Going beneath the surface to protect dolphins

Australia Broadcast Center

11 hours ago

Australia is home to the world's only city-based dolphin sanctuary, established in 2005 to protect a pod, considered rare for living in an Adelaide estuary. Since becoming protected, they have battled pollution, speeding boats and fishing lines. Their population has halved. And experts fear some of their biggest challenges are still ahead.
Port River is a mix of power plants, residential development and industrial business. ( ABC News: Che Chorley )
It can be a place of breathtaking beauty.
A place where dense 10,000-year-old mangroves line the rivers, inlets and narrowing creeks that make-up this Adelaide estuary.
An abandoned ship among mangroves in the Port River. ( ABC News: Che Chorley )
A place where abandoned ships dating back to 1909 are both seen and partially hidden by silt and mangroves in the backwaters of this ecosystem.
The Port River mangroves are home to waterbirds. ( ABC News: Che Chorley )
A place to spot birds from as far abroad as Siberia and Alaska.
The Port River Expressway at Port Adelaide. ( ABC News: Che Chorley )
But it is also a place where pockets of natural beauty meet industry.
A scrap metal business in Port Adelaide. ( ABC News: Che Chorley )
Lining the Port River, in metropolitan Adelaide, are power plants with high-voltage transmission towers, submarine construction, residential development, scrap-metal recycling and industrial businesses.
Port Adelaide was South Australia's first port. ( ABC News: Che Chorley )
In 1837, the river became South Australia's first port and remains the state's largest with 2,000 container ships coming in and out each year.
There are about 20 dolphins in the Port River. ( ABC News: Che Chorley )
Protected marine life and mangroves must coexist with some of the very things that may threaten their survival.
Marine scientist Mike Bossley spent years documenting Port River dolphins.
Researcher Mike Bossley has spent decades trying to protect a unique dolphin pod that lives in the Port River and its adjoining inlets.
His love of the ocean inspiring more than 50 years of marine conservation.
Mike Bossley has dedicated his life to protecting Port River dolphins. ( ABC News: Che Chorley )
"I grew up more or less in the ocean and I've loved the ocean ever since, all my life really," Dr Bossley said.
"If there was an epiphany for me it was when I was studying in Canberra and went down to the South Coast [of New South Wales] and was walking along the beach with my wife.
"I was watching some guys surfing and suddenly a group of dolphins came and started surfing the same waves as the guys were."
Horse trainer Sandy befriends a dolphin named Billy in the Port River. ( The Advertiser/State Library of South Australia/ABC News: Stephan Hammat )
Later, he received a letter from a friend about a dolphin that was swimming with racehorses, who were training in the Port River.
"It was early 1988, and I started watching this dolphin — whose name was Billy — swimming beside the racehorses," he said.
Mike Bossley bought a boat to continue his research into the Port River dolphins. ( ABC News: Che Chorley )
"I got so interested, the next year I bought a boat and started following them around to get to know them."
Mike Bossley does weekly surveys of the Port River dolphins. ( ABC News: Che Chorley )
His weekly surveys of the resident Port River dolphins started in 1988.
They continue to this day, making his research one of the longest-running dolphin data sets in the world.
He knows every dolphin by name ...
... every injury, every mark on their bodies.
"We know their life history, who their mother was, who their grandmother was, who they hang out with," Dr Bossley said.
Dolphins under attack
But in the late 1990s and early 2000s, dolphins were being shot and stabbed.
Warning: This section of the story contains some images that may cause distress to readers.
Dr Bossley started campaigning, trying to convince the state government to declare the estuary a marine protection zone.
He lobbied for a decade, and in mid-2005, the Adelaide Dolphin Sanctuary was established — the first of its kind in the world.
It became a criminal offence to harm the mammals, park rangers were employed to monitor the pod, and a plan was made to improve their habitat and the water quality of the Port River.
Back then, the pod comprised of about 40 resident bottlenose dolphins.
Dolphins were entangled in fishing lines or injured by speeding boats. Then-SA premier Mike Rann offered $10,000 for information on who was shooting dolphins. ( The Advertiser/Marianna Boorman/Whale and Dolphin Conservation )
Dolphin researcher Marianna Boorman spent decades recording Port River dolphin movements. ( ABC News: Che Chorley )
"We've certainly had some ups and downs — we used to see a lot more dolphins when the sanctuary was started," dolphin researcher Marianna Boorman said.
Ms Boorman met Dr Bossley when she was 13 years old and started volunteering by helping with mailouts.
Marianna Boorman (left) met Mike Bossley during her year 11 work experience in 1998. ( ABC News: Che Chorley )
In 1998, she did her year 11 work experience with the veteran conservationist.
"Sadly, it was also when I saw my first deceased dolphin," she said.
"This was a mother dolphin that had a young calf. It was one of two adult dolphins that had been deliberately shot.
