Download Lake Cargelligo Fish Management and Operations Plan

Lake Cargelligo
Fish Management and
Operations Plan
Lachlan Catchment Management Authority
October 2009
Lake Cargelligo fish plan
Prepared by:
Dr Dale McNeil
South Australian Research and Development Institute
Aquatic Sciences Centre
PO Box 120 Henley Beach, SA, 5001
[email protected]
Ivor Stuart
Kingfisher Research
20 Chapman St, Diamond Creek, Victoria, 3089
[email protected]
Lisa Thurtell
Lachlan Catchment Management Authority
PO Box 726, Forbes, NSW, 2871
Project Funded by:
Lachlan Catchment Management Authority
Published by:
Lachlan Catchment Management Authority
PO Box 726, Forbes, NSW, 2871
©NSW Government
ISBN:
Lake Cargelligo fish plan
Acknowledgements
Our gratitude to Peter Skipworth for showing us around Lake Cargelligo and for his detailed local
knowledge. Thanks to Harry Herath and Brett Lewis, State Water, for explaining water operations at
Lake Cargelligo and for access to the preliminary fishway drawings drafted by the NSW Department
of Commerce. Adam Kerezsy made valuable comments on a draft of the report. This report was
funded by the Lachlan Catchment Management Authority.
Published by:
Lachlan Catchment Management Authority
PO Box 726, Forbes, NSW, 2871
October 2009
© NSW Government
ISBN
PLEASE NOTE: This draft has been prepared for consideration and has not been fully
reviewed by Lachlan Catchment Management Authority.
Lake Cargelligo fish plan
Tables of Contents
Tables of Contents ................................................................................................ 4
List of Figures ....................................................................................................... 5
Executive Summary .............................................................................................. 6
1. Introduction.................................................................................................. 10
1.1 Objective ................................................................................................ 13
2 Lake Cargelligo Fish Community .................................................................. 13
2.1 History and Fish Community .................................................................. 13
2.2 Exploring Functional Guilds as Fish Management Units ........................ 17
2.2 Exploring Functional Guilds as Fish Management Units ........................ 18
2.2 Exploring Functional Guilds as Fish Management Units ........................ 19
3 Fish Management Issues within Lake Cargelligo ......................................... 23
3.1 Water Quality ......................................................................................... 23
3.2 Water Availability and Demand .............................................................. 24
3.3 Habitat ................................................................................................... 24
3.4 Carp ....................................................................................................... 25
3.4 Fish movements and migrations .............................................................. 1
3.5 Regulator management ........................................................................... 1
3.6 Current Knowledge Gaps......................................................................... 1
3.7 Monitoring ................................................................................................ 1
4. Fish Management and Operations Plan Objectives ...................................... 2
5. Management Units ........................................................................................ 2
5.1 Inlet Channel ............................................................................................ 5
5.2 Sheet of Water ......................................................................................... 2
5.3 Curlew Water ........................................................................................... 3
5.4 Main Lake ................................................................................................ 4
5.5 Outlet Channel and Lake Creek ............................................................... 5
6. Operational Procedures................................................................................. 6
6.1 Operations for Inflow Channel ................................................................. 7
6.2 Operations for Sheet of Water ................................................................. 8
6.3 Operations for Curlew Water ................................................................... 9
6.4 Operations for Main Lake....................................................................... 10
6.5 Operations for Outlet Channel ............................................................... 11
7. Regulator operations guide ......................................................................... 12
8. Native fish rescue ........................................................................................ 12
9. Fish Guilds and operational plans ............................................................... 13
9.1 Large-Bodied Pelagic Fish ..................................................................... 13
9.2 Large-Bodied Benthic Fish ..................................................................... 13
9.3 Small-Bodied Littoral Fish ...................................................................... 14
9.4 Small-Bodied Pelagics ........................................................................... 14
9.5 Operations Calendar .............................................................................. 15
10. Monitoring, Evaluation and Reporting ....................................................... 17
References.......................................................................................................... 19
Lake Cargelligo fish plan
List of Figures
Figure 1 Location of Lake Cargelligo in the Lachlan Valley ................................ 11
Figure 2 Current configuration of Lake Cargelligo system .................................. 12
Figure 3 Large fish which might be found at Lake Cargelligo ............................. 17
Figure 4 Small fish which might be found at Lake Cargelligo .............................. 18
Figure 5 Lake Cargelligo ..................................................................................... 26
Figure 6 Fish habitat values in Lake Cargelligo during the present dry phase .... 26
Figure 7 Life-history stages of common carp and their specific control measures
.
..................................................................................................................... 29
Figure 8 A movement model of fish between the Lachlan River and Lake Cargelligo
.
..................................................................................................................... 34
Figure 9 A concept layout for a Williams’ carp separation cage on the Lachlan River at Lake
Cargelligo Weir vertical-slot fishway. ........................................................... 41
Figure 10 Operational flow chart for inflows to Inflow Channel ........................... 48
Figure 11 Operational flow chart for inflows to Sheet of Water ........................... 49
Figure 12 Operational flow chart for inflows to Curlew Water ............................. 50
Figure 13 Operational flow chart for inflows to Lake Cargelligo Main Lake ......... 51
Figure 14 Operational flow chart for inflows to Outlet Channel and Lake Creek . 52
List of Tables
Table 1 The fish community that potentially occurs in the Lachlan River.. .......... 15
Table 2 Lake Cargelligo fish functional groups ................................................... 21
Table 3 Lake Cargelligo fish community habitat and food requirements ............. 22
Table 4 Flow requirements for Lake Cargelligo fish communities ....................... 22
Table 5 Timetable of integrated methods for carp management at Lake Cargelligo..
..................................................................................................................... 31
Table 6 Operating calendar to assist in Lake Cargelligo operations which will enhance
conditions for native fish .............................................................................. 57
Table 7 Lake Cargelligo fish data sheet .............................................................. 59
Lake Cargelligo fish plan
Executive Summary
Lake Cargelligo, is a regionally significant wetland and is a recognised as a wildlife reserve,
providing a habitat for waterbirds and native fish. However, as a result of inappropriate land use and
water regime management, the ecological health of the Lake has been deteriorating over a number
of years. The Lake Cargelligo Fish Management and Operations Plan was developed to improve
water and land management to better manage the wetland environment to improve the native fish
habitats.
Along with an adaptive land and water management plan for the Lake, a management plan for fish
is an important component in the restoration of the ecological health of Lake Cargelligo. The
objective of the Lake Cargelligo Fish Management and Operations Plan is to ensure that suitable
habitat for the survival, spawning and recruitment of native fish, as well as opportunities for fish
passage and migration between the lake and the wider Lachlan Catchment.
Operational procedures regarding the filling regime of the lake, as well as the protocols used for
moving water between the various lake units will be critical in restoring and maintaining healthy
populations of native fishes within the Lake and adjacent reaches of the Lachlan River. Recent
research also suggests that these operational protocols will be critical in controlling pest carp and
redfin populations within Lake Cargelligo.
The operation of regulating structures, such as undershot weirs, is critical to facilitating the
movement of native fishes into and out of the lake. By carefully managing gate opening heights,
tailwater depths and regulator water velocities, fish passage can be maximised.
The aim of the present plan is to restore native fish populations by promoting suitable aquatic
habitat and spawning sites as well as seasonal flow related exit and entry opportunities. This will be
achieved through flow management, provision of essential habitat and ecosystem processes (such
as food webs) and carp control. The specific strategies to improve native fish communities can be
summarised as:

To the greatest practical extent prevent adult carp from entering Lake Cargelligo under
normal flows without impacting on native fish;

To reduce the impact of carp on key environmental values of Lake Cargelligo such as water
quality, native fish communities and aquatic vegetation

Exploit opportunities to trap carp at key sites in Lake Cargelligo;

Create or facilitate critical hydrological events that maximise habitat and food availability for
native fish;

Facilitate key hydrological elements that trigger movement, breeding and recruitment of
native fish; and,

Create or facilitate critical hydrological events that trigger safe native fish movement
between Lake Cargelligo and the Lachlan River.

To promote community awareness and increase the involvement of community and local
management agencies in carp management and other rehabilitation activities within the site
Lake Cargelligo fish plan
To facilitate these strategies, this plan has addressed six key management units within the Lake
and high priority management actions have been summarised for each of these units. The
management units were defined by:


their geographic extent,
the presence of man-made fish passage barriers (regulators),
At a broader scale there are two key constraints for action at Lake Cargelligo are:


A lack of water in headwater storage to provide environmental flow releases and therefore a
reliance on seasonal rainfall;
The need to maintain existing weirs and regulators to provide irrigation supply/stock
watering;
A regulator and lake operations calendar has also been developed as a reference to assist onground staff in implementing the plan’s objectives and to maximise the long term viability of Lake
Cargelligo as a healthy wetland supporting a strong community of native fishes.
We advocate that an adaptive management strategy be put in place in close consultation with fish
and fisheries expertise. This strategy must incorporate effective monitoring and documentation of
wetland operations and the impacts and effects that these operations have on native and pest fish
populations, as well as wetland ecosystem health within the Lake.
By restoring and actively facilitating key habitat, life cycle, and migrational requirements of native
fish combined with high impact carp control actions, Lake Cargelligo can be restored as a principal
native fish refuge for the critically endangered lower Lachlan ecological community (EPBC Act
1999) and contribute significantly to the sustainability of fish populations in the Lachlan River
Catchment.
Recommendations for native fish management

Integration of the recommended actions proposed for managing native fish and carp within
the broader interventions and strategies proposed for Lake Cargelligo.

An assessment of the potential and the costs and benefits of restoring the timing and extent
of natural flows and flooding essential to the spawning and recruitment of native fish
species. This should include a targeted survey.

Survey Lake Cargelligo and nearby Lachlan River to clarify the distribution and abundance
of native and non-native fishes as part of a hypothesis a based monitoring program for key
values within the Lake Cargelligo system and provide baseline information for future actions.

