A South Australian yacht club claims heavy metals and other industrial pollutants have been discharged into a wildlife sanctuary for the past eight years, as the Port River dolphin pod loses another member.
Sightings of the mammal in the Adelaide Dolphin Sanctuary have dropped about 30 per cent in the past five years, and not one calf has lived beyond three years since 2019.
Eight males have died since 2020, and eight-month-old calf Rocket was orphaned after the suspected death of her mother Ripple in the past three weeks.
Experts believe toxins in the river have compromised their immune systems.
A state parliamentary inquiry is looking into the environmental impacts on the health of the unique Port River dolphin population.
'Quick at handballing'
The Royal South Australian Yacht Squadron has raised concerns as part of the inquiry, saying industrial pollutants have been pumped into the marina since 2016.
The marina at Outer Harbor sits within the sanctuary — an 118 square kilometre protection zone that runs from Port Adelaide to St Kilda and into the Port River.
Squadron committee member David Eldridge said the club first noticed the industrial pollution in 2016, and have raised concerns with the Port Adelaide Enfield Council, Environment Protection Authority (EPA) and Renewal SA.
"They're listening — they're just very quick at handballing," he said.
He said brown water flushes into the marina from the Coghlan Road storm water drain when it has not been raining for days, and is most likely coming from a nearby business.
Mr Eldridge said the inquiry wanted to "track down heavy metals that are coming into the river ... [and] we think we might be part of the problem".
"We don't want to be part of the problem, we want to be part of the solution," he said.
Mr Eldridge said golden-bellied beaver rats were now turning up dead in the marina pool, which has never happened before, and he believed the water was becoming "too toxic for wildlife and dolphins".
"The club has always loved the dolphins — they come in here and the parents teach the younger dolphins how to fish," he said.
The squadron spent $12,000 on commercial divers to remove two walls of silt in the marina and had the water tested, which found high levels of arsenic, iron, sodium and chloride.
"It's not coming off the road, so where is it coming from?" Mr Eldridge asked.
In a statement, the EPA said its staff also analysed the test results and found they had been "incorrectly assessed against drinking water guidelines".
The EPA also said it sent officers to the marina in August 2021 after a complaint by the club, and found businesses along nearby Coghlan Road and high traffic flows "could contribute to sediment run-off".
The council said it recently met with Renewal SA — which owns Coghlan Road — and urged the agency to employ a stormwater specialist to investigate the issue.
But a council spokesman said the broader issue was that not a single government department, agency or organisation was accountable for the quality of the Port River.
"The management of the river comes under the authority of many organisations, government departments and individuals," the spokesman said.
"There is a lack of clarity by these authorities on who is responsible for what within the catchment."
Report due in December
Greens MLC Tammy Franks, who has spearheaded the Port River dolphin inquiry, said she hoped to have a report back by December because the general health of the dolphins was dire.
She said dolphins were slowly starving, had compromised immune systems, had hooks in them and have been tangled up in fishing lines.
"It's actually quite tragic and there is so much more we could be doing. We need to start connecting the dots to ensure this sanctuary is a sanctuary," she said.
"Two dolphins have died since we launched this inquiry. We had a population of about 40 and that was halved in a few years — it's not good enough."
She said it would be devastating to lose the pod, not only for the local community but also for the biodiversity of the Port River.
"We must protect these dolphins and I hope they have a bright future," she said.
Mike Bossley from Whale and Dolphin Conservation said there were now about 10 to 15 dolphins in the Port River area — about "half of what it used to be".
"We've had a lot of deaths and the numbers of dolphins in the sanctuary has declined quite substantially in the last 10 years or so," he said.
He said multiple causes could be involved.
"My guess is there probably isn't any one thing; it'd be a bunch of different things," he said.
Dr Bossley said why numbers had declined since 2013, despite improving awareness of the environment and the dolphins, was unknown.
"It's a real mystery, and a worrying one," he said.
Apart from concerns for the dolphins, Dr Bossley said there were also economic impacts to consider.
"There's quite a lot of tourism focused on the dolphins now," he said.
"Real estate sales often feature dolphins if they are houses on the water, and a lot of people just come down on their boats or come down to the port to maybe look at the river and hope to see a dolphin and buy lunch or whatever it may be."
The inquiry will start public hearings on Monday.
Most of the submissions have called for the government to limit dredging, ban the use of large hooks, live bait and trawling, as well as harsher fines for industry discharge into the river.
But a submission by Flinders Ports did not support limiting dredging, claiming it is not "detrimental to the river or wildlife".
It stated a survey of seagrass two years after a dredging project to widen the Outer Harbor channel showed "no detectable reductions in seagrass cover".