"It was very upsetting and made me realise how callous people could be and how important it was that more measures were taken to help protect these dolphins.
"I've loved dolphins for as long as I can remember."
Ms Boorman started taking her camera on surveys to capture "some of these special moments between the dolphins".
"I probably have about 20 hard drives [of images]," she said.
Her extensive catalogue provides an insight into their fascinating history ...
... but also a stark reminder of how many dolphins have been lost.
Dolphin numbers fluctuate as calves are born, but the pod has suffered significant losses over the past 20 years.
"It is heartbreaking, especially when you know [the death] has been caused by human activity," Ms Boorman said.
"They do face many threats from humans including fishing line entanglements, boat strikes, pollution, being fed and harassment."
In 2021 six dolphins — Doc, Twinkle, Tallula, Hunter, Squeak and another in nearby Semaphore — became abnormally thin and died within a few months.
Doc and Twinkle went missing and presumed dead in June 2021. ( Supplied: Marianna Boorman )
Sparkle with her calf Tinsel died in March 2019. ( Supplied: Marianna Boorman )
The late Talulla learnt the act of tail walking from his mother, Wave. ( Suppied: Marianna Boorman )
Post-mortem examinations found heavy metals and other toxicants were present but not the cause. Most had compromised immune systems, leaving them vulnerable to infection.
It is unclear what exactly impacted their immune systems.
A further three dolphins — Hope, Ripple and Namor — died or disappeared in 2022 and 2023, but there have been no further adult deaths in the past two years.
Many calves have died, which is common given their vulnerability. A one-week-old calf died from blunt force trauma in March this year.
Two of five calves have survived the last breeding season.
There are now 20 dolphins left in the Port pod.
River a historic dumping ground
The decline in health of the Port River dolphins prompted a parliamentary inquiry last year, which found that toxicants likely contributed to the deaths.
"Not enough is understood about the legacy toxicants lying in the sediment in the ADS, particularly PFAS and microplastics, and the potential to impact the health of the dolphins," the committee report stated.
The estuary has a history of poor water quality, and has been a dumping ground for industrial pollutants, with raw sewage discharged into the river until 2004.
The former Penrice soda ash production plant at Osborne. ( ABC News: Che Chorley )
Transmission towers lined the Port River. ( ABC News: Che Chorley )
Five gas power plants sit on the shoreline of the sanctuary. ( ABC News: Che Chorley )
Swimmers are asked to avoid Angus Inlet in the sanctuary. ( ABC News: Che Chorley )
Penrice Soda pumped the byproducts of its soda ash and sodium bicarbonate into the Port River for decades.
Until 1999, it had a licence to pour 75 megalitres of processed water containing calcium chloride and ammonia into the river each day.
Along with 100,000 tonnes of insoluble residue, called "calsilt", and 540 tonnes of nitrogen per year into the waterway.
Every two-to-three years, Penrice would have to dredge the contaminated silt, and that spoil would be dumped in deeper waters off Outer Harbor.
The company was liquidated and stopped operating in 2014.
Five natural gas power plants — Torrens Island, Dry Creek, Pelican Point, Osborne and Quarantine — sit on the shoreline of the sanctuary.
The state's largest, Torrens Island, discharges thermal effluent into the Port River, increasing temperatures in Angus Inlet to over 30 degrees Celsius in summer.
According to a 2022 South Australian Research and Development Institute (SARDI) report, the increased water temperature lowers oxygen levels, driving away fish and killing seagrass.
Lynette Crocker is worried about the industrial impact on the Port River dolphins. ( ABC News: Che Chorley )
Senior Kaurna woman Lynette Crocker believes historic pollution and the destruction of seagrass and mangroves has damaged the ecosystem in the Port River.
She is terrified of plans to build nuclear submarines at Osborne, which sits within the sanctuary.
Australian submarine company ASC's headquarters at Osborne. ( ABC News: Che Chorley )
A November 2024 environment impact report by Australian Naval Infrastructure found habitat will be lost, and up to 891,000 cubic metres of river floor will need to be dredged.
"I'm fearful of what is going to happen with AUKUS, what is going to happen with the nuclear subs — not only for the dolphins, but for the rest of us," Ms Crocker said.
Lynette Crocker says once upon a time there were up to 80 dolphins in the Port River. ( ABC News: Che Chorley )
The former Adelaide Dolphin Sanctuary board member remembers a time when there were 80 dolphins — or yambo in Kaurna language — living in the Port River.
She is saddened by their demise.
"When is it going to stop? When is enough, enough for making things worse rather than making things better?" she said.
"There are several agencies that have a responsibility and they're failing miserably."
Osborne is the site where the proposed nuclear submarines will be built. ( ABC News: Che Chorley )
Ms Crocker said businesses "profiteering off the Port River" also have a responsibility to ensure the ecosystem survives for future generations.