Undertake an assessment of the priority areas of Lake Cargelligo to be key sites for the
recovery of native fish. These include potential spawning sites and other targeted
rehabilitation works to assist the recovery of key native species.
Lake Cargelligo fish plan

All actions proposed for Lake Cargelligo should link to the objectives through the
development of conceptual models. This way the actions also link the relevant monitoring
activities.
Lake Cargelligo fish plan
Recommendations for non-native fish management






Install a Williams’ separation cage on the proposed Lake Cargelligo Weir fishway – note that
connection of mains power to the fishway is an advantage.
Institute a formal monitoring, reporting, maintenance and disposal program for carp collected
from the Williams’ cage.
Transferring the Williams’ cage to other key road crossings, regulators, channels or flow
control devices in the Lake Cargelligo system, as required.
Formalise responsibilities for daily operations (e.g. State Water) and draft a fishway
operation plan based on passing native fish during spring/summer flow events.
To combat the inherently flexible life-history of carp an adaptive management approach is
needed. The carp plan and on-ground control methods should be adapted as necessary
and results documented.
Monitoring of non-native redfin populations and their impacts on native fish.
Conclusion
The Lake Cargelligo system supports a significant native fish community but is under increasing
stress from lack of flow and non-native fish. Re-connection of Lake Cargelligo with the Lachlan
River, along with natural wetland wetting and drying cycles is part of a balanced river ecosystem.
Fish passage from the river to the lake and carp control can be enhanced by operating the
regulators with consideration of the biology of native and non-native fish. Additionally enhancement
of several key habitats within the Lake Cargelligo system will enhance the ecology of native fish
populations.
Lake Cargelligo fish plan
Lake Cargelligo Fish Management and Operations Plan
1. Introduction
Lake Cargelligo comprises of a series of wetlands and open water areas that are nutrient-enriched,
turbid and subject to frequent blue-green algal blooms. The lake is located adjacent to the midsections of the Lachlan River near the centre of NSW (Fig. 1).
Figure 1 Location of Lake Cargelligo in the Lachlan Valley (Source: State Water 2006)
Lake Cargelligo was originally a series of natural ephemeral floodplain depressions, which filled via
medium to large floods in the Lachlan River. However, river regulation has resulted in the Lake
being continuously inundated by using releases from Wyangala Dam or from upper unregulated
tributary flows. The water stored in Lake Cargelligo is used as Town water Supply, for recreational
purposes and also to supplement irrigator requirements in the lower Lachlan. When the lake level
drops to approximately 20%, water can no longer be released to the Lachlan River due to
hydrological constraints. Figure 2 shows the current configuration of the Lake Cargelligo system.
Lake Cargelligo, is not currently recognised as a nationally significant wetland, however the
northern area of the Lake is classified as an “animal and bird sanctuary”. This sanctuary persists
despite the on-going ecological degradation of Lake Cargelligo through the current land and water
management. Inappropriate management has also reduced the lake’s capacity to support
Lake Cargelligo fish plan
Figure 2 Current configuration of Lake Cargelligo system
aquatic communities, with grazing pressure, weed infestations and increased erosion reducing
biological diversity, with a major decline in aquatic plants (macrophytes).
In addition to this, the “Aquatic Ecological Community in the Natural Drainage System of the
Lowland Catchment of the Lachlan River” has recently been listed as an Endangered Ecological
Community under Part 3 of Schedule 4 of the Fisheries Management Act 1994 (FM Act) due to a
number of threats to the natural values of this aquatic ecosystem including:
Lake Cargelligo fish plan

Instream structures, eg. weirs and dams;

Reduced floodplain and wetland inundation;

Water extraction;

Deterioration of water quality;

Loss of aquatic plants;

Introduced species;

Clearing of riparian vegetation;

Stock access;

Some agricultural practices;

Overfishing; and

De-snagging.
Importance of floodplain habitats for fish
The current drought has resulted in the complete drying of 50 plus floodplain wetlands through the
operation of regulators and an absence of floodplain inundation. At Lake Cargelligo, re-colonisation
of fish from the Murray River is an important aspect of population recovery. Wetlands, lakes,
lagoons and anabranches frequently contain excellent fish habitat and provide different habitats to
the main river channel.
The exchange of fish between river and floodplain is also important in maintaining native fish
biodiversity. Fish move between off-stream lakes and the Lachlan River via connecting channels
and these unique flowing habitats are critical in enabling the physical movement of fish.
3.2 Why is Lake Cargelligo an important fish habitat?
Lateral movement of native fish into Lake Cargelligo is important to access the diversity of habitat
offered by floodplains with heightened survival, feeding and reproduction opportunities. Exit of fish
from the lake back to the Lachlan River would naturally occur as flows recede and ensure that fish
escape stranding. Recent data also suggests that there is bi-directional movement of fish
throughout the floodplain filling and drying event (Lyon et al. in press).
Four of the 19 native finfish species of the lower Lachlan ecological community are listed on the
NSW threatened species schedules. These include the olive perchlet (Ambassis agassizii), silver
perch (Bidyanus bidyanus), southern pygmy perch (Nannoperca australis), and purple spotted
gudgeon (Mogurnda adspersa) and the latter two species appear locally extinct (Table 1). There
are also serious declines of at least four other fish species, the eel-tailed catfish (Tandanus
Lake Cargelligo fish plan
tandanus), river blackfish (Gadopsis marmoratus), Macquarie perch (Macquaria australasica), and
Murray cod (Macculochella peelii peelii) which are also native to the lowland Lachlan River
Catchment. The Murray jollytail (Galaxias rostratus) has an uncertain conservation status (little is
known about the species) but is likely to be highly endangered at local scales.
Actions which have been suggested for the recovery of the lower Lachlan ecological community
include the allocation and management of environmental flows, the restoration of riparian and
aquatic vegetation, providing fish passage by removing barriers or installing fishways, restoring
habitats and improving water quality.
Some of these issues will be addressed through the implementation of the Lake Cargelligo
Environmental Management Plan (LCCEMP). The LCCEMP aims to improve the water quality,
hydraulic regime and wetland environment of Lake Cargelligo with the key objectives:

To improve the quality of water within Lake Cargelligo for the benefit of water users and the
ecological community

To improve the quality of water being discharged from Lake Cargelligo for the benefit of the
riverine environment and downstream users;

To enhance wetland function to improve water quality while maintaining a residual pool and
waterbird breeding values; and,

To develop and implement an operational plan to maintain the wetlands and lake environs to
ensure ongoing water quality and habitat.
The project will use a management changes to achieve the key objectives listed above. The major
components of the project include:

Installation of fencing in strategic areas around the lake perimeter and associated channels
to prevent stock access and control gazing; and,

