The sea area of ​​Quang Ninh, concentrated in Ha Long Bay, Bai Tu Long Bay and Co To archipelago, has been surveyed and dived by scientists from the Institute of Marine Environment and Resources (Vietnam Academy of Science and Technology) for many years and is highly appreciated for the richness of coral reefs as well as the fish populations that develop in association with coral reefs. The areas all have rare species, listed in the Vietnam Red Book. In particular, the coral reefs in Hong Van (Co To) are very developed, once measuring 3-4 km long and 1 km wide.

Affected by both natural and human factors, many coral reefs in Quang Ninh waters have been severely degraded in recent years. The good news is that through recent surveys, scientists have confirmed that many coral reefs have been and are in the recovery stage with many small coral colonies developing well.

Here are some pictures of the beauty of coral provided by a group of scientists from the Institute of Marine Environmental Resources: