Monitoring fish stockinggs in Victoria: 2014 native fish surveys

Recreational Fishing Grants Program Research Report

Monitoring fish stockings in Victoria: 2014 native fish surveys

Building Northern Native Fisheries, Lake Eildon Million Murray cod, Lower Goulburn River and Nagambie Lakes stocking initiative creel survey

April 2015

Recreational Fishing Grants Program Research Report

© The State of Victoria Department of Economic Development, Jobs, Transport and Resources

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Preferred way to cite this publication: Ingram BA, Hunt TL, Lieschke J & Douglas J (2015). Monitoring fish stockings in Victoria: 2014 native fish surveys. Recreation Fishing Grants Program Research Report.

ISBN 978-1-74146-536-5 (Print)

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Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program ii

Contents

Executive summary 1

Conclusions and recommendations 3

Introduction 4

Background 4 Objectives of this report 4

Methods 6

Marking and stocking fish 6 Fish sampling 6 Catch per unit effort (CPUE) 10 Creel surveys 10 Detection of calcein in marked fish 11 Distance of stocked fish from stocking sites 11

Results and discussion 12

General information 12 Campaspe River 15 Gunbower Creek 17 Kow Swamp 18 Loddon River 19 Lake Eildon 21 Lower Goulburn River 23 Nagambie Lakes creel survey 25 Calcein marking 26

Conclusions 29

Recommendations 31

Acknowledgements 35

References 36

Appendix I. Sites surveyed and environmental data 39

Appendix II. Creel Survey questionnaire 41

Appendix III. Fish stocking history 44

Appendix IV. Species and number of fish observed in each waterbody during surveys 46

Appendix V: Age, total length and weight of golden perch and Murray cod captured during surveys 47

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program iii

Appendix VI: Percent of fish in each age bracket that were marked 48

Appendix VII: Detection of calcein in golden perch and Murray cod using different methods 50

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Executive summary

Since the late 1980’s The Victorian government has invested considerably in native fish stocking aimed at improving recreational fishing. Since December 2010, three large-scale native fish stocking initiatives involving golden perch and Murray cod, and one major stocking initiative recreational fisher (creel) survey, have been conducted. Building Northern Native Fisheries initiative aimed to stock an extra 670,000 native fish fingerlings into the Campaspe River, Gunbower Creek, Loddon River and Kow Swamp, in addition to the regular allocation of 180,000 native fish. A further 425,000 native fingerlings are expected to be stocked into these waters in 2014. As part of the “Million Murray Cod” Program (MMC), it is expected that Lake Eildon will be stocked with 1,150,000 Murray cod. This program, which is considered to be the largest single-waterway stocking of Murray cod in Australia was funded entirely by recreational fishing license fees at a value of $800,000. Lower Goulburn River enhancement initiative will see 359,500 Murray cod and 527,700 golden perch released over a period of 4 years. The anglers of Nagambie Lakes have been creel surveyed to determine their perception of the native fish fishery and catch. The broad objective of this project was to address key knowledge gaps in the management of Victorian inland fisheries by answering recognised measures of stocking success including • Is there evidence of stocked fish survival? • What is the percentage contribution from fish stocking to the fish population and fishery? • Is there a net increase in fish abundance in the fish population and angler catch? • Is there a net increase in fisher target preference, participation and/or satisfaction from fish stocking? Golden perch and Murray cod fingerlings marked with calcein were released into the selected waters over four years from 2010/11. In 2014 electro-fishing surveys were conducted to capture fish from the stocked sites. Sampled fish were measured, aged and analysed for the presence of a calcein mark. Results from these surveys were compared with surveys conducted before the stocking events. Between December 2013 and April 2014, anglers fishing at Lake Eildon and the Nagambie Lakes were interviewed to assess catch and satisfaction. These results were compared with surveys conducted during 2010 and 20-11. Key findings In waters that were stocked with calcein-marked golden perch, the percent of fish that were stocked ranged from 11% (lower Goulburn R.) to 54% (Campaspe R.) (overall mean 22%). The percent of Murray cod that were stocked ranged from 11% (lower Goulburn R.) to 100% (Campaspe R.) (overall mean 50%). Based on the proportion of stocked fish amongst sampled fish (as above), the distribution of stocked fish across sites sampled and change in abundance of fish, information on the contribution of stocked fish to wild stocks was provided for the water bodies assessed (see table below).

Species Water Contribution Comments of stocked fish to wild stocks Golden perch Campaspe R. Likely Current project supports past studies suggesting that regular stocking is maintaining the golden perch population. Presence of marked fish may be underestimated due to non- marked fish being released. No appreciable change in electro-fishing CPUE. Kow Swamp Inconclusive The contribution of stocking to the population is uncertain as sample size was too small for assessment and non-marked fish were released. Results were confounded by most marked fish being from the 2013/14 stocking that were captured 3 weeks after release. These fish also inflated the CPUE. Loddon R. Likely The high percentage of stocked fish present along with an appreciable change in electro-fishing CPUE suggests that golden perch stocking is making a substantial contribution to the population. Presence of marked fish may be underestimated due to non-marked fish being released.

