Neoceratodus forsteri (Queensland Lungfish, Australian Lungfish)

1. Scientific name, common name (where appropriate), major taxon group

Neoceratodus forsteri (Queensland Lungfish, Australian Lungfish).

2. National Context

The Australian Lungfish is restricted to the river systems of south-eastern Queensland.

The Australian Lungfish occurs naturally in the Burnett, Mary, and possibly Brisbane and North Pine, Rivers. In 1897, 78 adult fish were translocated from the Mary River, at Miva, to various waterways further south: in the North Pine (8), Condamine (21) and Coomera (16) Rivers; in a lagoon near the Albert River (5); in a dam near Cressbrook on the upper Brisbane River (8); in the Enoggera Reservoir (18); and in the Brisbane Botanic Gardens (2). Translocations were undertaken because the natural historians of the time could not locate juvenile Australian Lungfish, and the general consensus was that the Australian Lungfish were becoming extinct within their natural distribution. There have not been any recent surveys to ascertain whether the introductions into the Coomera and Condamine Rivers were successful. Recent sampling at several sites on the Albert River did not record this species.

The species is not listed under the EPBC Act. It was listed as 'non-threatened' in the Action Plan for Freshwater Fishes (1993). A nomination in 1997, under the Endangered Species Protection Act 1992, to have the species listed as endangered was unsuccessful. The nomination was assessed by the Endangered Species Scientific Subcommittee as not meeting the relevant criteria as “its numbers have not been reduced to such a critical level, and its habitats so drastically reduced, that it is in immediate danger of extinction.”

In Queensland, it is not listed as threatened under the Queensland Nature Conservation Act 1992. The taking of Australian Lungfish has been prohibited since they were declared a protected species under the Queensland Fish and Oyster Act 1914. It is currently protected from fishing, and collection requires a permit, in Queensland under the Fisheries Act 1994.

3. How judged by TSSC in relation to the EPBC Act criteria.

TSSC judges the species to be eligible for listing as vulnerable under the EPBC Act. The justification against the criteria is as follows:

Criterion 1 - Decline in numbers

The core natural distribution of the Australian Lungfish is the main river channels of the Burnett and Mary Rivers. Data indicates that 26% of this core distribution is presently impounded by weirs and dams, with a further 13% likely to be impounded if proposed water infrastructure developments for the Burnett River catchment go ahead. There are also water infrastructure developments planned for the Mary River. (The figures do not consider distribution of impoundments within the tributaries of the Burnett and Mary Rivers, where habitat is marginal for the Australian Lungfish, nor the translocated populations).

Currently, there is debate as to whether the Australian Lungfish in the Brisbane and North Pine Rivers are natural or translocated populations. At another translocated site, the Enoggera Reservoir, with the removal of plants which are required for successful breeding, the Australian Lungfish are likely to be no longer breeding. The conservation value of the successfully translocated populations of the Australian Lungfish is not clear: in areas where it occurs naturally, the species has an inherently low genetic variation, and, as only limited numbers of individuals from one natural site were used to found the translocated populations, the translocated populations are likely to have particularly limited genetic variation. Therefore, only the natural populations are likely to possess the full evolutionary potential of the species.

Australian Lungfish are slow-growing, with age of first breeding estimated to be 15 years for males and 20 years for females. Adults have a high survival rate and are long-lived, with a claim that they possibly live to 60-100 years of age. Large adults have been found to be relatively common in various localities at the present time, and may continue to be so for many years. There is no data on decline in adult numbers, and it is suspected that recruitment into the adult population is inherently low. Juveniles are harder to observe and locate than adults, and little is known of their ecology.

Current research shows that there is little evidence of juveniles or young fish recruiting into the Burnett River populations, particularly in impoundments: Data on population structure has been collected by the Queensland Department of Primary Industries over the last 6 years in the Burnett River. By 2000-2001, 2770 Australian Lungfish had been sampled, and the length-frequency analysis shows levels of recruitment to the adult population for at least the last five years that are lower than had been previously experienced. There is also an earlier distinct break in recruitment in the adult population based on length analysis, indicating a long period in the recent past where few fish were successfully recruited into the adult population. It is not clear if the current period of low recruitment is part of natural cycle or the result of past threats beginning to impact on the adult population. Some experts are expressing concern that an unsustainably low, or total absence of, recruitment of juveniles to the adult population could easily be overlooked for many years with disastrous consequences for long-term survival of the species.

Studies have shown that there has been a marked decline in the quality and extent of breeding habitat of the Australian Lungfish because of impoundments. While impoundments provide feeding habitat for the species, conditions suitable for successful spawning rarely occur within them, as the species has highly specific requirements for spawning. Generally, spawning habitat is characterised by relatively shallow water and dense macrophyte (aquatic plants) coverage. Impoundments tend to be steep-sided with deep water and fluctuating water-levels, conditions that are not suitable for the dense growth of macrophytes. In addition, impoundments do not provide suitable nursery habitat for the species as the young also require a cover of macrophytes.

There are also claims that the Australian Lungfish is potentially threatened by exotic and translocated native fishes (in particular the exotic Tilapia Oreochromis mossambica) that have been introduced to the river systems, and that are likely to be predating on eggs and young and competing with adults for breeding habitat. These introduced fishes may also contribute to future declines in the number of breeding adults.

