Download Refining dwarf galaxias (Galaxiella pusilla)

Refining dwarf galaxias (Galaxiella pusilla) habitat in
the Upper Barwon River catchment`
A report for the Corangamite Catchment Management Authority
Prepared by:
Environous
42b Fenton Way, Hillarys, WA, 6025
Telephone: (08) 6201 0808
Email: [email protected]
Produced for:
Corangamite Catchment Management Authority
64 Denis Street, Colac, Victoria, 3250
This publication may be cited as:
Ryan, T., Saddlier, S. and Scarborough, T. (2013) Refining dwarf galaxias Galaxiella pusilla
habitat in the Upper Barwon River catchment. Report for the Corangamite Catchment
Management Authority.
Cover photographs: Clockwise from upper left: a) Site 1 (Callahans Ck offtake; b) dwarf galaxias with
caudal fin damage (Site 18); c) Site 19 - billabong on East Barwon River; d) mountain galaxias captured
from site 3; e) walking down onto the East Barwon River floodplain; f) southern pygmy perch captured at
site 5; g) dwarf galaxias captured from site 9; and h) dense vegetation at site 17,
This document was produced by e n v i r o n o u s Pty Ltd. for the Corangamite CMA and may only be used
for the purposes and in accordance with the Terms of the Engagement for which it was commissioned.
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
EXECUTIVE SUMMARY
The aim of this study was to investigate other potential dwarf galaxias wetland habitat in the
upper Barwon River catchment in an attempt to find additional populations. This process
was intended to improve the level of understanding required for the development of the
new Corangamite Waterway Strategy. It also provided a re-assessment of important sites
identified in previous processes such as a review of Significant Fish Species Protection
under Dry Inflow Conditions (Saddlier et. al. 2009) and HERO Significant Fish Project
(CCMA 2010).
Dwarf galaxias is considered to be a non-migratory species adapted to wetland
environments and is able to survive short periods with very little water (Saddlier et. al.
2009). In these habitats, it is typically found in marginal vegetation in still or slow moving
waters of roadside ditches, swamps and backwaters of creeks. It is considered
‘Vulnerable’ in Australia (EPBC Act 1999), ‘Vulnerable’ in Victoria (DSE 2009) and is listed
under the Victorian Flora and Fauna Guarantee Act 1988. As non-migratory species, the
protection of primary refuge wetland habitat for dwarf galaxias is the most important
management priority. This refuge habitat must provide shelter from high stream flows,
sustained water quality and suitable instream habitat to provide shelter, feeding and
spawning opportunities. Dispersion of these species from the refuge habitat is expected to
occur predominately in a downstream direction. Throughout this investigation, where
primary refuge habitat is identified, it is considered to have a higher management priority.
Identification of these important primary offstream refuge and spawning sites should be a
priority.
Prior to this study there was only one recognised population of dwarf galaxias within the
Upper Barwon River catchment in a wetland on Gosling Creek. An additional 20 wetlands
and stream sites were surveyed using basic fish surveys, water quality and habitat
assessments. Prioritisation of these sites were made according to a set of parameters,
including:
•
previously identified threatened fish populations;
•
newly determined dwarf galaxias populations;
•
presence/absence of eastern gambusia (Gambusia holbrooki);
•
presence/absence stock exclusion fencing;
•
relative quality of riparian and instream habitat;
•
security from disturbance;
•
security of water supply; and
•
connectivity to main watercourse.
An additional primary dwarf galaxias refuge wetland was identified on the southeast side of
the old railway bridge on the East Barwon River floodplain near Barwon Downs. It is
essential that a comprehensive maintenance plan be developed and includes stock
exclusion fencing, weed and pest protection, protection of existing water resources and
flow regime and re-vegetation of the riparian zone. It is also important to undertake ongoing water quality and non-destructive fish surveys to assess the sustainability of the
populations.
Other secondary populations of dwarf galaxias were identified at another wetland near the
old railway bridge (East Barwon) – NW (site 18) and the ‘excavated billabong’ (site 19).
Unfortunately, the high numbers of eastern gambusia found at these sites negated the
many positive aspects of these sites (such as water permanency, good habitat quality). It
should however, be recognised that due to the lack of offstream billabongs in the Upper
Barwon Catchment, these sites provide shelter for many fish species in times of high and
low stream flow, and should be maintained and enhanced as a matter of priority.
Another key conservation measure noted for dwarf galaxias is the translocation of fish into
a conservation wetland. Key criteria for conservation wetlands for dwarf galaxias is similar
Environous report for Corangamite Catchment Management Authority
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
to the above criteria but also considers the location of the site as a suitable demonstration /
educational site.
According to these criteria, the five potential conservation wetlands have been ranked in
order of suitability and management practicality. The higher ranked wetlands are not
impacted by eastern gambusia, and appear to have sufficient elevation and currently
support predatory native species capable of controlling an invasion of eastern gambusia.
They also appear to have sufficient water depth and water security and therefore require
less restoration, apart from stock exclusion fencing and riparian vegetation planting.
These sites include the Billabong on Mahers Road (Site 5) and the Bird Reserve on
Pennyroyal Valley Road (Site 11). Other potential conservation wetlands (Wetland on
Wendy James property - Site 3 and the Dry Conservation Reserve on Muroon Road - Site
16) would require excavation and further investigation into the water availability.
The wetlands at Pennyroyal Creek Cottages (Site 12) provided a range of potentially
suitable dwarf galaxias habitat, but were not considered suitable due the occurrence of
eastern gambusia,
Recommendations
1.
2.
3.
4.
5.
6.
7.
ii
Maintain and where possible without disturbance, enhance habitat at the Old
Railway Bridge (East Barwon) – SE (Site 17). (Actions to include permanent
fencing, erosion control on the East Barwon, and Glyceria control);
Continue encouragement of landholder participation in stock exclusion fencing of
the Gosling Creek wetland (Site 9);
Undertake regular water quality, habitat condition and fish composition
assessments at sites 17 and 9;
Investigate feasibility of developing conservation wetlands (sites 3, 5, 11, 16)
Undertake stock exclusion fencing and native planting at other floodplain wetlands
(including sites 18, 19);
Wetlands assessed in this investigation (sites 5,9,11,16,17,18,19) be adopted and
implemented into the Corangamite Waterway Strategy (2013 -2019) as key
conservation features of the upper Barwon Catchment and
Assess other floodplain wetlands in the Upper Barwon catchment based on the
criteria in this report.
