According to the Halong Bay-Yen Tu World Heritage Management Board, the May 23-28 cleanup also removed three bamboo rafts covering 180 square metres, along with about 8 cubic metres of foam buoys and aquaculture waste.
All collected materials and waste were transported ashore for destruction or disposal to prevent reuse and environmental pollution.
During the operation, authorities deployed personnel and specialised vessels daily to inspect and clear waste from small island areas across the bay.
Before the campaign, the management board had urged residents to voluntarily dismantle illegal fish cages, recover property and stop unauthorised aquaculture activities.
Authorities said the cleanup aimed to strengthen environmental protection, preserve the bay’s landscape and improve tourism quality in Halong Bay.