Industry & Investment NSW – Fisheries Research Report Series

Industry & Investment NSW – Fisheries Research Report Series: 28

Lower Murray-Darling Catchment Action Plan: Fish Community Monitoring Report Card for 2009/10

by Dean Gilligan

November 2010

ISSN 1837-2120

Industry & Investment NSW – Fisheries Research Report Series This series presents scientific and technical information on general fisheries research and the documents in the series are intended to be progress reports on ongoing investigations. Titles in this series may be cited as publications, with the correct citation on the front cover.

Fisheries Research in New South Wales Fisheries research activities in the NSW Department of Primary Industries are based at various centres throughout the state. The studies conducted cover commercial and recreational fisheries and aquaculture, and conservation issues in coastal and riverine areas. The major role of the research is to provide information upon which relevant fisheries management policies and strategies are developed, monitored and assessed in terms of the Department’s obligations under the NSW Fisheries Management Act, 1994.

Title: Lower Murray-Darling Catchment Action Plan: Fish Community Monitoring Report Card for 2009/10 Authors: Dean Gilligan Published By: Industry & Investment NSW (now incorporating NSW Department of Primary Industries) Postal Address: PO Box 21, Cronulla, NSW, 2230 Internet: www.dpi.nsw.gov.au

© Industry & Investment NSW (Industry & Investment NSW) This work is copyright. Except as permitted under the Copyright Act, no part of this reproduction may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owners. Neither may information be stored electronically in any form whatsoever without such permission.

DISCLAIMER The publishers do not warrant that the information in this report is free from errors or omissions. The publishers do not accept any form of liability, be it contractual, tortuous or otherwise, for the contents of this report for any consequences arising from its use or any reliance placed on it. The information, opinions and advice contained in this report may not relate to, or be relevant to, a reader’s particular circumstance.

ISSN 1837-2120 Note: Prior to July 2004, this report series was published by NSW Fisheries as the ‘NSW Fisheries Resource Assessment Report Series’ with ISSN number 1440-057X. Then, following the formation of the NSW Department of Primary Industries the report series was published as the ‘NSW Department of Primary Industries – Fisheries Final Report Series’ with ISSN number 1449-9959. The report series is now published by Industry & Investment NSW as the ‘Industry & Investment NSW – Fisheries Final Report Series’ with ISSN number 1837-2120.

2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

TABLE OF CONTENTS

TABLE OF CONTENTS...... I

LIST OF TABLES...... II

LIST OF FIGURES ...... II

ACKNOWLEDGEMENTS...... IV

NON-TECHNICAL SUMMARY ...... V

1. INTRODUCTION...... 7

2. METHODS ...... 8

3. PROGRESS TOWARD THE LOWER MURRAY DARLING CATCHMENT ACTION PLAN FISH ‘NATIVENESS’ TARGETS FOR RIVERINE HEALTH...... 15 Native : Alien species ratio...... 15 Native : Alien abundance ratio...... 16 Alien biomass ratio...... 16 4. FISH ASSEMBLAGE PARAMETERS USEFUL FOR UNDERSTANDING THE ‘HEALTH’ OF FISH COMMUNITIES...... 23 Species richness...... 23 Total abundance...... 24 Total biomass ...... 25 Proportion of total species richness that are native species ...... 26 Proportion of total abundance that is native species ...... 27 Proportion of total biomass that is native species...... 28 Proportion of total catch made up of native fish recruits...... 29 Proportion of total catch suffering from a health condition ...... 30 5. TRENDS IN ABUNDANCE AND RECRUITMENT OF INDIVIDUAL FISH SPECIES...... 33

6. WATER QUALITY AND HABITAT PARAMETERS COLLECTED FROM EACH SITE DURING FISH SAMPLING...... 45 Water quality ...... 45 Habitat ...... 48 7. DISCUSSION ...... 52

8. REFERENCES...... 59

I&I NSW – Fisheries Research Report Series: No. 28 i 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

LIST OF TABLES

Table 1. Primary and secondary sites sampled within each of five catchment zones in the Lower Murray-Darling CMA catchment area...... 12 Table 2. Tertiary (wetland) sites associated with primary and secondary riverine sites within each of four riverine catchment zones in the Lower Murray-Darling CMA catchment area...... 13 Table 3. The proportional change in the abundance of each species (across the whole catchment) between the benchmark surveys in 2004 (Gilligan 2005), the 2009 annual survey (Gilligan 2009) and 2010 (this survey)...... 33

LIST OF FIGURES

Figure 1. Flow data from gauging stations within the Lower Murray Darling CMA area spanning the period over which the CMAs fish monitoring program has collected fish assemblage data...... 9 Figure 2. Lake levels from gauging stations within the Menindee Lakes and Lake Victoria spanning the period over which the CMAs fish monitoring program has collected fish assemblage data...... 10 Figure 3. The locations of primary and secondary fish survey sites sampled in the 2010 season...... 14 Figure 4. Comparison of the median native : alien species ratio observed in 2006, 2007, 2009 and 2010 with the benchmark and target ratios...... 16 Figure 5. Comparison of the median native : alien abundance ratio observed in 2006, 2007, 2009 and 2010 with the benchmark and target ratios...... 17 Figure 6. Comparison of the median native : alien biomass ratio observed in 2006, 2007, 2009 and 2010 with the benchmark and target ratios...... 17 Figure 7. Progress towards the CAP target of a 55% improvement in the ratio of native : alien species as at 2010...... 19 Figure 8. Progress towards the CAP target of a 25% improvement in the ratio of abundance of native : alien species as at 2010...... 20 Figure 9. Progress towards the CAP target of a 25% improvement in the ratio of biomass of native : alien species as at 2010...... 21 Figure 10. Overall progress towards the Lower Murray-Darling CMA CAP Riverine health targets for fish nativeness as at 2010...... 22 Figure 11. Total species richness for fish in the Lower Murray Darling River system in 2010...... 23 Figure 12. Total abundance of fish in the Lower Murray Darling River system in 2010...... 24 Figure 13. Total biomass of fish in the Lower Murray Darling River system in 2010...... 25 Figure 14. Proportion of total fish species richness that are native species in the Lower Murray Darling River system in 2010...... 26 Figure 15. Proportion of total fish abundance that is made up of native species in the Lower Murray Darling River system in 2010...... 27 Figure 16. Proportion of total fish biomass that is made up by native species in the Lower Murray Darling River system in 2010...... 28 Figure 17. Proportion of total catch that is native fish recruits in the Lower Murray Darling River system in 2010...... 29 Figure 18. Proportion of total fish catch that is suffering from a health condition in the Lower Murray Darling River system in 2010...... 30 Figure 19. The proportion of each fish species affected by a health condition...... 31 Figure 20. The proportion of individual fish affected by each of the health conditions observed...... 31 Figure 21. The proportion of each species suffering fin damage (either physical or pathogenic) between 2004 and 2010...... 32 Figure 22. Distribution of fish suffering skin lesions (primarily ulcers) between 2004 and 2010...... 32 Figure 23. The proportion of sites across the Lower Murray Darling catchment where each species was collected during each sampling round...... 34 Figure 24. Distribution, abundance and recruitment of common carp (Cyprinus carpio) – alien pest...... 36 Figure 25. Distribution, abundance and recruitment of Bony herring (Nematalosa erebi)...... 36

ii I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 26. Distribution, abundance and recruitment of Murray cod (Maccullochella peelii)...... 37 Figure 27. Distribution, abundance and recruitment of golden perch (Macquaria ambigua)...... 37 Figure 28. Distribution, abundance and recruitment of goldfish (Carassius auratus) – alien pest...... 38 Figure 29. Distribution, abundance and recruitment of silver perch (Bidyanus bidyanus) – Vulnerable. ..38 Figure 30. Distribution, abundance and recruitment of freshwater catfish (Tandanus tandanus) – Endangered population...... 39 Figure 31. Distribution, abundance and recruitment of Australian smelt (Retropinna semoni)...... 39 Figure 32. Distribution, abundance and recruitment of spangled perch (Leiopotherapon unicolor)...... 40 Figure 33. Distribution, abundance and recruitment of unspecked hardyhead (Craterocephalus stercusmuscarum)...... 40 Figure 34. Distribution, abundance and recruitment of carp-gudgeon species complex (Hypseleotris spp.)...... 41 Figure 35. Distribution, abundance and recruitment of eastern mosquitofish (Gambusia holbrooki) – alien pest...... 41 Figure 36. Distribution, abundance and recruitment of redfin perch (Perca fluviatilis) – alien pest...... 42 Figure 37. Distribution, abundance and recruitment of Murray-Darling rainbowfish (Melanotaenia fluviatilis)...... 42 Figure 38. Distribution, abundance and recruitment of flat-headed gudgeon (Philypnodon grandiceps). .43 Figure 39. Distribution, abundance and recruitment of dwarf flat-headed gudgeon (Philypnodon macrostomus)...... 43 Figure 40. Distribution, abundance and recruitment of Murray hardyhead (Craterocephalus fluviatilis) – Critically endangered...... 44 Figure 41. Average surface temperatire recorded at each fish sampling site in 2010...... 45 Figure 42. Average surface dissolved oxygen concentration recorded at each fish community sampling site at the time of sampling in 2010...... 46 Figure 43. Average surface pH recorded at each fish community sampling site at the time of sampling in 2010...... 47 Figure 44. Average surface conductivity recorded at each fish community sampling site at the time of sampling in 2010...... 47 Figure 45. Average surface turbidity recorded at each fish community sampling site at the time of sampling in 2010...... 48 Figure 46. The proportion of operations at each sampling site where each substrate category was present...... 49 Figure 47. The proportion of operations at each sampling site where each riparian vegetation category was present...... 49 Figure 48. The proportion of operations at each sampling site where each instream vegetation category was present...... 50 Figure 49. The proportion of operations at each sampling site where each structural habitat types was present...... 50 Figure 50. The proportion of operations at each sampling site where each meso-habitat type was present...... 51

I&I NSW – Fisheries Research Report Series: No. 28 iii 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

ACKNOWLEDGEMENTS

Funds for this project were supplied by the Lower Murray-Darling CMA and Industry & Investment NSW. Martin Asmus, Lachie Jess, Duncan McLay, Tim McGarry, Prue McGuffie and Justin Stanger undertook the fieldwork and sampling for the 2009/10 financial year. We thank staff from the CMA for arranging the loan of the CMAs Trimble unit and GPS camera, helping set up the Trimble and providing comments on an earlier draft of this report. This research was undertaken under the NSW Fisheries Animal Care and Ethics Committee approval number 98/14.

iv I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

NON-TECHNICAL SUMMARY

Lower Murray-Darling Catchment Action Plan: Fish Community Monitoring Report Card for 2009/10

PRINCIPAL INVESTIGATOR: Dr Dean Gilligan

ADDRESS: NSW Department of Industry & Investment Batemans Bay Fisheries Centre Braysyth Building Cnr of Beach Road and Orient Street Batemans Bay, NSW 2536

OBJECTIVES:

1. Determination of the progress toward the LMD Riverine Health Catchment Target in relation to improvements in the native to introduced fish ratio (55% improvement in species ratio, 25% improvement in abundance ratio, 25% improvement in biomass ratio). 2. Determination and analysis of trends in fish species & communities throughout the LMD catchment in terms of species richness, total abundance, total biomass, proportion native species, proportion native abundance, proportion native biomass, proportion recruits and proportion with a health condition.

The Lower-Murray Darling Catchment Action Plan (CAP) identifies Riverine Health as a Catchment Target: An identifiable net improvement in riverine health across the Lower Murray Darling Catchment by 2015. The CAP states that this will be determined by:

• an improvement in the native to introduced fish ratio (55% improvement in species ratio, 25% improvement in abundance ratio, 25% improvement in biomass ratio); • a 20% reduction in the number of days subject to blue green algal alerts; and • the reinstatement of more natural flow patterns as modelled in each of five river management zones.

This annual summary reports on progress towards the fish community catchment targets up until the end of the 2009/10 financial year. The fish community was benchmarked at a number of sites established and sampled in 2004 (Gilligan 2005). These were re-sampled in 2006 (Gilligan 2007), 2007 (Gilligan 2008), 2009 (Gilligan (2009) and again in 2010 (this report) to gauge progress towards the CAP targets. In 2010, fish sampling was undertaken at 52 sites between 16 March and 6 May.

