Science for Policy Research findings in brief Project 2.1

Big trouble for little : Identifying Australian freshwater at imminent risk of extinction

In brief

In , many freshwater fish described in the past decade, and (The Environment Protection and species have declined sharply since seven are awaiting description. Biodiversity Conservation Act 1999 the 1950s. Preventing extinctions Twenty-one of the species identified (EPBC Act)). Listing of the other will require identifying the species are small-bodied, with the majority 19 species would provide essential most at risk. occurring in southern Australia, a protection and recognition for the remaining individuals of these We used structured expert elicitation region where introduced predatory species and their critical habitat. and other available published and trout species have taken a heavy unpublished data to identify the toll, especially on native galaxiids. The fate of all 22 species will depend freshwater fishes at greatest risk Although the majority of these species upon individual targeted action, of extinction, and to estimate were once far more widespread, all 22 investment and collaboration among the likelihood of extinction within fishes now have small distributions with governments and non-government ~20 years if there is no change areas of occupancy ranging between organisations to mitigate threats to current management. 4 – 44 km2; this greatly increases the and support recovery. We identified 22 species at high risk of risk that single catastrophic events, such The assessments were undertaken extinction (from ~315 species known as a large bushfire, could cause species prior to the 2019–20 Black Summer to occur in Australia), 20 of which had extinctions. Climate change is another bushfires, which impacted many of at least a 50% probability of becoming threat to all of the identified species. the species that were identified as extinct within ~20 years under current Only three of the species identified highly imperilled in our assessment. management. Twelve of the species are currently listed nationally as Some species may now be on the identified have only been formally threatened under Australian legislation brink of imminent extinction.

Further Information Mark Lintermans – [email protected] Hayley Geyle – [email protected] The main threat to the Daintree rainbowfish is loss of flow due to , climate change and water extraction. Image: M. Hammer, MAGNT The stocky is one of 14 species of galaxias identified as at high risk of extinction. by introduced trout is a major threat to these small-bodied native species. Image: Tarmo Raadik

Background Research aims The Australian Government has For Australian freshwater fishes we 4. Identify what policy, resourcing, committed to averting extinctions, aimed to: management and prioritisation are and this first requires identification required to prevent extinctions. 1. Identify the species at most of the species at most immediate immediate risk of extinction; The findings of this research will be of risk. This can forewarn governments, greatest importance to policy-makers conservation managers and the 2. Estimate the probability of extinction in state and federal government community so that they can (in the wild) in the next ~20 years agencies and funding bodies, as well implement emergency care for each of the species identified; as conservation land managers and and recovery actions to prevent 3. Identify key threats to these species researchers looking to prioritise and extinctions before it is too late. and our progress towards lessening apply research and management Freshwater fishes (and their habitats) their impacts; and actions for threatened freshwater fishes. are declining at alarming rates in many parts of the world, including in Australia, where the populations What we did of many species have fallen sharply Our assessment of extinction risk a workshop in early 2018, where we since the 1950s. The declines of Australian freshwater fishes used used structured expert elicitation to have been attributed to habitat available published and unpublished estimate the extinction probabilities for loss, , alteration evidence, and was undertaken using a the final list of 22 species considered to natural flow regimes, habitat structured expert elicitation approach. to be at high risk of extinction. We fragmentation, water pollution performed statistical modelling of An initial list of 90 freshwater fishes at and overexploitation. the expert estimates to predict the high risk of extinction within ~20 years probability of extinction for each Despite evidence of catastrophic was produced by the ASFB Threatened species, finding that there was a high declines, freshwater fishes have Fishes Committee based on expert level of agreement among the experts typically been neglected in review by committee members and in their assessments of extinction risk conservation planning. Compared external experts. Further assessment for most species. We also assessed the to other vertebrate groups, there are reduced this to a shortlist of 37 timing (continuing, near future, distant currently few species listed under species. Included in this assessment future), extent (proportion of the range national environmental legislation were: 1) species that were assessed likely to be impacted) and severity (EPBC Act). Application of IUCN by the ASFB as meeting IUCN criteria (the proportion of the population likely criteria by the Australian Society for listing in a threatened category to be impacted) of threats, assessed for Fish Biology (ASFB) indicates (Critically Endangered, Endangered the level of current understanding that many more freshwater fish or Vulnerable); and 2) additional on how to manage each threat, species qualify for statutory listing. species that have only recently been and the effectiveness of current Without listing, at-risk species are recognised and currently undescribed, management actions. not afforded basic protection. but likely to meet threatened criteria. A final list of 22 species were Further, recent taxonomic work This waterfall in New South Wales is all that has shown that there are many considered to be at risk of extinction protects the upstream population of stocky undescribed species that are likely within ~20 years. For each of these galaxias from the invasive trout below. to meet criteria for listing as species, the ASFB identified the major Image: Mark Lintermans threatened, and in many cases in threats; historical, recent and predicted higher categories, e.g., Critically population trajectories; initial estimates Endangered. Only one fish species, of extinction risk; biology; habitat the , is officially requirements; population parameters; recorded as extinct in the wild and geographic range. in Australia (with another now Our research team included 15 considered extinct before it was researchers and freshwater fish described), although we have almost biologists from 10 Australian certainly lost other species before universities, state-based research we even knew about their existence. institutions (such as the Arthur Rylah Institute), and Bush Heritage Australia. Each of these experts participated in The little pygmy perch in the far south-west corner of Western Australia is one of only three of the imperilled species that is formally protected under the EPBC Act. Image: Stephen Beatty, Harry Butler Institute, Murdoch University