Environous report for Corangamite Catchment Management Authority
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
TABLE OF CONTENTS
Introduction ....................................................................................................................... 1
Background ..................................................................................................................... 1
Methods ............................................................................................................................. 2
Site Selection ................................................................................................................... 2
Aquatic Fauna Surveys .................................................................................................... 4
Results ............................................................................................................................... 5
Sites 1 and 2: Callahan Creek offtake .............................................................................. 6
Site 3: Wetland at Wendy James ..................................................................................... 7
Site 4: Causeway at Wendy James.................................................................................. 8
Site 5: Billabong on Mahers Road .................................................................................... 9
Site 6 and 7: Dewing Creek Weir and Rowlands Road .................................................. 10
Site 8: Dewing Creek Weir Offtake................................................................................. 11
Site 9: Gosling Creek Wetland ....................................................................................... 12
Site 12: Pennyroyal Road Cottages ............................................................................... 15
Site 13: Pennyroyal Railway dam................................................................................... 16
Site 14: Barholm Road elongated dam........................................................................... 17
Site 15: Matthews Creek tributary - Middle Muroon Road .............................................. 17
Site 16: Dry conservation reserve – Muroon Road ......................................................... 18
Site 17: Old railway bridge (East Barwon) - SE ............................................................. 19
Site 19: Excavated billabong (East Barwon) .................................................................. 21
Site 20. Wetland behind Forrest football oval ................................................................. 22
Discussion ....................................................................................................................... 23
Primary refuge sites ....................................................................................................... 23
Gosling Creek Wetland............................................................................................... 24
Old railway bridge (Barwon Downs) – SE ................................................................... 24
Secondary refuge sites .................................................................................................. 25
Potential Conservation Wetlands ................................................................................... 26
Recommendations .......................................................................................................... 28
References ....................................................................................................................... 29
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Environous report for Corangamite Catchment Management Authority
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Introduction
The Corangamite Regional Catchment Strategy 2013-2019 (CCMA 2013) has been developed
to provide a vision for the integrated management of natural resources in the Corangamite
region. One of the key components of the strategy is the objective for threatened flora and
fauna: ‘To manage the threat of species extinction so that key populations are resilient and
secure in the longer term.’ This paper aims to build on the knowledge and develop management
recommendations regarding the threatened fish species dwarf galaxias (Galaxiella pusilla) and
Yarra pygmy perch (Nannoperca obscura) in the Upper Barwon Catchment. These species are
predominately wetland species and are dependent on refuge habitat during dry conditions.
In 2009 the Department of Sustainability and Environment (DSE) and the Corangamite
Catchment Management Authority (CCMA) conducted an extensive review of all sites within the
Corangamite catchment where threatened fish species had been found. Results of this review
were published in the report Significant Fish Species Protection under Dry Inflow Conditions
(Saddlier et. al. 2009). Through this process and following an expert panel workshop, a number
of management objectives were developed and a list of sites of higher priority was established.
The CCMA subsequently developed the HERO Significant Fish Project (CCMA 2010). This
Project has been divided into a monitoring plan, a long-term action plan for resilience works
(involving re-vegetation works and fencing of waterways), and an emergency response action
plan. The short-term emergency actions target non-migratory threatened fish species, dwarf
galaxias (Galaxiella pusilla) and Yarra pygmy perch (Nannoperca obscura).
Isolated populations of dwarf galaxias occurring in Gosling Creek and the upper East Barwon
River have been monitored regularly (Ryan 2011), however, in recent years this population has
been placed under constant pressure due primarily to unrestricted stock access, leading to a
significant reduction in the long term security of this population. The aim of this study was to
investigate other potential dwarf galaxias wetland habitat in the upper Barwon River catchment
in an attempt to find additional populations. This process was intended to improve the level of
understanding required for development of the new Corangamite Waterway Strategy.
Background
There are only two recognised populations of dwarf galaxias within the Corangamite region, one
located in the Upper Barwon River catchment at Gosling Creek and the other further
downstream of Barwon Downs in wetland margins of the East Barwon River.
Dwarf galaxias is considered to be a non-migratory species adapted to wetland environments
and is able to survive short periods with very little water (Saddlier et. al. 2009). In these habitats,
it is typically found in marginal vegetation in still or slow moving waters of roadside ditches,
swamps and backwaters of creeks.
This species is small (as the name suggests) and ranges in length from 20 to 40 mm in length,
is without scales, but has a distinct silvery-white belly. The males have three distinct longitudinal
black stripes along each side of the trunk, and a distinct orange stripe between the mid and
lowest black stripe. (Cadwallader & Backhouse 1983, McDowall 1980). It spawns in late winter–
spring when females lay from 65–250 adhesive eggs usually on the underside of aquatic
vegetation or on a hard surface such as a rock or timber which can be fertilised by a number of
males (Saddlier, Hammer and Jackson 2010).
Dwarf galaxias is endemic to south eastern Australia and occurs from the Mitchell River Basin in
central Gippsland, westward where it is found in a variety of systems throughout southern
Victoria, to the Cortina Lakes, near the Coorong in South Australia and in lowland regions of
north Tasmania (Saddlier, Hammer and Jackson 2010). Dwarf galaxias is considered
‘Vulnerable’ in Australia (EPBC Act 1999), ‘Vulnerable’ in Victoria (DSE 2009) and is listed
under the Victorian Flora and Fauna Guarantee Act 1988.
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Environous report for Corangamite Catchment Management Authority
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
The maintenance of instream habitat is crucial for the survival of this species. In accordance
with the draft action statement for dwarf galaxias, important management actions include stock
exclusion fencing, maintenance of aquatic macrophytes, and maintenance of suitable water
quality and water level (Saddlier, Hammer and Jackson 2010). A drought management strategy
is recognised by Saddlier et. al. (2009) as a high priority and is supported by the CCMA through
the HERO Project (CCMA 2010).
Methods
Site Selection
GIS databases and imagery (MapInfo and LIDAR) were used to map the Upper Barwon River
catchment in the vicinity of the Gosling Creek and Barwon Downs region to locate likely
wetlands for assessment. Wetlands within the floodplain of East Barwon River channel and
further upstream in tributaries of the system were selected as a priority for assessment. A full
list of wetlands selected for survey are included in Table 1.
Table 1: Priority Significant Species Survey sites
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15
13
11
14
10
16
12
9
19
7
6
18
8
17
4
3
5
1
20
2
Legend
Waterway – Blue
Upper Barwon Landscape zone –
Red
Survey Sites – Green Stars
Figure 1: Potential dwarf galaxias habitat inspected in this study
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
At the time of the surveys, significant rainfall had occurred resulting in flooding of the East
Barwon River and its tributaries and floodplain habitat. Consequently, Yarra pygmy perch sites
(generally more mainstream than Dwarf galaxias habitats) could not be investigated as planned.
As a result, greater emphasis was given to assessing the potential refuge habitat of dwarf
galaxias. Recent rainfall in this system was characterised by no rainfall from January through to
April, with only small events of up to 6 mm occurring from this time to mid-May. Greater rainfall
occurred in June with the largest event coinciding with the survey event where 31 mm was
recorded on June 12 and 13 (Figure 1). The resulting flow event in the East Barwon River and
tributaries provided the perfect opportunity to observe the interaction of offstream wetlands and
the main discharge channels.
