Glenore Weir Cone Fishway
This report has been prepared by Australasian Fish Passage Services (AFPS).
The Glenore Weir Cone Fishway Monitoring Report has been prepared with due care
and diligence using the best available information at the time of publication. AFPS
accepts no responsibility for any errors or omissions and decisions made by other
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Please cite as: Marsden, T. (2017) Glenore Weir Cone Fishway Monitoring Report.
Australasian Fish Passage Services, 29pp.
- iii -
1. Introduction ............................................................................................ 5
2. Methods ............................................................................................... 14
3. Results ................................................................................................. 16
4. Discussion ............................................................................................ 21
5. Conclusion ........................................................................................... 27
6. Recommendations. .............................................................................. 28
7. References ........................................................................................... 29
The Glenore Weir Fishway project was initiated to meet the legislative requirements
for the continued provision of fish passage in the Norman River as part of the raising
of Glenore Weir. The major specific objective of this report was to evaluate the success
of the new cone fishway technology constructed on the new weir.
In the 2017 wet season, monitoring of the cone fishway was completed. In total, 27
species of fish were collected from the cone fishway, meeting its original design
objectives of providing passage for the migratory fish community of the Norman River.
In fact, the innovative cone design passed thousands of fish from a wide range of fish
species and size ranges.
The major outcomes were:
• Passage of a wide range of fish species, the most recorded in any tropical
• Achievement of the objective of efficient passage of the majority of species.
• Extension of the functionality of the weir from passing fish for 15% of flow to
100% of flows.
• Upstream passage of more than 70,000 fish per year.
• Fishways that make a major contribution to restoration of native fish
communities in the Norman River Basin.
For Carpentaria Regional Council, the Glenore Weir fishway has been a significant
step forward in restoring the environmental values of the lower Norman River and fulfils
its obligations under the Fisheries Act to maintaining fish passage in the Norman River.
The Glenore Weir Fish passage project was initiated to help ameliorate the impacts of
the raising of the existing Glenore Weir on fish passage in the Norman River Basin.
The old weir has long been recognised as a barrier to fish migrations and would have
been detrimental to aquatic habitats and fish communities in the lower reaches of the
Norman River and tributaries. The raising of the old weir to a new height, to increase
the certainty of supply of water to the township of Normanton, would further impact on
fish movements and thus triggered Fisheries legislation. This required the proponents
to construct a suitable fish passage system at the site at the same time as the weir
To ensure that the fish passage system constructed at the site was successful a
monitoring program was to be developed and implemented at the site. This required
that monitoring be undertaken during the first wet season of operation. The monitoring
would determine the effectiveness of the fish passage system and provide feedback
to the Department of Agriculture and Fisheries on the success of the fish passage
system at meeting the objectives set out during the design process. This report
provides the results of this monitoring program.
1.1. Norman River Basin
The Norman River Basin encompasses a catchment area of 50,423 km2 (wetlandinfo
2017) and flows into the south-east corner of the Gulf of Carpentaria near Karumba in
Queensland. The system drains a large relatively low and flat catchment, that stretches
from the western side of the Great Dividing Range in the east, to the gulf savannah
plains in the west. The area is largely unpopulated, with little development beyond
cattle grazing in the catchment. The major streams of the catchment include the
Norman River, Clara River, Yappar River, Belmore Creek and Walker Creek. The
Norman River has a low gradient of approximately 0.5m fall per kilometre of length
and terminates in a wide alluvial plain near Karumba.
The climate of the Norman River is dry tropical, with most rainfall received between
December and March and an extended dry season with little rain throughout the
remainder of the year. The catchment area receives on average between 500 mm and
1000 mm of rain per year, but the high evaporation rate (2000 mm per year) ensures
mostly dry conditions within the catchment and a highly seasonal stream flow. The
catchment has a large range of temperatures with average summer high temperatures
over 40oC and winter low temperatures below 10 oC (Wetlandinfo 2017).
