(CNN) An orphaned baby dugong that attained celebrity status in Thailand has died with plastic waste lining its stomach, prompting a surge of mourning on the internet.

The female dugong, named Marium, was found in April off the coast of Krabi, southern Thailand, and photos of her nuzzling marine biologists quickly went viral. When a second orphaned dugong was found, subsequently named Jamil by Princess Sirivannavari Nariratana Rajakanya, the pair became internet stars.

Dugongs, a species of sea cow, are listed as "vulnerable" on the IUCN Red List , facing environmental threats including pollution, habitat loss and hunting. In Thailand, Marium and Jamil soon became symbols for the conservation of the oceans.

Fans could watch Marium on a live feed, receiving veterinary treatment, and being fed up to 15 times a day. Last week, however, Thailand's Department of Marine and Coastal Resources (DMCR) posted on Facebook that the dugong was sick and refusing food.

Marium died after midnight on Saturday morning, the DMCR confirmed on Facebook. An autopsy revealed plastic debris in the intestine, resulting in inflammation and the accumulation of gas, as well as a respiratory infection and a buildup of pus.

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