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Species Water Contribution Comments of stocked fish to wild stocks Golden perch Lower Goulburn R. Unlikely Results suggest that stocking is contributing little to the population, which is more likely being supported by immigration and natural recruitment. Sample size was too small for assessment and marked fish caught at small number of surveyed sites only. Murray cod Campaspe R. Unlikely The sample size was too small to assess the contribution of stockings to the population. Marked fish caught in small number of surveyed sites only. No appreciable change in electro-fishing CPUE. Gunbower Ck Inconclusive The contribution of stocking to the population is uncertain as the sample size was too small for assessment and non- marked fish were released. Electro-fishing CPUE greater than for 2012 survey, but no appreciable change when historic data considered. Kow Swamp Inconclusive The contribution of stocking to the population is uncertain as sample size too small for assessment and non-marked fish were released. Results confounded as most marked Murray cod caught were thought to be fish that moved from Gunbower Ck to Kow Swamp (released 3 weeks before the survey occurred).

Lake Eildon Yes Stocked Murray cod have made a significant contribution to the Murray cod population. Marked fish were caught at all sites surveyed.

Loddon R. Unlikely No conclusions can be made regarding the contribution of stocking Murray cod to the population as the sample size was small and marked fish were caught in a small number of sites only. Presence of marked fish may be underestimated due to non-marked fish being released. Lower Goulburn R. Likely Small numbers of stocked fish were caught which are likely to contribute to the population, along with immigration and natural recruitment. Marked fish caught in a small number of surveyed sites only.

Building northern rivers A high percent of stocked golden perch and Murray cod were present within the Campaspe River, suggesting that stocking is likely to contribute to the Campaspe River recreational fishery as the stocked fish reach legal size. The presence of a high percentage of marked Murray cod suggests that stocking has had a positive impact in Gunbower Creek. Further monitoring will be required to determine if the large number of 0 and 1 year old fish observed in Kow swamp will recruit to the recreational fishery. No conclusions can be made regarding the contribution of stocking to Murray cod populations in the Loddon River as many of fish in the target age group (<4 years old) may have been stocked fish that were not marked with calcein. Lake Eildon Million Murray Cod Stocked Murray cod represented the vast majority (98%) of Murray cod caught in Lake Eildon. Angler satisfaction has not improved since the initiative commenced as few Murray cod were being caught or targeted by anglers. However, angler expectations are likely to change as the stocked fish recruit into the fishery in coming years. Lower Goulburn River enhancement With a low percent of stocked golden perch and Murray cod present in a small number of sites sampled during the study, results suggest that stockings of fish undertaken between 2010/11 and 2013/14 are not likely to noticeably influence the fishery in the Goulburn River. Nagambie Lakes creel survey More anglers were targeting golden perch and Murray cod compared to the earlier survey. Golden perch and Murray cod represented 47% and 17%, respectively. A notable change in the views of anglers since the earlier survey has been the increase in dissatisfaction of other recreational activities.

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Other findings Stocked golden perch and Murray cod have a high degree of site fidelity, especially in the first year following release, but are also capable of dispersing some distance after release Methods for detecting calcein in live fish in the field were found to be unreliable when compared with results obtained from examining sectioned otoliths.

Conclusions and recommendations This study showed that stocked fish were present in all waters surveyed, however, the contribution of stocked fish to fish populations was highly variable. The vast majority of Murray cod caught at Lake Eildon were stocked fish. Values in other waters were either substantially less or inconclusive due to numbers of reasons including, small sample sizes in some waters, variations in electro-fishing efficiency and non-marked fish being released into some waters in some years. In several waters, such as Lake Eildon (Murray cod), the Campaspe River (golden perch) and Loddon River (golden perch), stockings appear to be making a substantial contribution to stocks. However, many of the fish that were stocked during these initiatives were under legal size and so have yet to enter the recreational fishery. In order to fully assess the contribution of stocked fish to the fishery and the benefits to anglers, further monitoring of these stocked waters within the next two years will need to be undertaken. This is especially the case for Lake Eildon where the stocked fish represent a high proportion of the fish captured. A concurrent creel survey in Lake Eildon should be undertaken to evaluate changes in angler perceptions as these fish enter the fishery. This report represents a retrospective evaluation of three major stocking initiatives, which came out of funding made available in 2013/14, after the initiatives commenced. Future stock enhancement programs need to consider developing a well-designed monitoring and evaluation program at the commencement of such programs to fully assess their effectiveness, benefits and returns at their conclusion. This study suggested that stocking has been more effective in lakes than rivers.. An investigation into why stocking is more successful at some sites within a river and why stocking is more successful in some years compared to other years would also be beneficial. i.e. what is driving successful stocking? This study has questioned the value of marking fish with calcein. Since field detection methods are unreliable, fish will need to be destroyed to conclusively determine if a mark is present. Consequently, there is a need investigate alternative, and more cost-effective, methods to mass mark hatchery–bred fish for identification purposes.