The location of the Norman River in the dry southeast corner of the Gulf of Carpentaria
has led to a highly seasonal flow pattern. Flows within the system are restricted to the
wetter months, January to April, with little flow outside of these times (Figure 1). During
this period, significant flows can occur that lead to extensive flooding. The Norman
River has a long and well documented history of flooding, with the town of Normanton
regularly cut off by flooding in the Norman River during the wet season. The extensive
river floodplains mean that there is regular connectivity of waterways via distributary
networks during major flood events (Hydrobiology 2005). However, due to the
unpredictable nature of rainfall in this region flows during the wet season may also be
very small. For example, the peak flow during the 2008/09 wet season was around
3170m3/s, whereas peak flows during the 1984/85 wet season only reached 11m3/s
During the dry season (May-Nov) there are no flows within the system and all streams
dry back to a series of waterholes. Only in the larger lowland reaches and in some of
the upper rocky gorge streams do waterholes persist throughout the year.
Figure 1. Average monthly flows over Glenore Weir (SMEC 2014)
1.3. Fish Communities
The Norman River contains a biodiverse and important fish assemblage that is
relatively unique in tropical Australia with at least 49 species being recorded from the
catchment, including a variety of freshwater, estuarine/freshwater and endemic
species (Burrows and Perna 2006 and SMEC 2014) (Figure 2).
Almost all of these fish species migrate as part of their life-history with approximately
half moving between the estuary and freshwater (Pusey et. al. 2004). Glenore Weir,
112 km from the river mouth, is a major fish passage barrier and has contributed to
fragmentation of fish migration pathways between the estuary and freshwater. Several
previous studies have been undertaken in the catchment, these have shown between
26 and 30 fish species in the catchment. However due to the remote nature of the
catchment and when all studies are combined a total of around 49 species of fish have
been identified from the freshwater reaches. Of the 49 freshwater species, there are
seven catadromous species, eighteen amphidromous species with the remaining
species being considered potamodromous (Table 1), although limited information is
available for some species.
Figure 2. Migratory species of the Norman River Basin recorded in this study, a. Hyrtl’s
tandan, b. giant perchlet, c. barramundi, d. bony bream, e. undescribed tandan
(juvenile), f. tarpon, g. undescribed tandan (adult), h. archerfish, i. gulf grunter.
Table 1. Fish species and migration strategies of fish in the Norman River Catchment (Pusey
et.al. 2004, Burrows and Perna 2006 and SMEC 2014). Migration Type - A = amphidromous, C =
catadromous, P = potamodromous.
Common name Species Migration
Lesser salmon catfish
Triangular shield catfish
Neosilurus sp. nov.
Common name Species Migration
Glossogobius sp. 2 (munroi)
Melanotaenia splendida inornata
Seven‐spot archer fish
The species listed in Table 1, provides a comprehensive record of the fish community
of the Norman River Catchment. Within this list there are several rare, threatened and
endemic species. Species such as freshwater sawfish and the freshwater stingray are
listed species that have undergone population declines in many areas (Peverell 2009).
Both species freely move between freshwater and estuarine habitats and maintaining
free migration pathways is a critically important aspect of their conservation. (Peverell
2009). Other species such as the undescribed neosiluris catfish are only found in the
Norman River catchment. While little is known of this species, its movement through
the fishway as both adults and juveniles indicates the species is migratory.
1.4. Migratory Patterns
As the Norman River basin sits in the dry tropical zone of the Gulf of Carpentaria, the
fish species within the system undertake migrations associated with the short flows
that occur within the basin during the wet season. In tropical systems, a wide diversity
of species migrate upstream all year-round, whenever flow is available. However, the
largest movements are recorded associated with the elevated flows of the wet season.
As there are generally no flows occurring outside of the wet season in the Norman
River catchment, all migrations are restricted to this time. In adjacent catchments, such
as the Flinders River, where flows occur over a longer period of the year, fish
migrations occur also on low flows in the dry season.
