Videos circulating on social media show dolphins swimming close to shore, with residents reporting a rise in sightings. One local said at least eight clips recorded since 2025 document the animals, either filmed directly or shared within the community.
Dolphins are most commonly seen between Hon Mieu and Cua Dai, an area known for its clear and deep waters. Sightings tend to occur more frequently ahead of storms or during full moon periods, according to residents.
A pod of six dolphins was observed about 2 kilometres off Cai Chien Island on March 27. Each animal was estimated to measure around 1.5 metres in length and weigh about 80 kilogrammes.
Local authorities said sightings near the island have become more frequent in recent years, suggesting improving marine environmental conditions.
Quang Ninh has introduced a range of environmental protection measures, including automatic seawater and wastewater monitoring systems since 2019, stricter fisheries management, mangrove restoration, expansion of marine protected areas, and efforts to reduce plastic waste in Ha Long Bay and Co To.