In summary, there have been losses or reduction in quality of the breeding and nursery habitat of the Australian Lungfish of 26% within its core habitat, the main channels of the Burnett and Mary Rivers. At a result of this, it has been suggested that the adult breeding population may undergo a substantial decline over the next three generations. In addition to this, the breeding and nursery habitat will continue to be threatened by further water infrastructure development in these highly populated areas. The impact of introduced fishes into the river systems is not known, but it is suspected that it will result in a further population reduction. On the basis of the losses and threats, there is sufficient evidence to suspect that the adult breeding population will undergo a substantial decline over the next three generations.

Therefore, the species is eligible for listing as vulnerable under this criterion.

Criterion 2 - Geographic distribution

The Australian Lungfish is restricted to south-eastern Queensland, with its natural distribution being the Mary, Burnett and, possibly, Brisbane and North Pine Rivers. It was translocated to a number of sites in the late 1800s.

There have not been any recent surveys to ascertain whether the introductions into the Coomera and Condamine Rivers were successful. Recent sampling at several sites on the Albert River did not record this species Although the Australian Lungfish has been recorded as breeding at Enoggera Reservoir in the past, recent records suggest that the species is no longer breeding at this location.

One viewpoint is that the current natural distribution of the Australian Lungfish is the Mary and Burnett River systems with translocated populations surviving in the Brisbane and North Pine Rivers and Enoggera Reservoir. The corresponding area of occupancy is estimated at less than 2000 km². The exact number of locations where it occurs within this distribution is uncertain, but it is less than ten. It can be considered to occur at five locations, where each river system represents a location; or at nine locations, three being on the Burnett River, where each river system represents a location but, where barriers to movement exist, each section of the system is considered to be a location. It has been suggested that the very low genetic variation of the three translocated locations may be of little conservation value to the future of this species (see comments in Criterion 1). At Enoggera Reservoir, with the removal of plants which are required for successful breeding, the Australian Lungfish are likely to be no longer breeding.

A continued decline in quality and extent of spawning and nursery habitat is likely as further water infrastructure development occurs in this highly populated area of Queensland. In the past, there has been a marked decline in the area of suitable breeding habitat available to the species. Within the stronghold of its natural distribution, the main channels of the Burnett and Mary Rivers, the data indicates that, as a result of impoundments, there has been a loss or reduction in the quality of spawning and nursery habitat of 26%, with a further 13%, and likely more, to be lost if proposed water impoundments go ahead.

Therefore, the species is eligible for listing as vulnerable under this criterion.

Criterion 3 - Population size and decline in numbers or distribution

The total population number of Australian Lungfish is unknown at this time though is likely to be more than 10 000 mature individuals. There is no data on decline in adult numbers,

Therefore, the species is not eligible for listing under this criterion.

Criterion 4 - Population size

The total population number of the Australian Lungfish is unknown at this time, though it is larger than 1,000 mature individuals.

Therefore, the species not eligible for listing under this criterion.

Criterion 5 - Probability of extinction in the wild

Quantitative data for the Australian Lungfish is not available against this criterion.

Therefore, the species is not eligible for listing under this criterion.

4. Conclusion

The natural distribution of the Australian Lungfish appears to be restricted to the Burnett, Mary, and possibly Brisbane and North Pine, River systems of south-eastern Queensland. The Australian Lungfish was translocated to a number of sites in the late 1800s.

There have not been any recent surveys to ascertain whether the introductions into the Coomera and Condamine Rivers were successful. Recent sampling at several sites on the Albert River did not record this species. The species is present at the Brisbane and North Pine Rivers and at the Enoggera Reservoir. Although the Australian Lungfish has been recorded as breeding at Enoggera Reservoir in the past, recent records suggest that the species is no longer breeding at this location.

The conservation value of translocated populations is uncertain, both as self-replacing populations and on the basis of limited genetic diversity. Currently, it occurs at less than ten locations with an estimated area of occupancy of less than 2000 km².

The river systems where the Australian Lungfish occurs are subject to much disturbance, particularly by the construction of dams and weirs. Impoundments presently inundate about 26% of the river systems that are considered to be its core natural distribution, with a further 13%, and possibly more, under threat from the proposed construction. Data indicates that this represents a substantial loss of suitable breeding and nursery habitat. The species is also potentially threatened by introduced fishes. As Australian Lungfish are slow-growing and long-lived, fluctuations in the adult population are expected to occur slowly. As a result of past changes to its core habitat, it is suspected that the recruitment to the adult breeding population has been, and is still, unsustainably low, and that the species is likely to undergo a substantial population reduction over the next three generations.

Although there is some uncertainty in data pertaining to the Australian Lungfish, it is rarely possible to have access to data on native species that is complete. It is, however, common practice to use both anecdotal and historical data to assist in the determination of long-term population trends. Limitations are acknowledged, and the data has been used cautiously.

The species is eligible for listing as vulnerable under criteria 1 and 2.

5. Recommendation

TSSC recommends that the list referred to in section 178 of the EPBC Act be amended by
including in the list in the vulnerable category:

Neoceratodus forsteri (Australian Lungfish, Queensland Lungfish)