In the Norman River catchment, the short wet season forces a condensed migration
pattern for the local fish species. The first river flows at the beginning of the wet season
are thought to be a major movement cue for many species such as the forked and
eeltail catfishes, grunters, perchlets and bony bream. During the season, high and low
flows attract various different fish species and sizes. Low and moderate flow periods
represent a significant period for fish movement in the area for small species such as
empire gudgeon and perchlets and juveniles of larger species such as juvenile catfish,
giant glassfish, bony bream, archer fish and grunters. The higher flows present
opportunities for larger bodied fish such as freshwater sawfish, adult catfish and sub-
adult barramundi to undertake migrations. In general, throughout the wet season
whenever flows occur there will be fish migrations occurring.
1.5. The Requirement for Fish Passage
The construction of a barrier on a river can block or delay upstream fish migration and
thus contribute to the decline and even the extinction of species that depend on
longitudinal movements along the stream. Habitat loss or alteration, discharge
modifications, changes in water quality and temperature, increased predation pressure
as well as delays in migration caused by barriers are significant issues. Barriers to fish
passage are identified as one of eight key threats to native fish populations (MDBC
2012). In regulated rivers throughout the world lack of fish passage is frequently
identified as a major cause of the decline of freshwater fish (Barrett and Mallen-
All fish utilise and depend on being provided with access to the aquatic habitat which
supports all of their biological functions. Migratory movements of fish are described by
two broad classifications; potamodromy and diadromy. Potamodromous species
migrate solely within the freshwaters of a river system. Diadromous species migrate
between fresh water and sea water and are further classified into catadromous,
amphidromous and anadromous species. Catadromous species migrate to the sea for
breeding and back to freshwater to feed and grow. Amphidromous fishes migrate
between freshwater and the sea but not for the purpose of breeding. Anadromous
species migrate into freshwater to spawn, with adults generally being resident in
Regardless of migratory classification, all fish need to move along streams over scales
of metres or hundreds of kilometres to:
• seek shelter and refuge;
• enhance dispersal of young fish;
• counter downstream displacement following high flows;
• recolonise after droughts.
Movements can be regular seasonal migrations undertaken by much of the population
or they can be less regular and less well defined. In tropical environments fish
movement and migration occurs throughout the year and during high and low flows.
Fish often respond very quickly to subtle movement triggers such as localised rainfall
1.6. Glenore Weir
Glenore Weir (Figure 3 & 4) was constructed in 1968 and is located about 103km from
the mouth of the Norman River at Karumba. The weir is located just above the tidal
limit of the Norman river, with a single large waterhole downstream, before tidal
influence. The weir is a concrete overfall weir that was 2.1m high in its old configuration
and has been raised to 3.68m as part of the current project. The new weir is 250m
wide, with a central ogee crest and concrete and rock abutments. The weir forms a
3.3km long weir pool that provides the main water supply for the townships of
Normanton and Karumba.
From 1968 to 2016 no fish passage was incorporated into the weir and the weir
impacted on the migrations of fish communities during that time. As the weir was
relatively small and drowned out on a regular basis this impact was not great, with
many species of diadromous fish still found upstream of the weir. However, it was still
recognised for the fish accumulations that occurred below the weir. The greatly
enlarged new weir was deemed to be likely to have a much greater impact on fish
migrations and as such was required to include fish passage in the design.
Figure 1. Glenore Weir prior to raising in 2016, wall height 2.18m.
Figure 4. Glenore Weir after raising in 2016, wall height 3.68m
1.7. Glenore Weir Fishway
While long recognised as a barrier to fish movement, it was not until the recent raising
that Glenore weir incorporated fish passage into the design. The fishway was designed
specifically for the fish communities of the Norman River and was based on successful
designs used elsewhere in Queensland. The design needed to be capable of passing
very small and juvenile fish (<20mm), as well as large fish such as freshwater sawfish
(1.5m+), freshwater stingray (1m) and barramundi (600mm). The design also needed
to be relatively maintenance free and have a fixed crest level that maintained water
supply levels in the weir pool without draining the pool. To this end the precast
concrete cone fishway design (Figure 5) was chosen as the most suitable fishway that
could fulfil this brief. Other designs considered in the design evaluation phase included
the vertical slot fishway and the trapezoid fishway, however these could not meet the
fish size requirements.