Estimates of peak flow on June 13 were 223 ML/day at the East Barwon River Offtake and 1019
ML/day at the Callahan Creek Offtake (Victorian Water Resources Data Warehouse, 2013).
Figure 2: Rainfall at Gerangamete for January to June 2013.
Aquatic Fauna Surveys
Based on previous sampling capture rates for these species the predominant survey method
was actively sampling using fine mesh dip nets. Bait traps were also deployed overnight at site
17 to passively capture fish as the greater depth at this site precluded active sampling.
In-situ water quality was undertaken using a TPS 90FL multimeter to measure temperature,
electrical conductivity, pH, dissolved oxygen and turbidity.
Fish identifications were confirmed from appropriate references including Kuiter et al. (1996)
and McDowell and Frankenberg (1981).
All species caught were measured (to nearest mm). Fish lengths were measured and
calculated as Total Length (TL) for fish with rounded caudal, while Fork Lengths (FL) (measured
to the bottom of the forked tail) were measured and calculated for fish with forked tails.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Results
The complete set of fish survey data for each site is provided in detail in the Appendix and a
summary of results is provided in the following pages for each of the surveyed locations.
The aim of the summary pages for each of the following 20 sites is to outline a range of factors
for each site, including: the occurrence of previously identified threatened fish populations; the
occurrence of newly determined dwarf galaxias populations; presence/absence of eastern
gambusia (Gambusia holbrooki); whether stock exclusion fencing was present; the relative
quality of riparian and instream habitat; security from disturbance; security of water supply and
connectivity to main watercourse.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Sites 1 and 2: Callahan Creek offtake
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
X
X
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
High
Medium
Low
Very Low
X
X
X
X
Above the offtake, habitat was characterised by small interconnected pools containing low
levels of aquatic vegetation. Security at the site was moderate due to protection in private
property, however, the majority of the riparian vegetation consisted of exotic species. The large
pool immediately upstream of the off-take appeared to lack significant habitat for dwarf galaxias
of pygmy perch and appeared as though much of the habitat may dry completely during
summer periods. Presumably some remnant pools persist, reflected in the presence of very low
numbers of native fish captured (one mountain galaxias (Galaxias olidus) and two southern
pygmy perch (Nannoperca australis)).
Habitat below the offtake was dramatically different to that above the off-take, with fast flows
being restricted to a relatively narrow watercourse. Stock exclusion fencing and native
revegetation had improved terrestrial and aquatic habitat. Higher levels of aquatic vegetation
were observed at this site compared to sites above the off-take, providing substantially greater
levels of habitat for mountain galaxias which were observed in relatively high abundance
compared to upstream. The higher instream velocity may however been prohibitive to the
wetland specialised species such as dwarf galaxias and pygmy perch.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 3: Wetland at Wendy James
Yes
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
X
X
X
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
High
Medium
Low
Very Low
X
X
X
X
This site appeared to provide reasonable habitat, with moderate levels of aquatic vegetation
and water depth. A range of southern pygmy perch sizes were captured, suggesting that
recruitment had been successful over recent successive years. It is unknown whether these
individuals were permanent residents at this site or had migrated here when pools were
connected during high flow events, as the permanency of water at this site is unknown.
Although damage to this site by stock was evident (instream bank and bed damage and limited
fringing wetland vegetation), positive aspects of this site include the persistence of aquatic
vegetation, presence of southern pygmy perch and absence of eastern gambusia. These
positive features together with the relative isolation of this site from the main water channel
(apart from high flow events) contribute to it being considered a potential dwarf galaxias refuge
site.
Recommendations for this site include restriction of stock access and increasing the site depth
(preferably by excavating adjacent to this pool rather than within it) to increase both the area
and the ability of this site to maintain habitat through summer and/or drought conditions.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 4: Causeway at Wendy James
Yes
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
X
X
X
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
High
Medium
Low
Very Low
X
X
X
X
This site has been modified substantially and appears to have been subjected to unrestricted
stock access for some time. Riparian vegetation was predominantly made up of grasses, while
instream habitat quality is considered poor, with aquatic vegetation present in only very low
abundance. Despite considerable sampling, only one southern pygmy perch and one mountain
galaxias were captured. It is likely that the majority of this site would be dry over dryer summer
months, as deeper pool habitat was not observed.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 5: Billabong on Mahers Road
Yes
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
X
X
X
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
High
Medium
Low
Very Low
X
X
X
X
On initial inspection, this site appeared to be excellent habitat for species such as dwarf
galaxias, as aquatic vegetation was abundant throughout the site and a slightly deeper area
was present at one end. A total of 27 southern pygmy perch were captured from this site,
suggesting that this habitat was either permanently inundated or linked to waters at critical
times, enabling this species to recolonise during wetter periods. This site represents a potential
opportunity to work with the landholder to provide a refuge site into which dwarf galaxias can be
stocked. If this site was to be considered for this purpose, it is recommended that (as in site 3),
that a deeper permanent area adjacent to the site be created to provide a drought refuge for this
species.
Positive aspects of this site include the relatively deep water, persistence of aquatic vegetation,
isolated location above the main channel, presence of southern pygmy perch and absence of
eastern gambusia. Relatively easy restoration of this site would include excavation of a deeper
pool along the western south western bank, stock exclusion fencing and revegetation. The
close proximity to Mayers Road makes this a potentially good demonstration site.
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Site 6 and 7: Dewing Creek Weir and Rowlands Road
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
X
X
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
High
Medium
Low
Very Low
X
X
X
X
Habitat near the offtake weir consisted predominantly of a very low amount of smaller woody
debris as well as the boulder and rock which had been recently used to stabilise the bed and
banks upstream and downstream of the newly constructed weir wall. Sampling at this site did
not record the presence of any fish and it is possible that this site has been completely dry over
the summer period. The complete lack of aquatic vegetation also suggests that this site has not
received a permanent water supply over dryer months
Sampling at Rowlands Road (300 m upstream) did not record the presence of fish or
macroinvertebrates, suggesting that this site may be completely dry during the summer period.
This was supported by the lack of established aquatic vegetation at this site.
These two sites have a low conservation priority for dwarf galaxias due to low water security,
poor aquatic habitat and potential for eastern gambusia to move into the stream.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 8: Dewing Creek Weir Offtake
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
X
X
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
High
Medium
Low
Very Low
X
X
X
X
While this site has been highly modified, resulting in a concrete lined channel, deep silt deposits
have enabled dense levels of submerged aquatic vegetation to persist. This habitat supports
moderate numbers of flat-headed gudgeon (Philypnodon grandiceps), which were easily
captured from the channel bed. No other species were observed at this site.
