Breathing life into an ancient fish

The Australian lungfish: embodiment of the transition of life from water to land; listed as a vulnerable species; icon for the Save the Mary River campaign. It is only found in south-east Queensland and its existence is threatened by the construction of dams in these rivers. Decisions we are making now will determine the future of this species.

Unlike most fishes, the Australian Lungfish (Neoceratodus forsteri) has the unique ability to breathe air although under most conditions, they breathe exclusively using their gills. They can grow up to 1.5m in length and 40kg which is reflected in the Aboriginal names theebine  (Waka language)  or the djelleh, both meaning big fish.

The Australian lungfish or theebine. Photo by Tannin.

The Australian lungfish or theebine. Photo by Tannin.

Being able to breathe air is a good survival strategy for Australian fish. Lungfishes surface and breathe air during dry periods when streams become stagnant, or when water quality changes. The sound when they surface to empty and refill their lung reportedly sounds like that of the “blast from a small bellows“.

The Australian lungfish are only found in several rivers in south-east Queensland* including the Burnett, Mary and Brisbane and this is one of the reasons it is protected under the Environment Protection and Biodiversity Conservation (EPBC) Act. Historically, a broader family of lungfish successfully inhabited most of the central-eastern half of the Australian continent, but a number of natural and human-induced factors have led to contraction of its range.

The Mary River in  Queensland - one of the few remaining homes of the lungfish. Photo by MRCCC.

The Mary River in Queensland – one of the few remaining homes of the lungfish. Photo by MRCCC.

The spawning or reproduction of Australian lungfish involves a distinct and intricate courting routine and is highly reliant on a variable low-flow regime within riverine habitat.  This means the construction of water storages within the range of the lungfish is one of the key threatening processes listed for this species. A recent study* demonstrated the absence of flow variability through late winter and early spring and subsequent bulk release of water in early November, had significant impacts on spawning of Australian lungfish.

The Mary River community campaigned to stop Traveston Dam and thus improve the survival prospects for the lungfish. Photo by International Rivers.

The Mary River community campaigned to stop Traveston Dam and thus improve the survival prospects for the lungfish. Photo by International Rivers.

Increased knowledge about this unique species can help us manage existing water storages better. For example releases of water from storages should mimic not only the incoming flow regime but also temperature, to provide maximum opportunity for Australian lungfish to spawn.  Communities are also determining the survival of the species. The people of the Mary River catchment were vocal in expressing their value for the river and its wildlife and undoubtedly played a key role in the Traveston Dam not going ahead. One step toward making the future of the lungfish a little more secure.

*The full article on which this post is based is:

Spawning of the endangered Australian lungfish (Neoceratodus forsteri) in a heavily regulated river: a pulse for life. By T. Espinoza, S.M. Marshall and A.J. McDougall. In River Research and Applications 29: 1215–1225 (2013)

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