All the fish species collected in 2004, 2006, 2007 and 2009 were also collected in 2010. However, for the first time since the monitoring program commenced, two additional species were also collected; dwarf flat-headed gudgeon and spangled perch. Eight native species formerly resident in the Lower Murray Darling CMA area remain undetected since at least 2004. Seven of the 15 species collected during previous sampling have increased in abundance during the previous 12 months; the native silver perch, unspecked hardyhead, bony herring and golden perch, and the alien Eastern mosquitofish, goldfish and common carp. Most of these increases are likely to have occurred through recruitment at sites affected by the Darling River flood between January and April 2010. There have been no significant declines in abundance of any native or alien fish species since monitoring commenced in 2004. Native silver perch, unspecked hardyhead and alien Eastern mosquitofish, redfin perch and goldfish were found at more sites in 2010 than in 2004, whilst

I&I NSW – Fisheries Research Report Series: No. 28 v 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

native freshwater catfish, Murray-Darling rainbowfish, Murray cod, Australian smelt and carp- gudgeon species were collected at fewer sites.

The CAP target of a 55% improvement in the native : alien species ratio was not met in any catchment management zone in 2010. In fact, there was a significant decline in the native : alien species ratio in all individual catchment management zones. Since 2004, alien species have been expanding in distribution within the CMA area while the distribution of native fish has generally declined. The species richness ratio has declined from 4 native species per alien species in 2004 to 2 in 2010.

The CAP target of a 25% improvement in the native : alien abundance ratio was exceeded in the Darling River in 2010, probably as a direct result of extensive recruitment of both bony herring and golden perch, and the colonisation of the lower Darling River by spangled perch, each response triggered by significant inflows from the upper Darling catchment between January and April. There were also increases in the native : alien abundance ratio in the lower Murray River zone, although the increase was not statistically significant. However, there were concurrent declines in the native : alien abundance ratio in the Great Darling Anabranch and Lakes & Reservoirs zones and no changes in the upper Murray River or floodplain wetlands zones. Despite native abundance doubling since 2004, the abundance of alien fishes has roughly trebled, so the overall catchment- wide trend was for no significant change in the native : alien abundance ratio within the CMA area. The median abundance ratio has only changed from 12 native individuals to 1 alien individual in 2004 to 13 native individuals in 2010 (Figure 5).

The CAP target of a 25% improvement in the native : alien biomass ratio was exceeded in both the upper and lower Murray River management zones in 2010. The native : alien biomass ratio increased in all other catchment zones within the CMA area, however the increase is not yet statistically significant. The biomass of native fishes has remained stable but the biomass of alien species has declined, with the median ratio increasing from 792 grams of native fish to 1 kg of alien fish in 2004 to 878 grams of native fish in 2010 (Figure 6).

In 2010, only one site (3%) exceeded the CAP target for all three ‘nativeness’ ratios; Imperial Lake near Broken Hill. Despite substantial progress towards improving nativeness ratios over the past 12 months, with nativeness improving at 15 sites (45%), nativeness ratios remained stable at seven sites (21%), but had declined at seven sites (21%) and deteriorated substantially at four sites (12%). Therefore, conditions are still getting worse at 1/3 of the sites monitored.

These data suggest that the management actions implemented up until June 2010, and/or the extent of the works involved, have not been sufficient to result in progress towards the three Lower Murray Darling CMA CAP targets for fish community ‘nativeness’. At the current rate of change, the Lower Murray Darling CMA will not meet its riverine health catchment management targets by 2015. Recovery actions for threatened and uncommon species, ‘fish-appropriate’ wetland watering activities, utilising environmental water allocations to initiate recruitment of riverine fishes and implementing carp (and other pest fish) control activities are recommended as strategies to make progress towards achieving CAP targets by 2015.

vi I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

1. INTRODUCTION

The Lower-Murray Darling Catchment Action Plan (CAP) identifies Riverine Health as a Catchment Target: An identifiable improvement in riverine health across the Lower Murray Darling Catchment by 2015. The CAP states that this will be determined by:

This annual summary reports on progress towards the fish community catchment targets within the catchment area, including rivers, lakes & reservoirs and wetlands, with riverine sites stratified within five pre-determined catchment management zones (Figure 1):

1. Lakes & Reservoirs (Menindee Lakes, Lake Victoria, Euston Lakes and Broken Hill Reservoirs). 2. Darling River. 3. Great Darling Anabranch. 4. Murray River upstream of the Darling junction (Murray I). 5. Murray River downstream of the Darling junction (Murray II).

And a sixth additional category:

6. Floodplain wetlands (combined across zones 2 – 5 above).

The objectives of the fish monitoring program are:

The fish community was benchmarked at a number of sites established and sampled in 2004 (Gilligan 2005). Progress up until 2006, 2007 and 2009 were reported in Gilligan (2007), Gilligan (2008) and Gilligan (2009) respectively. This document reports on progress up until June 2010.

I&I NSW – Fisheries Research Report Series: No. 28 7 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

2. METHODS

The sampling procedure used was identical to that used for the benchmarking surveys undertaken in 2004 and described in Gilligan (2005) and are consistent with those used for the Murray Darling Basin Authority’s Sustainable Rivers Audit (Davies et al. 2008). In the 2010 season, the first sample was collected on 16 March and sampling had been completed by 6 May.

For the first time since the monitoring program commenced in 2004, almost the full complement of primary and secondary sites were able to be sampled. The sole exception was Lake Cawndilla, which commenced to fill on 9 April 2010, but did not contain enough water to enable access by sampling teams before sampling at all other sites in the northern area of the CMA area had been completed. Rainfall in the northern Darling catchment in late 2009 and early 2010 had resulted in a moderate flood event in the Darling River which reached the Lower Murray Darling CMA area in mid January 2010 and peaked at Weir 32 on the Darling River on 24 February. This flow event was 2.5 times larger than the flow event in March 2004, and over 4 times larger than the flows in January and October 2008 (Figure 1). These were the only four flow events in the Darling River since the fish monitoring program commenced in 2004. Inflows from the upper Darling catchment were sufficient to deliver flows down the Great Darling Anabranch for the first time since the fish monitoring program commenced. These were delivered via the natural offtake from the Darling River at Karoola, rather than regulated through the Lake Cawndilla outlet into Redbank Creek. However, the Great Darling Anabranch inflows were only sufficient to pass part-way downstream and did not reach the end of the system at the Murray River junction. However, as in previous seasons, backed-up waters from Lock 9 inundated a portion of the lower Great Darling Anabranch. The Darling flows influenced the flows in the lower Murray River zone recorded at Wentworth, but had little to no influence on flows recorded upstream of Lock 6 at the lower extremity of the Lower Murray Darling CMA area (Figure 1). Very low flows have persisted in the upper Murray River zone from late 2005 up until the time of sampling in 2010 (Figure 1). Therefore, during 2009/2010, hydrological conditions at primary and secondary sampling locations within the Darling and Great Darling Anabranch were markedly different from those in previous seasons, but hydrology within the upper and lower Murray River zones were largely consistent with previous years of sampling.

Water levels within the Lakes & Reservoirs were dictated by their position within the CMA area. The inflows from the northern Darling where sufficient to commence filling the Menindee upper lakes, Lake Wetherell, Lake Pamamaroo and Copi Hollow from early January 2010, Menindee Lake from 17 March and Lake Cawndilla from 9 April (Figure 2). Prior to filling, Lake Cawndilla and Menindee Lake had been dry for more than seven years, Lake Pamamaroo had been dry for several months and Copi Hollow had receded substantially but had not dried completely. In the upper Murray River zone, the Euston Lakes had been disconnected from the Euston weir pool since December 2007 to minimise evaporative losses as part of an emergency drought contingency plan for the Murray Basin and both Dry Lake and Benanee Lake had remained completely dry since early 2008. However, in November 2009, a 30 GL environmental water allocation was released into the lakes and they were both sample-able in 2010. Lake Victoria in the lower Murray River zone and Imperial Lake (Broken Hill Reservoirs) have both retained water throughout the period of the fish monitoring program, although water levels have fluctuated in both waterways (Figure 2).

8 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

25000 Lock 6 US Lower Murray River zone Wentworth

20000

15000

10000

5000

25000 Upper Murray River zone Euston DS Mildura (Chaffey Graveyard)

20000

15000 Flow (ML/day)

10000

5000

25000

Darling River Weir 32 Pooncarrie Burtundy 20000

15000

10000

5000

0 2006 1/ 1/04/2006 1/07/2006 1/10/2006 1/01/2007 1/04/2007 1/07/2007 1/10/2007 1/01/2008 1/04/2008 1/07/2008 1/10/2008 1/01/2009 1/04/2009 1/07/2009 1/10/2009 1/01/2010 1/04/2010 1/07/2003 1/10/2003 1/01/2004 1/04/2004 1/07/2004 1/10/2004 1/01/2005 1/04/2005 1/07/2005 1/10/2005 1/0

Date

I&I NSW – Fisheries Research Report Series: No. 28 9 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

63.0 Menindee Lakes 62.0

61.0

60.0

59.0

58.0

57.0

56.0 Lake Menindee Lake Pamamaroo 55.0 Lak e W etherell

54.0

28.0

Gauge Height (m) Lake Victoria 27.0

26.0

25.0

24.0

23.0

22.0

Lak eVic toria 21.0

20.0 1/07/2003 1/10/2003 1/01/2004 1/04/2004 1/07/2004 1/10/2004 1/01/2005 1/04/2005 1/07/2005 1/10/2005 1/01/2006 1/04/2006 1/07/2006 1/10/2006 1/01/2007 1/04/2007 1/07/2007 1/10/2007 1/01/2008 1/04/2008 1/07/2008 1/10/2008 1/01/2009 1/04/2009 1/07/2009 1/10/2009 1/01/2010 1/04/2010

Date

Figure 2. Lake levels from gauging stations within the Menindee Lakes and Lake Victoria spanning the period over which the CMAs fish monitoring program has collected fish assemblage data. Shaded columns represent sampling periods within which fish assemblage data were collected. No equivalent water level data were available from the Euston Lakes or Broken Hill Reservoirs.

10 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

The distribution of sample-able tertiary sites (floodplain wetlands) was also dictated by their position within the CMA area. Almost all wetlands adjacent to riverine monitoring sites in the lower Darling River had been inundated by the February Darling River flow peak. Consequently, a wetland site was sampled in association with each of the seven Darling River monitoring sites. This included one re-sampled wetland (Pomona Wetland) and six new sampling locations. Despite flows passing down the Great Darling Anabranch, only one of the wetlands adjacent to the seven riverine monitoring sites had been inundated and therefore it was the only Great Darling Anabranch wetland sampled. A lack of flow peaks in the upper Murray River zone meant that only those wetland sites inundated at base flow levels or behind weir pools were inundated. This included Peacock Creek which was re-sampled, plus a new site, Tuckers Creek, near the Boston Bend riverine site. Despite a similar lack of flows in the lower Murray River zone, at least one wetland adjacent to each of the seven primary riverine sites contained water and was sampled. These resulted from a combination of wetlands inundated at base flows or behind weir pools or from flows delivered by the Murray Wetlands Working group using siphons or pumps to deliver environmental water allocations. Three previously sampled wetlands were re-sampled (Coonpoor Creek, The Occupation wetland and Cliffhouse wetland) and three new wetlands were sampled in the lower Murray River zone 2010. As in previous years, Tareena Billabong adjacent to the Salt Creek site was too saline to allow fish sampling using electrofishing. Thegoa Lagoon, which had been sampled in both 2004 and 2006, but was dry during the sampling periods in 2007 and 2009 was initially dry when sampling commenced in 2010 but was allocated environmental water shortly after sampling had been completed in 2010. Therefore, unfortunately, no fish community data are available from Thegoa Lagoon in 2010.

Pre-existing data from 2004 were collected under Lower Murray Darling CMA project No. MD 005.03 and were presented in Gilligan (2005). Data from 2006 and 2007 were collected under Lower Murray Darling CMA project No.MD122.05 and were presented in Gilligan (2007) and Gilligan (2008). Data from 2009 were collected under Lower Murray Darling CMA project No.MD193.09 and were presented in Gilligan (2009). Data from 2005 and 2008 were collected for the Murray-Darling Basin Authority’s Sustainable Rivers Audit (SRA) IP1 and IP4 sampling rounds. Although the sampling locations for the SRA in 2005 and 2008 are not entirely consistent with those established for the LMD CMA monitoring program, both projects used a similar random site selection process and aim for the same site density per zone. However, only two and three sites were present in the lower Murray River zone in 2005 and 2008 respectively, as the zone boundary for the SRA straddles the NSW-SA border, and a portion of the seven SRA sites lay within South Australia. Therefore, SRA data for the lower Murray River zone is less comprehensive than that from the Darling and upper Murray River zones. Further, the SRA does not sample any locations within the Lakes & Reservoirs zone, Great Darling Anabranch or floodplain wetlands.