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Introduction

Background Since the late 1980’s The Victorian government has invested considerably in native fish stocking aimed at improving recreational fishing outcomes (Gooley 1992). The primary native fish species being stocked are golden perch (Macquaria ambigua) and Murray cod (Maccullochella peelii). Since December 2010, three large-scale native fish stocking initiatives involving these species, and one major stocking initiative angler (creel) survey, have been conducted: Building Northern Native Fisheries Building Northern Native Fisheries initiative aimed to stock an extra 670,000 native fish fingerlings (golden perch and Murray cod) into the Campaspe River, Gunbower Creek, Loddon River and Kow Swamp, on top of the regular allocation of 180,000 native fish. A further 425,000 native fingerlings are expected to be stocked into these waters in 2014. Prior to commencing stocking, in 2011/12 baseline surveys were conducted in these waters to assess golden perch and Murray cod stocks (Hunt and Gorfine 2012). Lake Eildon Million Murray cod As part of the “Million Murray Cod” Program (MMC), it is expected that Lake Eildon will be stocked with 1,150,000 Murray cod. This program, which is considered to be the largest single-waterway stocking of Murray cod in Australia was funded entirely by recreational fishing license fees at a value of $800,000. As part of this initiative, in 2011 a baseline creel survey has been conducted to determine the species composition of anglers’ catches from Lake Eildon, anglers’ preferences and targeted species at Lake Eildon and anglers’ perception of the native fish fishery (Pierotti and Hunt 2012). Lake Eildon will also be stocked with golden perch as part of the existing stocking program. Lower Goulburn River Lower Goulburn River enhancement initiative will see 359,500 Murray cod and 527,700 golden perch released into several sites along the lower Goulburn River by 2014. Nagambie Lakes stocking initiative creel survey The Nagambie Lakes has been periodically stocked with golden perch and Murray cod in an effort to improve the recreational fishing in this system. The fisheries for golden perch and Murray cod in this system are still reliant on stocking programs, as self‐sustaining populations of golden perch and Murray cod have not established (Ryan and O'Mahony 2005). To further enhance the recreational fishery in the Nagambie Lakes, Fisheries Victoria significantly boosted the stocking program for golden perch and Murray cod in this lake system in 2008/09. Over five years, Fisheries Victoria committed to releasing 200,000 golden perch and 50,000 Murray cod fingerlings each year into the lakes. In 2011, three years after these stockings commenced, Fisheries Victoria sought to determine the contribution this stocking program by conducting a creel survey to determine anglers’ catch and anglers’ perception of the native fish fishery.

Objectives of this report Despite the perceived success of these stocking initiatives, the benefit to Victorian recreational anglers has not yet been quantified. An opportunity exists to evaluate the success of these fish stocking initiatives as most stocked fish have been marked with calcein, a fluorescent food dye enabling stock identification (Crook et al. 2007). Naturally recruited fish will be unmarked enabling surveys to estimate the contribution of stocked fish. The broad objective of this project is to address key knowledge gaps in the management of Victorian inland fisheries by answering recognised measures of stocking success including  Is there evidence of stocked fish survival?  What is the percentage contribution from fish stocking to the fish population and fishery?  Is there evidence of an increase in fish abundance in the fish population and angler catch?  Is there evidence of an increase in fisher target preference, participation and/or satisfaction from fish stocking? This project is similar to other stocking evaluation projects in progress and recently conducted by Fisheries Victoria, such as Angling Club Science in Lake's Purrumbete and Bullen Merri (Hunt et al. 2013) and Kerang Lakes Stocking Evaluation (Hunt et al. 2010). More specifically, this study aims to:

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1. As part of the Building Northern Native Fisheries stocking initiative, quantify the contribution of age 0, 1, 2 and 3 year old marked golden perch and Murray cod to the Loddon River, Campaspe River, Gunbower Creek and Kow Swamp native fish populations. 2. As part of the Lake Eildon Million Murray cod initiative, (a) Quantify the contribution of age 0, 1, 2 and 3 year old marked Murray cod to the Lake Eildon Murray cod population, and (b) Assess changes in anglers’ perception of the native fish fishery and targeted species. 3. Quantify the contribution of age 0, 1, 2 and 3 year old marked golden perch and Murray cod to the lower Goulburn River native fish populations as part of the Lower Goulburn River enhancement initiative. 4. Assess changes in anglers’ perception of the native fish fishery and targeted species in Nagambie Lakes.

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Methods

Marking and stocking fish In 2010/11, fish were marked with the calcein using the method described in Crook et al. (2009). Briefly, fingerlings are immersed in a 5% (50ppt) salt (NaCl) solution for 5 min. then immersed in a 0.5% calcein solution (buffered to 7 with sodium hydroxide) for 5 min. Fish were placed into freshwater after treatment for at least 24 hours before release. While this method had minimal effect on golden perch fingerlings, Murray cod fingerlings suffered significant mortalities as a result of the marking procedure, presumably due to the high salt concentration (S. Vidler, DEPI Snobs Creek, pers comm.). Consequently, for all golden perch and Murray cod fingerlings, in 2011/12, 2012/13 and 2014/15 the salt treatment was reduced to 2.5% (25ppt) for 4 min. prior to immersion in calcein as described above. The number of marked golden perch and Murray cod released into each river catchment between 2010/11 and 2013/14 are presented in Table 1, Table 2 and Table 3. Stocking sites in river catchments are presented in Figure 1, Figure 2 and Figure 3.