While this irrigation channel had potentially good water security, potential high water velocity
(during irrigation periods) would be less suitable to the wetland specialised species. However, it
is possible that regulation pondages associated with the irrigation systems (situated out of the
main irrigation channel), could provide suitable refuge for these threatened species.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 9: Gosling Creek Wetland
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
X
X
High
Medium
Low
Very Low
X
X
X
X
A total of only two dwarf galaxias and three southern pygmy perch were captured from this site,
despite extensive sampling efforts. While eastern gambusia was not captured in this
assessment, they have previously been recorded at this location. Habitat at this site was
dominated by high levels of submerged aquatic vegetation, predominantly water ribbon
(Triglochin procera) and sedge species on a very soft silt/mud substrate.
Cattle damage at this site was severe, with pugging being evident around the entire wetland
margin as well as extending well into the wetland. This unrestricted cattle access has
undoubtedly led to deterioration of instream habitat through the loss of aquatic vegetation,
severe sedimentation and poor water quality and is most likely the reason for decreasing
numbers of dwarf galaxias being captured at this site compared to previous sampling
occasions.
While some effort has been made to exclude stock and revegetate the surrounding area with
native vegetation matching the Ecological Vegetation Class (EVC): Otway Plain EVC 53 –
Swamp Scrub, resistance from the landholder to fence the wetland to prevent cattle access has
undoubtedly had a major impact on population numbers. Under these circumstances, it is
unlikely that this population will persist over the long term. It is clear that further negotiations
are required with the landholder and where possible additional pressure should be applied to
ensure compliance with obligations associated with this significant site.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 10: Railway line dam off Gosling Creek
Yes
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
X
X
X
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
High
Medium
Low
Very Low
X
X
X
X
A total of three specimens of southern pygmy perch were captured from this location, however,
eastern gambusia was not present. Habitat at this site was poor, as unrestricted cattle access
has had an obvious impact on the riparian and instream habitat quality. Low levels of aquatic
vegetation (sedge species) were present and provided some cover for the southern pygmy
perch captured.
Positive aspects of this site include isolated location above the main channel, presence of
southern pygmy perch and absence of eastern gambusia. Restoration would include stock
exclusion fencing, provision of offstream water points, excavation of a deeper pool and
reintroduction of aquatic plant species.
NO PHOTO TAKEN
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 11: Bird Reserve - Pennyroyal Valley Road
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
X
X
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
High
Medium
Low
Very Low
X
X
X
X
This site represents a shallow wetland complex with two distinct (but linked) areas. The
larger wetland had a maximum depth of approximately 30cm and possessed moderate
levels of aquatic vegetation, while the second area was distinctly smaller in size but
greater in depth (up to approximately 70cm depth) with moderate to high levels of
aquatic vegetation. All fish captured from this site (southern pygmy perch) were found in
the smaller (deeper) area.
Although on private land, this site is used as a bird reserve, with a bird hide present on
the wetland margin (between the wetland and road). Due to the protected nature of this
site, this wetland habitat may represent an opportunity to work with the landholder to
provide a conservation area for stocking with dwarf galaxias (or Yarra pygmy perch). If
this option is considered, it may be advisable to increase the depth of some of the site
to provide great water security and drought refuge zones within the wetland complex.
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Site 12: Pennyroyal Road Cottages
Good quality habitat was observed at this site, with some dense patches of submerged aquatic
vegetation present in both pools. Fish fauna consisted of two specimens of southern pygmy
perch and over 300 eastern gambusia at this site.
The dominance of eastern gambusia makes this site an unlikely candidate for dwarf galaxias
translocation, as complete eradication of eastern gambusia and prevention of their return is very
difficult to achieve.
Sampling in the upper wetland did not record the presence of fish or macroinvertebrates,
suggesting that this site may be completely dry during the summer period.
NO PHOTO TAKEN
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 13: Pennyroyal Railway dam
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
No
X
X
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
High
Medium
Low
Very Low
X
X
X
X
This site had presumably been created in a similar fashion to sites 16 and 17, in that it appears
to have been created when earth was pushed up from the surrounding area to create an
elevated terrace onto which the railway line could be constructed. Habitat at this site was poor
with very little aquatic vegetation present.
Because this site was difficult to sample using dip nets, a total of 10 bait traps were deployed
overnight. Traps were set at dusk, during which time one specimen of short-finned eel (Anguilla
australis) was observed in the shallows. Bait traps were retrieved early the next morning without
result.
The high elevation of this site provide some protection from invasion by eastern gambusia, and
the relatively intact habitat, including stock exclusion fencing are positive aspects of this site as
a conservation wetland. Its proximity to but separation from the Pennyroyal Creek may provide
an ideal location for the preservation of Yarra pygmy perch that occur nearby below the offtake
weir.
The pine plantation along the margins of this billabong might however prove to be an
impediment to the successful rehabilitation of this site. This plantation would currently shade
aquatic vegetation and potentially add significant organic matter into the system. Replacement
of the pine plantation with native vegetation would be a primary restoration activity. Other
restoration activities would include removal of the predatory short finned eels, depth excavation
(if necessary) and reintroduction of aquatic vegetation.
NO PHOTO TAKEN
NO WATER QUALITY TAKEN
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 14: Barholm Road elongated dam
Yes
No
X
X
X
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
Very High
Water security
Habitat quality
Site security
Connection to watercourse
High
Medium
Low
Very Low
X
X
X
X
Sampling at this site did not record the presence of fish or macroinvertebrates, suggesting that
this site may be completely dry during the summer period.
Wetland was a shallow depression without stock exclusion fencing and not considered to have
a priority as a potential conservation wetland.
NO PHOTO TAKEN
NO WATER QUALITY TAKEN
Site 15: Matthews Creek tributary - Middle Muroon Road
Sampling at this site did not record the presence of fish or macroinvertebrates, suggesting that
this site may be completely dry during the summer period. Instream habitat was of a
reasonable standard with good fringing vegetation and some submerged vegetation, however
the lack of overall water depth reflects the lack of water security present at this site.
While eastern gambusia were not captured, it is highly likely that this species could recolonise
this location. As a result, this location is not considered to have a priority as a potential
conservation location.
NO PHOTO TAKEN
NO WATER QUALITY TAKEN
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 16: Dry conservation reserve – Muroon Road
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
X
X
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
No
High
Medium
Low
Very Low
X
X
X
X
Although it was clear that this site was dry at the time of sampling, vegetation in the centre of
this reserve and the spongy nature of the upper layer of soil and grass suggests that it may lie
along a natural drainage line within the pasture. This was supported by the presence of frogs,
which could be heard calling in the area.
Positive attributes of this reserve include an excellent fringing tree cover, isolation from invasive
pest fish and stock exclusion fencing.
