Progress of the Mixophyes balbus program
at Melbourne Zoo

NB: Program has finished

Program Finished:



Ex situ research completed


Mixophyes balbus

Common Name(s)

Stuttering Frog

Region where program is based


Country where program is based


The authority that recommended this species for an ex situ program

Department of Sustainability, Environment, Water, Populations and Communities

Has a genetic analysis been performed on wild populations to define the target taxon, i.e., verify that single, viable Evolutionarily Significant Units (ESU's) that are managed as separate populations, are not confounded by cryptic species or polymorphisms?


Name of the institution managing the ex situ population

Melbourne Zoo

Year the program started


Is at least some portion of the captive population maintained in range country?


Are sufficient resources available to manage the ex situ population?


Are adequate numbers of skilled staff available with the appropriate ex situ amphibian experience?


Is sufficient space available for the required population size?


Additional Support required

Has a Taxon Management Coordinator for the ex situ population been appointed?


Taxon Management Coordinator

Chris Banks of Melbourne Zoo

Has a Taxon Management Group or Recovery Team been established?


Has a Taxon Management Plan, Recovery Plan or Species Action Statement been written?


Have Husbandry Guidelines been written?

In preparation

Web link to Husbandry Management Guidelines

Have any knowledge gaps in the species biology or in their interaction with potential threats been identified that could benefit from research using the ex situ population?


List of knowledge gaps

The critical knowledge gap is genetic status of the two suggested clades/lineages _ clarifying this will define needs to conserve the å«specieså. Current status of the å«entire taxon/specieså in the wild is unknown, although declines are most likely continuing _ lack of resourcing is the major barrier in NSW to addressing this (also in Victoria, although the species only ever occurred in Victoriaås far east).

Have founder needs been calculated using the AArk Amphibian Population Management Guidelines ?


Have sufficient potential founders been collected? ( AArk Amphibian Population Management Guidelines recommends a minimum of 20 pairs of found animals).


If sufficient founders have not been collected, is there an ongoing search for additional founders?


Is the ex situ population managed by nationals from the range country?


What tools are used to maximize retention of genetic diversity?


Has the population produced viable offspring?


Have the first generation captive-bred animals bred successfully?


Is the ex situ population housed in permanent isolation from other populations occurring outside its range?


Is work being supported to study and mitigate threats to the species in the wild, either by the institution or by a regional wildlife agency?


Have captive-bred or captive-reared animals been released into the wild?


If releases were undertaken, have disease screening protocols or veterinary health checks been conducted prior to releases to the wild?

Is follow-up work being carried out to monitor progress of the released animals?

Is the taxon again secure in the wild, even if it might still require some ongoing in situ management? i.e. has the need for a captive assurance population been obviated such that we can call this a successfully terminated captive rescue program?


Genetic analysis of samples from across the species range has identified two distinct lineages, suggested to be at species level. This has not been published, but the research report recommends managing the two linages separately until this has been resolved. That recommendation has since been included in the National Recovery Plan published in 2011. Southern clade is represented in captivity by six adult frogs at Melbourne Zoo that were collected as tadpoles (most likely from the same spawning) in 2010. Southern clade frogs at MZ have bred, but are all closely related. All northern clade frogs were transferred from MZ to the Amphibian Research Centre in 2012. Melbourne Zoo only holds southern clade frogs now. Zoos Victoria, as the only institution currently holding these frogs, is liaising with researchers in NSW and South Australia to clarify status of any subsequent genetic work and resourcing constraints in order to determine the most effective course of action to support this species conservation.
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