Fish sampling Fish were sampled predominantly by electro-fishing, with additional mesh netting also undertaken in Lake Eildon. The duration of fishing time and size of area sampled were recorded (Appendix I). Sampling effort (machine seconds voltage and amps) were recorded as was the soak time of mesh nets. The size of mesh nets that captured fish was recorded. All fish sampled were identified and counted. The total length (to the nearest millimetre) and weight (to the nearest gram) of golden perch and Murray cod caught were recorded. Sub-samples of non-target species were measured (length and weight) before release. A subset of golden perch and Murray cod form each waterbody were retained for ageing and contribution analysis (presence of calcein mark), with an preliminary aim of a maximum of 5-10 fish per 100mm total length (TL) range (up to 600 mm) per species per waterbody. Both sagittal otoliths were extracted from each fish, which were processed and analysed by Fish Ageing Services Pty Ltd. (Portarlington, Victoria). Age of stocked fish in the present study were: 0+ spawned and released in 2013/14 season 1+ spawned and released in 2012/13 season 2+ spawned and released in 2011/12 season 3+ spawned and released in 2010/11 season Water temperature, conductivity, turbidity, pH and dissolved oxygen were recorded at each sampling site. Campaspe River, Gunbower Creek, Kow Swamp and Loddon River, The Campaspe River, Gunbower Creek, Kow Swamp and Loddon River were sampled for the “Building Northern Native Fisheries” project. Repeat boat-based electrofishing surveys were conducted as reported by Hunt and Gorfine (2012) by surveying fish populations at specified sites (Figure 1 and Figure 2). Lake Eildon Lake Eildon was sampled for Murray cod for the “Lake Eildon Million Murray cod” project. Since past Fisheries Victoria surveys have indicated that Murray cod are non-randomly situated in Lake Eildon, extra effort was made to sample randomly across the lake. Consequently, the lake was divided into four areas (e.g. Jerusalem Creek, Alliance ramp, Fraser National Park and Bonnie Doon). Within each area, some sampling sites were selected randomly and some sites that were thought to be good Murray cod habitat (rock walls and steep banks with and without woody habitat) were also sampled. Sites sampled are presented in Figure 3. Each netting sampling event used 25-m x 2.0-m mesh nets in sizes of 25, 51, 76, 102, 127 and 152 mm (1-6” stretch gill mesh). The nets were set in the afternoon, then monitored throughout the night (as per platypus guidelines). Each electrofishing sample was boat-based and conducted along the margin of the lake during the day and at night. Sampling was undertaken during the peak of summer when Murray cod are expected to be most active. Dietary items in the stomachs of a sub-sample of Murray cod, which were retained for ageing, were identified to the lowest possible taxon and counted.

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Figure 1. Sites in the Campaspe River that were stocked with golden perch and Murray cod between 2010/11 and 2013/14 (see Table 1 for details), and surveyed in 2014 (see Appendix I).

Table 1. Stocking data for the lower Campaspe River catchment below Lake Eppalock. Species Water Season 2010/11 2011/12 2012/13 2013/14 TOTAL Golden perch Campaspe River 40,000* 68,520 79,000 80,000 227,520 + 40,000*

Murray cod Campaspe River 39,700 40,000 40,000 119,700

TOTAL Marked 108,220 119,000 120,000 347,220 Not-Marked 40,000* 40,000*

TOTAL – all fish 40,000* 108,220 119,000 120,000 387,220

* fish that were not marked with calcein.

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Figure 2. Sites in the Loddon River, Kow Swamp and Gunbower Creek that were stocked with golden perch and Murray cod between 2010/11 and 2013/14 (see Table 2 for details), and surveyed in 2014 (see Appendix I).

Table 2. Stocking data for the Loddon River below Laanecoorie Reservoir, Kow Swamp and Gunbower Creek. Species Water Season 2010/11 2011/12 2012/13 2013/14 TOTAL Golden perch Kow Swamp 30,000* 59,980 59,900 60,000 209,880

Loddon River 50,000* 100,000 100,000 100,000 350,000

Pyramid Creek 10,000* 10,000 5,000 25,000

Total Marked 169,980 164,900 160,000 494,880 Not marked 90,000* 90,000*

Murray cod Gunbower Creek 20,000* 81,199 80,000 80,000 261,199

Kow Swamp 100,000 100,000 200,000

Loddon River 20,000* 54,500 70,000* 70,000 214,500

Pyramid Creek 5,500 5,000 10,500

Total Marked 241,199 185,000 150,000 576,199 Not-marked 40,000* 70,000* 110,000* TOTAL Marked 411,179 349,900 310,000 1,071,079 Not marked 130,000* 70,000* 200,000*

TOTAL – all fish 130,000* 411,179 419,900 310,000 1,271,079

* fish that were not marked with calcein.

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Figure 3. Sites in the Goulburn River and Lake Eildon that were stocked with golden perch and Murray cod between 2010/11 and 2013/14 (see Table 3 for details), and surveyed in 2014 (see Appendix I).

Table 3. Stocking data for Eildon Lake and the lower Goulburn River below Goulburn Weir. Species Water Season 2010/11 2011/12 2012/13 2013/14 TOTAL Golden perch Lower Goulburn River 20,000 17,000 35,000 35,000 107,000 + 2,000* + 2,000*

Murray cod Eildon Lake 383,000 383,000 383,000 3,500 1,152,500 + 33,500* + 33,500*

Lower Goulburn River 40,000 42,500 50,000 132,500

Total Marked 383,000 423,000 425,500 53,500 1,285,000 Not marked 33,500* 33,500*

TOTAL Marked 403,000 440,000 460,500 88,500 1,392,000 Not marked 33,500* 33,500*

TOTAL – all fish 403,000 440,000 460,500 124,000 1,427,500

* fish that were not marked with calcein.

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Lower Goulburn River The lower Goulburn River was sampled for both golden perch and Murray cod. Repeat, boat-based electrofishing surveys were conducted as reported by Koster et al. (2012). Due to these sites being part of a long-term monitoring program funded by the Commonwealth Environmental Water Holder, not all fish collected were retained from these sites. However, additional sampling in the vicinity of these sites was conducted (Figure 3).