Data collected in 2010 were compared at an overall catchment level with those collected from 2004 and 2009 using paired t-tests. Prior to analysis, total abundance and total biomass were log10 transformed, the proportion of total abundance that was native was arcsine transformed and the proportion of individuals suffering a health condition was square-root transformed in order to normalise the data and/or equalise the variances. All other parameters were suitable for parametric analysis without transformation.

I&I NSW – Fisheries Research Report Series: No. 28 11 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Table 1. Primary and secondary sites sampled within each of five catchment zones in the Lower Murray-Darling CMA catchment area. The shaded sites in the Lakes & Reservoirs and Great Darling Anabranch zones were not sampled during the benchmarking surveys in 2004 (Gilligan 2005), but were established during the second round of sampling in 2006 and are part of the ongoing monitoring program.

Site name Waterway Latitude Longitude Sampled in 2010

Murray I Tangles Corner Murray River -34.69159 143.06219 Yes Yangera Island Murray River -34.69187 142.96832 Yes Carina Bend Murray River -34.67714 142.70019 Yes Wemen Murray River -34.76543 142.64555 Yes The Boiler Murray River -34.74963 142.50942 Yes Nangiloc Murray River -34.48269 142.36868 Yes Boston Bend Murray River -34.12884 142.03491 Yes Murray II Upper Kulnine Murray River -34.13118 141.83983 Yes Ned’s Corner Murray River -34.12791 141.33987 Yes Frenchman’s Creek Frenchman’s Creek -34.10051 141.39952 Yes 10 km below Lock 7 Murray River -34.07452 141.19219 Yes Hancock Hill- Wompinni Murray River -34.04404 141.04413 Yes Salt Creek Salt Creek -34.00286 141.04241 Yes Tareena Salt Creek -33.96318 141.00710 Yes Darling River Bono Darling River -32.55987 142.39083 Yes Moorara Darling River -33.22470 142.37290 Yes Pooncarie Darling River -33.38246 142.56233 Yes Lethero Darling River -33.58937 142.44700 Yes Lelma Darling River -33.67577 142.39452 Yes Downham Farm Darling River -33.80628 142.07518 Yes Pomona Darling River -33.98030 141.91340 Yes Great Darling Anabranch Woodlands Great Darling Anabranch -33.27826 141.78891 Yes Wycott Great Darling Anabranch -32.97873 142.05350 Yes Cuthero Bridge Great Darling Anabranch -33.07444 142.00902 Yes Hunter waterhole Great Darling Anabranch -33.23857 141.92631 Yes Four Wings Shack Great Darling Anabranch -33.18811 141.99448 Yes Grand Junction Great Darling Anabranch -34.02255 141.81836 Yes Darling Anabranch mouth Great Darling Anabranch -34.09002 141.75970 Yes Lakes & Reservoirs Imperial Lake Broken Hill reservoir -31.94262 141.49698 Yes Lake Wetherell Menindee Lakes -32.31234 142.50727 Yes Copi Hollow Menindee Lakes -32.26773 142.38109 Yes Lake Pamamaroo Menindee Lakes -32.28276 142.42591 Yes Lake Menindee Menindee Lakes -32.28489 142.34975 Yes Lake Cawndilla Menindee Lakes -32.45032 142.26356 Dry Lake Benanee Euston Lakes -34.54734 142.88799 Yes Dry Lake Euston Lakes -34.52952 142.85711 Yes Lake Victoria Lake Victoria -34.03940 141.28626 Yes

12 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Table 2. Tertiary (wetland) sites associated with primary and secondary riverine sites within each of four riverine catchment zones in the Lower Murray-Darling CMA catchment area.

Wetland name (MWWG No.) Riverine site name Latitude Longitude Sampled in 2010 Murray I Manie Creek (No. 1863) Tangles Corner No (Dry) Peacock Creek (No. 1637) Yangera Island -34.66236 142.99676 Yes MWWG No. 1686 Carina Bend No (Dry) MWWG No. 3661 Wemen No (Dry) MWWG No. 1997 The Boiler No (Dry) MWWG No. 1405 Nangiloc No (Dry) Tuckers Creek (No. 294) Boston Bend -34.10112 141.99467 Yes Murray II Neilpo Billabong (No. 559) Upper Kulnine -34.11969 141.85343 Yes Coonpoor Creek (No. 407) Ned’s Corner -34.10316 141.30657 Yes The Occupation Wetland (No. 393) Frenchman’s Creek -34.0974 141.3818 Yes Nampoo Wetland (No. 164) 10 km below Lock 7 -34.06358 141.15756 Yes Cliffhouse Wetland (No. 128) Hancock Hill- Wompinni -34.04930 141.045696 Yes Tareena Billabong (No. 38) Salt Creek -33.9654 141.0356 No (saline) Tareena Horseshoe (No. 54) Tareena -33.99324 141.01254 Yes Darling River Keiara Billabong Bono -32.59723 142.39035 Yes Webcoles Camp Billabong Moorara -33.20807 142.37062 Yes Porters Lakes Pooncarie -33.40970 142.57506 Yes Stud Ewe Billabong Lethero -33.53324 142.45504 Yes Barne’s Billabong Lelma -33.63476 142.38715 Yes Sturt’s Billabong Downham Farm -33.85137 141.96808 Yes Pomona Wetland Pomona -33.99888 141.89935 Yes Great Darling Anabranch Unknown Woodlands No (Dry) Unknown Wycott No (Dry) Unknown Cuthero Bridge No (Dry) Unknown Hunter waterhole No (Dry) Unknown Four Wings Shack No (Dry) Unknown Grand Junction No (Dry) Rundeah Wetland (No. 309) Darling Anabranch mouth -34.08254 141.78593 Yes

I&I NSW – Fisheries Research Report Series: No. 28 13

Figure 3. The locations of primary and secondary fish survey sites sampled in the 2010 season. The locations of tertiary survey sites (floodplain wetlands) are presented as dots, but are not labelled. These site details can be obtained from Table 2.

I&I NSW – Fisheries Research Report Series: No. 28 Page 14 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

3. PROGRESS TOWARD THE LOWER MURRAY DARLING CATCHMENT ACTION PLAN FISH ‘NATIVENESS’ TARGETS FOR RIVERINE HEALTH

The CAP riverine health catchment targets related to the fish community are:

• A 55% improvement in the native to introduced fish species ratio. • A 25% improvement in the native to introduced fish abundance ratio. • A 25% improvement in the native to introduced fish biomass ratio.

To test progress towards these targets, data collected in 2004 (Gilligan 2005) were used as the benchmark for each of the target ratios.

As explained in Gilligan (2005), ratios are problematic indices given that a zero value in the denominator, as occurs when no alien fishes are collected at a site, results in an invalid value. Further, the ratio can be very large if the number of natives exceeds the number of aliens, violating the assumption of normality important for many standard statistical tests. Prior to sampling in 2010, there had been six instances of fish community samples that did not collect any alien species that prevent the calculation of ratios at those sites. These are Imperial Lake in 2004, Copi Hollow and Lake Pamamaroo in 2006, Imperial Lake and Dry Lake in 2007 and Imperial Lake in 2009. In 2010 alone there were an additional six samples where ratios cannot be derived, as no alien fish were collected at Imperial Lake or Cliffhouse Wetland, and no fish at all where collected from Lake Benanee, or Woodlands, Hunter Waterhole or Four Wings Shack in the Great Darling Anabranch. To enable an assessment of progress towards the CAP targets, we assumed that the ratios at each site where no fish were collected were = 0 and used the median rather than the mean values for assessment (Gilligan 2009). Variance around the median was estimated via bootstrap re-sampling of the data-set with 1,000 iterations with replacement and calculating the average standard deviation of the bootstrap replicates. Changes between the benchmarking survey (2004) and present (2010) and recent changes between 2009 and present (2010) were compared using z tests.

Native : Alien species ratio

The CAP target of a 55% improvement in the native : alien species ratio was not met in any catchment zone in 2010 (Figure 4). In fact, there was has been a statistically significant decline in the native : alien species ratio across the catchment area between 2004 and 2010 (p < 0.001). This trend was driven by an increase in the average proportion of sites occupied by alien species (38% in 2004 versus 55% in 2010) while the average proportion of sites occupied by native species declined (40% in 2004 versus 33% in 2010). The 2004 – 2010 decline in the native : alien species ratio was significant (p < 0.001) in all individual catchment zones apart from the Darling River and the Lakes & Reservoirs zones.

As at 2010, the native : alien species ratio was significantly lower than the CAP target in all catchment zones (p < 0.001). In all but the Lakes & Reservoirs and Darling River zones, the trend is for a decline in the native : alien species ratio.

I&I NSW – Fisheries Research Report Series: No. 28 15 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

10 Benchmark 9 2006 2007 2009 8 2010 Target 7

5 4

3 Native : Alien species ratio 2

0 Lakes and Darling Great Darling Murray I Murray II Wetlands Total Reservoirs Anabranch

Figure 4. Comparison of the median (± SD) native : alien species ratio observed in 2006, 2007, 2009 and 2010 with the benchmark (2004) and target (55% improvement) ratios.

Native : Alien abundance ratio

The CAP target of a 25% improvement in the native : alien abundance ratio was exceeded in both the Darling River and lower Murray River zones in 2010, but not across the catchment overall or within the Lakes & Reservoirs, upper Murray River, Great Darling Anabranch or floodplain wetlands (Figure 5). For the first time since fish monitoring commenced, the native: alien abundance ratio is significantly greater (p = 0.002) than the CAP target in the Darling River and represents achievement of this CAP target in this zone of the CMA area. Although the median native : alien abundance ratio in the lower Murray River zone exceeded the CAP target, the significant improvement upon the benchmark ratio (p = 0.02) does not yet represent a significant improvement above the CAP target level, although obviously a trend in a positive direction. In contrast, the changes in the abundance ratio in the Lakes & Reservoirs and Great Darling Anabranch zones between 2004 and 2010 represent statistically significant declines (p < 0.001) in fish community composition. The native : alien abundance ratio had not changed significantly between 2004 and 2010 in the upper Murray River zone, within floodplain wetlands or across the CMA area overall.

Although the average number of native individuals per site had roughly doubled since 2004, the number of alien species had trebled. As at 2010, although the native : alien abundance ratio had improved since 2009, the abundance ratio across the catchment overall is still significantly lower than the CAP target (p = 0.02).

Alien biomass ratio

The CAP target of a 25% improvement in the native : alien biomass ratio was exceeded in both the upper and lower Murray River zones in 2010 (Figure 6), with the changes in each of these two zones representing improvements that exceed the CAP targets to a statistically significant extent (p = 0.006 and p = 0.002 respectively). Further, the native : alien biomass ratio had increased in all

16 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

other catchment zones since 2009 and in 2010 the biomass ratio exceeds the benchmark condition in all catchment zones apart from the Lakes & Reservoirs. But the improvements observed are not yet to the extent that they represent achievement of the CAP targets.

160 Benchmark 2006 140 2007 2009 2010 120 Target

100

40 Native : Alien abundance ratio 20

0 Lakes and Darling Great Darling Murray I Murray II Wetlands Total Reservoirs Anabranch

Figure 5. Comparison of the median (± SD) native : alien abundance ratio observed in 2006, 2007, 2009 and 2010 with the benchmark (2004) and target (25% improvement) ratios.

5 Benchmark 4.5 2006 2007 2009 4 2010 Target 3.5

2.5

1.5

Native: Alien biomass ratio 1

0.5

0 Lakes and Darling Great Darling Murray I Murray II Wetlands Total Reservoirs Anabranch

Figure 6. Comparison of the median (± SD) native : alien biomass ratio observed in 2006, 2007, 2009 and 2010 with the benchmark (2004) and target (25% improvement) ratios.

I&I NSW – Fisheries Research Report Series: No. 28 17 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Overall, the biomass of native fishes has remained stable between 2004 and 2010, but the biomass of alien species has declined slightly. As at 2010, although the native : alien biomass had improved substantially since 2009 and now exceeds the benchmark condition, the biomass ratio across the catchment overall is still lower than the CAP target.

The following Report Card figures (Figures 7, 8 and 9) are provided to gauge progress towards meeting CAP targets at individual sites as at 2009/10. Progress is quantified as the change in the proportion observed since 2004, divided by the change that would be required to meet the CAP target. For example, a change in the proportion native biomass of + 0.13 (0.44 in 2004 to 0.57 in 2009) would equal a 59% achievement of the CAP biomass target, which is a change of 0.22 (e.g., 0.13/0.22 = 59%). In each of the report cards, progress towards the targets at each site are presented as one of five categories:

1. CAP target exceeded – The ratio of native : alien fish is greater than the CAP target value (progress > +100% of CAP target).

2. Good – The ratio of native : alien fish has increased since 2004 but has not yet exceeded the CAP target (progress +25 to +99% of CAP target).

