A post mortem on a dolphin found dead north of Port Adelaide showed it had been shot a dozen times.

12 bullets of three different sizes were found in the dolphin's body, with evidence indicating the animal did not die immediately after it was wounded. It may have belonged to the Port River pod and researchers are trying to identify the dolphin using photographs.

The dolphins are protected under the National Parks and Wildlife Act, with maximum penalties of $100,000 and two years imprisonment for harming them.