This location has potential as a conservation wetland, however, restoration efforts must include
excavation to create deeper pools which are capable of retaining water throughout the year. It
is therefore also necessary to determine the level of inflow into this site to establish whether
sufficient surface runoff is available to maintain a constructed pool habitat.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 17: Old railway bridge (East Barwon) - SE
This site was presumably created after earthworks for the railway bridge (now under disrepair)
created a deep depression and high earth wall to the north side. Habitat at this site was
characterised by a deep pool, fringed by dense aquatic vegetation, dominated by ribbonweed
(Triglochin procera) and Persicaria spp. This dense vegetation provides an ideal habitat for the
large numbers of southern pygmy perch and dwarf galaxias found at this site (a total of 9 and 37
individuals respectively). A more recent investigation in July 2013 also found numerous dwarf
galaxias but no eastern gambusia (pers. comm., Rhys Coleman, Melbourne Water, 2013).
While the site is relatively secure from destruction as it can only to accessed via private
property, the high potential for erosion or inundation is reason for concern.
The elevation of this wetland appears to be at a critical height above the water level of the East
Barwon to prevent the colonisation of eastern gambusia. Notably, eastern gambusia were not
captured at the time of sampling, but during the rain event on June 12 and 13, elevated flow
from the East Barwon River was flooding into the wetland.
Other positive attributes of this site include diverse and abundant instream habitat, some
riparian vegetation cover, sufficient water depth to provide water security in drought conditions
and stock exclusion fencing.
This wetland is considered to be the most important site for dwarf galaxias in the upper Barwon
River catchment and should therefore be given the highest management priority. All efforts
should be made to preserve the existing condition of the site from potential external influences
such as eastern gambusia or sweet grass (Glyceria maxima).
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Environous report for Corangamite Catchment Management Authority
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 18: Old railway bridge (East Barwon) - NW
This habitat was presumably created in the same manner as that of site 17 and was just 40 m
away on the northern side of the old railway bridge (~40m away) , with a high earth bank on the
south side of the pool and a depression creating a long pool along the old railway line. Habitat
at this site varied to that at site 16 in that the maximum depth was only around 80cm and had
not been fenced off to cattle access (presumably due to the pool not posing a threat to cattle
welfare). As a consequence, aquatic vegetation at this site was not as dense as that seen in
site 16. The wetland was also at a lower elevation than site 17 and was flooded by the elevated
river flows.
As with Site 17, while this site can only be accessed from private land, the high potential for
erosion or inundation is reason for concern.
These factors were reflected in the range and number of fish species captured (three dwarf
galaxias and greater than 250 eastern gambusia). It is significant to note that the three dwarf
galaxias captured displayed some degree of caudal fin damage, presumably a result of
aggressive behavior known to be displayed by eastern gambusia towards this species,
particularly when present in high densities. As consequence the value of this site as a
conservation wetland for dwarf galaxias is considered to be lower than for site 17.
Shortened caudal fin
(likely to have been
nipped by eastern
gambusia)
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 19: Excavated billabong (East Barwon)
This site represents a permanent deepwater billabong, which has periodic connection with the
main watercourse. Although stock have unrestricted access to this site, excellent habitat
persists in the form of high levels of submerged and emergent aquatic vegetation that fringe the
relatively deep waterbody. Consequently, high densities of fish were present, comprising high
numbers of southern pygmy perch (66 were captured in total) and eastern gambusia (>200
individuals were observed). One specimen of dwarf galaxias was recorded at this site.
As with sites 17 and 18, the high potential for erosion or inundation is reason for concern and
results in a low site security score.
Given the high numbers of eastern gambusia found at this site and the impacts this species has
on dwarf galaxias, low numbers of this species are not surprising. It is unfortunate that the many
positive aspects of this site (water permanency, habitat quality) are negated by the lower
elevation of the wetland relative to the East Barwon River and presence of this introduced
species. As a consequence, the value of this site as a conservation wetland for dwarf galaxias
is similar to site 18 and is lower than for site 17.
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Environous report for Corangamite Catchment Management Authority
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Site 20. Wetland behind Forrest football oval
Yes
Presence of dwarf galaxias
Presence of gambusia
Stock exclusion
No
X
X
X
Very High
Water security
Habitat quality
Site security
Connection to watercourse
High
Medium
Low
Very Low
X
X
X
X
On initial inspection, this wetland appeared to have been constructed well above the natural
drainage line of the surrounding land, with no natural connection to watercourses within the
area. Water level was low (less than 30cm) and habitat within the wetland was characterised by
high levels of inundated grasses and some aquatic vegetation cover. Given the position of this
wetland and the vegetation structure, it appears that this wetland periodically dries up over
summer months and not surprisingly, did not appear to support a fish fauna.
The ephemeral nature of this wetland makes it unsuitable as a refuge for fish species.
Additionally, the high occurrence of the exotic sweet grass represents a significant risk to this
wetland.
NO WATER QUALITY TAKEN
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Discussion
Most of the river frontage where dwarf galaxias have been captured in the upper Barwon
catchment is privately owned and passes through a cleared rural landscape with a limited
riparian zone and ‘less than 25% of original native vegetation remaining’ (CCMA 2013). The
provision of additional wetland protection will rely on the participation of landholders.
Stock exclusion fencing is likely to be the most important management tool for the restoration of
native riparian vegetation. Livestock not only eat and trample the riparian vegetation, but also
do the same to the aquatic vegetation and habitat.
Protection and restoration of riparian (streamside) vegetation is also an important management
tool. Riparian vegetation acts as a buffer zone for the instream environment and filters the hot
summer sun, sediment input as well as other diffuse source pollutants such as nutrients and
pollutants. It also contributes to organic matter within a waterbody (large woody debris, sticks
and leaves) and provides a link between the terrestrial and the aquatic biota.
Monitoring and management of the aquatic vegetation is likely to be an effective management
tool for important dwarf galaxias populations. Management of aquatic vegetation may include
water conductivity targets and appropriate wetting cycles for the taxa being managed which are
predominately Triglochin, Myriophyllum, Vallisneria and Phragmites. Dwarf galaxias are reliant
on an abundance and diversity of aquatic habitat for shelter, feeding and spawning.
Conservation of this habitat is therefore of paramount importance when attempting to secure
populations of this species.
Natural flow regimes that regularly replenish the shallow freshwater habitats are essential for
the survival of dwarf galaxias. Changes to natural flood and drying cycles, particularly in
swamps and shallow creeks, through activities such as catchment clearing, establishing
extensive plantations, construction of dams and direct extraction of water, pose threats to
critical habitat (Saddlier et. al. 2010). Establishing greater water security should also be a
priority for each of the primary refuge locations, particularly where additional water is available
such as the upper and middle Barwon River catchment sites.