3. Stable – The ratio of native : alien fish has not changed substantially since 2004 (progress -25 to +25% of CAP target).

4. Poor – The ratio of native : alien fish has decreased since 2004 (-25 to -99% of CAP target).

5. Very Poor – The ratio of native : alien fish has changed by more than the change required to meet the CAP target, but in the opposite direction, since 2004).

To present an overall assessment that amalgamates the three nativeness indices (Figure 10), a score was assigned to each of the progress categories defined above for each ratio, where: CAP target exceeded = 3 points, Good = 1 point, Stable = 0 points, Poor = -1 point and Very poor = -3 points. These points were summed across the three nativeness ratios. Overall progress towards the CAP targets was defined based on the summed scores according to the following bands:

Score = 9: All CAP targets exceeded Score >5: Very good progress Score > 1: Good progress Score = 0: No progress Score < -1: Progress poor Score < -5: Progress very poor

18 I&I NSW – Fisheries Research Report Series: No. 28

Figure 7. Progress towards the CAP target of a 55% improvement in the ratio of native : alien species as at 2010.

I&I NSW – Fisheries Research Report Series: No. 28 Page 19

Figure 8. Progress towards the CAP target of a 25% improvement in the ratio of abundance of native : alien species as at 2010.

I&I NSW – Fisheries Research Report Series: No. 28 Page 20

Figure 9. Progress towards the CAP target of a 25% improvement in the ratio of biomass of native : alien species as at 2010.

I&I NSW – Fisheries Research Report Series: No. 28 Page 21

Figure 10. Overall progress towards the Lower Murray-Darling CMA CAP Riverine health targets for fish nativeness as at 2010. The pie graphs present the proportion of sites in each progress category in 2009 and 2010.

I&I NSW – Fisheries Research Report Series: No. 28 Page 22 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

4. FISH ASSEMBLAGE PARAMETERS USEFUL FOR UNDERSTANDING THE ‘HEALTH’ OF FISH COMMUNITIES

Species richness

Species richness is the total number of different species occurring at a site, including native and alien species. Species richness has increased in the Lakes & Reservoirs, the Darling River and both Murray River zones within the past 12 months, with the increases being statistically significant in the Darling River (from 5.6 to 8.4 species per site, p = 0.002) and upper Murray River zones (from 8.4 to 10.1 species per site, p = 0.04). These recent increases have resulted in the species richness in these two zones being significantly greater in 2010 than was observed during the benchmarking surveys in 2004. Average species richness across the catchment overall has also increased significantly within the last 12 months (from 7 to 8.8 species per site, p < 0.0001) (Figure 11). But average species richness has declined slightly in the Great Darling Anabranch and floodplain wetlands sites. Species richness was lowest in the Great Darling Anabranch. It was also lower in Lakes & Reservoirs and floodplain wetlands sites than in the Darling or Murray River sites (Figure 11). No fish were collected at three of the Great Darling Anabranch sites or at Lake Benanee.

Figure 11. Total species richness for fish in the Lower Murray Darling River system in 2010.

I&I NSW – Fisheries Research Report Series: No. 28 23 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Total abundance

Total abundance is the total number of individuals sampled from a site, including native and alien fish. Average total abundance has increased significantly in all CMA zones over the past 12 months except for the Great Darling Anabranch. The increases were statistically significant in the Lakes & Reservoirs (p = 0.018), Darling River (p = 0.001) and upper Murray River zones (p = 0.02) (Figure 12). The recent increases have resulted in the total abundance in these three zones being significantly greater in 2010 than was observed during benchmark sampling in 2004 (Figure 12). The average total abundance at sites in the lower Murray River zone and floodplain wetlands sites is also greater than, but not significantly different from that observed in 2004 (Figure 12). The average total abundance of fish has increased significantly across the CMA area from an average of 232 individuals per site in 2004 to 493 individuals per site in 2010 (p < 0.0001). Total abundance was distinctly lower in the top part of the Great Darling Anabranch (inundated by natural flows from the Darling) and recently inundated Euston Lakes than elsewhere within the CMA area, largely because of the zero catches at three of the Great Darling Anabranch sites and at Lake Benanee (Figure 12).

Figure 12. Total abundance of fish in the Lower Murray Darling River system in 2010.

24 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Total biomass

Total biomass is the total weight of all individuals sampled at a site, including native and alien fish. Average total fish biomass has increased significantly in the upper Murray River (p = 0.004), floodplain wetlands (p = 0.017) and across the CMA area overall (p = 0.003) over the past 12 months. The resulting total biomass in the upper Murray River is significantly greater than was observed in this zone in 2004 (p = 0.015). However, the significant recent increase across the CMA area overall has only served to reverse the declines observed in 2009, and the average total biomass in 2010 is not significantly greater than that observed in 2004 (p = 0.113). In contrast, although total biomass in the Lakes & Reservoirs zone has declined since 2007 (Figure 13), the 2010 biomass is still significantly greater than the biomass observed in 2004 (p = 0.029). Recent and longer term changes in biomass in both the Darling River and lower Murray River were not significant (Figure 13). Total biomass was distinctly lower at sites in the top part of the Great Darling Anabranch (inundated by natural flows from the Darling), the Lakes & Reservoirs and floodplain wetlands sites (Figure 13). Total biomass was greatest in the upper Murray River zone (Figure 13).

Figure 13. Total biomass of fish in the Lower Murray Darling River system in 2010.

I&I NSW – Fisheries Research Report Series: No. 28 25 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Proportion of total species richness that are native species

The proportion of total species richness that is native is the number of different native species collected at a site divided by the total species richness (native plus alien species). Over the past year there has only been a single zone specific change in the proportion of total species richness that are native species, with the proportion declining from 0.79 in 2009 to 0.7 in 2010 within the upper Murray River (p = 0.016) (Figure 14). This recent incremental decline has led to a statistically significant decline in the proportion of fish species that are native since 2004 (p < 0.0001). Similarly, consistent annual incremental declines since 2004 have lead to an overall significant decline in the proportion of fish species that are native across the overall CMA area (p = 0.001), with the average proportion of species that are native declining across the CMA area from 0.77 in 2004 to 0.62 in 2010. There was no consistent spatial pattern in the proportion of native species richness across the CMA area, although there was substantial variation among sites, with no alien species collected at some sites (Imperial Lake and Cliffhouse wetland) and no native species collected from others (Cuthero Bridge and Barne’s Billabong).

Figure 14. Proportion of total fish species richness that are native species in the Lower Murray Darling River system in 2010.

26 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Proportion of total abundance that is native species

The proportion of total abundance that is native is the number of native fish divided by the total number of individuals (native plus alien species) collected at the site. There were no significant changes in proportion of total abundance that were native species within any individual catchment management zone, or across the catchment area as a whole between 2004 and 2010 (Figure 15), but the proportion of total abundance that is native species has declined slightly from 86% native in 2004 to 81% in 2010. The average proportion of total abundance that is native species was lowest in the Great Darling Anabranch and floodplain wetland sites (Figure 15). There was little spatial pattern in the proportion of total abundance that was native species across the CMA area (Figure 15). All of the Darling River and Murray sites were dominated by native fish. Only one of the eight Lakes & Reservoirs sites (Dry Lake) and two of the seven Great Darling Anabranch sites (Cuthero Bridge and Wycott) were dominated by alien fish. In contrast, eight of the 16 floodplain wetland sites (50%) were dominated by alien fish (Barne’s Billabong, Nampoo Wetland, Stud Ewe Billabong, Porters Lakes, Sturt’s Billabong, Neilpo, Rundeah and Pomona Wetland).

Figure 15. Proportion of total fish abundance that is made up of native species in the Lower Murray Darling River system in 2010.

I&I NSW – Fisheries Research Report Series: No. 28 27 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Proportion of total biomass that is native species

The proportion of total biomass that is native is the total weight of native fish collected at a site divided by the total weight of fish (native plus alien species) collected at the site. Over the last year there were significant increases in the proportion of total biomass that is native in the upper Murray River zone (p = 0.026) and across the CMA area overall (p = 0.0006). These improvements served to reverse the declines observed in 2009 and there has been no net increase in the proportion of total biomass that is native since the catchment area was benchmarked in 2004 (Figure 16). The overall proportion of total biomass that is native remains around 45%. Although there was a broad range of values across the CMA area, there was little spatial pattern in the proportion of total abundance that was native species across the CMA area (Figure 16). Fish biomass at relatively few sites was dominated by native fish. These were the Lakes & Reservoirs; Imperial Lake, Lake Pamamaroo, Menindee Lake and Copi Hollow; Bono, Moorara and Pooncarie on the Darling River; Tangles Corner, Yangera Island, Carina Bend and Nangiloc in the upper Murray River zone; Upper Kulnine, Ned’s Corner and The Occupation in the lower Murray River zone; the Great Darling Anabranch mouth; and the floodplain wetlands Cliffhouse Wetland, Webcoles Camp Billabong, Kieara Billabong and Tareena Horseshoe.

Figure 16. Proportion of total fish biomass that is made up by native species in the Lower Murray Darling River system in 2010.

28 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Proportion of total catch made up of native fish recruits

Recruits are young juvenile fish that represent the recent breeding activity of the population. For this study, we assumed recruits to be fish less than one year old for larger long-lived species and immature individuals for smaller species that mature at less than one year of age. Individuals were identified as recruits if they were smaller than the length cut-offs as provided in Gilligan (2005). Length cut-offs for the two new species collected for the first time in 2010 are 20 mm for dwarf flat-headed gudgeon and 68 mm for spangled perch (Leggett & Merrick1987).

For all native species combined, there has been a significant recent increase in the amount of native fish recruitment with the Darling River, with the proportion of native fish recruits increasing from 0.09 in 2009 to 0.51 in 2010 (p = 0.007) (Figure 17). The level of recruitment observed in 2010 is also a significant improvement on the level of native fish recruitment observed in the Darling River during benchmarking surveys in 2004 (0.16) (p = 0.002). There was also a significant increase in the proportion of native fish recruits in the Lakes & Reservoirs zone over the past year, with the proportion of recruits increasing from 0.09 to 0.61 (p = 0.003) (Figure 17). The level of native fish recruitment in the upper and lower Murray River zones has not changed significantly over the last 12 months, or since 2004, but was lower than that observed in the these zones in 2005, 2006, 2007 and 2009 (Figure 17). However, across the CMA area overall the proportion of native fish recruits has increased significantly (p = 0.039) from 0.42 to 0.54 since the CMA area was benchmarked in 2004 (Figure 17). In 2010, native fish recruitment was lowest in the Great Darling Anabranch, floodplain wetlands, the downstream reaches of the Darling River and the Euston Lakes (Figure 17).

The level of recruitment of individual species is presented in Figures 24 to 40.

Figure 17. Proportion of total catch that is native fish recruits in the Lower Murray Darling River system in 2010.

I&I NSW – Fisheries Research Report Series: No. 28 29 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Proportion of total catch suffering from a health condition

Although the proportion of individuals affected by a health condition has declined over the past year in the Lakes & Reservoirs, Darling River, floodplain wetlands and across the CMA area overall, the decline has not been statistically significant in any individual zone or across the catchment. In 2010, the proportion of the total catch suffering from a health condition across the catchment is still significantly higher than it was in 2004 (2.0% in 2004 versus 3.8% in 2010) (Figure 18). Zone specific increases since 2004 are significant in the Lakes & Reservoirs zone (p = 0.002), upper Murray River (p = 0.005) and lower Murray River (p = 0.01) (Figure 18). As in previous years, the proportion of affected individuals was not consistent across species, with the most affected taxa continuing to be golden perch, Murray cod, goldfish, silver perch and common carp (Figure 19). It is likely that smaller species are also affected to similar extents to the larger species, but as they are more prone to predation when suffering a health condition, they do not remain in the population for very long and are not detected.

The proportion of individuals affected by fin damage (physical and pathogenic), and lesions (primarily ulcers) was higher in 2010 than observed during any previous round of sampling (Figure 20). Further, the distribution of individuals affected was greater in 2010 than in previous rounds of sampling. Golden perch and Murray cod were particularly affected by an apparently pathogenic fin infection (Figure 21). Goldfish and to a lesser extent golden perch and common carp were the species most affected by lesions or ulcers (Figure 22). The proportion affected by the parasitic anchorworm (Lerneae spp.) was lower than in 2006, 2008 and 2009, but was still higher than the proportion observed to be affected during the benchmarking round of samples in 2004.

Figure 18. Proportion of total fish catch that is suffering from a health condition in the Lower Murray Darling River system in 2010.

30 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 19. The proportion of each fish species affected by a health condition.

Figure 20. The proportion of individual fish affected by each of the health conditions observed.