Development and implementation of an operational plan for Lake Cargelligo integrating
water and land management, wetland management, pest and weed control.
1.1 Objective
The aim of the Lake Cargelligo Fish Management and Operations Plan (FMOP) is to ensure that the
land and water management of Lake Cargelligo account for the needs of native fish and the control
of carp (and other non-native fish) through adaptive management and hypothesis-based monitoring.
2 Lake Cargelligo Fish Community
2.1 History and Fish Community
Trueman (2007) provides historical evidence from interviews with elderly anglers for trout cod,
Murray cod, Macquarie perch, golden perch, silver perch, river blackfish and freshwater catfish in
the upper Lachlan catchment. Anecdotally, some fisherman blamed declines of Macquarie perch
and other native fish on trout stocking and then carp impacts. Other impacts on native fish
appeared to be caused by serious bushfires and indiscriminate dynamiting.
Lake Cargelligo fish plan
Up until the 1960s the waters of Lake Cargelligo were mostly clear and supported dense
submerged vegetation and large quantities of fish. The spread of carp, possibly as a consequence
of the 1974 floods, saw significant increases in turbidity resulting in the progressive loss of the
majority of perennial submerged plants (Sainty pers. comm.. 2009). Such changes might be a result
of a combination of seasonal and long-term changes in the river flows, rapid changes in water level,
turbidity coupled with the effects of the feeding habitats of carp and inappropriate grazing regimes.
Carp have since boomed within Lake Cargelligo and these fish spawn and produce many millions of
larvae in response to very small flows through the lake.
Lake Cargelligo was widely acknowledged as a significant habitat for native fish and supported
commercial fishers from 1955 until 1993 when the fishery finally collapsed. Interestingly, the native
fish fishery in Lake Cargelligo had largely collapsed before the 1970s when carp began to dominate.
The peak catch of carp occurred in 1978/79 with 9929 kg while in the last year of the fishery
(1992/93) 1260 kg was harvested.
NSW DPI records from 1955 onward indicate a fishery primarily based on golden perch, freshwater
catfish and Murray cod. The catfish fishery peaked at approximately 3642 kg/year before declining
in the mid 1960s. Catfish were virtually absent from the commercial catch from 1985 onward.
The golden perch fishery peaked early at approximately 16452 kg/year in 1956/57 and catch was
highly variable among years. Murray cod, Macquarie perch and silver perch were commonly
collected from 1955-1957 and thereafter declined to negligible numbers. Murray cod catch peaked
at 1078 kg in 1956/57 but less than 20 kg per year were collected after 1962. Macquarie perch
were harvested in reasonable amounts in 1955/56 and 1956/57 with 253 and 334 kg, respectively.
However, from 1957 onward there were only sporadic and small catches of Macquarie perch and
silver perch had a similar catch history.
Non-native redfin perch (Perca fluviatilis) were also collected in reasonable numbers (over 11500
kg in 1973/74) but declined thereafter. Non-native tench (Tinca tinca) were also taken in low
abundance (<400 kg/year). Yabbies were never harvested in significant numbers from Lake
Cargelligo with approximately 55 kg taken in total.
In addition to the large bodied commercially fished native fish, Lake Cargelligo is likely to have been
a significant habitat for small-bodied native fish. Although historical surveys are rare and not
comprehensive, it is likely that populations of small-bodied fish were prominent within Lake
Cargelligo prior to the 1970’s, concurrent with the presence of aquatic vegetation, stable
spring/summer water levels and good water quality.
Historical and current fish data emphasise that whilst the lake has recently become a significant
carp hot-spot, rehabilitation of the lake should aim to restore the abundant populations of native
fishes once present in this significant wetland. All care should be taken, therefore, to not only
remove carp and reduce their impact on the Lake, but also to restore and maximise the value of the
lake as a significant native fish refuge. Table 1 and Figures 3 and 4 illustrate the range of fish
Lake Cargelligo fish plan
species that have been recorded or could potentially occur in the lower Lachlan and Lake Cargelligo
areas.
Table 1 The fish community that potentially occurs in the Lachlan River. H=high flow, M=medium
flow, L=low flow.*=appears locally extinct. #=listed species under NSW State or Commonwealth legislation.
Large-bodied fish
Bidyanus bidyanus#
Macquaria ambigua
Gadopsis marmoratus
Maccullochella peelii peelii#
Maccullochella macquariensis#
Tandanus tandanus
Macquaria australasica#
Leiopotherapon unicolor
Small-bodied fish (<100 mm
long)
Hypseleotris spp
Craterocephalus
stercusmuscarum
Melanotaenia fluviatilis
Philypnodon grandiceps
Retropinna semoni
Galaxias olidus
Galaxias rostratus
Mogurnda adspersa*#
Nannoperca australis#
Ambassis agassizii#
Non-native fish
Carassius auratus
Cyprinus carpio
Gambusia holbrooki
Perca fluviatus
Tinca tinca
Lake Cargelligo fish plan
Common name
Silver perch
Usual maximum
size
450 mm
Juvenile
migration
Yes
Migration
river flow
H,M,L
Golden perch
600 mm
Yes
H,M,L
River blackfish
350 mm
Unknown
M,L
Murray Cod
1200 mm
Yes
H,M,L
Trout cod
800 mm
Unknown
H,M,L
Eel-tailed catfish
800 mm
Unknown
M,L
Macquarie perch
400 mm
Unknown
M,L
Spangled perch
200 mm
Yes
H,M,L
Carp gudgeons
45 mm
likely
M,L
Un-specked
hardyhead
80 mm
M,L
Murray rainbow
fish
90 mm
M,L
Flat-headed
gudgeon
Australian smelt
Mountain
galaxiid
Murray jollytail
Purple spotted
gudgeon
Southern pygmy
perch
Olive perchlet
90 mm
M,L
100 mm
70 mm
M,L
M,L
100 mm
70 mm
M,L
M,L
65 mm
M,L
Goldfish
Common carp
Gambusia
Redfin perch
Tench
300 mm
800 mm
60 mm
400 mm
300 mm
60 mm
likely
M,L
M,L
H,M,L
M,L
M,L
M,L
1m
Murray cod
carp
Silver perch
catfish
Silver perch
Bony bream
Golden perch
Lake Cargelligo fish plan
Figure 3 Large fish which might be found at Lake Cargelligo (diagrams from McDowall 1996)
70 mm
Australian smelt
Carp gudgeon
Flatheaded gudgeon
Murray rainbowfish
Unspecked hardyhead
Figure 4 Small fish which might be found at Lake Cargelligo (diagrams from McDowall 1996)
Lake Cargelligo fish plan
70 mm
Murray jollytail
Olive perchlet
Purple spotted
gudgeon
Lake 4Cargelligo
fish plan
Figure
cont. Small
fish which might be found at Lake Cargelligo (diagrams from McDowall 1996)
2.1 Recent Fish Community Surveys
Several researchers have conducted sporadic work in the Lachlan Catchment (Llewellyn 1983;
Harris and Gehrke 1997; Growns 2001; and pilot SRA surveys [MDBC 2004]). However, for Lake
Cargelligo, the only quantified fish data are contained in an Honours thesis by Adam Kerezsy, from
sampling in 2004 and 2005. That study used a combination of fyke nets, bait traps and backpack
electrofishing at four sites: Canal 1, Lake Curlew, Canal 2 and Lake Cargelligo. During the study
Lake Cargelligo was not connected to the Lachlan River. The total catch of 3223 fish was
dominated by carp gudgeons (Hypseleotris spp) and non-native fish (carp, redfin, Gambusia and
goldfish). Native small-bodied fish included: Australian smelt, flatheaded gudgeons, and unspecked
hardyhead, Small numbers of bony herring, golden perch and silver perch were collected and a
single freshwater catfish. The only species which might have occurred in Lake Cargelligo but were
missing from Kerezsy’s survey, were Murray cod and olive perchlet. The Lake Cargelligo survey by
Kerezsy also documented considerable numbers of freshwater turtles (Chelodina longicollis and
Emydura macquaria).
Kerezsy’s thesis also suggested that the high priority habitats for conservation were Lake Curlew
and Canal 2 (between Lake Curlew and Lake Cargelligo) where silver perch, freshwater catfish and
unspecked hardyhead were collected. Another area of interest as a high conservation fish habitat is
Lake Creek which is a meandering river like environment with riparian vegetation and instream
snags. At present Lake Creek and the nearby are of Lake Cargelligo is dry.
2.2 Work by SADRI and NSW DPI in 2007-2009
From 2007-2009, further survey work was undertaken by NSW DPI and SARDI in Lake Brewster
and the Lachlan River. These surveys were part of the Lachlan CMA and IACRC funded carp
management project. A major finding was the presence of olive perchlet in Mountain Creek and the
Lachlan River for the first time in over 50 years (McNeil et al. 2008).
2.3 Exploring Functional Guilds as Fish Management Units
To assist in determining the specific management requirements of native fish species, each was
grouped into functional guilds based on the general ecology of each species (Table 2). The large
bodied pelagic group contains fish that predominantly require open water and/or large structural
habitat such as woody debris (snags). These species are generally the least tolerant of poor water
quality and (with the exception of bony herring) tend to be at the very apex of the wetland foodweb.
Catfish are unique amongst the fish fauna as they are predominantly benthic, making nests
amongst aquatic vegetation and feeding upon snails, mussels, insect larvae and small fish amongst
vegetated habitats and the lake bottom.
The small bodied littoral species are also highly dependant on complex structure such as
macrophyte beds or twigs/branches. They predominantly feed on zooplankton and/or insect larvae
that are located within the complex habitats they inhabit. This group is strongly associated with
littoral habitats at the edge of wetlands amongst emergent (reeds and rushes) as well as
submerged aquatic plants.
Lake Cargelligo fish plan
The species listed as potential targets for translocation back into the Lake are generally small
bodied pelagics dependant on wetland vegetation, although the Murray jollytail is a pelagic
schooling species. Other pelagic schooling species are smelt and hardy head, which are found in
large numbers, generally of short lived single age groups. These fish provide an important food
resource for the top predators such as the perches.
The non-native species differ greatly in ecology with redfin perch a large bodied pelagic predator,
carp and goldfish generalist omnivores and gambusia a small bodied littoral associated with
complex macrophyte beds. The range of habits of these introduced pests highlights their collective
potential to compete with and impact upon a wide range of native cohabitants. Amongst them, only
tench are likely to have little impact on native fishes. In addition, managing for native fish is also
likely to have some benefits for native turtles, crustaceans and molluscs, water rats, and piscivorous
birds.
Table 2 Lake Cargelligo fish functional groups
LargeBodied
Pelagic
LargeBodied
Benthic
SmallBodied
Littoral
SmallBodied
Pelagic
Potential
SmallBodied
(Translocated)
Non-Native
Golden Perch
Catfish
Olive Perchlet
Smelt
Galaxiids
Carp
Silver Perch
Rainbowfish
Hardyhead
Purple-spotted Gudgeon
Tench
Murray Cod
Carp
gudgeons
Southern pygmy perch
Redfin
Bony Herring
Flatheaded
gudgeons
Macquarie
perch
Gambusia
Goldfish
The various food and habitat requirements of each of these functional guilds are summarised below
in Table 3.
Lake Cargelligo fish plan
Table 3 Lake Cargelligo fish community habitat and food requirements
Fish Type
Habitat Requirements
Food
Large-Bodied Pelagic
Juveniles – Littoral Habitat
Yabbies
Woody Debris
Small Fish
Deep Water
Mussels
Good Water Quality
Invertebrates
Zooplankton
Large-Bodied Benthic
Suitable substrate for nesting
Snails
Aquatic vegetation
Invertebrates
Yabbies
Small Fish
Mussels
Small-Bodied Littoral
Leaf Litter
Invertebrates
Fine woody debris
Zooplankton
Aquatic
vegetation
(eg. Shrimp
Vallisneria,
Myriophyllum,
Potamogeton)
Small-Bodied Pelagic
Open water
Zooplankton
Good water quality
Small-Bodied
Translocated
Aquatic vegetation
Invertebrates?
Zooplankton
Shrimp
Lake Cargelligo fish plan
Fish species also are cued to spawn or migrate depending on timing and volumes of flows. The flow
requirements to cue spawning and/or requirement are outlined in Table 4.
Table 4 Flow requirements for Lake Cargelligo fish communities
Fish Type
Activity
Flow requirement
Comment
Murray Cod
Spawning
Range of flow types
Adhesive
eggs
Migration
Range of flow types
Spawning
Rising flows
Migration
Rising
floods
Spawning
Rising flows
Migration
Rising
floods
Spawning
Golden Perch
Silver Perch
Pygmy Perch
Spawning habitat
??
Pelagic
eggs
Open Water
Pelagic
Eggs
Open Water
Flow recession
Nonadhesive
Aquatic
vegetation/substrate
Flow recession
Adhesive
Aquatic
vegetation/substrate
Low flow
Adhesive
eggs
Aquatic Vegetation
Low flow
Shallow
In nest on substrate
water,
amongst vegetation
gravel beds,
vegetation
Low flow
Pelagic
eggs
Open Water
Low flow
Adhesive
eggs
Open
Water/substrate
flows
flows
and
and
Migration
Galaxiids
Spawning
Migration
Olive Perchlet
Spawning
Migration
Catfish
Spawning
Migration
Bony Bream
Spawning
Migration
Aus. Smelt
Spawning
Migration
Gudgeons
Spawning
Migration
Lake Cargelligo fish plan
Low flow
Leaf
litter/substrate/woody
debris
3 Fish Management Issues within Lake Cargelligo
Management strategies addressed within this FMOP are targeted towards two key objectives; 1)
restoring healthy and diverse native fish communities and 2); controlling carp and reducing their
impacts to water quality and wetland health. As such, each of the key management issues must be
addressed with both of these objectives in mind.
The adaptive management of the reconfigured Lake Cargelligo will also present a number of
challenges to fish management, particularly with providing an appropriate timing and duration of
water regime components, necessary habitat and food resources, spawning sites, fish passage and
options for controlling pest species such as carp. Importantly, however, the LCCEMP should
increase management within Lake Cargelligo in terms of water movement and manipulation. This
improvement in managed flow and water movements at a fine scale, will be a key tool in delivering
the outcomes of the present fish management plan.
Fencing off of strategic areas of Lake Cargelligo and the resulting exclusion of stock should assist in
the regeneration of a healthy wetland system, providing enormous benefit to native fish within the
Lake. In the following sections we will identify and address the key management issues and
attempt to design and recommend strategies and procedures for maximising the benefit of the
LCCEMP works towards improving wetland health and the native fish community in Lake
Cargelligo.
It is important to note the interaction between the Lachlan River and Lake Cargelligo Weir and
inflow/outflow from Lake Cargelligo. The main river channel is intimately linked to managing fish
populations with Lake Cargelligo and provides opportunities to enhance passage and fish
populations while also controlling carp.
3.1 Water Quality
Many native fish require good water quality and can withstand only mild or limited exposure to
waters of high temperature and salinity or low in oxygen. In contrast, introduced pests such as
carp, goldfish, gambusia and weatherloach can withstand long exposure and extreme
environmental conditions (McNeil and Closs 2007). In the past Lake Cargelligo has experienced
black water events, high turbidity and major blue-green algal blooms (Thurtell et al. 2002). It can
exhibit diurnal stratification in the deeper sections during summer, which has been found to reduce
dissolved oxygen levels at the bottom of the water column (Thurtell et al. 2002).
A number of factors will impact on water quality within the wetlands and main storage area of Lake
Cargelligo. Macrophyte growth and retention times within the wetlands will determine the
effectiveness of these areas as treatments to improve water quality and therefore the suitability for
native fish and associated ecosystem.
Lake Cargelligo has long suffered the effects of high nutrients and turbidity resulting in major bluegreen algal blooms. This seriously impacts on both the township and the ecological community.
Lake Cargelligo fish plan
3.2 Water Availability and Demand
Environmental water allocations may be available to assist with fish related management. Sources
for environmental water include:

The Lachlan Regulated River Water Sharing Plan (DIPNR 2004), which stipulates that
Water Quality Allowance (WQA) might be released for water quality improvement purposes
including but not limited to, alleviation of algal blooms and salinity impacts. Rules for
determining the volume and timing of releases from the WQA account are not
predetermined;

The Water Sharing Plan (DIPNR 2004) also stipulates that Wyangala Environmental
Contingency Allowance (WECA) might be released for ecological purposes including but not
limited to, completion of waterbird breeding events, promotion of fish breeding, promotion of
fish passage, wetland watering and to increase flow variability in the lower river. Rules for
determining the volume and timing of releases from the WECA account are not
predetermined.

Opportunities to access water might also be provided by the Adaptive Environmental Water
(AEW) Licence and the Lake Cargelligo Environmental Management Plan; and,

And potentially through federal allocation programs such as Water for a Healthy Country

Lake Cargelligo is currently relied on as the Town Water Supply for the township. Therefore,
high security water is made available to the Lake to ensure water supply.
As releases from the Lake will be determined to a large extent, by downstream demand there may
be a conflict between water users and fish requirements in terms of timing and volumes of releases.
However, some of these conflicts can be resolved through planning and the provision of cues to
native fish.
3.3 Habitat
Aquatic plants provide habitat and food for a number of native fishes, particularly submerged plants
such as Potamogetan, Vallisneria and Myriophyllum and Triglochin and emergent species such as
Eleocharis and Juncus. Promoting the growth of suitable macrophyte types is also an important aim
of the LCCEMP and to a large extent, the restoration of these macrophyte beds will have flow on
benefits to native fish, as habitat, foodweb, nesting, spawning and water quality needs of fish can
be largely met through macrophyte restoration.
As part of the creation of a favourable habitat for not only desirable macrophytes but also fish and
macroinvertebrates, it is proposed that large woody debris be re-introduced to the inflow wetland
system. Woody debris would provide habitat and protection for larger fish species and is recognised
as an important substrate for invertebrates. The large woody debris could be sourced from dead
trees removed as part of the construction of the inflow wetland and associated channels. The
potential for other sites to receive large woody debris will further enhance the Lake Cargelligo’s
habitat value for large bodied native fish (Figures 5 & 6).
Lake Cargelligo fish plan
Figure 5 Lake Cargelligo.
Figure 6 Fish habitat values in Lake Cargelligo during the present dry phase.
Lake Cargelligo fish plan
3.3 A context for carp management
For any carp control exercise the underlying concept should be one of undertaking a range of
management interventions to show the cumulative benefits of river rehabilitation on native fish
populations. Hence, carp control is only undertaken in the context of native fish recovery. For Lake
Cargelligo, a suite of these interventions might maximise and demonstrate the benefit of multiple
actions.
3.4 Carp
The high biomass of carp in the Lake Cargelligo system is of concern for managers and operators.
A number of plans to limit carp numbers (including tailored plans for Lake Cargelligo) have been
developed through the LCMA’s River Revival Program and will be incorporated into the FMOP.
There is potential to remove or inhibit large carp entering or leaving the inflow and outflow channels
using fish traps installed by the South Australian Research and Development Institute (SARDI) as
part of the Lachlan Carp Cleanup project, a carp research and control program in partnership of the
LCMA with the Invasive Animals Co-operative Research Centre. Specifically, this project will trial
the use of carp separation cages (Williams’ cages), which remove the majority of carp (through their
innate jumping behaviour) whilst allowing native fish to pass through the trap (Stuart et al. 2006).
As well as developing and applying technologies for carp control in Lake Cargelligo, the carp
cleanup project is collecting data on the microchemical composition of carp earbones (otoliths) to
identify specific signatures that will tell managers where each carp was spawned. This technology
can be applied to estimating the contribution of Lake Cargelligo to the overall carp problem in the
Lachlan River, but also assess the success of any control activities as the contribution of the Lake is
reduced (Dale McNeil unpublished data). Carp control will be bolstered through commercial fishing
and removal of large aggregations of carp as they occur within the lake and surrounding waters.
Despite the application of Carp Separation Cages efforts, however, smaller (<250 mm long) carp
will be able to enter the wetland system and, as carp mature rapidly, other control methods will be
required in the Lake system over time.
As water will remain in some areas of Lake Cargelligo continuously and, as remnant pools can
potentially contribute considerable numbers of carp to the system, removing carp through direct
capture or commercial means will be required. This may also necessitate the manual collection and
rescue of large-bodied native fish. This potential will require adaptive management and emergency
response efforts in co-operation with fish biologists and fisheries managers.
There are a number of ways carp control can be implemented depending on the physical
constraints and available resources. Infrastructure should be put in place to enable the capture and
removal of carp at various key points within the Cargelligo system.
Lake Cargelligo fish plan
3.5 A general model of carp life-history
Adult carp actively move onto floodplains and offstream lakes and are also mobile within the main
channel of the Murray River. Lateral migrations to floodplains are for two major purposes: spawning
and feeding. Carp lay their adhesive eggs in the shallow relatively warm waters of the floodplain,
usually on vegetation that is more abundant than in the main river channel. Adult carp movements
are relatively predictable, with a general model (Figure 7) of:
 Winter aggregations in main river refuges with a high degree of site fidelity
 Spring (mid-August onward) migration to floodplains as soon as they are accessible or
upstream in the main river
 Spring/summer spawning (multiple events) associated with floodplain inundation (Smith
2005)
 Autumn movement from floodplains to the river as water recedes from the floodplain
o Large numbers of carp may be naturally stranded during these conditions.
Adult carp are generally characterised by a floodplain habitation strategy of “first on – last off’.
Larval and juvenile carp drift downstream from floodplain spawning areas in the main river stem and
also on the floodplain.
The implications for Lake Cargelligo carp management are:
 Adult carp disturb macrophytes and suspend sediment and these fish are the priority for
control.
 Fishways or culverts on wetland regulators may provide opportunities to cull carp
populations;
 If spawning sites are identified, it is possible to reduce spawning activity by minimising
access of adult fish and by manipulating water levels to expose and kill eggs through
desiccation;
 Any inflows from the river into floodplain habitats can carry larvae, even with screens to stop
larger fish.
Lake Cargelligo fish plan
3.6 Carp management at Lake Cargelligo
At Lake Cargelligo the carp management strategy will be one of control rather than complete
eradication. The two major objectives are to 1) minimise the number of adult and sub-adult carp
entering/exiting the system and 2) minimise damage by adult carp on lake values.
The three main strategies to achieve these goals and therefore manage carp populations comprise:
i) screens to exclude adult and sub-adult carp, ii) the introduction of a wetting and drying regime,
and iii) harvest or destruction of carp accumulations.
Lake Cargelligo fish plan
.
Carp cages, screens, poison, harvest,
electrofishing, fish-outs, habitat manipulation,
native fish predation
Carp cages, screens, poison,
harvest, electrofishing, fish-outs,
habitat manipulation
Floodplain drawdown,
natural flows patterns
Adults
Sub-adults
Eggs
Larvae
Young-of-the-year
Carp cages, natural flow patterns
native fish predation, screens
Figure 7. Life-history stages of common carp and their specific control
measures
Lake Cargelligo fish plan
Natural flow patterns,
Native fish predation
3.7 Wetting and drying cycle
The wetting and drying regime introduced into some wetlands is intended to restore a natural cycle.
The lake is likely to be a key habitat for carp spawning and recruitment therefore any control of
water levels would be beneficial for reducing spawning success. To limit ingress of larval and
juvenile carp a winter filling cycle is recommended. It is important to note that Lake Cargelligo
would have naturally filled in late winter and spring and therefore the recommended filling in winter
does not simulate natural conditions.
In terms of carp management, the justification for a winter fill is that if carp have access to offchannel habitats in spring and summer there is potential to limit carp entry (including small
larvae/juveniles) and adult spawning. If natural values require a spring/summer filling event then a
reduction in carp spawning success might be achieved by manipulating water levels. Carp lay eggs
in shallow water and reducing water levels in marginal wetlands just after carp have spawned would
kill many eggs. The feasibility and impacts of this option should be investigated for Lake Cargelligo
and needs to be consistent with other resource use strategies.
3.8 Harvest or destruction of carp accumulations
The new technology known as the William’s carp separation cage (Williams’ cage) has successfully
been applied at a number of fishways on the mainstem of the Murray River where it automatically
separates adult carp from native fish. Briefly, carp and native fish are trapped in a funnel cage after
which carp leap into a second holding cage while native fish are automatically released. The
Williams’ cage has been highly successful at Lock 1 (Blanchetown) with over 80 tonnes of carp
removed since late 2007 (Figures 8 and 9). A concept for a similar system is shown in Figures 20
and 21. Additionally, SARDI are presently concluding wetland trials with the jumping technology
and also with a new carp ‘pushing’ innovation at Banrock wetlands.
Trapping and removal of carp at Lake Cargelligo has some potential but would likely require
