Macquarie University News current edition

             By  Jean Joss 

The Queensland Government’s surprise decision to proceed with a mega dam on the Mary River is wrong for almost every reason, writes Professor Jean Joss. For most of the year throughout most of its length, the Mary is nothing more than a small, meandering coastal creek but it is uniquely suited as habitat for several of the country’s endangered species.

Jean Joss is a Professor of Biology in the Department of Biological Sciences

One of these is the only one of its kind in Australia and the most important of only six of its kind left in the entire world - the Australian or Queensland lungfish.

Lungfish were once abundant 400 million years ago, during the Devonian - the Age of Fish. At this time there were three main groups of fish: the lobe-finned fish, the cartilaginous fish (sharks, rays) and the ray-finned fish. Today, the last two groups represent almost all the fish in all the seas and waterways of the world. The lobe-finned fish have evolved into all the living species of land vertebrates - amphibians, reptiles, birds and mammals. Just a few lungfish and coelacanths remain in this group as fish so it is to these fish that we must look to discover the pre-adaptations for life on land.

The Australian lungfish is a much older species than any of the other living lobe-finned fish. It was alive during the Cretaceous along with the dinosaurs. Now it only occurs naturally in the Mary and Burnett rivers in south-east Queensland.

Introductions into other rivers in the past have largely been unsuccessful, with the exception of the Brisbane River, but this population of lungfish is only just hanging on due to extensive damming of the river to provide water for greater Brisbane.

Most freshwater fish species are affected by dams but for lungfish, dams are fatal for recruitment and therefore ultimate survival. Lungfish require shallow, slow-flowing, densely-vegetated riffles as spawning and nursery habitat. These environmental features are characteristic of both the Burnett and the Mary but it is exactly these features that are lost entirely by permanent flooding resulting from the construction of dam walls.

The Paradise Dam has only just been completed on the Burnett River. When it is full, it will have permanently destroyed 42 kilometres of lungfish spawning/nursery grounds. The construction of this dam was vigorously protested but it still received the go-ahead from the Federal Minister prior to the listing of lungfish on the Federal Environment Protection and Biodiversity Conservation Act.

Once listed, the construction of the dam was required to include a fishway that would allow the movement of fish between the impoundment and the river. Unfortunately, this requirement addressed only one of the provisions of the Act for lungfish. The other requirement is that no significant impact is made on lungfish spawning and nursery habitat areas. This has not been addressed at all.

However, Premier Peter Beattie when asked about the lungfish and the Mary River Dam gave this reply: “It is alarmist and untrue. We’ve been able to protect them in the Bundaberg region and we will do exactly the same in the [Mary River] region… We’ve succeeded in doing it at the Paradise Dam and we’ll do it here.”

Such comments are not only premature (the Paradise Dam is less than 20 per cent capacity, the fish lift is yet to operate successfully and population studies following completion of the dam wall are yet to commence), but are downright deceitful.

Premier Beattie must know that his government is pushing this extraordinarily important and vulnerable species to extinction by extinguishing more than 80 per cent of its natural spawning and nursery sites.

The significance of the Australian lungfish cannot be overstated. As a ‘living fossil’ it provides the only opportunity to study the development and physiology of the aquatic predecessors of all land vertebrates, including ourselves.

Australia is the custodian of the source of this invaluable library of information for the rest of the world. How can we justify pushing our unique lungfish to extinction for such a questionable short term gain?

Email the commentator: jean.joss@mq.edu.au
Email the Media Manager: kathy.vozella@mq.edu.au

Macquarie University News current edition