I&I NSW – Fisheries Research Report Series: No. 28 31 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

0.16 2004 2006 0.14 2007 2008 0.12 2009 2010

0.1

0.08

0.06

0.04

0.02

0 p n Proportion of individuals affected by fin damage fin by individualsProportion of affected d r sh h ng a on rch fis eo ri e ish e cod dfi g r he perch p y n ca l w d e y dg atf n r h u ambusia c Go g r lve inbo d gu ny ard te Murra mmo a e o h rp-g a Si d B d a rn Golde Co C te ea cke Australian smeltas Spangled perchshw t-h e E re la F F nsp U Murray-Darling r Figure 21. The proportion of each species suffering fin damage (either physical or pathogenic) between 2004 and 2010. The inset photo is a golden perch collected from the Murray River at Carina Bend suffering fin damage of the dorsal and anal fins.

0.16 2004 2006 0.14 2007 2008 2009 0.12 2010

0.1

0.08

0.06

0.04

0.02

0 n o d

Proportion of individuals affected by lesions/ulcers by individuals affected of Proportion ing erch erch e r ea p p dg h perch r u d en e Goldfish g rdy ambusia d g ilv Murray cod rp-gudgeon ngle S Bony her d ha a rn a Gol Common carp aded e C te ling rainbowfishe ck Australian smelt Sp pe Eas s Freshwater catfish y-Dar Flat-h n U Murra Figure 22. Distribution of fish suffering skin lesions (primarily ulcers) between 2004 and 2010. The inset photo is a bony herring collected from Coonpoor Creek (lower Murray River zone).

32 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

5. TRENDS IN ABUNDANCE AND RECRUITMENT OF INDIVIDUAL FISH SPECIES

At a catchment level, all the fish species collected in all previous rounds of sampling were also collected in 2010. However, for the first time since the monitoring program commenced, two new species of native fish; dwarf flat-headed gudgeon (Philypnodon macrostomus) and spangled perch (Leiopotherapon unicolor) were collected. Dwarf flat-headed gudgeon were sampled from a single floodplain wetland site in the lower Murray River zone (Coonpoor Creek). This represents the first ever collection of this species in the Murray region by I&I NSW. Spangled perch were collected from three of the four Menindee Lakes sites, four of the seven Darling River sites and four of the seven Darling wetland sites. This species is regularly collected from more northerly reaches of the Darling and its tributaries and is considered a vagrant in the lower Darling. It is likely that spangled perch colonised the Menindee Lakes and lower Darling River with the recent floodwaters. As a more northerly distributed species, it is uncertain whether they will persist in the CMA area through the winter of 2010.

The proportional changes in the abundance of each species across the CMA area between 2004 and 2009 and 2010 are presented in Table 3. The changes between 2004 and 2010 were statistically significant at the catchment level for eight of the 17 species, with all changes being increases in abundance (Table 3). This is a substantial change from the observed decrease in abundance of two species reported up until 2009; bony herring and carp-gudgeon species (Gilligan 2009). Those species increasing in abundance since 2004 were the native silver perch, unspecked hardyhead, bony herring, golden perch and spangled perch, and the alien Eastern mosquitofish, goldfish and common carp. Those species that had increased significantly in abundance during the previous 12 months were bony herring, goldfish, common carp, golden perch and spangled perch (Table 3). Most of these increases are likely to have occurred through recruitment at sites affected by the Darling River inflows.

Table 3. The proportional change in the abundance of each species (across the whole catchment) between the benchmark surveys in 2004 (Gilligan 2005), the 2009 annual survey (Gilligan 2009) and 2010 (this survey). * statistically significant changes in abundance.

Species Change between 2004 and 2010 Change between 2009 and 2010 Eastern mosquitofish 2,167% increase* 21% decrease Silver perch 967% increase* 54% increase Unspecked hardyhead 421% increase* 1% increase Bony herring 349% increase* 759% increase* Goldfish 184% increase* 227% increase* Common carp 83% increase* 101% increase* Murray cod 81% increase 55% increase Golden perch 78% increase* 115% increase* Murray hardyhead No change No change Carp-gudgeon species complex 33% decrease 245% increase Australian smelt 45% decrease 8% increase Murray Darling rainbowfish 61% decrease 21% decrease Redfin perch 75% decrease No change Flat-headed gudgeon 78% decrease 90% decrease Freshwater catfish 86% decrease 50% increase Spangled perch Increase* Increase* Dwarf flat-headed gudgeon Increase Increase

I&I NSW – Fisheries Research Report Series: No. 28 33 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Those species that increased in prevalence by more than 10% between 2004 and 2010 (in terms of the proportion of sites at which they were sampled in 2004) were Eastern mosquitofish (523%), silver perch (90%), redfin perch (56%), unspecked hardyhead (44%) and goldfish (42%) (Figure 23). Those species that decreased in prevalence (by more than 10% of sites) were freshwater catfish (48%), Murray-Darling rainbowfish (48%), Murray cod (45%), Australian smelt (29%) and carp-gudgeon species (26%) (Figure 23).

Figure 23. The proportion of sites across the Lower Murray Darling catchment where each species was collected during each sampling round.

34 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

The following native and alien species known to have historically occurred within the Lower Murray Darling CMA area (see Gilligan 2005: Table 1.1) have still not been detected by the CMAs monitoring program since sampling commenced in 20041.

• Brown trout (Salmo trutta) – alien (Murray only). • Congoli (Pseudaphritis urvillii) – vagrant. • Flat-headed galaxias (Galaxias rostratus) – Critically endangered. • Hyrtl’s tandan (Neosilurus hyrtlii) – vagrant (Darling only). • Macquarie perch (Macquaria australasica) – Endangered (Murray only). • Murray hardyhead (Craterocephalus fluviatilis) – Critically endangered • Olive perchlet (Ambassis agassizii) – Endangered population. • Short-headed lamprey (Mordacia mordax). • Southern purple spotted gudgeon (Mogurnda adspersa) – Endangered. • Southern pygmy perch (Nannoperca australis) – Endangered. • Spotted galaxias (Galaxias truttaceus) – alien. • Tench (Tinca tinca) – alien. • Trout cod (Maccullochella macquariensis) – Endangered (Murray only).

The following figures (Figures 24 to 40) present four types of data for each fish species currently present in the catchment area (in order of greatest to least biomass across the whole catchment); 1) the distribution of each species within the catchment area in 2010, 2) the abundance of each species at each site in 2010, 3) the distribution and abundance of recruits at each site in 2010 and 4) trends in abundance since 2004 in each catchment zone.

1. Distribution is reflected by the presence of white (absent) versus black or green dots (present) at each sampling location. 2. Abundance is reflected by the size of the dot (black and/or green) at each sampling location. The size scaling of the dots varies across species and can be gauged relative to the legend in the bottom right corner of each figure. 3. Recruits are defined as those individuals smaller than the length cut-offs presented in Gilligan (2005: Table 3.1) which represent fish less than 1 year of age (0+) or size at sexual maturity for species that mature rapidly. The distribution and abundance of recruits is reflected by the distribution and size of green dots at each sampling location. The absence of a green dot at a site means that no recruits of that species were sampled in 2010. If recruits were present, the size of the green dot matches the abundance scale described by the legend. 4. Trends in abundance from 2004 through to 2010 are presented for each catchment zone and for the catchment as a whole as a bar graph. The height of the bar reflects the average abundance across all sites in that zone and the error bars represent the standard error of the mean.

1 However, a single Murray hardyhead was detected in the Lower Murray River (Murray II zone) during Sustainable Rivers Audit sampling in 2005.

I&I NSW – Fisheries Research Report Series: No. 28 35 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 24. Distribution, abundance and recruitment of common carp (Cyprinus carpio) – alien pest.

Figure 25. Distribution, abundance and recruitment of bony herring (Nematalosa erebi).

36 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 26. Distribution, abundance and recruitment of Murray cod (Maccullochella peelii).

Figure 27. Distribution, abundance and recruitment of golden perch (Macquaria ambigua).

I&I NSW – Fisheries Research Report Series: No. 28 37 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 28. Distribution, abundance and recruitment of goldfish (Carassius auratus) – alien pest.

Figure 29. Distribution, abundance and recruitment of silver perch (Bidyanus bidyanus) – Vulnerable.

38 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 30. Distribution, abundance and recruitment of freshwater catfish (Tandanus tandanus) – Endangered population.

Figure 31. Distribution, abundance and recruitment of Australian smelt (Retropinna semoni).

I&I NSW – Fisheries Research Report Series: No. 28 39 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 32. Distribution, abundance and recruitment of spangled perch (Leiopotherapon unicolor).

Figure 33. Distribution, abundance and recruitment of unspecked hardyhead (Craterocephalus stercusmuscarum).

40 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 34. Distribution, abundance and recruitment of carp-gudgeon species complex (Hypseleotris spp.).

Figure 35. Distribution, abundance and recruitment of eastern mosquitofish (Gambusia holbrooki) – alien pest.

I&I NSW – Fisheries Research Report Series: No. 28 41 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

2.5 Mean 2004 Mean 2005 Mean 2006 Mean 2007 2 Mean 2008 Mean 2009 Mean 2010

1.5

1 Redfin perch

0.5

0 Lakes and Darling Anabranch Murray I Murray II Wetlands Total Reservoirs Zone

Figure 36. Distribution, abundance and recruitment of redfin perch (Perca fluviatilis) – alien pest.

80 Mean 2004 Mean 2005 70 Mean 2006 Mean 2007 Mean 2008 60 Mean 2009 Mean 2010

Murray-Darling rainbowfish 20

0 Lakes and Darling Anabranch Murray I Murray II Wetlands Total Reservoirs Zone

Figure 37. Distribution, abundance and recruitment of Murray-Darling rainbowfish (Melanotaenia fluviatilis).

42 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

120 Mean 2004 Mean 2005 Mean 2006 100 Mean 2007 Mean 2008 Mean 2009 Mean 2010 80

40 Flat-headed gudgeon

0 Lakes and Darling Anabranch Murray I Murray II Wetlands Total Reservoirs Zone

Figure 38. Distribution, abundance and recruitment of flat-headed gudgeon (Philypnodon grandiceps).

Figure 39. Distribution, abundance and recruitment of dwarf flat-headed gudgeon (Philypnodon macrostomus).

I&I NSW – Fisheries Research Report Series: No. 28 43 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 40. Distribution, abundance and recruitment of Murray hardyhead (Craterocephalus fluviatilis) – Critically endangered.

44 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

6. WATER QUALITY AND HABITAT PARAMETERS COLLECTED FROM EACH SITE DURING FISH SAMPLING

Water quality

The following water quality parameters were recorded at each site at the time of fish community sampling; temperature (oC), pH, dissolved oxygen (mg/L), conductivity (μS/cm) and turbidity (NTU). For each parameter, two measurements were taken at 20 cm below the surface. Then single measurements were taken at each 1 metre depth interval. These depth profile measurements were recorded in the deepest part of the sampling site. Data presented are the average of the two measurements taken 20 cm below the surface as no stratification of water quality parameters was observed at any site.

Despite being important parameters for fish, the temperature (Figure 41) and dissolved oxygen (Figure 42) data presented are un-informative in the context of monitoring long term changes, as both parameters can fluctuate on a daily as well as longer-term basis. For these parameters, long- term data continuously collected from instream data loggers is the most reliable means to detect long-term change. However, several sites had sub-optimal (<5 mg/L) dissolved oxygen concentrations at the time of sampling in 2010 (Figure 42). These included sites with dense aquatic macrophyte beds (Rundeah and Great Darling Anabranch mouth) as well as sites likely to have oxygen depletion through biological breakdown of relatively recently inundated vegetation and litter (Four Wings Shack, Cliffhouse Wetland and Kieara Billabong).

Figure 41. Average surface (20 cm) temperature recorded at each fish sampling site in 2010.

I&I NSW – Fisheries Research Report Series: No. 28 45 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 42. Average surface (20 cm) dissolved oxygen concentration (mg/L) recorded at each fish community sampling site at the time of sampling in 2010.

Although pH, conductivity and turbidity can also vary widely as a result of the immediate climatic and hydrological conditions, they are a little more indicative of the conditions in the weeks or months preceding fish community sampling and have the ability to drive changes in the composition of fish communities.

All but eleven sites had pH values in the ‘normal’ range of 6 – 8 (Figure 43). Those that ranged outside these values all had slightly higher pH values ranging between 8 and 9 and included Lake Benanee and Lake Victoria, Woodlands, Hunter Waterhole and Grand Junction on the Great Darling Anabranch, Nangiloc, Boston Bend, Upper Kulnine, 10km below Lock 7 and Hancock Hill – Wompinni on the Murray River and Webcoles Camp Billabong on the Darling River.