experimental trials to optimise the design and ensure native fish are protected. At this stage the
trap cannot separate juvenile carp (<250 mm long). Carp cage infrastructure can be transferable at
various key points within the Lake Cargelligo system and should be managed in an adaptive
manner.
A key to successful carp management is a co-operative approach with professional fisherman. At
Lock 1, carp are removed and frozen on-site by professional fishers and a similar process could
occur at Lake Cargelligo. Alternatively, BiobiNs (composting bin systems) might provide an
opportunity for an experimental trial (www.biobin.net). During floods, when access is restricted,
debris loads are elevated the carp cage should be removed.
Table 5 describes the different management strategies for carp at Lake Cargelligo. The present
management of wetting and drying wetlands to mimic a natural regime will disadvantage carp and
should continue during the present regulated flow conditions.
Lake Cargelligo fish plan
Table 5. Timetable of integrated methods for carp management at Lake Cargelligo. Note that natural filling of the lake would
have occurred in spring and a May filling event is based on carp management scenarios.
Culverts
May
Carp control:
Wetting/drying
Wetland filling event while few carp
larvae and juveniles are present.
Experiment with raising water level by 300 mm over 24 h to
initiate carp spawning and then dropping levels by 300 mm to
dessicate eggs.
Repeat, assess and adaptively manage.
Minimise filling of lake and marginal carp spawning
habitats post Christmas.
Begin marginal wetland drawdown and prevent adult
carp from exiting lake and harvest fish.
Carp cages
Organise commercial fishers, permits
and carp disposal.
Fit carp cages to inlet/outlets.
Remove cages if major flood.
Remove carp cages in late-December or at discretion.
Lake Cargelligo fish plan
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
3.9 Summary
A significant aspect of rehabilitating offstream wetlands is managing carp populations.
At present this has focused on cages to prevent access of carp to these areas, and
reintroducing a wetting and drying regime. These techniques need to be applied in an
adaptive manner with the minimum impact on native fish. It is also important to note that
these methods are for controlling adult carp abundance and their impacts not for
eradication. Planning and integration of the carp control techniques will maximise their
effectiveness particularly if the lake is regularly cycled into a complete partial or drying
event.
3.10 Redfin management
Redfin are a major predator on small native fish and crustaceans, and have also been
implicated in the transfer of the EHN virus (Lintermans 2007). In Lake Cargelligo, redfin
are reasonably common and formed approximately 20% of the biomass in Kereszsy’s
(2005) small-bodied fish dominated dataset. Redfin are difficult to control, though there
has been some success in small enclosed ponds using physical removal (Ludgate and
Closs 2003).
Redfin appear to prefer the open water of Lake Cargelligo in preference to Lake Curlew
and the canals (Kereszy 2005) which might be related to abiotic variables or prey
behaviour. Consequently, native fish restoration efforts which target areas where redfin
are least abundant are recommended and monitoring of redfin populations and their
impacts will be a key to demonstrating success.
3.11 Native fish movements and migrations
The timing, frequency and duration of natural wetting and drying periods in wetlands has
been altered by dams and weirs, as well as localised operation of regulators that control
the movement of water, sediment, nutrients and fish between permanent river and
temporary off-channel habitats. The Lake Cargelligo Weir, on the Lachlan River, delivers
water to Lake Cargelligo via an inlet channel and regulator. Within Lake Cargelligo,
operation regulating structures at the inflow and outflow can be managed to facilitate the
timely delivery, retention and draining of water within the lake system to achieve
ecological objectives.
Operational procedures regarding the filling and emptying of Lake Cargelligo will greatly
impact on the way fish behave in terms of passage and migration. Fish react to
increases and reductions in flows. However, the timing and volumes of these flows
provoke different responses for different fish species. Fish response to inflows, instorage movement and outflows will need to be assessed as part of the adaptive
management process. This should include the fish response in the Lachlan River at
Lake Cargelligo Weir and the proposed vertical-slot fishway will be a key tool for
monitoring.
Lake Cargelligo fish plan
Structures, particularly undershot weirs, are major barriers to the successful passage of
fish but these can be operated to reduce their impact. The height at which an undershot
gate is lifted, the tailwater depth and the velocity of water passing through the regulator
can greatly impact upon the survival of fish attempting to navigate downstream through
the structure.
The promotion of aquatic plant growth to provide habitat and to aid water quality
improvements is a top priority of the LCCEMP. However, siltation followed by thick
aquatic plant growth, particularly cumbungi, may hinder the movement of some larger
fish species. This aspect of the macrophyte beds must be considered and may require
management.
The present report aims to set fish passage objectives for Lake Cargelligo and individual
regulators, specifically:
1. Operational criteria for regulators for upstream and downstream fish passage.
2. Identify opportunities to manage carp with optimised regulator operation.
3. Identify how regulator operations can be managed to increase native fish
colonisation of Lake Cargelligo but minimise the potential for stranding native fish
in the lake during drying periods.
Consideration of fish passage for Lake Cargelligo regulators depends on a model of fish
movement that incorporates species, direction, timing, flow conditions and water levels.
A model is proposed to aid management decisions on fish passage that divides the
system into two broad habitat categories of small constructed wetlands (inlet and outlet)
and large off-channel habitats (the main storage cell). Fish can become trapped in offchannel habitats if suitable fish passage is not provided. Generally, fish movements
within Lake Cargelligo and the nearby Lachlan River can be summarised as (see Fig. 8):
1. Fish move upstream in the Lachlan River and congregate below Lake Cargelligo
Weir during spring flow events.
2. Fish movement into wetland areas, such as Sheet of Water, is dominated by
small-bodied species;
3. Fish movement into the Main Lake and Curlew Water includes large bodied fish
(e.g. golden perch) as well as small-bodied fish;
4. Large-bodied native fish appear to leave the floodplain at the beginning of the
flood recession, apparently cued by small drops in water level;
5. Small bodied fish have active bi-directional movement between the Lachlan River
and Lake Cargelligo over a broad range of water levels. High numbers of fish
generally enter the Lake system as it starts to fill and higher numbers return to
the river as the wetlands starts to drain;
6. Carp actively seek floodplain habitats in spring and summer to spawn;
7. Carp are generally the ‘first on – last off’ the floodplain during a flood or managed
inundation compared to large bodied native fish. Carp actively use small
wetlands and large storage areas; and,
8. Carp moving back into remnant (dead space) pools as lake draws down.
Lake Cargelligo fish plan
Fish moving from Lachlan
River to Lake Cargelligo and
Fish moving from Lake
Cargelligo to Lachlan
River and fish moving
upstream from Lachlan
into Lake Cargelligo
Fish moving
NO. OF
FISH
Water
level
Inlet regulator on
TIME
Inlet regulator off
Figure 8 A movement model of fish between the Lachlan River and Lake
Cargelligo.
Lake Cargelligo fish plan
3.12 Regulator management
Using the fish movement model described above, the recommended approach is:
1. Provide fish passage through the proposed vertical-slot fishway on Lake
Cargelligo Weir.
2. Provide passage for downstream migrating fish (into Lake Cargelligo) by
minimising injury and mortality at the Cargelligo Weir inlet regulator;
3. Provide passage of downstream migrating fish (out of the wetland) by managing
water levels to;
a) maximise periods where flow levels are close to equal at the outlet
regulator, and
b) stimulate fish to leave the wetlands as they start to dry.
4. Provide passage for upstream migrating fish (into Lake Cargelligo) by;
a. attracting fish upstream from the Lachlan River into the Lake
b. attracting fish to travel through from outlet to the Lake
5. Prevent carp movement into and out of Lake and/or harvest migrations and
aggregations.
3.13 Current Knowledge Gaps

Baseline survey of native fish communities in the Lachlan River and Lake
Cargelligo

Timing, cues and biomass of fish entering and exiting the proposed main stem
fishway and wetland system;

Habitat use and spawning/recruitment patterns of fish in Lake Cargelligo;

Movement patterns of fish within the Lake Cargelligo system;

Carp entry and harvest/control opportunities;

Effect of hydrological management on native fish populations;

The effectiveness of Carp Separation Cages in excluding large bodied carp from
Lake Cargelligo; and,

The impact of small carp growing up within the Lake Cargelligo complex.
3.14 Monitoring
Hypothesis-based monitoring which complements existing monitoring undertaken by
other agencies is strongly recommended. Monitoring will provide key data for water
operation to improve management opportunities for enhancing native fish populations.
Monitoring and assessment should be incorporated into all control activities to allow the
successful evaluation of control efforts and to ascertain the outcomes against NRM
investment targets. Monitoring should not be restricted to the fish population.
Lake Cargelligo fish plan
4. Fish Management and Operations Plan Objectives
The previous section has outlined some of the key issues relating to the management of
native fish and the control of carp in Lake Cargelligo. Suggested changes in water
regime and land management would be expected to have beneficial effects on the
Lake’s ecological community and also the lower Lachlan riverine community in general.
The specific strategies to improve native fish communities are similar to that developed
for wetlands elsewhere in NSW (Boys 2007) and can be summarised as:

To the greatest practical extent prevent adult carp from entering Lake Cargelligo
and harvest any nearby mainstem migrations.

