Australian Lungfish ‘Neoceratodus forsteri’
Did you know that there is a remarkable fish that is still found in a small number of Queensland’s southern rivers, and it has recently been the centre of much attention…
River fish have always been, and still are, an important food source for Australians. From tens of thousands of years of Indigenous subsistence to today’s angling and fish-farming industries, our waterways and our fish, are a lifeblood of the nation. But what happens when our beloved fish need our help?
The fascinating Australian Lungfish
The Australian Lungfish (Neoceratodus forsteri) is, without doubt, one of the most intriguing of all Australia’s river fish species. It has fins that are built like legs, it has a fully functioning lung, it can survive on land breathing air as we do, and it is a species that has been around on earth for over 145 million years! This makes it the oldest living vertebrate animal in the world today – and it lives in our very own backyard! How cool is that?
Even more exciting, is the fact that it is one of only 6 surviving species of lungfish in the whole world, with one surviving in South America, and four others in Africa. This small group of ancient fish (known scientifically as the order Dipnoi) were once much more diverse, with many more species dating back to the Devonian period of geological time (over 365 million years ago). They are all part of a much larger clade of fish known as lobe-finned fishes, or Sarcopterygii. This clade of fish includes many extinct species that share interesting characteristics with our Aussie survivor, such as lobed fins that resemble limbs more than fins and strong armour-like scales. The only other order of this intriguing clade of lobe-finned fishes that remains alive today is the equally amazing Coelacanths which are deep ocean-dwelling fishes from southern Asia.
Perhaps one of the most interesting discoveries about our friends the lungfishes, is that they, along with their cousins the Coelacanths and all other now-extinct lobe-finned fishes, are actually our very first air-breathing relatives. This means that these guys paved the way for all land-based evolution that blossomed thanks to the development of the lung, and eventually resulted in us! It is amazing to think that these remarkable fish are our great, great, great (multiplied many times!) grandparents, some of whom we still have living among us today!
An ancient creature under threat
But there is a down-side to this story. As fascinating and important as our Australian Lungfish is, it is in peril. Over the last 100 years, river-damming, agriculture, over-fishing and pollution have negatively impacted our lungfish and their habitat. Their fry (baby fish) rely on the shelter and nutrition provided by an intriguing group of aquatic plants called Vallisneria, or more commonly, eelgrass. These beautiful emerald-green ribbon-like plants were once common in gently running, pebble riverbeds across South East Queensland. However, large dams which cause the creation of big reservoirs have resulted in much of the eelgrass dying off from inundation. Additionally, down-stream fewer new plants are establishing from the lack of propagules (seeds or reproductive tid-bits of plants) floating with the current. This lack of connectivity has meant many of our lower waterway catchments lack the important eelgrass plants, and coupled with intensive human uses such as agriculture, angling and recreation, lungfish slowly began to disappear.
The road to recovery is paved with eelgrass for the Australian Lungfish!
However, in the late 20th century, translocations of the very last populations of the Australian Lungfish were made from their dwindling populations in the Mary and Burnett Rivers, to the Brisbane River and its catchments. Even better, now this larger population has been the subject of a fantastic initiative co-managed by Seqwater and Healthy Land and Water to monitor and health-check those remaining fish. The so-calledLungfish Habitat Rehabilitation Program forms part of a broader strategy that Seqwater has developed to ensure the long-term survival of the Australian Lungfish in South East Queensland rivers by artificially restoring eelgrass. The plants are grown on special mats in holding ponds and then planted out using starch-based pegs to hold them to the riverbed, and this is happening right across the Brisbane River catchment. This amazing project is the subject of Natura Pacific’s most recent Back from the Brink film, which is now available online. So why not find out more and see how YOU can get involved by checking it out on our webpage, YouTube or on Facebook.
It has been over 145 million years in the making, so we think the fantastic Australian Lungfish deserves our help! Don’t you?
For more reading, check out:
https://hlw.org.au/newsroom/lungfish-habitat-rehabilitation-program/
https://onlinelibrary.wiley.com/doi/10.1111/1755-0998.13440