Only a single site, Tareena Billabong, had conductivity readings above 800 μS/cm at the time of sampling. The conductivity at Tareena Billabong was ~ 25,000 μS/cm and precluded fish sampling. Only six sites had conductivity readings above 400 μS/cm; Grand Junction, Tareena, Pomona wetland, Woodlands, Four Wings Shack and Lake Benanee (Figure 44). However, the conductivity exceeded the end of catchment target of 463 μS/cm at only two of these sites; Grand Junction 713 μS/cm and Tareena 628 μS/cm (Figure 44).

There were a broad range of turbidity readings recorded amongst sites within the catchment area (Figure 45). In general, those sites receiving Darling River floodwaters had the highest turbidity. Interestingly, turbidity at Kieara Billabong and the four most upstream sites within the Great Darling Anabranch, which all received Darling River floodwaters were quite clear. Averaged across sites, the most turbid to least turbid zones in 2009 were the Darling River, Lakes & Reservoirs, Lower Murray River, floodplain wetlands, Great Darling Anabranch and upper Murray River.

46 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 43. Average surface (20 cm) pH recorded at each fish community sampling site at the time of sampling in 2010.

Figure 44. Average surface (20 cm) conductivity (μS/ cm) recorded at each fish community sampling site at the time of sampling in 2010.

I&I NSW – Fisheries Research Report Series: No. 28 47 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 45. Average surface (20 cm) turbidity (NTU) recorded at each fish community sampling site at the time of sampling in 2010.

Habitat

Aquatic habitat features were recorded as present or absent within each of the replicate electrofishing operations, each corresponding to a transect of 59 ± 4 m (mean ± SE). The presence/absence data is presented as the proportion of operations at each site where each habitat feature was present in 2010 (i.e., if native trees were present in 9 of the 12 replicate operations, then they would be scored as 9 / 12 = 0.75). Additionally, depth and width were recorded for each electrofishing operation and averaged across operations. Flow velocity was assessed as either no flow, slow, medium or fast for each operation and the modal velocity (the value that occurs most frequently) is presented.

48 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 46. The proportion of operations at each sampling site where each substrate category was present.

Figure 47. The proportion of operations at each sampling site where each riparian vegetation category was present.

I&I NSW – Fisheries Research Report Series: No. 28 49 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 48. The proportion of operations at each sampling site where each instream vegetation category was present.

Figure 49. The proportion of operations at each sampling site where each structural habitat types was present.

50 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Figure 50. The proportion of operations at each sampling site where each meso-habitat type was present.

I&I NSW – Fisheries Research Report Series: No. 28 51 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

7. DISCUSSION

Management actions undertaken in an effort to achieve an ‘identifiable net improvement in riverine health across the Lower Murray Darling Catchment by 2015’ include (Troy Muster, Lower Murray Darling CMA, pers. comm.):

1. The release of ~382,000 Murray cod and golden perch fingerlings at various locations in 2005, 2007, 2008 and 2009.

o February 2005: 33,475 Murray cod released at three locations in the Darling River. o February 2007: 27,000 Murray cod and 60,000 golden perch released at four locations in the Murray (2) and Darling (2) Rivers. o February 2008: 125,000 Murray cod and 125,000 Golden perch released at 17 locations on the Murray (13) and Darling (4) Rivers. o February 2009: 11,100 Murray cod and 11,100 Golden perch released at 11 locations in the Murray River between Euston and the Murrumbidgee junction and an additional four locations on the Murrumbidgee River downstream of Balranald (Club Marine Insurance and Coastcare).

2. The NSW Murray Wetlands Working Group, NSW Department of Water & Energy, NSW Department of Environment, Climate Change & Water and the Murray-Darling Basin Authority used a combined total of ~33 GL of environmental water allocations to inundate.

o 17 wetlands in the upper and lower Murray River floodplain (Murray I and Murray II zones), totalling 228 ha of wetland habitat in 2004. o 6 wetlands in the lower Murray River floodplain (Murray II zone), totalling 113 ha in 2005. o 4 wetlands in the lower Murray River floodplain (Murray II zone), totalling 52 ha in 2006. o 5 wetlands in the lower Murray River floodplain (Murray II zone) and 2 wetlands in the upper Murray River floodplain (Murray I zone), totalling 118 ha in 2008. This included Thegoa Lagoon (MWWG ID No. 367), Cliffhouse Wetland (MWWG ID No. 128) and Nampoo Wetland (MWWG ID No. 164) associated with the riverine sites Upper Kulnine, Hancock Hill-Wompinni and 10 km below Lock 7 respectively. o 1 wetland in the upper Murray River floodplain (Murray I zone), 6 wetlands in the lower Murray River floodplain (Murray II zone) and 1 wetland on the Darling River floodplain, totalling 538.5 ha in 2009. This included the re-wetting of Cliffhouse wetland (MWWG ID No. 128) and Nampoo Wetland (MWWG ID NO. 164). Additionally, Dry Lake and Lake Benanee were refilled using a 30 GL environmental water allocation, totalling 1,370 ha in November 2009. o 2 wetlands in the lower Murray River floodplain (Murray II zone) totalling 10.6 ha in 2010 (prior to fish sampling in 2010). This included Cliffhouse Wetland (MWWG ID No. 128). Additional wetlands were flooded subsequent to sampling being completed in 2010.

3. In 2008, the Lower Murray Darling CMA completed works at seven wetlands on the lower Darling River and two wetlands on the lower Murray River (Murray II zone) to improve flows and fish passage to wetlands. The works included the replacement of pipe culverts with box culverts, the installation of regulators at some sites and the removal or lowering of levee banks. Eight of the nine managed wetlands were inundated to some extent during the early 2010 flood.

52 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

4. In 2007, 19 snags were placed in the lower Darling River upstream of Burtundy Weir by the NSW Department of Primary Industries.

5. The Lower Murray Darling CMA installed a nine cell vertical-slot fishway at Burtundy Weir that became operational in August 2008.

6. The Lower Murray Darling CMA installed a vertical-slot fishway at Weir 32 that became operational in December 2009. Following the installation of a third fishway at Pooncarrie Weir, un-interrupted fish passage will have been facilitated along the entire main channel of the Darling River from Menindee Main Weir to the Murray River junction.

7. The Pomona Reach Habitat Management Plan implementation project was undertaken by the LMD CMA on four properties at Pomona on the Darling River between March and June 2009. Works involved removal of 39 willows, erection of 2,073 m of riparian fencing, weed removal, provision of 3 off-stream stock watering points and riparian revegetation with 650 native tubestock. Between November 2009 and May 2010 a further 51 willows were removed, 1,200 m of riparian fencing was erected, 6 additional off-stream stock watering points were installed and 280 native tubestock were planted in the riparian zone. The works are being undertaken about 13 km downstream of the Pomona sampling site. Given this distance and the nature of the works completed, it is unlikely that any benefits of the works will be detected by the fish monitor program.

8. The River Frontage Action Strategy implementation project was undertaken by the LMD CMA at three sites between May and July 2009 (Pooncarie Mission and the Menindee Aboriginal Reserve on the Darling River and Boston Bend on the Murray River). Works intended to protect and preserve 11.7 km of river frontage included archaeological surveys, installation of stock grids and gates, fence repair, track construction and traffic exclusion, rubbish and machinery removal, targeted rabbit and weed control and signage. The Menindee works were being undertaken ~40 km upstream of the Bono sampling site, the Pooncarrie Mission works 10 km upstream of the Pooncarrie sampling site. In contrast, the Boston Bend works are being completed immediately adjacent to the Boston bend fish monitoring site. Between February and August 2010, River Frontage Action Strategy implementation works were undertaken at two sites (Neilpo Station (downstream of Pomona on the Darling River) and Willow Bend Caravan Park (Wentworth)) representing a combined 4.1 km of river frontage. Works included the removal of 62 willow trees, the erection of 2,800 m of riparian fencing, provision of 3 off-stream watering points, revegetation with 820 native tubestock, bank protection works and interpretive signage. However, due to both the large distances from sampling sites and the nature of the works involved, these projects are unlikely to lead to substantial changes in fish communities at monitoring sites apart from possible benefits of vehicle exclusion from river banks at Boston Bend.

In addition:

9. The Murray-Darling Basin Commission’s Sea to Hume Dam fish passage program has completed construction of functional vertical-slot fishways on each of Locks 7 (in 2004), 8 (2003), 9 (2005), 10 (2006) and a denil fishway on Euston weir (Lock 15) (in 2004) on the Murray River (Barrett and Mallen-Cooper 2006, Stuart et al. 2008). Lock 10 also has an additional denil fishway which only provides fish passage under conditions of high tailwater. The only remaining Murray River weir within the Lower Murray Darling CMA area that did not have a fishway installed at the time of sampling in 2010 is Mildura Weir (Lock 11). However, construction of a denil fishway commenced at this site in July 2010 and is scheduled for completion by December 2010. The existing fishways have been

I&I NSW – Fisheries Research Report Series: No. 28 53 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

demonstrated to provide fish passage for > 1,000 fish per day, for 13 species of fish and for individuals ranging from 31 mm – 1040 mm (Stuart et al. 2008).

10. Within the Lower Murray Darling CMA area, William’s Carp Separation Cages (Stuart et al. 2006) have been constructed and installed at the Euston Weir fishway in early 2006 and at Lock 10 in April 2008 (Stuart 2008). Automated Mark V carp separation cages have also been provided at Locks 7, 8 and 9, however use of the carp traps at these sites will be dependent on the development of a cost-effective disposal strategy for remote locations and they are yet to be utilised to remove carp from the system. Such a strategy is currently being developed by Peter Jackson on behalf of the Murray Darling Basin Authority (Jackson 2009). To date, there has been limited removal of carp from NSW fishways due to unresolved disposal difficulties. In comparison, Stuart and Conallin (2009) report that the Mark V WCSC installed at Lock 1 in South Australia in November 2007 had removed 80 tonnes, or approximately 32,000 individual carp up until around August 2009 (at a separation efficiency of 60 – 70%) and a further 80 tonnes up until 5 November 2010 (Anthony Conallin, pers. Comm.).

Over the last 12 months, progress towards CAP targets has improved. Although, as at the end of 2009/10 only 1 site (3%) exceeded the CAP targets for all three ‘nativeness’ ratios; Imperial Lake near Broken Hill. Nativeness was improving at a further fourteen sites (42%), was stable at seven sites (21 %), but had declined at seven sites (21%) and deteriorated substantially at four sites (12%) (Figure 10). Although conditions are still declining at 33% of sites, this is a marked improvement on conditions at the same time in 2008/2009, where nativeness ratios were declining at 73% of sites.

During 2009/10, the native : alien biomass ratio increased in all catchment zones within the CMA area. The biomass of native fishes has remained stable but the biomass of alien species has declined, with the median ratio increasing from 792 grams of native fish to 1 kg of alien fish in 2004 to 878 grams of native fish in 2010 (Figure 6). The increases were statistically significant in both the upper and lower Murray River zones and the CAP target for native : alien biomass ratio have been exceeded in these two parts of the CMA area. Despite positive progress, the increases observed in the remaining catchment zones do not yet represent achievement of the CAP target or achievement of the target across the CMA area overall. The native : alien abundance ratio increased significantly in the Darling River, probably as a direct result of extensive recruitment of both bony herring and golden perch, and the colonisation of the lower Darling River by spangled perch, each response triggered by significant inflows from the upper Darling catchment between January and April. There were also increases in the native : alien abundance ratio in the lower Murray River zone, although the increase was not statistically significant. However, there were concurrent declines in the native : alien abundance ratio in the Great Darling Anabranch and Lakes & Reservoirs zones and no changes in the upper Murray River or floodplain wetlands zones. Despite native abundance doubling since 2004, the abundance of alien fishes has roughly trebled, so the overall catchment wide trend was for no significant change in the native : alien abundance ratio within the CMA area. The median abundance ratio has only changed from 12 native individuals to 1 alien individual in 2004 to 13 native individuals in 2010 (Figure 5). Lastly, the native : alien species ratio has declined in all catchment zones and there has been a statistically significant decline in the native : alien species ratio across the CMA area overall. This has occurred because alien species are becoming more prevalent within the CMA area at the same time as native fish are becoming less prevalent. The species richness ratio has declined from a median of 4 native species per alien species in 2004 to 2 in 2010 (Figure 4).