Identify and exploit opportunities to trap and harvest carp at key sites in Lake
Cargelligo.

Facilitate key hydrological elements that trigger movement, breeding and
recruitment of native fish.

Create or facilitate critical hydrological events that trigger safe native fish entry
and exit from Lake Cargelligo.

Create or facilitate critical hydrological events that maximise habitat and food
availability for native fish.

We also recommend an assessment of the potential and the costs and benefits
of restoring the timing and extent of natural flows and flooding essential to the
spawning and recruitment of native fish species. This should include a targeted
survey to clarify the distribution and abundance of native and non-native fishes
as part of a hypothesis a based monitoring program for key values within the
Lake Cargelligo system.

All actions proposed for Lake Cargelligo should link to the objectives through the
development of conceptual models. This way the actions also link the relevant
monitoring activities.
4.1 Lake Cargelligo: enhancing native fish habitats
There are several ways to enhance Lake Cargelligo habitats and foodweb values and
the associated inflow channels for improved native fish survival and recruitment. These
methods will also largely fit with the present wetland management plan and for other
rehabilitation objectives for the site. These are:

Control of livestock and pest animals grazing on the wetland margins.

Remove or control adult carp and invasive plants.

Encourage growth of native macrophytes.

Enhance large woody debris (LWD) abundance.
Lake Cargelligo fish plan

Provide a diversity of hydraulic (still and flowing water) habitats.

Consider introduction of gravel and sand substrates in several shallow marginal
areas which might be adopted by freshwater catfish for nests.

Monitor water quality (particularly salinity and acid soils)

Promote flushing flow between the lagoons and to/from the Murray River

Continue to encourage growth and native fringing/riparian vegetation health
4.2 Priority habitats for native fish conservation
The Lake Cargelligo system, often being isolated from the Lachlan River, has several
five discrete habitats:
1. Inlet channel,
2. Sheet of Water,
3. Lake Curlew & Channel 2,
4. Main Lake Cargelligo and,
5. Outlet channel/Lake Creek
At this stage the priority areas for native fish management and enhancement (see
Section 4.1) appear to be 1) Lake Curlew and Channel 2, and 2) the outlet channel and
Lake Creek. Lake Curlew and Channel 2 are relatively deep habitats that usually remain
connected and both have significant instream habitat. The outlet channel and Lake
Creek have excellent fish habitat values but are presently dry. During a wetting event
these areas would likely support considerable numbers of native fish. The aim for these
habitats (Lake Curlew, Channel 2 and the outlet channel/Lake Creek) should be to
provide appropriate flows and habitat conditions to conserve and enhance native fish
populations. Because these discrete habitats are linked by regulated channels there are
opportunities to deliver water and manage habitats for native fish values. This would
include:

Spring delivery of water

Maintain appropriate quality

Minimise summer filling events

Deliver water that enables fish to move to and from discrete habitats

Mange water to maintain refuge or high value habitats/species

Deliver flows that enable fish to return to the Lachlan River via Lake Creek
Lake Cargelligo fish plan
5. Conclusion
The Lake Cargelligo system supports a significant native fish community but is under
increasing stress from lack of flow and non-native fish. Re-connection of Lake Cargelligo
with the Lachlan River, along with natural wetland wetting and drying cycles is part of a
balanced river ecosystem. Fish passage from the river to the lake and carp control can
be enhanced by operating the regulators with consideration of the biology of native and
non-native fish. Additionally enhancement of several key habitats within the Lake
Cargelligo system will enhance the ecology of native fish populations.
Lake Cargelligo fish plan
6. Management Units
As Lake Cargelligo is made up of a number of operational components that will have
different physical forms and uses, the Lake has been divided into a series of
management units.
6.1 Lachlan River at Lake Cargelligo Weir
Aim: To provide native fish with safe passage through the Lake Cargelligo Weir fishway
while using automated technology to remove adult carp.
Requirements:

Construction of a Williams’ carp cage

Mains power to the Williams’ carp separation cage, daily maintenance and
monitoring during spring.

Removal and commercial disposal of carp.
Key monitoring issues –
1. What native fish species and biomass utilise the fishway?
2. Timing and biomass of carp migration.
Lake Cargelligo fish plan
Figure 9 A concept layout for a Williams’ carp separation cage on the Lachlan River at Lake Cargelligo Weir vertical-slot
fishway. The engineering drawing is by the NSW Department of Commerce courtesy of State Water. The red box indicates the
location of a weirpool carp separation cage and the green box a within-channel separation system.
Lake Cargelligo fish plan
6.2 Inlet Channel
Aim: To provide native fish with safe access between Cargelligo Weir and the inlet
channel
Requirements:

Minimum undershot regulator gate opening protocols to enhance migration and
reduce mortality; this is achieved through reducing turbulence near the regulator,
ensuring adequate tailwater depth (>0.8 m), extended gate opening duration and
minimum gate openings (recommend >0.4 m);

Enhance native fish migration into Cargelligo inlet channel with spring filling and
summer closing of regulator, provide cues for native fish spawning and migration;
and,

Operate for carp control (catching carp moving into and out of Lake Cargelligo),
reduce inflows post Christmas, reduce discharge of small amounts of water over
summer, connection of inlet channel flows with Sheet of Water carefully
managed.
Habitat Values: Mussels, shrimp, turtles, yabbies, aquatic veg.
Key monitoring issues –
1. What native fish species are resident in Lake Cargelligo?
2. What is the timing and cues for native fish and carp movement from Cargelligo
Weir into the inlet channel and from Lake Cargelligo inlet channel into Cargelligo
Weir?
Lake Cargelligo fish plan
6.3 Sheet of Water
Aim: To provide habitat and access for native fish into the Sheet of Water
Requirements:

Provide key habitat/refuge for native fish, particularly small-bodied littoral fish;

Sheet of Water be filled/emptied to maintain maximum native fish abundance,
diversity and health. This will require spring filling and staged drawdown;

Adequate depth (1m+) maintained/manipulated to provide migration and
spawning cues, maintain vegetation and food web structure, maintain suitable
water quality for fish survival, mimic natural variability and hydraulic diversity;

Draining may be required to eradicate carp, return native recruits downstream to
the Lachlan River, trigger vegetation response, and to reset the wetland;

Draining may lead to fish and turtle stranding, stranded carp may need to be
harvested;

Must have carp control at inlet wetland access and exit points; and,

Fish passage into and out from the Sheet of Water is required. Sheet of Water
may require some additional works to act as a fishway and enhance fish
movement.
Habitat Values: Littoral fish habitat, aquatic veg, invertebrates, waterbirds
Key monitoring issues:
1. Survey Sheet of Water to provide information on the fish community and carp
size classes.
2. Assess fish passage rates of fish into and out from the Sheet of Water.
3. Identify key access/egress points for carp and potential control options.
Lake Cargelligo fish plan
6.4 Curlew Water and Channel 2
Aim: Provide habitat for pelagic and large-bodied native fish species, provide
unrestricted movement from the main storage into the inlet and outlet wetlands, and
Lachlan River
Requirements:

Operate water levels to enhance passage of small-bodied fish, young-of-the-year
and large fish into and out of the Curlew Waters wetlands;

Control carp at key locations in the Curlew Water inlet channel – potential
harvest of carp accumulating in Curlew Water as flows enter from inlet channel;

Consideration of water quality in Curlew Water for maintaining native fish;

Manage Curlew Waters for recreational fishing;

Habitat enhancement including re-snagging;

Fish passage from the Curlew Water and the main Lake must be provided which
is maintained by flow;

Carp collection and native fish rescue plan; and,

Carp control and native fish passage in the main Lake.
Habitat Values: Pelagic fish habitat, waterbirds, zooplankton
Key monitoring issues:
1. Test the response of native fish and carp to water level reduction,
2. Assess fish passage requirements between Curlew Water and the Main Lake,
3. Manage native fish rescue and carp collection if Curlew Water dries.
4. Identify key access/egress points for carp and potential control options.
5. Monitor fish populations after re-snagging and habitat enhancement.
Lake Cargelligo fish plan
6.5 Main Lake Cargelligo
Aim: Provide habitat and access for native fish to the main lake and outlet channel
Requirements:

Provide suitable habitat in Main Lake for native fish their recruits and threatened
species;

Enhance the opportunity for the Main Lake to act as permanent fish habitat and
drought refuge. Could use environmental water to do this;

Enhance fish passage between Curlew Water, Main Lake and outflow channel;

Potential to use the northern section as a target for environmental water to
increase wetland area for aquatic macrophyte response and native fish
recruitment for Main Lake;

The Main Lake has great potential to increase fish recruitment, growth and health
in the Lachlan downstream of Cargelligo Weir; and,

Carp and redfin control required at Main Lake.
Habitat Values: Littoral fish habitat, aquatic veg, invertebrates, waterbirds
Key monitoring issues:
1. Test the response of native fish and carp to water level changes,
2. Assess fish passage requirements between the Main Lake, Curlew Water and
outflow channel, and,
3. Manage carp and redfin collection when numbers increase.
Lake Cargelligo fish plan
6.6 Outlet Channel and Lake Creek
Aim: To provide environmental cues and enable migration of native fish downstream
from Lake Cargelligo and potentially upstream into Lake Cargelligo.
Requirements:

Lake Cargelligo will be drained through outlet regulator where flows must be
ramped down gradually.