Table 1. The 22 Australian freshwater fish species at greatest risk of extinction; their likelihood of extinction within ~20 years; if they have been formally described; and their conservation listings under the EPBC Act (as at August 2019) and the Australian Society for Fish Biology (as assessed using IUCN criteria).

Species Region Area of Likelihood of Year described EPBC Status ASFB Status occupation extinction (%) (km2) Shaw galaxias Critically Vic 4 ≥70 2014 Not Listed Galaxias gunaikurnai Endangered West Gippsland galaxias Critically Vic 12–16 ≥70 2014 Not Listed Galaxias longifundus Endangered Tapered galaxias Critically Vic 16 ≥70 2014 Not Listed Galaxias lanceolatus Endangered Dargo galaxias Critically Vic 16 ≥70 2016 Not Listed Galaxias mungadhan Endangered Morwell galaxias Vic 20 ≥70 Undescribed Not Listed Not Assessed Galaxias sp. McDowall’s galaxias Critically Vic 8–28 ≥70 2014 Not Listed Galaxias mcdowalli Endangered Malanda rainbowfish Critically Qld 28 ≥70 Undescribed Not Listed Melanotaenia sp. Endangered Stocky galaxias Critically NSW 4 50–69 2014 Not Listed Galaxias tantangara Endangered Red-fin blue-eye Critically Scaturiginichthys Qld 4 50–69 1991 Endangered Endangered vermeilipinnis Kosciuszko galaxias Critically NSW 8 50–69 2014 Not Listed Galaxias supremus Endangered Yalmy galaxias Vic 36 50–69 Undescribed Not Listed Not Assessed Galaxias sp. East Gippsland galaxias Critically Vic 12 50–69 2014 Not Listed Galaxias aequipinnis Endangered Hunter galaxias NSW 44 50–69 Undescribed Not Listed Not Assessed Galaxias sp. Moroka galaxias Vic 4 50–69 Undescribed Not Listed Not Assessed Galaxias sp. Barrow cave gudgeon WA 8 50–69 2013 Not Listed Not Assessed Milyeringa justitia Swan galaxias Critically Tas 15 50–69 1978 Endangered Endangered Short-tail galaxias Critically NSW 16 50–69 2014 Not Listed Galaxias brevissimus Endangered Running rainbowfish Critically Qld 16 50–69 Undescribed Not Listed Melanotaenia sp. Endangered SW Victoria river blackfish Vic 28 50–69 Undescribed Not Listed Not Assessed Gadopsis sp. Daintree rainbowfish Qld 12 50–69 2018 Not Listed Not Assessed Cairnsichthys bitaeniatus Little pygmy perch Critically WA 40 40–49 2013 Endangered Nannoperca pygmaea Endangered Bloomfield River cod Qld 12 40–49 2001 Not Listed Vulnerable Guyu wujalwujalensis Key findings The research identified 20 Australian The results suggest that the total drivers for protection and recovery freshwater fishes that have at least a number of future extinctions may actions are largely absent. Seven 50% probability of becoming extinct be significantly higher than historic are not yet formally described. within the next ~20 years if there is no extinction rates of Australian Fourteen of the fish are galaxiids change in current management (see freshwater fishes. (), three are rainbowfishes Table 1). A further two species had a The 22 species are widely scattered (Melanotaeniidae), and three are 40-49% likelihood. The Shaw galaxias across Australia, although the majority temperate basses (Percichthidae). (Galaxias gunaikurnai) and the West are located in southern Australia All but one, (the southwest Victoria Gippsland galaxias (G. longifundus), (see Figure 1). river blackfish, body length of both from Victoria, had the highest approximately 150–240mm) are small- estimated extinction risks, each with Nineteen of the 22 species we bodied, with an adult total length a likelihood greater than 70%. considered are not listed as threatened of less than approximately 150mm. under national legislation, so legislative