Catch per unit effort (CPUE) In order to examine changes in the relative abundance of fish in each waterbody, catch per unit effort (CPUE) was estimated from electro-fishing data using the following formula:

Number of fish caught per sample site Electro-fishing CPUE (fish/min.) machine seconds⁄ 60

Each electrofishing site sample was treated as a replicate within each waterbody. These data were compared with electrofishing data from previous studies, such as that of Hunt and Gorfine (2012), and historical datasets maintained by Fisheries Victoria. As with the current study, sites surveyed within each waterbody were treated as replicates.

Creel surveys To understand potential changes in fisher target preference, participation and/or satisfaction from fish stocking at Lake Eildon and the Nagambie Lakes (NLS), targeted creel surveys of anglers were conducted pre and post stocking of marked fish. Pierotti and Hunt (2012) and Pierotti and Brown (2012) detail creel surveys conducted in 2011 (pre stocking) whereby anglers were intercepted and interviewed as they embark or return from their fishing expedition. During interviews, respondents were asked a limited number of questions (Appendix II) so that the survey could be administered in a face-to-face setting without generating complexity or fatigue issues. Information was collected on anglers; catch (including species composition, species kept and discarded), targeting information, fishing satisfaction level and fishing preference. Although some anglers were interviewed more than once, only daily catch, effort and satisfaction data were recorded on subsequent trips (economic and demographic information was only recorded on first trip). In 2013/2014, targeted creel surveys of anglers were repeated (post stocking), by interviewing anglers in the same manner as described by Pierotti and Hunt (2012) and Pierotti and Brown (2012). For the purposes of the analysis, only replicated survey days over both 2010/11 and 2013/14 creel surveys were compared (Lake Eildon = 9 peak fishing days, Nagambie Lakes = 21 peak fishing days). These were weekends and public holiday long weekends in January and April for Lake Eildon and December to April for the NLS. Considering the Lake Eildon and the NLS encompass multiple fishing access points, bus-route access point survey designs were employed (Pollock et al. 1994). In Lake Eildon, due to logistical constraints, only three access points were surveyed daily with a random starting point (Pierotti and Hunt 2012). These were the Fraser National Park boat ramp, the Alliance boat ramp at the dam wall and the Jerusalem Creek boat ramp. In the NLS, eight key access points between Goulburn Weir and Mitchellstown Bridge were identified and visited each survey shift with a random starting point. To maximise the number of interviews conducted per survey shift, waiting time at access points were stratified by ranking the access point as either high, medium or low effort (Table 4). Strata effort probabilities were informed by local expert knowledge through discussions with regular anglers of the NLS (e.g. Wally Cubbin and members of the Nagambie Lakes Angling Club). In order to examine changes in the catch rate of fish by anglers at Nagambie (golden perch and Murray cod) and Lake Eildon (Murray cod), angler catch per unit effort (CPUE) was estimated from the creel survey data collected during the current study, Pierotti and Brown (2012) and Pierotti and Hunt (2012) using the following formula:

Number of fish caught per angler Angler CPUE (fish/angler/hour)= Number of hours spent fishing

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Table 4. Strata effort probabilities per access point in the Nagambie Lakes Fishing Site number Site name effort Waiting time 1 Goulburn Weir Low 10 mins 2 Kirwan’s Bridge west (angling club) High 30 mins

3 Kirwan’s Bridge Lane and Kirwan’s High 30 mins Bridge east picnic point 4 Buckley Park Medium 30 mins 5 Nagambie Regatta Centre Low 10 mins 6 Nagambie Bridge (Chinamans Bridge) Medium 20 mins 7 Mitchellstown Bridge High 30 mins 8 Major Mitchell Creek Reserve High 30 mins

Only data for days replicated in 2010/11 and 2013/14 were used to estimate angler CPUE. In cases where anglers were surveyed before completing fishing for the day, the number of hours spent fish was the time between starting to fish and the time that the survey interview was conducted. An example of the creel survey questionnaire used in this study is presented in Appendix II. Further information regarding angler creel surveys of the NLS, including economic data, is presented in Hunt (In Prep.).

Detection of calcein in marked fish Three methods were employed to detect the presence of calcein in marked fish.  Live fish were inspected visually with the aid of a UV torch and special glasses fitted with an appropriate filter. This inspection was conducted in a darkened environment to aid visualization of the calcein mark  Calcein fluorescence in the anal fin ray and pelvic fin ray of live captured fish was measured using a hand-held fluorometer (GFP-Meter, Opti-Sciences Inc., Hudson, NH, USA). Several measurements were taken and the highest reading recorded  Both sagittal otoliths were extracted from each fish, which were processed and analysed by Fish Aging Services Pty Ltd. (Portarlington, Victoria). Otoliths were thin sectioned and viewed microscopically for the presence of a calcein mark using fluorescence backscatter (with a I3 filter block). The intensity of the calcein marked was scored subjectively on a scale from 1 (Low) to 5 (High).

Distance of stocked fish from stocking sites The distance between stocking sites and the sites where stocked fish were captured during the present study was estimated (to the nearest km) by imported stocking and capture co-ordinates into Google Earth Software and then measuring river km manually.

