were rapidly decreased in late 1960s or early 1970s in Qingdao in the inner part of Yellow Sea, probably caused by the discharge of pollutants into the bay from many chemical plants (Wu et al. 1992). At the same period, the heavy mercury pollutions causing the severe injury of human health of many local people through food chain occurred in Japanese coasts (i.e., Minamata disease, Ui 1992, Harada 1995). Similarly, in Onsan, South Korean, a disease related with heavy industrial pollution occurred in 1980s (i.e., Onsan disease), and the potential biological effects associated with some organic chemicals seem to be still under exposure in this area (Koh et al. 2002a). Another aspect of recent serious human impacts is the large-scale of reclamation project in shallow coastal zones, especially in intertidal flats of the Asian countries. We feel anxious that the whole original biodiversity and ecological process in these areas might be lost by the serious human impacts in relation to the rapid developments in the Asian countries before we know them. The experiences of ‘Sihwa Project’ in Korea and ‘Isahaya Project’ in Japan would be representative examples. Currently in South Korea, huge reclamation projects such as the ‘Saemangeum Project’ modifying 400 km2 of tidal flat area into farmland are rigidly in progress although their serious impacts are clearly expected.