The story of the Australian lungfish has made this week’s issue of Nature. Remember, it’s not too late to keep the pressure on.
Dam project threatens living fossil
Lungfish face extinction, say environmentalists.
We are about to lose a key piece of our evolutionary history, warn biologists. They are campaigning to save the Australian lungfish, which they fear could be sent extinct by an enormous dam planned for southeastern Queensland.
The hefty, muddy-brown fish (Neoceratodus forsteri) is thought to have survived virtually unchanged for at least 100 million years, making it one of the oldest known vertebrate species around and earning it the moniker of ‘living fossil’. It is also one of the closest living relatives of the ancestral fish that crawled on to land and eventually gave rise to all land vertebrates, including humans. Being able to study the species is important for understanding how that transition took place.
The lungfish is now largely confined to two river systems in Queensland — among the only places that provide the shallow, running and weedy water in which the fish likes to spawn. A dam in one of these, the Burnett river, was completed last year in order to supply water to the drought-stricken region. The area has the fastest growing population in the country, and delivering water to the inhabitants is likely to be a huge problem in the future. But lungfish researchers say that by flooding or drying them out, the dam will eventually destroy nearly half of the lungfish spawning areas.
On 5 July, Queensland Premier Peter Beattie announced a decision to dam the second river, the Mary. Partly because the Australian lungfish is listed as a threatened species, the dam must pass a federal environmental-impact assessment before the project can proceed. But lungfish supporters believe the second dam could be enough to drive the species to extinction.
The latest decision prompted lungfish expert Jean Joss at Macquarie University in Sydney to step up a campaign to block the dam and persuade the federal government to intervene.
Joss has asked colleagues to e-mail Beattie and federal environment minister Ian Campbell to tell them about the scientific importance of the fish — so far more than 100 scientists have responded to her call. “It would be a calamitous and irreplaceable loss if this animal went extinct,” says Per Ahlberg of Uppsala University, Sweden, who collaborates with Joss and is helping with the campaign.
There are five other species of lungfish living in South America and Africa. But the Australian lungfish, which can live for a century and grow 1.5 metres long, is thought to most closely resemble the last common ancestor of land vertebrates.
Biologists say that living fish can be used for genetic and embryology studies that probe how vertebrates moved from water to land — analyses that would be impossible with preserved specimens. Joss and Ahlberg, for example, are studying the lungfish’s patterns of gene activity, to try to work out how fins became limbs. “These things are amazingly important organisms in the history of the Earth,” says William Bemis who studies vertebrate evolution at the University of Massachusetts, Amherst.
The Queensland government has guaranteed that the dam will include a ‘fish elevator’ to carry lungfish across the dam and says that it will do whatever it takes to meet federal environmental requirements, as it did with the last dam. But Joss says that this is not enough, because the lungfish’s old spawning grounds will still be destroyed. Lungfish lay very few eggs, and return to the same spawning sites year after year.
Should the campaign fail, Joss says she will petition Beattie for money to set up a lungfish breeding centre. But guaranteeing the species’ survival in captivity would be tough. So far Joss is the only researcher who has managed to breed them, using two ponds, each the size of an Olympic swimming pool.
Pearson H (2006) Dam project threatens living fossil. Nature 442:232-233.