Fish passage is required in the outlet channel but it is unknown (and probably
unlikely) whether upstream migrating fish can pass the outlet regulator and into
Lake Cargelligo. Hence operation of the outlet regulator needs to maximise
tailwater height (decrease total head) by widely opening the single undershot
radial gate.

The outlet channel is the final carp control point where large carp and recruits
might be collected.

Native fish/carp stranding may occur above regulator and Sheet of Water if
draining occurs.

The outlet channel must be operated to maintain a fish refuge in Lake Creek;

The outlet channel must be operated to maximise native fish recruitment to the
Lachlan River; and

Lake Creek provides connectivity to the Lachlan River regardless of operations.
Habitat Values: Refuge for olive perchlet and other fish species.
Key monitoring issues:
1. Test fish passage upstream and downstream at the outlet regulator,
2. Assess fish response to draining Lake Cargelligo at outlet regulator,
3. Manage native fish rescue and carp collection as the lake dries.
4. Devise options to limit adult and carp entry downstream from Lake Cargelligo into
the Lachlan River
Lake Cargelligo fish plan
6.7 Operational Procedures
These procedures should be used in conjunction with the Lake Cargelligo Environmental
Management Plan (LCCEMP).
The volume and timing of inflows and releases will have a large influence on fish within
the Lake Cargelligo system. However, requirements for other components such as
aquatic vegetation, town water supply and downstream demand must also be taken into
account.
Each management unit has been addressed separately to address the different
purposes they serve, both hydrologically and ecologically. The flow charts must be used
in association with advice from State Water, LCMA, OEH, NSW Fisheries and the
Lachlan Council.
Lake Cargelligo fish plan
6.8 Operations for Inflow Channel
The LCCEMP will outline management targets to protect the ecological features of the
wetland system. The volume and timing of the inflows should then consider the potential
impacts of fish within the system and ensure large carp are not able to enter Lake
Cargelligo through the use of Williams’ carp separation cages. Figure 6 provides a guide
for the decision-making process during the assessment of inflow delivery options
Inflow timing meets
management targets (see
LCEMP)
Yes
No
Allow water delivery to
Lake Cargelligo
Inflow WQ within 20% of
recommended target maximums
Assess if timing and
volume will cue
spawning and/or
migration of key fish
spp.
Yes
No
Assess likely impacts to
existing lake biota if flow
occurs
Assess options to
reduce mortality
through regulator
Ensure CSC
operational and
maintained
Will the rejection of inflows from Lake
Cargelligo result in unacceptable risk
to downstream environments & users
Yes
Risk to fish and
associated biota
unacceptable
Yes
Monitor fish response
to flows
Allow minimum
inflows for
shortest period
No
Continue
monitoring
No
Allow inflows to
lake system
Figure 10 Operational flow chart for inflows to Lake Cargelligo Inlet Channel
Lake Cargelligo fish plan
6.9 Operations for Sheet of Water
The Sheet of Water should be used as an ephemeral wetland and the water level
fluctuate to enhance wetland diversity through resetting processes and also drained to
control carp. The method of water inflow and release from Sheet of Water will determine
operational responses with regard to fish. Figure 7 outlines possible responses to
releases from Sheet of Water.
Inflows for SoW meets
env. targets (see
LCEMP)
Yes
No
Allow water delivery to
Sheet of Water
By-pass SoW and allow water
to continue to Curlew Water
Assess if timing and
volume will cue
spawning and/or
migration of key fish
species
Assess options to
reduce mortality
through regulator
Monitor fish response
to flows
Figure 11 Operational flow chart for inflows to Sheet of Water
Lake Cargelligo fish plan
6.10 Operations for Curlew Water
Curlew Water contains the deepest areas of open water, which may encourage the
presence of both large and small-bodied pelagic fish. The filling and emptying of the
Curlew Water must cater for the migration of these large bodied fish. Figure 8 outlines
the decision-making process when water is being moved to and from Curlew Water.
Water enters from inlet
channel
Via sheet of water
Straight from weir
Ensure fish passage is
unhindered through fishway
Ensure regulator is operated to
reduce fish mortality
Assess the need for
carp control
Ensure carp separation cages are in
operational
Assess options and
implement the removal
carp from the system
Monitor fish response
Figure 12 Operational flow chart for inflows to Curlew Water
Lake Cargelligo fish plan
6.11 Operations for Main Lake
The outlet wetlands will function as ephemeral wetlands but may at times provide habitat
for small-bodied littoral fish species. The greatest threat to fish within these wetlands will
be the stranding of large bodied species and possible hostile water quality. Figure 9
guides the processes operators will need to consider.
Water movement through
curlew water and inlet
channel
Water entering
Monitor fish response
Water leaving
Ensure outlet channel regulator is
operated to reduce fish mortality
Ensure carp separation cages are
operational
Carp control required
No
Continue to
monitor fish
response
Yes
Arrange carp
harvest
Figure 13 Operational flow chart for inflows to Lake Cargelligo Main Lake
Lake Cargelligo fish plan
6.12 Operations for Outlet Channel
The Lake Cargelligo Integrated Monitoring and Evaluation Plan (Thurtell 2008) outlines
water quality targets that should be met before outflows can be released to the Lachlan
River. These targets protect the ecological features of the downstream riverine
environment. The volume and timing of the outflows should then consider the potential
impacts of fish within the lake and riverine system and ensure large carp are not able to
leave Lake Cargelligo and enter the Lachlan River. This can be achieved through the
use of Williams’ carp cages. Figure 10 provides a guide for the decision-making process
during the assessment of outflow releases.
outflow wq meets algal
protocols
Yes
No
Allow water release to
River
Dilution factors in place (see
algal protocols)
Assess if timing and
volume will cue
spawning and/or
migration of key fish
spp.
Yes
No
Assess likely impacts to
riverine biota if flow
occurs
Will the lack of outflows from Lake
Cargelligo result in unacceptable risk
to downstream environments & users
Assess options to
reduce mortality
through regulator
Ensure carp
separation cages
operational and
maintained
Yes
Risk to fish and
associated biota in
River unacceptable
Yes
Monitor fish response
to outflows
Allow minimum
outflows for
shortest period
No
Continue daily
WQ monitoring
No
Allow outflows to
River
Figure 6 Operational flow chart for inflows to Lake Cargelligo Outlet Channel and
Lake Creek
Lake Cargelligo fish plan
7. Regulator operations guide
Inlet regulator: opening

Open in winter/spring (May onwards) or first flow event

Open regulator gate as wide as possible (>0.4 m)

Maximise opening duration (do not open & shut at short intervals)

Maximise tailwater height and minimise turbulence

System water level can vary several cm per day (pulsed water OK)
Inlet regulator closing

Unless there is flooding close regulator around Christmas

Close regulator so there is a 150 mm lake level drop in the first 24 hours, allow to
stabilise and then slowly thereafter (<100 mm in lake water height per day).

If incremental closer is slower than that is better for fish

Observe above & below regulator for native fish accumulation and then maintain
flow if native fish are present.
Outlet regulator

When releasing water maintain maximum depth below regulator.

Maximise regulator gate opening (>0.4 m) during lake and wetland drawdown
8. Native fish rescue
There is a considerable risk that native fish will not be able to some marginal areas
within the Lake Cargelligo system as they dry out (eg. Sheet of Water). To mitigate this
risk a contingency plan is required and this might consist of the following steps.

Strong communication between State Water and NSW Fisheries.

Pre-set times for wetland drawdown.

Commercial fishers or NRM agencies on-site for wetland draw-downs and native
fish rescue.

Development of an adaptive fish rescue plan (gear, harvest and release sites).

Availability of appropriate gear for harvest and transport of native fish and carp.