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Results and discussion

General information Stocking effort Between 2010/11 and 2013/14 a total of 0.961 million golden perch (86.3% marked with calcein) and 2.124 million Murray cod (93.2% marked with calcein) were released into rivers that were surveyed as part of the study (Table 3, Table 1 and Table 2). Between 0.437 million golden perch and Murray cod (2013/14) and 0.999 million (2013/14) were stocked annually. During the study each water received between 0.0355 million fish (Pyramid Ck, Loddon R.) and 1.186 million fish (Lake Eildon). A total of 49 locations were stocked with fish, with calcein-marked fish being stocked into 46 locations and non-marked fish stocked at 18 locations. Note that large numbers of both golden perch and Murray cod had been stocked into the study waters in the years prior to this study commencing (see Appendix III).

Survey effort and environmental information Surveys were conducted between mid-January 2014 and mid-March 2014. A total of 44 sites were sampled (Table 5, Appendix I), with effort being 0.57-4.7 hrs/site (mean 1.8 hrs/site) for electro-fishing and 2.3-12 hrs/site (mean 9.3 hrs/site) for netting. Electro-fishing was undertaken at all sites while mesh netting was undertaken at 5 sites in Lake Eildon only (Appendix I). Environmental data recorded at each sit samples is presented in Appendix I.

Species composition Nearly 25,000 fish from 16 species (10 native species and 6 introduced species) were sampled from the 44 sites across the 6 waterbodies (Table 5, Appendix IV). The most abundant species caught was Australian smelt (Retropinna semoni) (73% of fish caught) followed by carp (Cyprinus carpio) (5.6%) and redfin perch (Perca fluviatilis) (5.6%). Golden perch and Murray cod represented 8% and 13%, respectively, of the large bodied species caught (Table 50. A summary of golden perch and Murray cod caught during the surveys is provided in Table 6 and Table 7, respectively.

Table 5. Number of fish observed at each waterbody, percentage of which were golden perch and Murray cod for each waterbody.

Waterbody No. No. No. Large bodied fish1 sites species fish Percent of Percent Percent total Murray cod golden perch Campaspe R. 7 7 907 38 5 13

Lower Goulburn R. 13 10 482 53 41 20

Gunbower Ck 6 13 3,132 10 6 6

Kow Swamp 3 8 340 60 9 18

Lake Eildon 7 10 9,648 12 22 3

Loddon R. 8 12 10,477 12 2 8

Overall 44 16 24,986 1. Large-bodied species = Murray cod, trout cod, golden perch, silver perch, brown trout, redfin perch and carp (see Appendix IV).

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Table 6. Summary of golden perch captured and analysed, and the percentage of fish that were marked with calcein (as determined from sectioned otoliths). Waterbody No. Age of No. sites where golden No. sites No. No. fish analysed1 No. Percent (%) of fish tagged sites stocked perch were caught where fish fish (mean ± s.e.)2 sampled fish tagged caught marked All fish At age of All fish At age of All fish At age of (yrs old) fish caught stocked fish stocked fish analysed stocked fish Campaspe R. 7 1-3 6 4 3 44 33 17 10 54 ± 27 65 ± 24

Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014native Victoria: in stockings fish Monitoring L. Goulburn R. 13 1-3 12 4 1 50 19 4 1 11 ± 11 25 ± 17

Gunbower Ck 6 Not stocked 6 1 0 18 14 1 0 Not stocked Not stocked

Kow Swamp 3 0-3 3 3 2 37 35 19 15 32 ± 26 46 ± 25

Loddon R. 8 0-3 8 4 4 100 37 23 10 39 ± 17 59 ±16

Overall 37 35 16 10 249 138 64 36 22 ± 7 46 ± 11

1. Otoliths removed for aging and detection of calcein mark. 2. Mean and standard error for all sites sampled within each waterbody where golden perch were captured and analysed

13 Table 7. Summary of Murray cod captured and analysed, and the percentage of fish that were marked with calcein (as determined from sectioned otoliths).

Waterbody No. Age of No. sites where Murray cod No. sites No. No. fish analysed1 No. Percent (%) of fish tagged sites stocked were caught where tagged fish fish (mean ± s.e.)2



sampled fish fish caught caught marked Recreational Fishing Grants Program Grants Fishing Recreational All fish At age of All fish At age of All fish At age of (yrs old) stocked fish stocked fish analysed stocked fish Campaspe R 7 0-2 3 2 2 16 10 10 10 100 100

L. Goulburn R. 13 0-2 12 9 3 104 35 25 5 11 ± 6 18 ± 9

Gunbower Ck 6 0-3 6 4 3 18 12 12 9 62 ± 24 62 ± 24

Kow Swamp 3 1-2 3 1 2 18 13 3 7 47 ± 13 33

Lake Eildon 7 0-3 7 6 7 252 150 148 145 98 ± 1 99.6 ± 0.4

Loddon R. 8 0-3 5 3 1 22 13 13 2 22 ± 22 22 ± 22

Overall 44 36 25 18 430 233 211 178 50 ± 8 54 ± 9

1. Otoliths removed for aging and detection of calcein mark. 2. Mean and standard error for all sites sampled within each waterbody where Murray cod were captured and analysed.