Figure 2. Left bank side of Fitzroy River Barrage showing the fishway, Gate 1 and ogee
crest structures. Image from Google Earth.
The cone fishway was incorporated into the left abutment of the weir and constructed
perpendicular to river flow. It consisted of a 5.0m wide sloping channel into which 40
precast high/low cone baffles (Figure 6) were inserted. The downstream entrance to
the fishway is located directly adjacent to the spillway and has a turning pool that
directs flow downstream for maximum attraction.
Within the fishway channel, baffles were spaced 1.5m apart, with each baffle being
60mm lower than the next baffle upstream. The baffles consisted of high cones and
low cones which enabled the design to cope with up to 900mm of headwater variation.
During low flows fish could ascend through each of the 6 slots between the cones. As
headwater rises the low cones become inundated, creating a wider channel suitable
for large fish like sawfish. The high cones maintain reduced flow conditions that are
suitable for smaller fish to ascend during higher headwater levels.
The upper most baffle of the fishway has an invert level set 200mm lower than the
crest level of the weir. This promotes low flows to go through the fishway and creates
the best possible attraction conditions at the fishway entrance.
In addition to the cone fishway on the left abutment a rock ramp fishway was
constructed on the right abutment. This fishway consists of a 15m wide, 45m long low-
slope ramp of rock concreted in place (Figure 7). The rock ramp fishway does not
become engaged until significant flows occur in the system, with a control level of
3.99m. This ensures that fishways on the weir operate from commence to flow until
near drownout of the weir.
Figure 6. Illustration of the layout of pre-cast cone baffles within the fishway channel.
Figure 7. Secondary rock ramp fishway on the right abutment.
The assessment of the Glenore Weir cone fishway was based on evaluating the
successful passage of all fish passing through the fishway during the first wet season
of operation for the fishway. This was completed by comparing the fish community
composition and size at the entrance to the cone fishway with that from exit of the
fishway. In this way, the passage success of different species and different life stages
of those species could be compared. The hypothesis behind this sampling
methodology is that an efficiently operating fishway will have similar fish communities
and size ranges at the top of the fishway (successful ascent) and the bottom of the
fishway (attempting ascent). This direct top/bottom fishway comparison methodology
is useful when sampling by necessity must be carried out over a short timeframe, as
to detect changes to fish communities in the river upstream and downstream of the
fishway may require many years of sampling.
To complete this sampling two lightweight single cone traps were manufactured from
steel square tube and covered with standard 70% shade-cloth with an average mesh
diameter of 1.5 mm (Figure 18). The traps had a single horizontal cone with a 150mm
opening that collected fish from three cone slots, covering either the low cone or high
cone section of the channel. This trap could collect fish as small as 10mm in length,
while still capturing larger fish and not becoming clogged with algae that could affect
Figure 3. Cone fishway traps located at the exit of the fishway during a top sample.
A sample of fish that had successfully ascended and exited the fishway was obtained
by placing the trap immediately upstream of the last fishway baffle as shown in figure
8. Traps were installed to prevent fish escaping from the fishway, with a tight fit against
the baffle walls to prevent escape. A sample of fish that were attempting to ascend the
fishway was obtained by placing the trap immediately upstream of the first fishway
baffle that displayed a headloss at the bottom of the fishway. As the tailwater was
relatively stable throughout the sampling period this generally meant the bottom
sample trap was placed in the 1st resting pool upstream of ridge 10.
Traps were set for 2hrs in either the top or bottom of the fishway in a randomised
paired top/bottom sample, for a total top/bottom paired sample time of 4hrs. The 4hr
paired sample was undertaken in both the morning (7.30am to 11.30 am) and
afternoon (12.30pm to 4.30pm). This increased sampling effort to account for diurnal
movements, reduced escapement from the traps and reduced the effects that fish
schooling could have on the sampling.
