A fisherman was shocked to see the battered corpse of a dolphin in mangroves near Fibre Creek north of Port Pirie yesterday.
The dolphin seems to have severe bruising on its body and there was a blue rope tied around its tail fin.
The fisherman, who did not want to be identified, said it seemed as though cruel offenders had towed the dolphin behind a boat or they could have tethered it to the mangroves at high tide.
"The dolphins around Port Pirie are playful and entertaining for the children who are out with their families in fishing boats," he said.
"We need to protect them. Tourists come from other States just to see our sea creatures. A lot of fishermen kick up because they reckon the dolphins are eating all their bait out of their crab nets.
"This may have been a cruel and disgraceful act."
Another local said she feared the victim was a friendly dolphin, Mr B, that had formed a bond with some fishermen.
"The dolphin would have to be friendly for someone to tie a rope around its tail fin," she said.
The "fishermen's friend" was known for frolicking near boats and on one occasion had surfaced and stared at a dog aboard a vessel, united in companionship to man.
"It is just so wrong," she said of the attack.
"This will create shockwaves around the world."
The Water, Environment and Natural Resources Department contacted The Recorder this afternoon to ask for the location of the dolphin, saying it would investigate and that severe penalties applied in cases where offenders killed marine mammals.
Departmental spokesman Tony Zidarich said there were concerns the victim might have been the "much-loved" Mr B.
Mr Zidarich then took another phone call and rang back to say that he had a "source" and he was satisfied that a commercial fisherman had found a dead dolphin, towed it to the mangroves and alerted the South Australian Museum so that it could conduct scientific research on the mammal.
"There is nothing malicious here, only it looks grotesque," he said.
"It was found dead and put there for the museum to collect to preserve the body for scientific purposes.
"The fisherman simply tied if off and contacted the museum."
The question still remains - how did the dolphin die in the first place? And was it Mr B?