In a separate post from his verified Facebook page, he said the tropical waters are home to the country's only corals, as well as pods of elusive Indo-Pacific humpback dolphins and endangered whale sharks, now sheltered by the region's newest protected area.

"Next steps will be to develop a science-based, community-informed management plan, raise awareness about regulations in the MPA, build capacity for conducting government and community-led enforcement and monitoring patrols, controlling domestic waste, and beginning to restore degraded corals," he mentioned.

He congratulated the government of Bangladesh, Wildlife Conservation Society with support from Re:wild, the local communities and NGOs on this important accomplishment.

A high-profile and vocal advocate of the battle against climate change, DiCaprio often uses his social media profiles to discuss climate change.

To safeguard marine biodiversity, the Bangladesh government has designated a 1,743-square-kilometer section in the Bay of Bengal around Saint Martin's as the 'Saint Martin's Marine Protected Area.'

According to the ministry of environment, forest and climate change, the decision was taken to help prevent uncontrolled ships and motor boats, overfishing, dumping of waste and harmful chemicals in the sea, destruction of coral colonies and depletion of the area's biodiversity.