At the conclusion of each 2hr sample the trap was manually lifted out of the fishway
and fish released into a 100-litre tank partly filled with aerated water. All fish captured
during fishway sampling were identified to species level, counted and a sub-sample of
50 fish from each species were measured to the nearest millimetre (fork length for
forked-tail species, total length for all other species). Fish were then released into the
Figure 9. Cone fishway traps located first resting pool of the fishway during a bottom
Over the duration of the sampling, 27 species of fish were captured either in the top or
bottom of the cone fishway (Table 2). Bony bream species (Nematalosa come and
Nematalosa erebi) were the most abundant species overall, accounting for 28% of the
total catch. Macleay's Glassfish (Ambassis macleayi) were the second most abundant
species (9.5% of catch), while longtom (Strongylura krefftii), 7.8% of the catch,
spangled perch (Leiopotherapon unicolor), 6.5% of the catch and giant glassfish
(Parambassis gulliveri), 4.2% of the catch, were the next most abundant species. All
other species where found in lower numbers, with no other species forming greater
than 3% of the total catch.
Despite relatively similar sampling intensity, more fish were captured at the exit of the
cone fishway than at the entrance, with the exit of the fishway accounting for 67% of
the total catch. This is further reflected in the catch rate, with the catch rate from the
bottom of the fishway (14.1 fish/hr) being lower than that from the top of the fishway
The top of the cone fishway captured one less species in total (23 species) than the
bottom of the fishway (24 species). Four species, Common Ponyfish, (Leiognathus
equulus), unidentified goby (Glossogobius sp.), toothless catfish (Anodontoglanis
dahli) and sleepy cod (Oxyeleotris lineolatus) were only captured in the bottom of the
fishway. While three species, Flathead goby (Glossogobius giuris), Hyrtl’s tandan
(Neosilurus hyrtlii) and Tarpon (Megalops cyprinoides) were only captured at the top
of the fishway. All of these species except the common ponyfish were captured in very
low numbers (<2 individuals).
The data from the entrance and exit of the cone fishway was compared to determine
differences in size classes for abundant species entering and exiting the fishway.
Data from the length frequency graph for bony bream indicates that a sizable
proportion of fish of the smallest size classes were successfully ascending the cone
fishway (Figure 10). Generally, a higher percentage of smaller fish were found at the
entrance of the fishway, however due to the relatively small sample size some variation
could be expected. The cone fishway successfully passed fish as small as 30mm, but
sampling indicates that these smaller fish may be slightly inhibited in their movement
Table 2. Species and number of fish sampled from top and bottom of the cone fishway.
Species Common Name
Lesser salmon catfish
spot archer fish
Neosilurus sp. nov.
Melanotaenia splendida inornata
Total Number of Fish
Total Sampling Time (hrs)
Catch Rate (Fish/Hour)
Total Number of Species
Figure 4. Length frequency of bony bream from entrance and exit trap samples.
Data for Macleay's glassfish and giant glassfish were combined to allow analysis and
due to the difficulty of identifying these species apart at these small sizes. The
combined length frequency for both species indicated that all size classes were
successfully ascending the cone fishway (Figure 11). Fish as small as 10mm were
captured at the top of the fishway and indicted that these species could successfully
Figure 115. Length frequency of long-finned eels captured in the March 2016 entrance
and exit trap samples.
Data from the length frequency graph for longtom indicated that most fish passed
through the cone fishway successfully, with even small fish successful (Figure 12).
Longtom, being a long thin species were generally larger than other species that
ascended the fishway, but the largest and smallest of this species could ascend the
Figure 126. Length frequency of longtom from both entrance and exit trap samples.
Many other species successfully ascended to the top of the fishway, but their total
numbers were too low to allow length frequency analysis. However generally for these
species, all size classes could successfully ascend to the top of the fishway. In Table
3 the largest and smallest fish for each species recorded from the top and bottom
samples are presented. Note that only species that were not present in either one of
the traps have dissimilar size ranges, with all species captured in both locations having
generally comparable size ranges.
