A five-year survey finds China's sea islands are disappearing due largely to disorderly and crude exploitation.

Reclamation, sand dredging and bombing are some of the destructive human activities that have caused the disappearance of islands, according to the survey, conducted by the State Oceanic Administration.

In addition, the survey, which aims to collect information about China's coast, sea islands and inter-tidal regions, shows longer natural coastlines have been converted into man-made structures over the past several years as urban development and port construction picked up.

Using a high-resolution remote satellite and aerial remote sensing, the survey obtained information on the distribution of coastal resources.

The State Oceanic Administration said a directory of China's sea islands would be published soon, which would provide the latest and comprehensive coastal information.