In addition to these actions, it is important to recognise the potentially catastrophic effects of
large numbers of eastern gambusia (as seen at site 18). Consideration must therefore be given
to how secure a site is from colonisation by this highly invasive species. This process will also
need to consider the water sources to supplement conservation wetlands and may involve
finding alternative water sources and water filtration.
Primary refuge sites
As non-migratory species, the protection of primary refuge wetland habitat for dwarf galaxias is
the most important management priority. This refuge habitat must provide shelter from high
stream flows, sustained water quality and suitable instream habitat to provide shelter, feeding
and spawning opportunities. Dispersion of these species from the refuge habitat is expected to
occur predominately in a downstream direction. Throughout this investigation, where primary
refuge habitat is identified, it is considered to have a higher management priority. Identification
of these important primary offstream refuge and spawning sites should be a priority.
Primary dwarf galaxias refuge wetlands identified include the wetland upstream of Division
Road on Gosling Creek and the wetland on the south east side of the old railway bridge on the
East Barwon River floodplain near Barwon Downs. Now that these sites have been identified, it
is essential that a comprehensive maintenance plan be developed and include stock exclusion
fencing, protection of water resources and flow regime and re-vegetation of the riparian zone. It
is also important to undertake on-going water quality and non-destructive fish surveys to assess
the sustainability of the populations.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Gosling Creek Wetland
The dwarf galaxias in Gosling Creek wetland (site 9) have been thought to be sustainable
during previous surveys (Ryan 2011). Population numbers recorded during this current survey
are the lowest recorded and some doubt exists on the ability of this species to maintain a robust
population at this site. This is undoubtedly due (in part) to the impact of unrestricted stock
access that occurs at this location. Cattle access has led to deterioration of instream habitat
through the loss of aquatic vegetation, pugging of the wetland banks and poor water quality and
is most likely the reason for decreasing numbers of dwarf galaxias being captured at this site
compared to previous sampling occasions.
Additional sediment is likely to have been deposited in the wetland due to a large erosional
event upstream generated by a large flood event (1:100 ARI) in June 2012. In 2013 the CCMA
completed extensive erosion control works upstream to prevent further sediment deposition
downstream.
While some effort has been made to revegetate the surrounding area with native trees and
shrubs, resistance of the landholder to maintain stock exclusion fencing around the wetland has
had a major impact on population numbers. It is likely that it is easier for the landholder to
continue access to enable cattle to drink water and feed on the aquatic vegetation during dry
periods. Under these circumstances, it is unlikely that this threatened population will persist over
the long term.
A more recent investigation in July 2013 found evidence of mature female dwarf galaxias, thus
indicating breeding was still occurring (pers. comm., Rhys Coleman, Melbourne Water, 2013).
This provides some additional confidence for the prospects of a population recovery if site
restoration targets can be met.
Recommendations for this site include continuing to encourage the landholder to fence off this
site and instead encourage cattle access to the dam immediately upstream. There is an
existing causeway between this dam and the dwarf galaxias wetland, thus providing a sufficient
boundary for fencing and access.
There appears to be sufficient water depth in the dwarf galaxias wetland, therefore further
excavation is not required. A large floating mass of aquatic vegetation (predominately
Myriophyllum) exists in deeper water outside the reach of the cattle. This mass of vegetation is
likely to be providing refuge for the fish. Aquatic vegetation is likely to reestablish along the
wetland margins once stock exclusion is achieved.
Old railway bridge (Barwon Downs) – SE
Of all sites supporting populations of dwarf galaxias, site 17 is the most significant. This is
based upon a range of factors including the high numbers of individuals, the water holding
capacity (affording the site some protection during drought periods), as well as the habitat
quality and exclusion of stock from the site. It is possible that the presence of high numbers of
southern pygmy perch at this site may also be a distinct advantage for the dwarf galaxias
population. While the deleterious interactions of eastern gambusia towards dwarf galaxias are
well known and have been directly observed during this survey (site 17), the impact of eastern
gambusia on dwarf galaxias populations in the presence of high numbers of southern pygmy
perch (and other native species) are not well understood. It is likely that complex interactions
occur under these circumstances as is acknowledged by Rehage et al. (2004) who states that
biotic interactions may enhance the resistance of communities to invasion and that invading
organisms typically encounter a novel suite of competitors and predators, and thus their
invasiveness may be affected by how they cope with these interactions.
It must be noted that although we were unable to determine the exact depth of this pool, depth
is obviously sufficient to support this healthy population of native species. Importantly, at the
time of sampling, it was noted that the high rainfall event and subsequent overflow of the East
Barwon onto the surrounding floodplain caused floodwaters to enter this site. Consequently,
connection between this usually isolated pool and the greater Barwon River system was made
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
possible. As such, migration of species into this pool (including exotic species) and migration
out of this pool (including dwarf galaxias) may occur.
Significantly, eastern gambusia was not captured from this site, suggesting one of two
scenarios. The first possibility is that this species has not entered the site in past flood events
due to its higher elevation above the water level of the East Barwon River channel. Movement
of small fish like eastern gambusia under flooding flow conditions would be difficult and
therefore potentially restrict colonisation into this wetland. Conversely, it is also likely that the
large population of southern pygmy perch population in this site is controlling eastern gambusia
abundance. The critical aspect to this scenario is that there is sufficient diversity and quantity of
aquatic habitat to provide refuge for the large dwarf galaxias and southern pygmy perch
populations.
Given that a connection between the main watercourse and this site currently exists and that
the population of dwarf galaxias (and southern pygmy perch) appear to be in a very healthy
state (with no sign of eastern gambusia persisting at the site), alterations to the flooding regime
at this site should be discouraged. In short, without a full understanding of the complex
interactions regarding flooding cycles and movement of eastern gambusia and dwarf galaxias to
and from this site, abiotic changes to an apparently healthy population should be discouraged.
The comparison of the two wetlands at this location provides the perfect opportunity to further
investigate this relationship to provide information on the ideal wetland parameters required to
conserve dwarf galaxias.
Secondary refuge sites
While the old railway bridge (East Barwon) – NW (site 18) is just 40m away from the primary
refuge site (site 17), but has very different fish composition. While some dwarf galaxias were
captured, the impact of eastern gambusia on individuals is clear. Low dwarf galaxias
abundance was apparent and those captured showed obvious signs of aggression, presumably
caused by the fin nipping of eastern gambusia. Control of eastern gambusia at this site is
problematic, firstly due to the difficulty to completely eradicate this species from the site, and
secondly, the inability to prevent further re-introductions during subsequent flood events. The
lower elevation at this wetland would probably enable eastern gambusia to recolonise under
most high flow events.
