Acknowledgements V Summary VI 1 General introduction 1 1 Barred Galaxias 1




НазваниеAcknowledgements V Summary VI 1 General introduction 1 1 Barred Galaxias 1
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1.4 Report structure


This report is organised into a summary, a general introduction chapter (this chapter), followed by three research chapters.

The summary provides a brief overview of the project, research methods, key outcomes, and management recommendations. Chapter 2 presents research on identifying potential Barred Galaxias translocation sites and assessing their suitability. Chapter 3 describes the trial translocations of two Barred Galaxias populations and Chapter 4 investigates the genetic diversity of Barred Galaxias populations across the species’ range. These research chapters are intended to be published as articles in leading scientific journals because they have broader scientific value and management applicability.

Guidelines for the translocation of Barred Galaxias for conservation purposes are provided in a separate publication in this series (Ayres et al. 2012). Briefly, they describe the methodology for translocating Barred Galaxias from a wild source population to a release site in public waters, with translocations subject to compliance with Victorian and Commonwealth policies and protocols, and are intended to guide development of translocation plans for specific Barred Galaxias translocation events. General principles regarding preparation and pre-planning for translocation, implementing the translocation and post-release monitoring are discussed.


2 Identifying suitable translocation sites for the reintroduction of Barred Galaxias

2.1 Introduction


An important aspect to facilitate a successful translocation is releasing individuals into a suitable location. It is important that release sites have appropriate habitat available to support the survival and establishment of translocated individuals into the foreseeable future and threats to the species are eliminated or mitigated.

Identifying suitable translocation sites for Barred Galaxias is urgently required to enable reintroduction and establishment of new populations within the species native range to aid recovery and reduce the overall extinction risk of impacted populations. Currently, the majority of sampled reaches in upland streams within the natural range of Barred Galaxias contain predatory trout (Figure 2) and are therefore unsuitable as translocation sites, though the suitability of unsampled reaches or streams is unknown. Having a readily available list of suitable Barred Galaxias translocation sites will benefit planning of future translocation events, particularly if urgent translocations are required.

This chapter presents research behind identifying and assessing potential translocation sites for two trial reintroductions of Barred Galaxias.

The specific objectives were to:

1. Identify and assess numerous upland and remote catchments to develop a list of potentially suitable translocation sites

2. Prioritise identified catchments with respect to their suitability against defined site criteria

3. Choose two suitable catchments to conduct immediate trial translocations, and

4. Identify potential sites that require further management actions before acceptance as suitable for Barred Galaxias translocations.

2.2 Methods


In Victoria, the translocation of live aquatic organisms into and within inland waters requires approval under the Fisheries Act 1995. As part of this process, the ‘Protocols for the translocation of fish in Victorian inland public waters’ (Department of Primary Industries 2005) provides guidance regarding the identification and assessment of potential translocation sites.

The following general criteria were considered when identifying and assessing the suitability of potential Barred Galaxias translocation sites:

• Confined to public waters;

• The waters are within the known former range of the species (> 400 m altitude, in the upper Goulburn River catchment, Victoria, Australia);

• Fish will not be translocated into waters for conservation purposes where they will be exposed to previous causes of decline;

• No fish, including resident populations of Barred Galaxias, will be present. This will eliminate predation, competition, disease spread, hybridisation and possible reductions in genetic integrity and diversity;

• Sites will have an effective instream physical barrier, hereon referred to as a barrier, present downstream to prevent upstream movement of other fish species into the site. Effective barriers:

– Consist of a solid, long-lasting material such as rock;

– Are vertical or near vertical with a height of 2.0 m or greater;

– Are within a V-shaped valley so that higher flows remain directed to the centre of the channel (to minimise likelihood of fish moving upstream across recently inundated land along the stream bank); and,

– Do not have a pool immediately below of significant depth or size which could aid fish in jumping over the barrier.

• Availability of suitable habitat to sustain Barred Galaxias into the foreseeable future. The waters should have sufficient capacity to sustain survival and growth of the translocated population (e.g. > km2 in catchment area) and support a viable population in the long term. The catchment should have high water security and minimal or no disturbance from, for example, bushfire, drought, or timber harvesting activities;

• The translocation will not pose an unacceptable risk to another threatened species or community (e.g. listed under FFG Act or EPBC Act); and,

• The release site should, in part, be selected based on remoteness or human inaccessibility to reduce the likelihood of adverse anthropogenic effects, e.g. human introduction of predator species.