Table 3. size range of all species captured from top and bottom sampling of the cone
Bottom (size – mm)
Top (size – mm)
Lesser salmon catfish
Seven‐spot archer fish
At Glenore weir, a new complimentary cone and rock ramp fishway was constructed
to assist the passage of fish past the new weir constructed for Normanton’s water
supply. The new cone fishway was determined by this study to be quite successful,
with large numbers of large and small fish successfully ascending the fishway. No
sampling was undertaken of the rock ramp fishway as flows in the river were not
sufficient to engage this fishway. In general, the sampling of the cone fishway indicated
that it was suitable for almost all species, with only one species (ponyfish) appearing
to be unable to ascend the fishway.
4.1. Increased Fish Passage
The operation of the new fishway has greatly increased the opportunity for fish to pass
the weir into the Norman River upstream. Prior to the construction the new weir and
fishway, fish passage was blocked by the existing Glenore Weir, which did not include
any fish passage. Fish passage could only occur at the site when drown out flood flows
occurred. These allowed fish to swim over the weir into the pool upstream. Based on
the gauged data from the site and the estimated drown out flow for the weir of 232
cumecs (SMEC 2014), passage past the weir would have been available for 16% of
the time the river flowed during the wet season previously. Meaning that for 84% of
the time fish could not pass the weir despite there being flow in the river.
With the installation of the fishway, that operates from commencement of flow through
to the drownout of the new weir, fish have full passage for the entire wet season. Since
the duration of flows within this system are relatively short compared to many other
streams, ensure 100% passage availability is critical to ensuring fish communities can
4.2. Fish Numbers
Although sampling was undertaken throughout the wet season, the sampling was
relatively brief and partially compromised by the right abutment breach. It therefore
can only provide a snapshot of the fish communities that would be migrating past
Glenore Weir. However, the fish passage rate achieved during sampling still indicates
that a considerable number of fish would have passed the fishway into the Norman
Extrapolating from the sampling data it is likely that the cone fishway on Glenore Weir
will pass at least 70,000 fish annually, contributing to significant restoration of fish
numbers of the lower Norman River catchment. This increase in fish numbers is likely
to significantly enhance fish communities upstream of the weir over the coming years
and validates installing the new fishway.
The economic benefit to the Norman River and the Carpentaria Region of the new
fishway is difficult to measure without extensive before and after studies of the
fisheries. However, the addition of more than 70,000 fish annually to the river upstream
will likely have a positive impact on fisheries in the region. With many of the species
captured during the sampling being commercially or recreationally important species,
providing these fish with access to freshwater nursery habitats upstream can only
improve the productivity of this system. Hence, providing improved access for these
species through the Glenore Weir cone fishway will help to boost populations and in
the long-term provide major benefits to the Norman River recreational fishery.
4.3. Small Fish Passage
Several species were captured in large enough numbers that allowed comparison of
their length frequencies between the entrance and exit of the fishway. This is a good
reference to determine if any life stages, particularly small sizes, are inhibited in their
movement through the fishway. The results of this analysis indicated that the cone
fishway could successfully pass smaller fish. Species such as the bony bream could
pass the cone fishway as small as 30mm, with no significant difference between
entrance and exit samples. Glassfish species (Figure 13) also had comparable results,
with glassfish as small as 10mm ascending the cone fishway.
Figure 13. Juvenile giant glassfish and adult Macleay's Glassfish from the exit trap.
Increasing passage of these smaller fish is critical to the long-term survival of these
species. The lack of passage for small fish has been identified at several other fishway
sites as leading to declines in fisheries (Stuart 1999, Marsden et. al. 2017). Delaying
their successful passage and forcing these fish to congregate below a weir is likely to
have disastrous consequences on their mortality.