One specimen of dwarf galaxias was captured from the ‘excavated billabong’ (site 19). Given
the high numbers of eastern gambusia found at this site and the impacts this species has on
dwarf galaxias, low numbers of this species are not surprising. As with site 18, it is unfortunate
that the many positive aspects of this site (such as water permanency, good habitat quality) are
negated by the presence of eastern gambusia.
The occurrence of dwarf galaxias at these two floodplain wetlands demonstrates that this
species may have dispersed in offstream wetlands throughout the Upper Barwon catchment.
However, the difficulty in completely eradicating eastern gambusia from these low lying
wetlands makes this site difficult to manage effectively and without substantial effort and
resources. In an environment of increasingly scarce levels of both funds and physical
resources, better value for money can be made by directing efforts to populations that do not
contain large numbers of eastern gambusia.
It should however, be recognised that as a result of substantial catchment modification, very few
off stream wetlands have persisted in this catchment and any off-stream wetlands should be
regarded as potential habitat for a range of threatened and non-threatened native fish species.
These wetlands provide shelter for many fish species in times of high and low stream flow, and
should be maintained as a matter of priority. As part of the on-going catchment restoration
program, actions such as stock exclusion fencing along the elevated banks (above the
appropriate flood level) and revegetation should be undertaken at these locations as a matter of
priority.
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Potential Conservation Wetlands
Another key conservation measure noted for dwarf galaxias is the translocation of fish into a
conservation wetland. Key criteria for conservation wetlands for dwarf galaxias, in no particular
order, include:

lack of eastern gambusia;

sufficient elevation to prevent re-colonisation of eastern gambusia;

occurrence of other native wetland species;

sufficient water quantity and water quality;

sufficient pool volume and depth to sustain periods of drought as well as shallow
ephemeral margins;

abundant and diverse habitat particularly aquatic vegetation;

stock exclusion fencing and riparian vegetation; and

suitability as a demonstration / educational site.
Potential conservation wetland sites identified in this assessment include the Wetland on
Wendy James property (Site 3), the Billabong on Mahers Road (Site 5), the Bird Reserve on
Pennyroyal Valley Road (Site 11), the wetlands at Pennyroyal Creek Cottages (Site 12) and the
Dry Conservation Reserve on Muroon Road (Site 16). Ranking for each of these wetlands is
presented in Table 2.
Sites without the eastern gambusia populations indicate that recolonisation is less likely and will
ultimately require less management resources. The complete eradication of eastern gambusia
once they have been established is difficult and likely to be detrimental to other management
practices. Therefore sites with eastern gambusia already present and/or likely to be reintroduced are not considered suitable as conservation wetlands. Based on this criterion alone,
the wetlands at Pennyroyal Cottages are therefore not considered to be suitable as a priority
conservation wetland.
The elevation of the wetland above the 1:100 year flood level is also considered to be an
important criteria to prevent infestation (Rhys Coleman, Pers. Comm. Melbourne Water, August
2013). In addition, the occurrence of other wetland native species is also considered to be a
positive feature as it indicates suitability of the habitat and potentially represents a predatory
influence on any re-introduced eastern gambsuia (particularly for southern pygmy perch and flat
headed gudgeon).
Sites with sufficient water security and pool depth are likely to involve fewer resources to
establish as hydrological assessments and excavation would not be required. Conservation
wetlands being developed by Melbourne water for dwarf galaxias are being excavated with
deep pools to sustain periods of low flow and with gentle sloping banks to provide shallow
ephemeral wetland habitat. Importantly, these wetlands are designed to dry out along the
gently sloping margins to encourage greater productivity of various components of the wetland
ecosystem that have evolved in ephemeral systems, including dwarf galaxias (Rhys Coleman,
Pers. Comm. Melbourne Water, August 2013).
An abundance and diversity of aquatic habitat is relatively easy to re-establish if not present and
may include replanting aquatic plants and introducing large structures such as logs or rocks.
Stock exclusion fencing is essential for all wetlands to protect the quality of the wetland habitat,
and is also relatively inexpensive to achieve.
A location with easy access and relatively high exposure (such as next to a regularly used road)
would also have advantages in promoting the importance of dwarf galaxias and the importance
of habitat restoration measures such as stock exclusion fencing.
According to this criteria, the five potential conservation wetlands have been ranked in order of
suitability and management practicality. The higher ranked wetlands are not impacted by
eastern gambusia, and appear to have sufficient elevation and currently support predatory
native species capable of controlling an invasion of eastern gambusia. They also appear to
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Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
have sufficient water depth and water security and therefore require less restoration, apart from
stock exclusion fencing and riparian vegetation planting. These sites include 5 and 11 and are
well-located adjacent roads thus providing good demonstration sites.
Site 16 would require excavation and an investigation into the water availability and therefore is
likely to be harder to establish. It does, however have existing fencing and good riparian
vegetation and is located in an accessible area.
Table 2: Ranking of Conservation Wetlands for dwarf galaxias translocation
Criteria for
Conservation
Wetlands
27
Wetland at
Wendy James
(Site 3)
Billabong on
Mayers Road
(Site 5)
Bird Reserve
Pennyroyal
Valley Road
(Site 11)
Pennyroyal
Creek
Cottages
(Site 12)
Dry
Conservation
Reserve
(Site 16)
Eastern
gambusia
NO
NO
NO
YES
NO
Elevation
MODERATE
MODERATE
MODERATE
MODERATE
HIGH
Other native
species
YES
YES
YES
NO
NO
Water quantity
and quality
Wetland volume,
depth and
shallow margins
LOW
HIGH
MODERATE
MODERATE
LOW
MODERATE
HIGH
MODERATE
MODERATE
LOW
Aquatic habitat
MODERATE
MODERATE
MODERATE
MODERATE
LOW
Fencing
NONE
NONE
PRESENT
PRESENT
PRESENT
Riparian
vegetation
GOOD
NONE
GOOD
GOOD
GOOD
Demonstration/
education
LOW
HIGH
HIGH
MODERATE
HIGH
OVERALL
RANKING
3
1
2
5 (NOT
SUITABLE)
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4
Refining dwarf galaxias Galaxiella pusilla habitat in the Upper Barwon River catchment
Recommendations
1. Maintain and where possible without disturbance, enhance habitat at the Old Railway
Bridge (East Barwon) – SE (site 17). (Actions to include permanent fencing, erosion
control on the East Barwon, and Glyceria control)
2. Continue encouragement of landholder participation in stock exclusion fencing of the
Gosling Creek wetland.
3. Undertake regular water quality, habitat condition and fish composition assessments at
sites 17 and 9.
4. Investigate feasibility of developing conservation wetlands (sites 3, 5, 11, 16)
5. Undertake stock exclusion fencing and native planting at other floodplain wetlands
(including sites 18, 19).