Fish assemblage parameters that have changed significantly at a catchment level over the six years since benchmark sampling in 2004 are the total species richness increasing from 6.7 species per site in 2004 to 8.8 species in 2010 (Figure 11), total abundance increasing from 231 in 2004 to 493 in 2010 (Figure 12), the proportion of total species richness that is native declining from an average of 0.77 native species per site in 2004 to 0.69 in 2010 (Figure 14), the proportion of the total catch

54 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

that is native fish recruits increasing from 0.42 in 2004 to 0.54 in 2010 (Figure 17) and the proportion of the total catch suffering from a health condition increasing from an average of 2.0 % of individuals in 2004 to 3.8 % in 2010 (Figure 18). The proportion of individuals affected by fin damage (physical and pathogenic) and lesions/ulcers was higher in 2010 than observed during any previous round of sampling (Figures 21 and 22). None of the other parameters assessed; total biomass or the proportion of total abundance or biomass that was native fish have changed at a whole of catchment level between 2004 and 2010.

Within individual catchment management zones, total abundance and total biomass increased and the proportion of fish affected by health conditions increased in the Lakes & Reservoirs management zone; species richness, total abundance and the proportion of native fish recruits increased in the Darling River management zone; total species richness, abundance and biomass increased, the proportion of fish affected by a health condition increased and the proportion of species that were native declined in the upper Murray River zone; the proportion of fish affected by a health condition increased in the lower Murray River zone; and total biomass increased in floodplain wetlands between 2004 and 2010.

At an individual species level, two new species were collected in 2010 that have not been sampled during previous sampling rounds, dwarf flat-headed gudgeon and spangled perch. The dwarf flat- headed gudgeon were collected from two floodplain wetlands. Spangled perch were collected from the Menindee Lakes and the upper most Darling River sites and their associated floodplain wetlands. Seven of the 15 species collected during previous sampling have increased in abundance during the previous 12 months; the native silver perch, unspecked hardyhead, bony herring and golden perch, and the alien Eastern mosquitofish, goldfish and common carp. Most of these increases are likely to have occurred through recruitment at sites affected by the Darling River inflows. Native silver perch, unspecked hardyhead and alien Eastern mosquitofish, redfin perch and goldfish were found at more sites in 2010 than in 2004, whilst native freshwater catfish, Murray- Darling rainbowfish, Murray cod, Australian smelt and carp-gudgeon species were collected at fewer sites (Figure 23).

These data suggest that the management actions implemented up until June 2010, and/or the extent of the works involved, have not been sufficient to result in progress towards the three Lower Murray Darling CMA CAP targets for fish community ‘nativeness’. Although some improvements in ‘nativeness’ ratios have been recorded and the condition of 45% of monitoring sites in improving, ratios have continued to decline at 33% of monitoring sites. Further, it is possible that the significant positive changes that have occurred over the last 12 months are attributable to natural recruitment of the fish community in response to the moderate Darling River flood pulse between January and April 2010, rather than to management actions undertaken by the CMA.

The release of ~ 382,000 Murray cod and golden perch fingerlings since 2005 did not result in significant increases in the population sizes of either of these species. Data suggest that either the survival of the released fingerlings was very poor or that they rapidly dispersed long distances from the release points (and possibly outside the CMA area for golden perch). In contrast, the flood pulse in the Darling River, which peaked at around 16,000 ML/day and lasted for a period of 90 – 100 days resulted in significant and widespread recruitment of both golden perch and bony herring and facilitated the colonisation of the lower Darling River by spangled perch. Further, the collection of a 2009 cohort of golden perch recruits from the Darling River in 2010 also indicates that the more modest flow pulse peaking at 3,700 ML/day, but also lasting for 110 – 120 days between September 2008 and January 2009 resulted in golden perch recruitment, although to a less significant extent than the larger January – April 2010 flow. However, the same cannot be demonstrated for Murray cod as no Murray cod recruitment was detected in the Darling River in 2010. Perhaps because the flood water arrived too late to benefit Murray cod larvae which are believed to disperse in November. However, as per previous years of sampling, Murray cod recruitment was detected in both the upper and lower Murray River zones despite continued low flow conditions and a lack of stocking of Murray cod fingerlings. The current level of natural

I&I NSW – Fisheries Research Report Series: No. 28 55 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

recruitment plus the input of stocked fingerlings between 2005 and 2009 has not been sufficient to result in significant increases in the abundance of Murray cod within the CMA by 2010.

The environmental watering of wetland systems in the lower Murray River zone between 2004 and 2010 has similarly not led to a detectable improvement in native fish assemblages in this catchment zone. However, as most of the water delivered was pumped or siphoned, the opportunity for fish to enter the wetlands was limited. Fish passing through pumps have been demonstrated to suffer substantial mortality (Baumgartner et al. 2007) and data exist demonstrating that some species have an aversion or inhibition to passing voluntarily through or into dark passages or pipes (Mallen- Cooper 1996; Mallen-Cooper 2001; Harris et al. 2007). Even more pertinent is the fact that once the wetlands were filled, there has been no or only a limited opportunity for fish to escape back to the river before the wetlands are dried and any food-web responses resulting from the wetting of the wetland (plankton blooms etc) would not have contributed to the riverine fish community. In summary, wetland inundation activities will only lead to a positive response in fish communities if a) fish are allowed unimpeded access to the wetland during the filling phase and b) that the wetland is subsequently re-opened to the river at a later date (with adequate fish passage provided) so that fish recruited in the wetland can re-enter the river before it dries and so that the bio-production from the wetland has an opportunity to contribute to the riverine ecosystem. Wetland habitats are particularly important for several species of fish native to the CMA area, especially the threatened species; Murray hardyhead, southern purple spotted gudgeon, olive perchlet, southern pygmy perch, flat-headed galaxias and freshwater catfish. Implementing ‘fish-appropriate’ wetland rehabilitation activities will be essential in the recovery of these species in the CMA area.

Fish-appropriate wetland watering is most readily achieved by natural gravity feeding water to wetlands, as occurs at Thegoa Lagoon and occurred at floodplain wetlands of the Darling River during the recent flood event. Water should be delivered to wetlands by either raising the river level above the natural commence-to-fill sill within the wetland inlet, or by excavating the inlet sill to below base-flow river level and installing a culvert and regulator gates that provide adequate fish passage both into and out of the wetland (see Mallen-Cooper 2001; Fairfull & Witheridge 2003; Nichols and Gilligan 2004). Further, a sufficient volume of environmental water should be allocated to initially fill the wetland and then to reconnect the wetland to the river at a later date (12 – 18 months after filling) before the wetland is allowed to return to its dry state. Lastly, wetland wetting-drying cycles should be coordinated among neighbouring wetland systems so that at any point in time at least some wetland habitat is available to wetland specialists. Under natural hydrology, dry phases resulting in natural wetland drying would have coincided with low river levels, which resulted in lentic pseudo-wetland habitats being available in drying main river channels. However, under current river management regimes, river channels persist as lotic systems even during drought and wetland specialist fishes have no or few refugia within which they can persist. Therefore, fish-appropriate wetland management must ensure that wetland specialist fishes have an opportunity to evacuate drying wetlands and re-populate filling ones without having to spend long periods of time trying to survive in potential hostile riverine (lotic) environments. A high priority for the recovery of the large number of threatened wetland specialist fishes is the development of such a ‘fish appropriate’ wetland wetting-drying management strategy.

Despite data indicating that each of the fishways constructed in the Murray River is providing effective fish passage past Locks 7, 8, 9, 10 and 15 (Stuart et al. 2008), fishway construction has not yet led to a detectable improvement in fish community parameters in the lower Murray River management zone. A potential explanation may be that although the fishways are in place at Locks 7, 8, 9, and 10, and providing free fish passage within the lower Murray River zone, substantial improvements in the fish communities may be dependent on the provision of fish passage at Locks 1 – 6, that would enable fish to migrate into the Lower Murray-Darling CMA area from the lower Murray River in South Australia. Fishway construction has been completed at Lock 1, 3, 5 and 6 in South Australia. It could be hypothesised that a response in fish communities in the lower Murray River management zone will not eventuate until fishway construction has also been completed at Locks 2 and 4, which is scheduled to occur in 2011. Alternatively, the rate of recovery of a fish

56 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

community following provision of fish passage has been demonstrated to take several years in a coastal catchment (Gilligan 2003) and a similar time frame may be required to detect fish community responses in the Murray River.

The contribution of the CMAs Burtundy and Weir 32 fishways to changes in fish communities in the Darling River cannot be conclusively tested with existing data. Particularly given that the January – April 2010 Darling River flow is likely to have drowned out all three weirs on the lower Darling River and overwhelmed any signal of improved fish passage through the fishways prior to January 2010. An acoustic or PIT reader system installed at both fishways is the best method available to provide the necessary data to establish effectiveness of the two Darling River fishways.

In order for the Lower Murray-Darling CMA to make progress towards meeting its CAP targets for riverine health, it is recommended that the CMA invests its resources into the following aquatic rehabilitation programs, each of which should contribute to meeting the CMAs aquatic health CAP targets:

• Threatened species recovery actions such as those described in the I&I NSW Priorities Action Statement for threatened fish and marine vegetation. Murray hardyhead, southern purple spotted gudgeon, olive perchlet, southern pygmy perch, flat-headed galaxias and freshwater catfish would all benefit from fish-appropriate wetland management, habitat rehabilitation and pest fish exclusion at key wetlands in the system. For all six of these species, recovery would require reintroduction programs as four of the six species are likely to be locally extinct in the Lower Murray Darling CMA area and therefore natural recolonisation of rehabilitated habitats is unlikely to occur. It is specifically recommended that the LMD CMA liaise with Michael Hammer (Aquasave Consultants) regarding potential for reintroduction of the endemic southern basin form of the endangered Southern purple-spotted gudgeon (Hammer et al. 2009) and Iain Ellis (Murray-Darling Freshwater Research Centre) regarding potential for reintroduction of critically endangered Murray hardyhead to specific sites that meet their habitat requirements and can be managed by the CMA to ensure ongoing survival of the reintroduced populations. It is also recommended that the LMD CMA purchase endangered freshwater catfish and vulnerable silver perch fingerlings in addition to Murray cod and golden perch as part of the catchments ongoing fish stocking activities. The goal of these threatened species recovery actions is to increase the ‘proportion of total species richness that is native’ across the catchment, which is one of the Lower Murray Darling riverine health CAP targets and is the one that the CMA are making the least progress towards achieving.

• Developing more ‘fish-appropriate’ wetland watering programs (Closs et al. 2006, Meredith et al. 2006, Gilligan et al. 2009) to aid the recovery of non-threatened wetland specialist fishes and also to ensure that wetlands maintain food-web and nutrient transfer linkages with the riverine ecosystem. Implementing managing wetting–drying cycles for fish in wetlands will require an adaptive management framework necessitating the trialling of a range of alternative strategies and the ongoing scientific assessment of the resultant outcomes. The range of factors that will require consideration include (but may not be limited to) aspects of; i) providing fish passage into and out of wetlands, ii) the duration of the dry phase, iii) the duration of the period of reconnection to the river channel, iv) the seasonality of reconnection, v) the provision of migration cues to direct fish to enter of leave the wetland, vi) the potential implications of de-coupling landscape-scale migration cues and indicators with the wetting and drying times, vii) whether the wetland should be dried completely or whether a refuge pool should be maintained and viii) whether screens should be installed to exclude carp and other large bodied fish. Implementing ‘fish- appropriate’ wetland watering programs should facilitate progress towards all three nativeness targets – but particularly those for native : alien species richness and abundance ratios.

I&I NSW – Fisheries Research Report Series: No. 28 57 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

• Utilising Environmental Water Allocations to initiate natural in situ spawning and recruitment events for riverine species such as Murray cod, golden perch, silver perch, bony herring and Australian smelt. Data from the Darling River suggests that a flow pulse persisting for 100 days and with a peak flow volume of 3,700 – 16,000 ML/day (total flow event volumes of 279GL and 634 GL respectively) will provide the desired recruitment response for both golden perch and bony herring. But the higher flow volumes produced a substantially greater response. Further, managed flow pulses peaking at 6,324 ML/day and 4084 ML/day, but persisting for only 33 days in February – March 2004 and 38 days in January – February 2008 respectively did not result in golden perch recruitment. The total flow volume of both these events was 66 GL and 99 GL respectively. Therefore, the creation of flow events persisting for at least 100 days and with total flow volumes of between 279 – 634 GL would facilitate immediate progress towards the native : alien abundance ratio target and longer term progress towards the native : alien biomass ratio target. This would most readily be achieved by utilising Environmental Water Allocations to enhance existing flow pulses to increase their duration and peak flow volume.

