In 1994, the Bay of Tonkin, which includes Halong Bay, was made an UNESCO Heritage Site. The fishing villages were moved to sheltered bays to protect the people living there from from the typhoons that rage in this part of the world.
But there are still concerns about pollution caused by the villages, and to protect the ecology of the bay UNESCO has decided to remove the fishing villages. To me this seems to be an extreme reaction, especially for the people that have lived in these villages for generations. They will get free housing on the mainland but their whole way of life is being wiped out.
For more on this UNESCO site: http://whc.unesco.org/en/list/672