Cat Ba and Long Chau archipelagos are naturally connected with the islands in Ha Long bay (HLB) and Bai Tu Long bay (BTLB) to form a "unique cluster of limestone islands" not only in Vietnam’s sea but also worlwide with recognized global and national heritage values. However, the limestone islands cluster is separated by two administratively different bodies: Cat Ba and Long Chau archipelagos belong to Haiphong city, and HLB - BTLB to Quang Ninh province. | An integrated approach in management of Vietnam’s Ha Long bay – Cat Ba limestone islands marine area
