The document was signed by Bangladesh, Bolivia, Brazil, Cambodia, Colombia, Ecuador, India, Nepal, and Venezuela in the Colombian capital Bogota, reported German news agency dpa.

Pakistan and Peru also joined the declaration but did not want to officially sign the document until the coming weeks.

The countries involved agreed to improve water quality in the dolphins’ habitat, create protected areas, tackle overfishing, and involve Indigenous communities in the affected regions in protecting the animals.

“This historic declaration creates a roadmap for the recovery of river dolphin populations across the globe – offering real hope for the survival of these iconic species despite the enormous threats they face,” said Stuart Orr of the conservation organisation World Wide Fund for Nature (WWF).

“But this declaration is about more than saving river dolphins; it’s also about enhancing the health of their great rivers, which are the lifeblood of so many communities and economies as well as sustaining critical ecosystems from rainforests to deltas.”

The global population of freshwater dolphins has declined by 73% since the 1980s, due to pollution and fishing, according to the WWF.

Currently, six different species still live in rivers such as the Amazon and the Orinoco in South America, and the Ganges and the Mekong in Asia.

Recently, more than 150 dolphins died in the Brazilian Amazon, according to the WWF. Scientists assumed that heat and drought could have triggered the mass die-off.