• Promoting the maintenance of large stable populations of large adult Murray cod, golden perch, silver perch and freshwater catfish in order to maximise the biomass of native fish in fish communities and improve the ‘proportion of total biomass that is native’ (one of the Lower Murray Darling riverine health CAP targets). This could most readily be achieved by promoting ‘catch and release’ of large individuals amongst the recreational fishing community of the region. An alternative, but more contentious and problematic strategy would be the establishment of freshwater reserves or ‘River Parks’ at intervals throughout the CMA area to protect the biomass of native fishes within them and to promote populations of fish in adjacent river reaches (Saunders et al. 2002, Kingsford and Nevill 2005, Phillips and Butcher 2005).

• Implementing carp control programs to reduce their biomass within the CMA area and consequently improving the ‘proportion of total biomass that is native’, which is one of the Lower Murray Darling riverine health CAP targets. This could begin with funding or otherwise facilitating or coordinating the use of the William’s Carp Separation Cages at Locks 7, 8, 9, 10 and 15, and the installation of carp separation cages on fishways at Burtundy Weir, Pooncarrie Weir and Weir 32. This management action should be an immediate high priority for the CMA. In addition to native species, common carp also responded to the Darling River flows with widespread recruitment. The growth of those numerous recruits over the next 2 – 3 years is likely to substantially reverse progress towards achieving the native : alien biomass ratio target within the CMA area unless actions are taken to remove carp from the system.

58 I&I NSW – Fisheries Research Report Series: No. 28 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

8. REFERENCES

Barrett, J. and Mallen-Cooper, M. (2006). The Murray River’s ‘Sea to Hume Dam’ fish passage program: progress to date and lesson learned. Ecological Management and Restoration 7, 173 – 183. Baumgartner, L. J., Reynoldson, N., Cameron, L. and Stanger, J. (2007). The effects of selected irrigation practices on fish of the Murray-Darling Basin. NSW Department of Primary Industries – Final report Series No. 92. 89pp. Closs, G.P., Balcombe, S.R., Driver, P., McNiel, D.G. and Shirley, M.J. (2006). The importance of floodplain wetlands to Murray-Darling fish: What’s there? What do we know? What do we need to know? Pages 11 – 28 in B. Phillips (ed.) Native fish and wetlands in the Murray- Darling Basin: Action plan, knowledge gaps and supporting papers. Proceedings of a workshop held in Canberra ACT, 7 – 8 June 2005. Murray-Darling Basin Commission, Canberra. Davies, P.E., Harris, J.H., Hillman, T.J., Walker, K.F. (2008). SRA Report 1: A Report on the Ecological Health of Rivers in the Murray-Darling Basin, 2004 – 2007. Independent Sustainable Rivers Audit Group for the Murray-Darling Basin Ministerial Council. MDBC Publication No. 16/08.Fairfull, S. and Witheridge, G. (2003). Why do fish need to cross the road? Fish passage requirements for waterway crossings. NSW Fisheries, Cronulla. Gilligan, D. (2005). Fish communities of the Lower Murray Darling catchment: Status and trends. New South Wales Department of Primary Industries, Fisheries Final Report Series No. 83. Gilligan, D. (2007). Annual progress report towards achievement of the Lower Murray Darling Catchment Action Plan 2004 – 2015: Fish Community Monitoring 2005/06. New South Wales Department of Primary Industries, Fisheries Research Report Series No. 16. Gilligan, D. (2008). Annual progress report towards achievement of the Lower Murray Darling Catchment Action Plan 2004 – 2015: Fish Community Monitoring 2006/07. New South Wales Department of Primary Industries, Fisheries Research Report Series No. 22. Gilligan, D. (2009). Lower Murray-Darling Catchment Action Plan: Fish Community Monitoring Report Card for 2008/09. Industry & Investment NSW, Fisheries Research Report Series No. 24. Gilligan, D, Harris J. and Mallen-Cooper, M. (2003). Monitoring changes in the Crawford River fish community following the replacement of an ineffective fishway with a vertical-slot fishway design: Results of an eight year monitoring program. NSW Fisheries, Final Report Series No. 45. Gilligan, D., Mclean, A. and Lugg, A. (2009). Murray wetlands management and water recovery initiatives: rapid assessment of fisheries values of wetlands prioritised for water recovery. NSW Department of Primary Industries – Fisheries Final Report Series No. 108. Hammer, M., Barnes, T., Piller, L. and Sortino, D. (2009). Reintroduction plan for the Southern Purple-Spotted Gudgeon in the Southern Murray-Darling Basin. Report funded by the Murray- Darling Basin Authority, Aquasave Consultants, Adelaide. Harris, J.H., Baumgartner, L. and Keller, R.J. (2007). Draft final report of the Pump Fishway Project. Harris Research Pty Ltd, Tinonee, NSW. Jackson, P. (2009). Carp Harvest and Disposal at Murray River Fishways. Pages 129 – 133 in J. Pritchard (ed.), Proceedings of the Murray-Darling Basin Authority Native Fish Forum 2009. 1 – 2 September 2009. Albury Entertainment Centre. Murray-Darling Basin Authority. Kingsford, R.T. and Nevill, J. (2005), Scientists urge expansion of freshwater protected areas. Ecological Management & Restoration 6, 161–162.

I&I NSW – Fisheries Research Report Series: No. 28 59 2009/10 Lower Murray-Darling CMA CAP fish report, Gilligan

Leggett, R. and Merrick J. (1987). Australian Native Fishes for Aquariums. J.R. Merrick Publications, Artarmon. Mallen-Cooper, M. (1996). Fishways and freshwater fish migration in South-Eastern Australia. Ph.D. Thesis, University of technology, Sydney. Mallen-Cooper, M. (2001). Fish passage in off-channel habitats of the Lower River Murray. Report to Wetland Care Australia. Fishway Consulting Services, Sydney. Meredith, S.N., Zukowski, S. and Conallin, A., 2006. A case study approach to managing ephemeral wetlands for native fish: linking fish ecology to regulatory structure design and operation. Pages 29 – 44 in B. Phillips (ed.) Native fish and wetlands in the Murray-Darling Basin: Action plan, knowledge gaps and supporting papers. Proceedings of a workshop held in Canberra ACT, 7 – 8 June 2005. Murray-Darling Basin Commission, Canberra. Nichols, S. and Gilligan, D.M. (2004). What about fish? Improving fish passage through wetland flow control structures in the lower River Murray. Australian Landscape Trust, Renmark, South Australia. Phillips, B. and Butcher, R. (2005). River Parks: building a system of “Habitat Management Areas” across the Murray-Darling. An international and national review of freshwater ‘protected areas’ for conserving aquatic biodiversity and river health. Murray-Darling Basin Commission Report. Saunders, D.L., Meeuwig, J.J. and Vincent, A.C.J. (2002). Freshwater Protected Areas: Strategies for Conservation. Conservation Biology 16, 30–41. Savage, G. and Lukies, S. (2009). Lower Murray Darling CMA Report for Hydrology, Salinity and Algal Bloom Target Monitoring: Monitoring report for 2007/08. GHD, Mildura. Stuart, I. (2008). The Mark V Williams’ cage for co-ordinated trapping of Murray fishways. Report for the Murray-Darling Basin Commission, Canberra. Stuart, I. and Conallin, A. (2009). The Williams’ Carp Separation Cage: New Innovations and a Commercial Trial. Pages 118 – 122 in J. Pritchard (ed.), Proceedings of the Murray-Darling Basin Authority Native Fish Forum 2009. 1 – 2 September 2009. Albury Entertainment Centre. Murray-Darling Basin Authority. Stuart, I., 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. Stuart, I., Zampatti, B.P. and Baumgartner, L.J. (2008). Can a low gradient vertical-slot fishway provide passage for a lowland river fish community. Marine and Freshwater Research 59, 332– 346.

60 I&I NSW – Fisheries Research Report Series: No. 28 Other titles in the series

Other titles in this series:

ISSN 1442-0147 (NSW Fisheries Research Report Series)

No. 1 Otway, N.M. and Parker, P.C., 1999. A review of the biology and ecology of the grey nurse shark (Carcharias taurus) Rafinesque 1810. 36pp. No. 2 Graham, K.J., 1999. Trawl fish length-weight relationships from data collected during FRV Kapala surveys. 105pp. No. 3 Steffe, A.S., Chapman, D.J. and Murphy, J.J., 1999. A description of the charter fishing boat industry operating in the coastal and estuarine waters of New South Wales during 1997-98. 33pp. No. 4 Reid, D.D. and Smith, I.R., 1998. The 1998 Pacific oyster survey. 14pp. No. 5 Walford, T. and Pease, B., 2000. Strategies and techniques for sampling adult anguillid eels. Proceedings of a workshop held at FRI, Cronulla, Australia, August 1999. 176pp. No. 6 Heasman, M. and Lyall, I., 2000. Proceedings of the workshop held on 3 March 2000 at the Sydney Fish Markets: Problems of producing and marketing the flat oyster Ostrea angasi in NSW. 57pp. No. 7 Heasman, M., 2003. Proceedings of the Sydney Rock Oyster Hatchery Workshop held on 8 and 9 August 2002 at Port Stephens, NSW. 164pp. No. 8 Allan, G.A., 2003. Proceedings of the Aquafin CRC Snapper Workshop held on 26 September 2002 at the Convention Centre, Melbourne (Aquafin CRC 2001/208). 107pp. No. 9 Faragher, R.A., 2004. Hooking mortality of trout: a summary of scientific services. 9pp. No. 10 Daly, T., 2004. Summary of Proceedings from the Perkinsus Workshop held at the Cronulla Fisheries Centre on 3 September 2003. 32pp.

ISSN 1449-9959 (NSW Department of Primary Industries - Fisheries Research Report Series)

No. 11 Baumgartner, L., 2005. Fish in Irrigation Supply Offtakes: A literature review. 22pp. No. 12 Ganassin, C. and Gibbs, P., 2005. Descriptions of the wildlife species that commonly occur in the marine and estuarine waters of NSW. 88pp. No. 13 Nell, J., 2006. Manual for mass selection of Sydney rock oysters for fast growth and disease resistance. 57pp + 110pp attachments. No. 14 Gilligan, D. and Rayner, T., 2007. The distribution, spread, ecological impacts and potential control of carp in the upper Murray River. 25pp. No. 15 Baumgartner, L., 2007. Fish communities of the Nepean River in the vicinity of Pheasants Nest Weir. 18pp. No. 16 Gilligan, D., 2007. Annual progress report towards achievement of the Lower Murray Darling Catchment Action Plan 2004 – 2015: Fish Community Monitoring 2005/06. 42pp. No. 17 Gale, R., Silberschneider, V. and Stewart, J., 2007. A biological and economic assessment of the 2001 change in the Minimum Legal Length (MLL) of snapper in NSW. Report to the NSW Ocean Trap & Line Management Advisory Committee, December 2007. 43 pp. No. 18 Rowling, K., 2008. Review of ‘Bobbin Gear’ in the NSW Ocean Trawl Fishery. 15 pp. No. 19 Baumgartner, L., Cameron, L., Faragher, B. and Pogonoski, J., 2008. An assessment of the trout fishery in Oberon Dam and the Fish River. 23pp. No. 20 O’Connor, W., Dove, M., Finn, B. and O’Connor, S., 2008. Manual for hatchery production of Sydney rock oysters (Saccostrea glomerata). 53pp. No. 21 Gillson, J.P., Scandol, J.P. and Suthers, I.M., 2008. Impacts of freshwater flow on catch rates of estuarine fisheries resources in New South Wales. 66pp. No. 22 Gilligan, D., 2008. Lower Murray-Darling Catchment Action Plan 2004 – 2016: Fish community monitoring report card for 2006/07. 58pp.

I&I NSW – Fisheries Research Report Series: No. 28 61 Other titles in the series

ISSN 1837-2120 (Industry & Investment NSW – Fisheries Research Report Series)

No. 23 Ghosn, D., 2009. Data summary from the monitoring of Australian bass and native fisheries via competition-based angling in NSW: 1988 – 2008. Interim Report. 74pp. No. 24 Gilligan, D., 2009. Lower Murray-Darling Catchment Action Plan: Fish Community Monitoring Report Card for 2008/09. 62pp. No. 25 Knight, J.T. 2010. Penrith Lakes Fish Scheme – 2009 Fish Monitoring Program. 69pp. No. 26 Stewart, J., Ballinger, G. and Ferrell, D., 2010. Review of the biology and fishery for Australian sardines (Sardinops sagax) in New South Wales – 2010. 59pp. No. 27 Stewart, J., Rowling, K., Hegarty, A-M. and Nuttall, A, 2010. Size and age at sexual maturity of snapper Pagrus auratus in New South Wales 2008/09. 38pp No. 28 Gilligan, D., 2010. Lower Murray-Darling Catchm,ent Action Plan: Fish Community Monitoring Report Card for 2009/10. 62 pp.

62 I&I NSW – Fisheries Research Report Series: No. 28