Proportion of captured fish that were stocked fish Of the 249 golden perch captured during the surveys, 138 fish were analysed to determine age and the presence of a calcein mark. There was a broad range of ages in captured golden perch, from 0 to 20 years old (mean 4.5 years old) (Appendix V). Overall, calcein was detected in 36 fish. In waters that were stocked with calcein-marked fish, the percent of fish that were stocked ranged from 11% (Goulburn R) to 54% (Campaspe R.) (overall mean 22%) (Table 6). The percent of fish at the age of the stocked fish that were marked was considerably higher (overall mean 46%.). The percent of fish in each age class of stocked fish that were marked is presented in Appendix VI. A total of 430 Murray cod were captured during the surveys with more than half (252) being from Lake Eildon. A total of 233 captured fish were analysed to determine age and the presence of a calcein mark. Since no Murray cod over 600 mm were aged, fish that were aged were generally young, ranging from 0 to 8 years old (mean 2 years old) (Appendix V). Overall, calcein was detected in 178 fish. The percent of Murray cod that were stocked ranged from 11% (Goulburn R.) to 100% (Campaspe R.) (overall mean 50%) (Table 7). The percent of Murray cod at the age of the stocked fish that were marked was 18-100% (overall mean 54%). This generally high percentage was attributed to many captured fish from Lake Eildon, most of which (98%) being stocked fish. The percentages of fish that were stocked fish were generally higher for Murray cod than golden perch for all waters except Loddon River (Table 6 and Table 7). This may reflect variation in:  mortality rates of the species after release (higher for golden perch),  dispersal patterns (greater in juvenile golden perch)  variation in the ability of the electro-fishing to sample these species. A summary of the age, total length and weight of golden perch and Murray cod caught from each water body during the survey is presented in Appendix V. Overall, sampled golden perch were 52-611 mm (mean 352 mm) in total length and 13-3,230 g (mean 1,076 g) in weight. Sampled Murray cod were 36-1,100 mm (mean 293 mm) in total length and 11- 19,000 g (mean 907 g) in weight. Some of the older fish that were captured may also have been stocked fish. Although this study focused on evaluating stockings of mostly calcein-marked fish that occurred between 2010/11 and 2013/14, large numbers of both golden perch and Murray cod were stocked into the study waters in previous seasons (see Appendix III). Most of these fish were not marked (a small number of fingerlings were marked with oxytetracyclene and some yearlings were dart-tagged). Since calcein marking of stocked fish commenced in 2009/10, it is not possible to determining if fish stocked into the study waters before 2009/10 were present in the fish analysed. Distance of stocked fish from stocking sites The proportion of fish that were hatchery-derived (marked), declined with increasing distance from the nearest stocking site (Figure 4). For Murray cod, 84% of fish caught within 1 km of the nearest stocking site were marked, whereas 42% of those caught more than 25 km away were marked. These values were biased by the large number of Murray cod that were caught in Lake Eildon during the study (Table 7). In Lake Eildon, all 1 and 2 year old Murray cod were collected within 5 km of the closest release site, whereas only 3 year old fish were collected at sample sites 5-25 km away from release sites (Figure 5a). In other waterbodies, all 1 year old Murray cod were caught within 5 km of a release site while 2 year old fish were more dispersed (Figure 5b). In the Campaspe River, most (90%) of marked Murray cod were caught in the river at Rochester, where they were released one year earlier (see Section on Campaspe River). There was a large number of 0 year old Murray cod that were caught downstream Dyes Weir near Kow Swamp. These fish were thought to have been stocked into Gunbower Weir pool, approximately 9 km upstream of the capture site, 3 weeks before the survey (Figure 5b). (see Section on Kow Swamp). For golden perch, 28% of fish caught within 1 km of the nearest stocking site were marked, whereas 10% of those caught more than 25 km away were marked. All marked 0 year golden perch were caught within 1 km of a release site and all 2 year old fish were caught with 5 km of a release site (Figure 5c). Notably, three 1 year old golden perch caught in the lower Loddon River were presumably from a stocking nearly 40 km away in Pyramid Ck (the nearest release site (Figure 5c). These results suggest that juvenile golden perch and Murray cod have a high degree of site fidelity, especially in the first year following release, but also capable of dispersing some distance after release (Murray cod – 9 km after 3 weeks; golden perch nearly 40 kms after one year). Previous studies have described the downstream drift of golden perch and Murray cod larvae (e.g. Humphries 2005, King et al. 2005), and movement of older fish (>yearling) (e.g.Reynolds 1983, Ryan and O'Mahony 2005, Koehn et al. 2009, Koster et al. 2014), but there have been no previous studies on the movement of golden perch and Murray cod fingerlings. This has been mainly due to lack of a reliable method of marking fingerlings.

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 14

Figure 4. Proportion of fish that were marked caught at different distances from stocking sites (figures in brackets equals sample size).

Figure 5. Number of calcein-marked 0-3 year old fish caught at different distances fromm stocking sites. (a) Murray cod in Lake Eildon only. (b) Murray cod in other waters. (c) golden perch in all waters.

Campaspe River Seven sites were sampled in the Campaspe River with golden perch being captured from 6 sittes (Table 6) and Murray cod from 3 sites only (Table 7). In total, 44 golden perch and 16 Murray cod were caught and of these, 33 golden perch and 10 Murray cod were analysed to determine age and the presence of a calceiin mark. A high percent (53.6%) of golden perch and all (100%) of Murray cod were stocked fish. This result is consistent with ann earlier study that found stocked Murray cod comprised a high proportion of thhe catch in the Campaspe River in 2005 (Hall and Douglas 2008). The presence of a high proportion of stocked fish in the Campaspe river may be due to the presence of a number of weirs, and periods of reduced flow, which may be restricting the movement of fish away from stocking areas. Although 100% of Murray cod analysed from Campaspe River were identified as stocked fish, the sample size was small (10 fish) and came from two of the seven sites sampled. Nine of these fish, which were 1 yearr old, were caught at Rochester, which was also where the fish were stocked in the previous year. Age and length frequency distribution of marked and non-marked golden perch and Murray cood captured from the Campaspe river are presented in Figure 6a. Marked golden perch and Murray cod were 194-299 mm and 102-335 mm in length, respectively. All marked golden perch that were caught were from the 2011/12 stocking only, whereas golden perch stocked in other seasons were notably absent from the samples. Mosst golden perch up to 300 mm TL were 2 year old stocked fish that had been released in 2011/12 (Table 1). Golden perch < 300mm were mostly absent in the prrevious survey of the