2.2.1 Study area


The study area was confined to public waters of the Goulburn River catchment above 400 m altitude, within the suspected former range of Barred Galaxias (Raadik et al. 2011). In particular, the upper catchments of the following systems were targeted for sampling: Sunday Creek; Yea River; Acheron/Taggerty River system; Rubicon River, and Big River. Greater priority was given to the Big River catchment as the aquatic fauna of its headwater reaches was considered less surveyed than the other catchments, was less impacted by the 2009 bushfires and consequently was considered to have a higher probability of harbouring suitable translocation sites. It was also in an area with higher streamflow (i.e. from snowmelt) and therefore may provide greater water security.

The Goulburn River catchment is part of the Murray-Darling Basin, covering an area of approximately 16 192 km2 in north-central Victoria, Australia. The Goulburn River begins in the mountainous Great Dividing Range near Woods Point (1325 m altitude) flowing north-west to its confluence with the Murray River near Echuca (100 m altitude). Land use in the headwaters of the catchment varies from national park, state forest, forestry, agriculture, recreation and rural living. The main forms of disturbance are bushfire, drought and forestry practices.

Other than Barred Galaxias, Mountain Galaxias (Galaxias olidus) is the only native fish species likely to be found in the very upper reaches of the catchment. Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss), which are a key threat to Barred Galaxias (Raadik et al. 2011), may also inhabit these small headwater streams.

2.2.2 Selection of survey sites


Preferably, Barred Galaxias translocation sites would be located in streams above 400 m altitude, relatively remote from human access, have no fish species present, be within larger catchments (>1 km2), and be upstream of a natural barrier, such as a waterfall (see 2.2 above), to provide a contained area free from the incursion of predators (i.e. trout). Sites identified as meeting these criteria required field assessment to verify their suitability as translocation sites.

Figure 2. Distribution of Barred Galaxias, Mountain Galaxias and trout within the study area. (Data source: Victorian Biodiversity Atlas).

Initially, high resolution aerial images and topographic maps covering the study area were examined to locate known waterfalls or potential instream barriers. Also regional DSE staff were queried about the location of known barriers. Additional potential sites, which met the majority of the above criteria, were selected from topographic maps, with emphasis given to sites located upstream of steep gradients which possibly indicated the presence of waterfalls, particularly those on streams which flowed across a high elevation plateau before plummeting down a steep valley. Site selection was further refined by overlaying fish distribution data (Figure 2) and rejecting sites which contained fish.

2.2.3 Assessment of translocation site suitability


Sites provisionally identified above were further assessed for suitability by onground inspection. The rationale for assessment is summarised in Figure 3 and is based on the general criteria noted at the beginning of the methods section, and involved a detailed inspection of catchment condition, streamflow, aquatic fauna and presence and structure of instream barriers. Sites were assessed as either suitable and short-listed as translocation sites, or unsuitable according to the selection criteria, and rejected.

Fish assessment


Fish surveys were conducted at potential translocation sites using a portable backpack electrofishing unit (Figure 4) with the aim to confidently verify the presence or absence of fish species in the small headwater streams. The operator fished all accessible habitats in an upstream direction, followed by an assistant to collect stunned fish. The stream distance surveyed varied from 1–150 m depending on whether fish were found (i.e. fishing ceased once fish were recorded), site conditions, and operator judgement. A 100 m reach was sampled if no fish were collected, though a minimum of 25 m was surveyed at sites with very low streamflow and lack of suitable habitat (e.g. pools, undercut banks, etc.).

Figure 3. Decision support framework for assessing the suitability of potential Barred Galaxias translocation sites.


Figure 4. Electrofishing the upper Goulburn River (left) and a Rainbow Trout found in Spring Creek (site FT025) (right)
(Images: left – Renae Ayres, right – Michael Nicol)


All fish captured were identified and, at the majority of sites, measured for length (length to caudal fork (LCF) (mm)), weighed (g) and examined for condition (presence of parasites, lesions, body colour, fin damage etc.) prior to release. The following water quality parameters were also recorded at most sites prior to fish surveys using a field-laboratory analyser (TPS 90-FLT: TPS, Brisbane, Australia): dissolved oxygen (mg/L); temperature (º C); pH; turbidity (NTU); and, electrical conductivity (µS/cm) (Appendix 1).

Physical barrier assessment


Known barriers were inspected on the ground to reconfirm their locality and to assess their physical structure for suitability in preventing the upstream movement of trout.
At all other potential translocation sites where the presence of a downstream barrier was uncertain, surveys for potential barriers were undertaken during and following fish assessments and the rationale is summarised in Figure 5. If trout were found during fish assessments it was assumed that an effective barrier was absent downstream.


Figure 5. Decision support framework for assessing the presence of instream barriers.


Selection of two trial translocation catchments


Following site assessments and the identification of a number of suitable translocation sites, two sites were provisionally selected for use in the trial translocation component of this study (see Chapter 3). Before final acceptance of suitability, these sites were resurveyed for fish to ensure the absence of trout and the presence of suitable conditions and habitat for Barred Galaxias.
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