Standard documentation of fish rescue activities.
Lake Cargelligo fish plan
9. Fish guilds and operational plans
9.1 Large-Bodied Pelagic Fish
The principal aim for large bodied species is to provide:
A: Free movement and migration of fish between Lake Cargelligo and the Lachlan River,
both upstream to Cargelligo Weir and downstream below Lake Creek. This requires that
adequate fish passage be provided to allow free movement between all wetlands
associated with Lake Cargelligo and that structures are designed, constructed and
operated in a way that maximises passage and minimises damage to fish.
B: Adequate nursery habitat within the wetland areas. Juvenile large bodied fish often
require similar habitat and food resources to small-bodied littoral species. In particular,
golden perch will utilise vegetated wetland areas as nursery habitats. Adequate
passage for juveniles must be provided if they are to recruit into adult populations either
within the main cell or in the Lachlan River.
C: Provide adequate water quality, habitat and foodweb values within Curlew Water and
the Main Lake to prevent fish kills and enable survival of large bodied native fish. To a
large extent this will be provided by restoration of wetland health in these areas through
stock grazing control and carp removal, but will require operational attention to prevent
conditions from deteriorating significantly or for extended periods.
D: Incorporate effective measures for separating native fish from carp during all carp
control activities. This includes Carp Separation Cages as well as ad-hoc harvesting
opportunities. This may require that filling and draw-down procedures be timed to
complement the movement and survival of native fish whilst maximising carp control
efficiency.
E: Emergency rescue and translocation activities may be required to prevent fish kills
and stranding of large bodied fish during cell draining (all areas of the Lake system).
9.2 Large-Bodied Benthic Fish
This section relates to freshwater catfish, which were once an abundant and dominant
species in the Lachlan River and associated wetlands and provided a significant
commercial and recreational fishery.
The principal aims for freshwater catfish are:
A: To provide adequate wetland vegetation in areas of Curlew Water and the Main Lake,
to allow catfish to build and maintain nests, which they form amongst submerged aquatic
vegetation. This habitat will also provide food resources for adult and juvenile catfish
and is the key factor in restoring their population to the Lake.
B: Lake draw-down must be timed to allow catfish to build nests and raise young whilst
adequate water levels are maintained. If cells are drained whilst catfish are still building
nests, or young fish are not ready to leave the nests, then catfish recruitment will fail and
younger fish will die.
Lake Cargelligo fish plan
9.3 Small-Bodied Littoral Fish
The majority of fish species that will inhabit the lake will be small-bodied pelagic (open
water) species. These are critical links in the lake foodweb in processing nutrients and
carbon through from algal and particulate sources and moving them through the food
chain to support large-bodied fish and waterbirds. They are also an important
component of insect control and healthy and diverse populations of small bodied fish will
control aquatic sourced insect pests such as mosquitoes and reduce the risk of human
pathogens such as Ross River and Barmah forest virus and Murray Valley encephalitis
effecting humans.
The principal aims for small-bodied littoral species are:
A: Maintain and operate Sheet of Water to maximise the abundance and diversity of
small-bodied fish species. Food, spawning substrates and habitat are all provided
through maintaining complex vegetation, woody debris and leaf litter within this wetland.
B: Small fish are particularly susceptible to poorly designed or operated regulator
structures and procedures. Care must be taken during emptying and filling to reduce
water turbulence and allow passage of small fish between the Lake and Lachlan River.
C: Some small-bodied pelagic species may not move naturally into the Lake during
inflows. We highly recommend that key species be translocated into the Lake system to
allow them to build up strong and sustainable populations within the Lake. This will in
turn build up their populations in the adjacent area, which in turn will allow them to recruit
back into the Lake following over subsequent seasons.
D: Some threatened small bodied fish, particularly purple spotted gudgeons, Murray
jollytail, pygmy perch (and possibly olive perchlet) are likely to require translocation into
Lake Cargelligo to establish self-sustaining populations. The establishment of these
species in the lake will lead to Lake Cargelligo becoming one of the most significant
wetlands in the Murray-Darling Basin and will underpin efforts to increase its
conservation listing (i.e. RAMSAR).
E: Although these fish will naturally spread throughout the Lake, stranding may occur if
draw-down is carried out in the wrong season or too rapidly. There may be a
requirement to capture fish within these areas of the lake and translocate them out under
these scenarios, particularly to protect against the loss of endangered or threatened
fishes.
9.4 Small-Bodied Pelagics
Australian smelt, unspecked hardyhead and Murray jollytail all school in mid water, but
also utilise some structural habitat such as plants and wood. To a large degree, these
species (with the exception of the jollytail which may need to be translocated back into
the lake) will establish across all areas of the Lake with little difficulty. These populations
will provide essential food resources for the large bodied fish and water birds and have
high biomass playing a significant role in wetland food chains and in processing nutrients
and carbon derived from algal sources.
The principal aims for small-bodied pelagic species are:
Lake Cargelligo fish plan
A: To maintain water quality and wetland and lake processes that will provide adequate
habitat and food (especially zooplankton)
B: As with the previous guild, these small species are very susceptible to damage as
they pass through regulator structures. Care should be taken to reduced water
turbulence. Furthermore, these species reproduce generally on an annual basis with
huge numbers of very small juveniles dominating the community at certain times. Filling
should take place in spring when larger adults dominate, but draining should occur later
in summer when smaller fish have outgrown their most sensitive life-stage.
9.5 Operations Calendar
An operations calendar has also been developed as a reference to assist on-ground
staff in implementing the plan’s objectives and to maximise the long term viability of Lake
Cargelligo as a healthy wetland supporting a strong community of native fishes (Table
5).
Lake Cargelligo fish plan
Table 6 Operating calendar to assist in Lake Cargelligo operations which will enhance conditions for native fish
Regulator
Jun
Jul
Aug
Sep
Lake
Cargelligo
inlet regulator
On river rise or State Water discretion, Lake
Cargelligo inlet regulator opened incrementally (0.4
m wide opening to start) in a manner that mimics
natural flow variability until regulators are fully
open.
Following river rise, regulators remain fully open to
allow water level in inlet wetland to fluctuate with
rise and fall of the river.
Oct
Nov
Dec
Inlet regulators remain fully
open maximising extent of
inundation and filling inlet
wetland.
Minimise turbulence below
regulators by maximising tail
water depth.
Short-term opening and closing provides little fish
benefit.
Outlet
regulator
Outlet regulator operated in co-ordination with inlet
regulator to mimic natural flow variability.
Regulator to stimulate upstream migration of fish
by passing flow during the LC filling event. Gate
opening should be maximised (>0.4 m).
Maximise extent of LC
inundation.
Jan
Feb
Reduce lake level by 200
mm over 2 days to cue
exit of native fish.
Hold for 1 week - can be
repeated.
Carp control cages fitted to inlet channel during
filling event.
Remove cages for major flooding.
Remove carp cages in midDecember or at State Water
discretion.
Operate to reduce LC
level by 150 mm over 2
days. Maximise gate
opening for this period.
Can be repeated.
Minimise filling of
wetlands and marginal
carp spawning habitats
post Christmas.
Prevent adult carp from
exiting lake and harvest
fish.
Lake Cargelligo fish plan
Apr
May
Fully closed – unless inlet wetland is
operated as a fish refuge – then manage
by adding small amounts of water to
prevent drying.
Inflows reduced
incrementally to 20-50%
of capacity for 2-3 weeks
and then incrementally
closed
If significant rain event
occurs then maximise
entry of golden perch
from Lake Ck. By fully
opening regulator.
Carp control
Mar
Operate in co-ordination with inlet
regulators to reduce water height in LC if
required following the native fish exit
cue.
Operate in co-ordination with any native
fish rescue or carp harvest efforts.
Exit regulator fully open duringany
release phase.
10. Monitoring, Evaluation and Reporting
A key to improving fish passage in Lake Cargelligo is monitoring and assessment. Initial
monitoring should include measurement of hydraulic parameters (e.g head loss and
depth) to ensure that appropriate hydraulic conditions are present for fish passage. In
some cases more detailed and adaptive monitoring will be needed including sampling of
fish. Sites and sampling strategies should be prioritised. It is important that the project
questions (hypotheses) are appropriate and transparent for all stakeholders. Monitoring
and assessment will detect refinements that may be needed in regulator design and
operation that will contribute to future operations.
An important component of assessment is collection of standardised data and to this end
a generic data sheet is attached (Table 6). These should be submitted to regulating
agencies at regular intervals. On-ground staff will likely require some training in fisheries
techniques and reporting. A key monitoring component is to provide intensive
observation and fish monitoring during the first operation of each lake management unit.
It is likely that knowledge obtained during these procedures will be invaluable in the
adaptive management and ongoing operations of the Lake and produce the most
realistic information regarding the best management options for the various scenarios
addressed throughout this report.
Lake Cargelligo fish plan
Table 7 Lake Cargelligo fish data sheet
Lake Cargelligo fish plan
11. References
Boys, C. (2007). Lateral movements and colonisation of floodplain habitats by fish in
Moira Lake. NSW Department of Primary Industries. 13 pp.
DIPNR (2004). Water Sharing Plan for the Lachlan Regulated Water Source.
Department of Infrastructure, Planning and Natural Resources. NSW Government.
Sydney.
GHD, (2006). Biodiversity outcomes of reconfiguration works. Gutteridge, Haskings and
Davis, Sydney.
GHD (2007). Lake Cargelligo Water Efficiency Project. Gutteridge, Haskings and Davis,
Sydney.
Growns I. (2001). An Assessment of the status of Native Fish and Fish Habitats in the
Lachlan River. NSW Fisheries Office of Conservation.
Harris J.H. and Gehrke P.C. (1997). Fish and Rivers in Stress – the NSW Rivers Survey.
NSW Fisheries Office of Conservation and the Cooperative Research Centre for
Freshwater Ecology, Cronulla and Canberra. 298 p.
Kerezsy, A. (2005). The Distribution and Abundance of Fish in the Lake Cargelligo
system, New South Wales. Honours Thesis. Charles Stuart University. 92 pp.
Llewellyn L.C. (1983). The distribution of fish in New South Wales. Australian Society for
Limnology Special Publication No.7. 23 p.
Ludgate, B. G. and Closs G. P. (2003). Responses of fish communities to sustained
removals of perch (Perca fluviatilis). Science for Conservation 210, 38 p.
Lyon, J., Stuart, I., Ramsey, D., and O’Mahony, J. (in press). The effect of flow on
lateral movements of fish between river and off-channel habitats. Marine and
Freshwater Research.
McDowall, R.M. (1996). Freshwater fishes of south-eastern Australia. Reed Books,
Sydney.
McNeil, D.G., Wilson, P.J., Hartwell, D. and Pellizzari, M. (2008). Olive Perchlet in the
Lachlan River: Population Status and Sustainability in the Lake Cargelligo Region.
South Australian Research and Development Institute (Aquatic Sciences), Adelaide.
McNeil, D.G. and Closs G.P. (2007). Behavioural responses of a south-east Australian
floodplain fish community to gradual hypoxia. Freshwater Biology 52, 412-420.
Murray-Darling Basin Commission (2004). Fish Theme Pilot Audit Technical Report –
Sustainable Rivers Audit. MDBC Publication No. 06/04.
Sainty & Associates (2005). Lake Cargelligo Water Quality
Reconfiguration. Management Issues. Report prepared for GHD Pty Ltd.
Improvement.
Stuart, I.G., Williams, A., McKenzie, J. and Holt, T. (2006). Managing a migratory pest
species: a selective trap for common carp. North American Journal of Fisheries
Management 26, 888-893.
Lake Cargelligo fish plan
Thurtell, L., McKenzie-McHarg, A. and Raisin, G. (2002). Lower Lakes Water Quality
Investigation. Department of Sustainable Natural Resources. Central West Region. NSW
Government.
Lake Cargelligo fish plan