Gold Coast electrician Brent Lodge found the reptile while out fishing and recorded a video that he posted to Instagram.
As of July 23 the post has attracted more than 3000 likes and 1800 comments.
Mr Lodge told Nine Entertainment he found the 1.8-metre-long crocodile floating belly-up among litter in the water.
‘‘I just thought it was a big Murray cod or a dead goanna. But when I got closer I realised it was a crocodile,’’ he said.
‘‘It was six-foot-long, a bit taller than me, and there was a hook going through its mouth.
‘‘Everyone thinks it’s a hoax but I’m not joking around. That’s why I took a video because I knew nobody would believe me.’’
Mr Lodge said he contacted NSW DPI before the police.
When contacted for comment, NSW DPI said reptiles were not in its jurisdiction.
Freshwater and saltwater crocodiles are protected species under Australian law.
The illegal taking of a crocodile could warrant a penalty of more than $28000 in some states.
Meanwhile, the report of the discovery has found its way into the nation’s foremost crocodile newspaper, the Northern Territory News, with staff surprised their favourite reptile had found its way so far south.
Northern Territory News reporter Judith Aisthorpe, who covers crocodile stories for the Darwin paper exclusively, was once reported as saying: ‘‘I would not be sad if I got eaten on the job because I am doing what I love. And I would film it as it happened.’’
She said Darwin sometimes tangled with other tropical cities like Townsville and Darwin who also claim to be crocodile capitals, and she would be disappointed to see anyone on the Murray River trying to take the title, ‘‘particularly a cold, southern place like Victoria’’.
Ms Aisthorpe thought the discovery of a crocodile down here could make swimming in the Murray far more interesting and potentially dangerous.
The most recent crocodile story published by the NT paper was about the possibility of native wildlife ingesting drugs by consuming contaminated sewage water, with the headline: ‘Crack-odile’.