6. Wetlands assessed in this investigation (sites 3, 5, 9, 11, 16, 17, 18, 19) be adopted and
implemented into the Corangamite Waterway Strategy as key conservation features of
the upper Barwon Catchment.
7. Assess other floodplain wetlands in the Upper Barwon catchment based on
Conservation Wetland Criteria in this report.
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References
Cadwallader, P. L. & Backhouse, G. (1983) A Guide to the Freshwater Fish of Victoria.
(Government Printer: Melbourne).
CCMA (2010) Pilot Emergency Response Action Plan for the Protection of Significant Fish
Species. Corangamite Catchment Management Authority.
CCMA (2013) Corangamite Regional Catchment Strategy 2013-2019, Corangamite Catchment
Management Authority 2013
DSE (2009) Advisory List of the Threatened Vertebrate Fauna in Victoria - 2007, Department of
Sustainability and Environment, Melbourne.
McDowall, R.M. (1980) Freshwater Fishes in South-Eastern Australia. Reed: Sydney.
Raadik, T. and Koster, K. (2000) Pre- and post-fishway construction assessments - Barwon and
Moorabool Rivers, and Otway streams. Report for the Corangamite Catchment
Management Authority. Department of Natural Resources and Environment, Arthur Rylah
Institute for Environmental Research.
Rehage, J.S., Barnett, B.K. and Sih, A. (2005). Behavioral responses to a novel predator and
competitor of invasive mosquitofish and their non-invasive relatives (Gambusia sp.).
Behavioral Ecology and Sociobiology 57: 256-266.
Ryan T. and McGuckin J. (2008a). Selected fish surveys in the Barwon and Moorabool River
catchments following the prolonged low flow period of 2006-2007. A report prepared by
environous for the Corangamite Catchment Management Authority.
Ryan, T. and McGuckin, J. (2007) Drought impact on river health in the Corangamite Region.
Prepared for the Corangamite CMA.
Ryan, T. (2011) Assessment of priority dwarf galaxias (Galaxiella pusilla) and Yarra pygmy
perch (Nannoperca obscura) populations within the CCMA (2010). Report for the
Corangamite Catchment Management Authority.
Saddlier, S., Ryan, T and Wooley, J. (2009). Corangamite CMA — Significant fish species
protection under dry inflow conditions. Arthur Rylah Institute for Environmental Research
Technical Report Series No. 198. Department of Sustainability and Environment,
Heidelberg, Victoria.
Saddlier, S, and Hammer, M. 2010. National Recovery Plan for the Yarra Pygmy Perch
Nannoperca obscura. Department of Sustainability and Environment, Melbourne.
Saddlier, S., Jackson, J. and Hammer, M. 2010. National Recovery Plan for the Dwarf Galaxias
Galaxiella pusilla. Department of Sustainability and Environment, Melbourne.
Victorian Water Resources Data Warehouse (2013) “www.vicwaterdata.net”
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Appendix: Summary of Fish Assessments
No. Site
Date
1
Callahan Creek - u/s offtake
12/06/2013
2
Callahan Creek - d/s offtake
12/06/2013
3
Wetland at Wendy James
12/06/2013
4
Causeway at Wendy James
5
Billabong on Mahers Road
6
7
Dewings Creek Weir
Dewing Creek at Rowlands Road bridge
8
12/06/2013
12/06/2013
12/06/2013
12/06/2013
Irrigation channel at Dewing Creek Weir
12/06/2013
9
Gosling Creek Wetland
12/06/2013
10 Railway line dam off Gosling Creek
14/06/2013
11 Bird Reserve - Pennyroyal Valley Road
12/06/2013
12a Pennyroyal Creek Cottages - lower wetland
12/06/2013
12b Pennyroyal Creek Cottages - upper wetland
Length
Fish type
No. (mm)
G. olidus
1
57
N. australis
1
58
N. australis
1
56
G. olidus
4
G. olidus
1
63
G. olidus
1
51
G. olidus
1
60
Engaeus sp.
1
~10
N. australis
1
54
N. australis
1
48
N. australis
1
34
N. australis
1
28
N. australis
1
47
G. olidus
1
50
N. australis
1
55
N. australis
1
46
N. australis
1
37
N. australis
1
36
N. australis
23
No fish us or ds
No fish or inverts
P.
grandiceps
P.
grandiceps
P.
grandiceps
P.
grandiceps
P.
grandiceps
G.
G.
N.
N.
N.
N.
N.
N.
N.
N.
N.
N.
N.
N.
N.
N.
G.
G.
G.
G.
1
34
1
39
1
43
1
56
3
pusila
1
pusila
1
australis
1
australis
1
australis
2
australis
1
australis
2
australis
1
australis
1
australis
1
australis
1
australis
1
australis
1
australis
1
australis
1
australis
1
holbrooki
1
holbrooki
1
holbrooki
1
holbrooki 300
36
30
40
36
50
12/06/2013
13-14/6/13
A. australis
14/06/2013
15 Matthews Creek tributary - Middle Muroon Road
13/06/2013
16 Dry conservation reserve (Muroon Road)
13/06/2013
17 Old railway bridge (East Barwon) - SE
13/06/2013
18 Old railway bridge (East Barwon) - NW
13/06/2013
19 Excavation billabong (East Barwon)
14/06/2013
20 Wetland behind Forrest football oval
30
14/06/2013
G.
G.
G.
G.
G.
G.
N.
N.
N.
N.
N.
pusila
pusila
pusila
pusila
pusila
pusila
australis
australis
australis
australis
australis
Easter gambusia
present
No eastern gambusia
27
28
28
30
39
26
30
46
52
14
36
46
13 Pennyroyal Railway dam
14 Barholm Road elongated dam
Comment
1
1
1
1
1
32
1
1
1
1
5
24
26
25
34
22
G. pusila
1
G. pusila
1
G. pusila
1
G. holbrooki
1
G. holbrooki
1
G. holbrooki
1
G. holbrooki
1
G. holbrooki
1
G. holbrooki
15
G. holbrooki 250
N. australis
1
N. australis
1
N. australis
1
N. australis
1
N. australis
1
N. australis
1
N. australis
60
G. holbrooki
1
G. holbrooki
1
G. holbrooki
1
G. holbrooki
1
G. holbrooki
1
G. holbrooki 200
G. pusila
1
P. australis
50
33
33
32
39
34
18
24
17
Observed
No fish or inverts would dry out
10 bait traps - not fish
of inverts
Observed
No fish or inverts would dry out
No fish or inverts would dry out
Wetland dry but
fenced and well
vegetated
Only 5 - 10% habitat
sampled
32
38
31
37
Serious fin nipping
observed
Observed
63
58
47
38
17
24
26
27
22
20
26
Observed
27
No fish or inverts would dry out (High
above floodplain)
Environous report for Corangamite Catchment Management Authority