Figure 1. The approximate locations of each of Australia’s 22 most imperilled freshwater fishes.

BELOW: The narrow range endemic Running River rainbowfish (top) pictured with introduced eastern rainbowfish (lower), a native Australian species translocated outside its natural range. Image: M. Hammer, MAGNT

The SW Victoria River blackfish is a recently identified, undescribed new species. It persists as three very small, isolated populations. The main threat to this species is recreational angling. Image: Tarmo Raadik The Malanda rainbowfish is at risk from hybridisation with the larger and more common eastern rainbowfish. Image: Michael Hammer, MAGNT

The threats facing the most imperilled carefully considered translocations of are the result of severe range freshwater fishes are presented in galaxiids to establish new populations contractions due to threats such Table 2. are key to ensuring their long-term as introduced species (including survival. However, urgent sustained native species moved outside of More than half of the species on effort is needed to improve trout their natural range). the list are galaxiids. Galaxiids have management, including collaborations been severely impacted by trout, While other threats have pushed with recreational anglers, increased predatory species which were these species to their currently awareness, and changing values introduced for recreational fishing perilous states, the biggest factor among government and key sectors (which continue to be stocked). that is now contributing to their of society. Other threats to galaxiids Many galaxiids do not thrive or likelihood of extinction is having small include inappropriate fire regimes and readily breed in captivity, so their geographically isolated populations, other climate-related threats. persistence relies on the availability which makes remaining populations of perennial trout-free . Each of the fishes identified are highly vulnerable to further threats. extremely range-restricted, occupying For example, ash flows following a There has been some progress areas ranging between 4 and 44km2 large fire, trout reaching a section towards managing the threat of each. With the exception of the of stream during high flows, or trout, but our assessment indicates Barrow cave gudgeon, Running River headwater streams drying out that the status quo management rainbowfish and Bloomfield River during a drought could result in of trout will result in extinctions of cod (which appear naturally range the total extinction of a species. native galaxiids. Installing trout barriers restricted), these small distributions where possible, and performing

Table 2. The threats facing the most imperilled Australian freshwater fishes, the number of species affected by each threat, and the threat impact score (a measure of the overall impact (considering timing, extent and severity) of a threat across all species relative to other threats).

