According to statistics from the Research Institute for Marine Fisheries, Cat Ba is home to approximately 84 species of hard corals across 33 genera and 11 families. Healthy coral reefs gather around Ang Tham, Cat Dua, Mui Hong, and Ba Trai Dao islands in the southeast of the Cat Ba Archipelago and in the Da Be-Hang Trai and Long Chau island groups.
Although the coral reefs in Cat Ba may not be as vibrant as those in the southern region, they are considered the typical reefs in the Gulf of Tonkin.
However, coastal research programmes in the Cat Ba Archipelago over the past 15 years have shown a considerable fall in coral reefs, with several reefs destroyed.
Cat Ba was once identified as one of the four regions with the most severe coral reef degradation among the 19 coastal reef areas studied in Vietnam.
Monitoring results from 2021 conducted by Cat Ba National Park have shown that at several main coral reef areas being preserved, like Ba Dinh, Van Ta, and Gio Cung, just 37 species of corals from 9 families have been recorded.
Cat Ba National Park has consistently carried out research and monitoring while also taking measures to protect coral reefs. These include deploying mooring buoys to define ecological zones and requiring local fishing boats and tourist vessels to avoid anchoring in these areas.
And thanks to ongoing efforts, the coral reefs in Cat Ba have shown signs of recovery.