The ray-finned fish have been the focus of research for over a century, with the Victorian south-west at the forefront more recently.

In conjunction with NAIDOC Week 2021, Uncle Denis Rose and Dr Wayne Koster shared their eel migration research On the tail of the eel - creatures of mystery, highlighting the importance of eels culturally and ecologically, and their learnings through satellite tracking.

Mr Rose is a Gunditjmara traditional owner from south-west Victoria and has had a long involvement in natural and cultural heritage management.

He manages the Budj Bim Cultural Landscape, one of the world's largest and oldest aquaculture systems, through his role with the Gunditj Mirring Traditional Owners Aboriginal Corporation.

He is also the chair of the Victorian Indigenous Seafood Corporation and helped establish the nationally and internationally recognised Indigenous Protected Areas (IPAs) program, which has now voluntarily dedicated more than 67 million hectares of Indigenous-owned and managed lands as Protected Areas throughout Australia.

When Mr Rose was a "young fella" he would often go fishing with his family in the area that now makes up the Budj Bim National Park.

"The Budj Bim cultural landscape contains one of the world's most extensive and oldest aquaculture systems," Mr Rose said.

"As Traditional Owners we didn't have much access to country up until about 35 years ago.

"One of our major aims is to improve the health of country."

Continuing connections to country were recognised in the Gunditjmara native title determination in 2007, which Mr Rose said marked a huge shift in understanding at Budj Bim and the surrounding landscape.

"It's not just about the sites and animals, it's about people and people using the Budj Bim lava flow," Mr Rose said.

"The country tells the story. The Gunditjmara were able to prove their strong and unrelenting connection to this area where their ancestors farmed eels for food and trade at the time of European settlement and back through the millennia."

His goal through his work in the south-west is to give better access to country for Indigenous youth.

"It's really important our younger people are exposed to a range of cultural activities," Mr Rose said.

"It's really important for our mob to get back out and reconnect on country and recognise what our ancestors did."

The site was inscribed on the World Heritage list two years ago this week.

Mr Rose did lots of eeling growing up, but admits that while he knew a lot about the different ways to catch them and at what time of year, he didn't know much about their lifecycle and journey before 2007.

The project with ARI has been a two-way learning said Mr Rose, with Traditional Owners learning about the science of eels, and the scientists learning about the cultural significance of the species.

"I think things like the satellite tagging for example really helped us in terms of our understanding and knowledge but more also about the management of our country," he said.

"There are quite a number of lava flows in Victoria but this is the only one that has the scale of fish traps and the stone house sites because it has such a great water supply and creek system."

Working closely with Mr Rose is Dr Wayne Koster, a senior scientist in the Applied Aquatic Ecology team at the Arthur Rylah Insitute for Environmental Research.

Much of Mr Koster's recent work has focused on the movements and migrations of freshwater fish species and environmental water requirements of native fish.

His current projects include oceanic migrations of anguillid eels using satellite tracking.

"Globally eel populations have declined substantially over the last 50 years or so, particularly in the Northern Hemisphere," Dr Koster said.

"Many species are classified now as threatened or endangered and that's due to factors like barriers to migration like dams, habitat loss and degradation.

"When it comes to Australian eels almost nothing is known about their migrations in the ocean and spawning."

Over the past few years Dr Koster and his team have started investigating the migrations of Australian eels, primarily the short-finned eel.

Since 2018, pop up satellite transmitters have been used to track the eels, centred around the Fitzroy and Hopkins Rivers which form part of Budj Bim.

"Lake Condah seems to have some of the biggest, fattest eels I've come across," Dr Koster said.

The tracking found eels mostly move out of Lake Condah at night and mostly in the spring when water spills out over the lake into the fishway.

They then migrate through Darlot Creek and exit the estuary in February to March around the new moon.

The final part of the journey reveals the eels migrating out of a small creek into Port Phillip Bay - the last time they will encounter fresh water before their oceanic migration.

"They spend potentially decades and decades in freshwater and then begin that long journey north to warm tropical waters," Dr Koster said.

His team recently used satellite transmission technology to track the eels from western Victoria for five months. They travelled almost 3000 kilometres.

None of the tags, worth thousands of dollars, stayed on the eels for the full journey with some getting eaten by sharks and falling off due to attachment issues.

IN OTHER NEWS:

In 1923, Johannes Schmidt wrote of his quest to locate the eel spawning area: "These years of research have been rich in suspense; disappointment alternating with encouraging discoveries, and periods of rapid progress with others during which the solution of the problem seemed wrapped in deeper darkness than before."

Schmidt studied eels for over 20 years; while Dr Koster hasn't been at it that long, he thinks he knows how he felt at times.

"I can appreciate what he's saying; we've had some tags eaten by sharks or come off, then at other times there's some really exciting results," he said.

The ongoing research taps in to the NAIDOC Week 2021 theme 'Heal Country'.

Mr Rose said it's helped both researchers and Traditional Owners make better-informed decisions for the environment.

"We need to be able to have good, honest and open dialogue to make sure we are healing country. We all have the same aim," he said.

"It is about healing and improving health of country with the best possible information.

"Cultural practice was pretty much flogged out of us in the Mission days - I'm not aware of any Aboriginal spiritual connection to eels but they were a great food source for our people."