An Irrawaddy dolphin calf who was rescued and nursed day and night for weeks by vets and volunteers after his rescue from a tidal pool on Thailand’s shore has died, officials who were caring for the animal said on Wednesday.

The calf was nicknamed Paradon, roughly translated as “brotherly burden,” when he was found by fishermen on July 22.

Dozens of vets and volunteers helped care for him at Thailand’s Marine and Coastal Resources Research and Development Centre in Rayong in the Gulf of Thailand.

“We were quite shocked because it happened so fast. Paradon had made much improvement since we have found him,” said Oranee Jongkolpath, a vet at the centre.

“He started to get sick again on August 31, having difficulty breathing and suffering from diarrhoea. He deteriorated so quickly, and he died that night.”

Oranee, with her colleagues and volunteers, had been providing 24-hour watch over the injured calf.

The team looking after Paradon said an initial examination found infection in his lungs, but were waiting for full laboratory results to determine the exact cause of death.

“While we can’t save Paradon’s life, we have learnt a lot from it. Not many people have cared for Irrawaddy dolphins, let alone a calf.

“Everything we have done in a month of caring for him are all lessons learned for us, from its behaviour, its food intake, and even its sickness,” said Oranee.

Irrawaddy dolphins, considered a vulnerable species by the International Union for Conservation of Nature, are found in the shallow coastal waters of south and south-east Asia and in three rivers in Myanmar, Cambodia and Indonesia.

Their survival is threatened by habitat loss, pollution and fishing, when dolphins are caught unintentionally with other species.

The marine research centre believes about 400 Irrawaddy dolphins remain along the country’s eastern coast bordering Cambodia.