As an example, the Fitzroy Barrage on the Fitzroy River near Rockhampton has
extensive predation of small fish from other animals such as birds, catfish (Figure 14),
barramundi and bull sharks. These predators can quickly deplete the stocks of juvenile
fish delayed while passing the barrage, negatively affecting the production of the whole
river system. With the fishway in operation at Glenore Weir, no accumulations of these
small fish were detected below the weir, a good indicator that the fishway is allowing
free passage of these fish. Successfully passing these fish through the cone fishway
will increase survival rates and increase the productivity of fisheries above and below
Figure 14. Large predators consume copious quantities of juvenile fish that are unable
to pass migration barriers.
4.4. Large Fish Passage
The passage of large fish through the cone fishway was also quite successful, with
moderate numbers of barramundi, longtom, catfish and large bony bream observed
moving through the cone fishway during the sampling. Adult freshwater stingrays
(Figure 15) were also observe moving upstream within the fishway, the first time this
species has been recorded using a fishway. Although not captured in the sampling
stingray were observed moving through several slots as they progressed upstream.
Although wider than the slots, the stingray could fold back its wings as it passed
through the slot to make a successful ascent.
Freshwater sawfish were not observed during the sampling. As this species is listed
as endangered and is quite rare it is not unexpected that it was not encountered.
Further sampling of the system for sawfish is warranted to determine if they are found
in the system (highly likely given the multiple reports from local fishermen during
sampling) and if they can successfully ascend the fishway for which it was specifically
Figure 15. Adult Freshwater stingray using the fishway.
4.5. New Fish Species
The sampling of the cone fishway also revealed a new species of catfish (Figure 16)
that has not been recorded migrating previously and has only been recently been
discovered. The undescribed species is thought to be a member of the Neosilurus
family, although some reports suggest that it may be a member of the Porochilus
family. The species has only been recorded as adults in the upstream reaches of the
Norman River previously, so the capture of this species in the lower Norman River
extends the known range for this species.
Previously only adults had been collected from the river upstream, so the presence of
an adult and multiple juveniles during fishway sampling is the first record of juveniles
of this species. The movement of adults and juveniles through the fishway also greatly
enhances the knowledge of this species. The sampling shows that there is potential
for a downstream spawning migration of adults followed by an upstream dispersal
migration of juveniles and adults. This highlights the need to maintain free passage
along the river system for both adults and juveniles.
Figure 16. Adult and juvenile Neosilurus catfish of an undescribed species.
While not a species new to science the capture of giant glassfish successfully
ascending the fishway is the first record of this species undertaking migrations.
Previous information recorded that this species bred in July in the upper reaches of
streams (Merrick and Schmida 1984). However, the sampling at Glenore Weir
captured both adults and juveniles (Figure 17) successfully ascending the fishway.
The movement of juvenile giant glassfish at this time (February/March) contradicts the
previous records for recruitment of this species and may point to dispersal migrations
of this species occurring during the wet season that have not previously been
Figure 17. Adult (left) and juvenile (right) giant glassfish that successfully passed
through the cone fishway.
4.6. Effects of the Weir Abutment Breach
The sampling of the fishway during the 2017 wet season was affected by the breach
of the right abutment that occurred early in the season. This breach passed much of
the volume of water flowing through the site past the weir and around through a new
channel on the right abutment. The water from this breach entered the tailwater pool
well downstream of the weir. When fish are migrating, they are attracted to large flows
at barriers as these point to flow paths past the barrier. The large flow created by the
right abutment breach would have negatively affected the movement of fish to the
fishway entrance as the flow would have attracted large numbers of fish away from
the weir. Even though good numbers of fish were attracted to the fishway and
successfully ascended, the presence of the breach would have reduced the number
of fish that could find the fishway entrance.
Figure 18. Breach around the weir on the right abutment.
Later in the season the breach was sealed and normal attraction flows occurred at the
site. Under these conditions, fish could easily find the fishway entrance as it was
directly adjacent to the spillway and the flows that occur there (Figure 19).
Figure 19. Location of the fishway entrance adjacent to the spillway of the weir.
Even though the cone fishway was sampled in less than ideal circumstances with the
right abutment breach, it still recorded fish passage comparable to other fishways in
Queensland (Marsden et. al. 2017). Due these circumstances during sampling, the
maximum passage rate of 25 fish/hour is likely to be only a fraction of the highest likely
rate of passage.