Rank Threat No. of Threat species impact affected score

1 Small, single or few isolated populations (increased vulnerability to other threats) 21 100

2 Increase in drought frequency, intensity (reduced water quality and availability of suitable habitat) 19 79

3 Increase in storm, flooding frequency, intensity (erosion impacts) 18 81

4 Increase in fire frequency, intensity (post-fire debris flow/toxic retardants) 17 76

5 Trout predation 15 71

6 Soil erosion, sedimentation (habitat and water quality deterioration) 12 58

7 Feral pig (habitat degradation) 3 3

8 Eastern gambusia (competition/predation) 3 14

9 Tilapia (competition/predation) 3 13

10 Native eastern rainbowfish (displacement/hybridisation) 2 10

11 Translocated native sooty grunter (competition/predation) 2 9

12 Temperature extremes 2 7

13 Secondary salinisation (water quality) 1 4

14 Deliberate disposal of industrial effluents (water quality) 1 1

These predictions for extinction risk were generally higher than those for Australian birds and mammals using the same methods. Most of the fishes we considered have far smaller distributions, and have received far less management investment and conservation effort than the birds and mammals assessed to be at high risk of imminent extinction. Acknowledgements

This research was also supported by the National Environmental Science Program’s Northern Australia Environmental Resources Hub, and specifically Project 3.3 “Prioritising threatened species in northern Australia”.

Shaw galaxias Implications and recommendations The Shaw galaxias (Galaxias Our assessments of extinction formally listed as threatened under gunaikurnai) is the Australian fish probability preceded the 2019–20 the EPBC Act, and even before at greatest risk of extinction, with wildfires, which are likely to have they are formally described. a greater than 70% likelihood of severely worsened the conservation 2. The highly imperilled but currently extinction within ~20 years without outlook for many of the species unlisted taxa should be formally additional conservation action. considered in our study, but also listed as threatened under relevant Surveys have estimated that there are many others that were not included. state and federal legislation in only 80 mature individuals remaining In the case of one of the species order to afford protection to 2 in an area of only 4km . The species we considered, the undescribed remaining individuals and their has been lost from most of its former “Yalmy” galaxias, an extensive post- critical habitat. range due to predation by introduced fire assessment has confirmed one 3. There is an urgent need to develop trout species; it currently persists as male and one female to be alive in a national freshwater fish action a single population upstream of a separate locations. While there is plan to coordinate recovery waterfall with trout below. Artificial an intention to reunite them as efforts. Further, any update to barriers restrict movement of trout soon as possible, the species is the Threatened Species Strategy into the stream, but the risk of now on the brink of extinction. should include freshwater fishes. reinvasion is high – mechanisms We predict that most of the Australian If the strategy is not updated, the for potential invasion include illegal freshwater fishes considered have a need for an action plan becomes transportation by anglers and drown- high probability (50% or greater) of even more important. out of trout barriers during high becoming extinct in the next two flows. Other threats include drought 4. Completion of the national decades. Only immediate, individual (leading to loss of water in majority of Freshwater Pest Fish Strategy and targeted action, investment and the catchment, reducing habitat and adoption as a Threat Abatement collaboration to mitigate threats water quality), (mobilising large Plan will be a crucial and effective and to support recovery of each quantities of in-channel sediment) and step in managing this major threat of these species will prevent this fire (post-fire debris flow during high to Australian freshwater fishes. from happening. intensity rainfall) and fire suppression 5. Climate change was another major impacts (toxic retardants). Specific recommendations include: threat affecting all 22 species. 1. Threat mitigation and recovery A national framework and funding Victoria’s Shaw galaxias is one of 14 species actions for many species should to address climate-related threats of galaxias identified as at high risk of is also urgently required. extinction. Predation by introduced trout is commence before they are a major threat to these small-bodied native species. Photo: Tarmo Raadik

More information Lintermans, M., Geyle, H.M., Beatty, S., Brown, C., Ebner, B., Freeman, R., Hammer, M.P., Humphreys, W.F., Kennard, M.J., Kern, P., Martin, K., Morgan, D., Raadik, T.A., Unmack, P.J., Wager, R., Woinarski, J.C.Z., and Garnett, S.T. (2020). Big trouble for little fish: Identifying Australian freshwater fishes in imminent risk of extinction. Pacific Conservation Biology. https://doi.org/10.1071/PC19053

Further Information Mark Lintermans – [email protected] Hayley Geyle – [email protected]

This project is supported through funding from the Australian Government’s National Environmental Science Program.