"We're not leaving a legacy for anybody else — it's just more damage for young people to deal with," she said.
"It's not a sanctuary; but it could have been."
Mike Bossley spends most of his life in marine conservation. ( ABC News: Che Chorley )
Dr Bossley is less concerned about the nuclear ship build but believes the Port River dolphins face three major challenges in the future.
Future algal blooms disrupting the wider ecosystem ...
... the H5N1 bird flu, which has spread to mammals in Antarctica and will, he said, make its way to Australia eventually ...
Port River is where nature meets industry. ( ABC News: Che Chorley )
... and development along the Port River.
"For somebody who spent their life trying to protect these dolphins and their habitat, it can keep me awake at night," Dr Bossley said.
The algal bloom can be seen above the water.
The SA government earlier this month confirmed traces of a toxic algal bloom impacting South Australian waters has now been detected in the Port River.
The National Parks and Wildlife Service has confirmed the deaths of 10 dolphins along the metropolitan coast since March 1, but authorities believe the bloom does not directly affect mammals — a view shared by Dr Bossley.
"Hopefully it won't have any direct impact on the Port dolphins because it hasn't had an impact [on mammals] in any other areas where the bloom has been much worse," Dr Bossley said.
Dolphins swimming in the Port River. ( ABC News: Che Chorley )
But he said the bloom could kill off food for the Port River dolphins, which are "extremely site-attached".
"Most of them have grown up there, their mother grew up there, their grandmother grew up there, so I suspect that they would stay, even without any food."
Jon Emmett works for the National Parks and Wildlife Service. ( ABC News: Che Chorley )
Jon Emmett oversees both the protection of the dolphins within the sanctuary, and their habitat.
"A big part of that is making sure users of the sanctuary — boaters, fishers and others — abide by the regulations, especially with respect to feeding the dolphins and keeping a distance," he said.
St Kilda mangroves are an important habitat for shorebirds. ( ABC News: Che Chorley )
He said progress had been made over the past 20 years to improve the dolphins' wellbeing.
"Since it was established, we've managed to stop that practice of dolphins being deliberately harmed," he said.
"We haven't seen that happen in a long time."
Housing development along the Port River. ( ABC News: Che Chorley )
He said water quality has improved, and community and industry were a lot more aware of the need to look after the river.
But Mr Emmett agreed development in the Port could threaten the dolphins.
"There are challenges coming their way. We have a lot of development going on in the Port — it is going to get busier," he said.
"There's a lot of residential development; there's a lot of industrial development and I think that's a good thing. I'm optimistic about that.
"[But] we need to make sure the things the dolphins need for their survival are taken care of. We must be mindful of the quality of the habitats in this area.
"If we look after the habitats, the dolphins will look after themselves."
Lewis Pullman says the dolphins need to be protected. ( ABC News: Che Chorley )
Local tour guide Lewis Pullman has spent years paddling around the sanctuary on dolphin sight-seeing trips.
"These are completely wild animals — we don't tame them, influence them in any way. Our goal is to not have an impact on them at all," he said.
"Sometimes we see them jumping out of the water and that invokes a bit of a roar with the crowd."
Adelaide Dolphin Sanctuary tour guide Lewis Pullman. ( ABC News: Che Chorley )
He said the dolphins were important for the business, but the "environment itself is incredible".
"The dolphins are the face that we all know and love, but there's a lot beyond the surface that needs to be protected as well," he said.
The St Kilda mangroves are of national significance. ( ABC News: Che Chorley )
"Mangroves are the best vegetation species for storing carbon — four times better, per square kilometre, than the Amazon rainforest.
"For its carbon storage properties alone, that's massive. But all the life that happens under the water as well, that's critical.
"This area has suffered in the past but now, things are looking pretty good."
While the Port River has been a source of heartbreak for the dolphins and the people who monitor and care for them, it is also a place of miracles.
A dolphin named Rocket was orphaned at seven months old after her mother Ripple appeared unwell and disappeared in September 2022.
"Rocket has managed to survive, she's catching fish and seems to be doing well," Ms Boorman said.
Rocket is part of the Port River pod. ( Supplied: Marianna Boorman )
Playful Rocket leaps out of the water. ( Supplied: Marianna Boorman )
Now three years old, Rocket is spending more time with mother and calf Mouse and Piki, as well as another mother and calf Summer and Comet.
"We hope she continues to socialise with them, and she'll start behaving a bit more normally," Ms Boorman said.
Two of five calves survived the last breeding season. ( ABC News: Che Chorley )
"We're very lucky, there's not many places in the world where you have a pod of dolphins living so close to a city.
"It's a very special place."
Credits:
Reporting: Meagan Dillon
Photography and videography: Che Chorley
Digital production: Josephine Lim
Editing: Sara Garcia
Additional photos: Marianna Boorman