The construction of the cone fishway on the newly raised Glenore Weir has vastly
increased the passage of fish species within the Norman River and will contribute to
maintaining and improving the fish communities upstream of the weir. The modest
investment in the cone fishway has increased fish passage rates to more than 70,000
fish per year. For the Carpentaria Regional Council, the Glenore Weir fishway has
been a significant step forward in restoring the environmental values of the Norman
River upstream of the weir and can be summarised as
1. Improved fish passage past the weir, with access increased from 16% of flows
to 100% of flows that occur in the river.
2. A reduced reliance on flood flows to provide passage as passage will now be
provided the fishways whenever there is flow in the river,
3. an exponential increase in the number of fish passing, with at least 70,000
extra fish able to use the fishway when previously none would pass due to the
4. the successful passage of a multitude of small-bodied fish (<45 mm long) very
few of which would have survived predation below the weir previously,
5. the successful passage of large fish past the weir that would have been
restricted in their passage due to the weir.
Building on these achievements with further fish passage improvements at other
barriers in the region, such as at Walkers Creek, fish communities in the streams of
the Carpentaria Regional Council area can be maintained and even enhanced to
provide opportunities for the large number of recreational and commercial anglers that
utilise the streams of the region.
The Glenore Weir fishway has met its design requirements for the passage of fish past
the new weir, but could be further complemented with:
• Direct monitoring of sawfish communities in the Norman River to determine if
this species can successfully migrate past Glenore Weir.
• Investigation of fish passage options for other barriers in the region,
o Providing fish passage at the old causeway upstream of the railway line
on the Norman River (downstream Glenore Weir).
o Providing fish passage at the old causeway upstream of the Karumba
Road on Walkers Creek.
o Maintenance of the fishways on the Flinders, Bynoe and Little Bynoe
Rivers to ensure they meet their design objectives.
Barrett J. and Mallen-Cooper M. (2006) The Murray River’s ‘Sea to Hume Dam’ fish
passage program: progress to date and lessons learned. Ecological Management &
Burrows, D.W. & Perna, C. (2006) A Survey of Freshwater Fish and Fish Habitats of
the Norman River, Gulf of Carpentaria. Report No. 06/31 Australian Centre for Tropical
Freshwater Research. James Cook University, Townsville, Queensland, 39 pp.
Hydrobiology Pty Ltd, (2005), Ecological and Geomorphological Assessment for the
Gulf and Mitchell Water Resources Plan. Consultant Technical Advisory Panel Report
to The Queensland Department of Natural Resources and Mines.
Marsden, T., Berghuis, A. and Stuart, I. (2017) Fitzroy Barrage, Cone Fishway
Upgrade and Monitoring Report. Report to the Fitzroy Basin Association for the Fish
Friendly Fitzroy Project. The Fisheries Collective, 49pp.
MDBA (2012). Key threats to native fish. Flyer for the Murray-Darling Basin
Commission (MDBC). Source:
Peverell, S. (2009) Sawfish (Pristidae) of the Gulf of Carpentaria, Queensland.
Masters (Research) thesis, James Cook University. 163pp
Pusey, B.J., Kennard, M.J. and Arthington, A. (2004). Freshwater Fishes of North-
Eastern Australia. CSIRO publishing: Collingwood, Victoria.
SMEC (2014) Glenore Weir, Concept Design for Raising of Glenore Weir, Fishway
and Pump Station. Report to Carpentaria Regioanl Council. 82pp.
Stuart, I.G. and Mallen-Cooper, M. (1999). An assessment of the effectiveness of a
vertical-slot fishway for non-salmonid fish at a tidal barrier on a large
tropical/subtropical river. Regulated Rivers: Research and Management 15:575-590.
Wetlandinfo (2017) Norman River drainage sub-basin — facts and maps, WetlandInfo,
Department of Environment and Heritage Protection, Queensland, viewed 29 May