Fifth Port River dolphin found dead as Hunter’s cause of death revealed

A fifth dolphin has been found dead in the Port River, as a new report reveals “unacceptably high” toxic contamination levels.

A fifth dolphin was found dead in the Port River on Sunday, as a new report has revealed levels of toxic contamination in some South Australian dolphins were “unacceptably high”.

The body of four-year-old male dolphin Mimo, also known as Squeak, was found near the Fletcher’s slip area of the Port River by the National Parks and Wildlife team, on Sunday.

Squeak, a baby of the Port River, was observed losing weight with visible skin lesions last week.

His six-year-old brother Hunter was controversially euthanised in October after displaying similar symptoms, sparking outrage from local dolphin watchers who believed his health was improving.

Tallula, 12, died in August, and two male dolphins Doc and Twinkle disappeared in June and July, prompting the Department of Environment and Water to launch an investigation into the cause of the deaths.

The interim investigation report was today released, which is being conducted with the help of specialist researchers by the SA Museum, Adelaide University CSIRO and more.

“The Museum’s research has found that level of toxic contaminants in dolphins from some areas of SA are unacceptably high,” the report said.

The investigation is looking into the age and time of death of dolphins in the Adelaide Dolphin Sanctuary, and the emaciation indices over the past 20 years.

Port River dolphin Hunter and a podmate in happier, healthier times. Credit: Jenni Wyrsta,

The reason for the emaciation of Tallula and Hunter was not clear.

“The presence of toxicants including … heavy metals and other persistent pollutants are expected in a species such as dolphins that live in a large urban centre like Adelaide and because they are long lived predators,” the report said,

“The extent to which these could be impacting the health of the dolphins is being explored through these studies.”

The investigation is ongoing and is expected to take several months to complete.

Serious threats have been made against people involved in the Adelaide Dolphin Sanctuary in the wake the mercy killing of the Port River’s little battler, Hunter.

Threats have been made against staff working for the Environment Department, which said it was aware of them and has encouraged those targeted to make reports to police.

The circumstances around Hunter’s death have also exposed rifts between dolphin-watching groups, leading to threats between members of different groups.

Department staff last month euthanased Hunter, 6, after the bottlenose dolphin’s health deteriorated and he was assessed by independent veterinarian experts.

Volunteer-led Australian Marine Wildlife Research and Rescue Organisation hosted a community forum on Monday night in an attempt to calm the situation and discuss new ideas to protect dolphins that would then be taken to authorities.

The organisation’s founder and operations director Aaron Machado said about 45 people took part in a very productive, “constructive conversation”.

Mr Machado said he had received threats in the past after he made the call on an animal that needed putting down and “passionate” people threatened him with knives and slashed his tyres.

This time, when he declined to be involved in the capture of Hunter, he copped abuse for not intervening.

Hunter loved to perform for onlookers. Credit: Jenni Wyrsta,

SA Police was not aware of any threats, but said anyone who felt threatened or intimidated or feared for their safety should make reports.