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 15

Campaspe River conducted in December 2011 (Hunt and Gorfine 2012). There was a large number of golden perch between 350 and 450 mm in length (3-11 years old), which may have been from natural recruiitment. However, this may be unlikely as previous studies conducted between 1995 and 2003 did not find evidence of gollden perch and Murray cod spawning in the Campaspe River (Humphries and Lake 2000, Humphries et al. 2008), and Hummphries et al. (2008) suggested that regular stocking was maintaining the golden perch population in the Campaspe River. The Campaspe River below Lake Eppalock has been stocked with goolden perch and Murray cod intermittentlyy since 1986/87, with main stocking efforts occurring in the late 1980’s and from the late 1990’s to present (Table 1, Appeendix III). In 2010/11 (22 March 2011), 40,000 non-marked golden perch were released into the Campaspe River at five sites that were subsequently stocked with calcein-marked golden perch. There were five 3 year old fish caught during surveys, none were marked, but a proportion of these may have been stocked fish. All Murray cod captured from the Campaspe river were 1 and 2 year stocked fish, which were released in 2012/13 and 2011/12, respectively (Table 1). Murray cod from otheer stocking year classes (i.e. 2013/14) were not present, though this may have been due to the relatively small sample size of 10 fish, and the limited ability of electro-fishing boats to sample 0 year old fish. While there has been limited assessment of stockings in the Campaspe River, anecdotal reports suggest positive results, especially from stockings of Murray cod (Hall and Douglas 2008). In tthe previous survey of the Campaspe River conducted in December 2011, just two Murray cod (>500 mm) were caught (Hunt and Gorfine 2012). Electro-fishing CPUE for both golden perch and Murray cod in the Campaspe River increased slightly but not changed appreciably between the late 1990’s and the current study (Figure 6b). One notable exception was the relatively high CPUE for Murray cod for the period 1997-00 which, based on the size of fish sampled, corresponded with natural recruit rather than stocking. The Campaspe river is considered to be a highly regulated and degraded river that is dominated by alien species and few native fish species with self-sustaining populations (Humphries and Lake 2000, Humphries et al. 2008). These factors may limit the carrying capacity of the Campaspe River below Lake Eppalock.

Figure 6. Campaspe River fish survey results. (a) Age of marked and non-marked golden perch and Murray cod, and length frequency distribution of marked and non-marked golden perch and Murray cod, and fish not analysed. (b) Electro-fishing catch per unit effort (CPUE) from historic surveys and the current survey (values represent mean and s.e.).

With a high percent of stocked golden perch present, these results suggest that stocking is likely to contribute to the Campaspe River recreational fishery as the stocked golden perch reach legal size (30 cm). Allthough there was a high proportion off marked Murray cod present, the sample size was small (10 fish) and these fish were caught at just 2 sites, which suggests that the stockings are unlikely to contrribute to stocks in the Campaspe River. However, the increased stocking effort over the last three years has had limited effect on abundance (as indicated by electro-fishing CPUE). This study, together with previous research indicates that there is limited and/or spasmodic natural recruitment of golden perch and Murray cod within the Campaspe river, and that stocking is supplementing these populations. An investigation into the background environmental conditions as to why one site out of seven was successful iis recommended, to aid in stocking site selections in future years.

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Key Findings  Current project supports past studies suggesting that regular stocking is maintaining the ggolden perch population in the Campaspe River.  The sample size was too small to assess the conntribution of Murray cod stockings to the population.

Gunbower Creek Six sites were sampled in the Gunbower Creek with golden perch and Murray cod being captuured at all sites (Table 6, Table 7). A total of 17 golden perch were captured and 14 of these were aged between 2 and 8 years old, but none were stocked fish (i.e. marked with calcein). Age and length frequency distribution of marked and non-marked golden perch and Murray cood captured from Gunbower Creek are presented in Figure 7a. Most golden perch (11 fish) were 4 years old, which would have been spawned in the 2009/10 season. The origin of these fish is unknown, many may be wild-spawned, but the possibility that some are stocked fish cannot be discounted. Rehwinkel et al. (2010) suggested that juvenile golden perrch sampled from the Gunbower Creek in Autumn 2010 indicated that recruuitment was occurring in the region. Historically, Gunbower Creek was stocked with golden perch on four occasions between 1990/91 and 1997/98 (Appendix III)). Today these fish would be 16-23 years old which is considerably older than the age of golden perch captured in the current study. There have been multiple stockings of non-marked golden perch fingerlings into Kow Swamp and Pyramid Ck since 2003/04 and 2004/05, respectively (Appendix III), and it is possiblee some of these fish moved upstream into Gunbower Ck via Taylor Ck. These fissh, however, would have had to transverrse three in-stream barriers. Eighteen Murray cod ranging in size from 642-1,100 mm in length (Appendix V) were caught frrom Gunbower Creek. The percent of stocked Murray cod present in the catch, avveraged for all sites at which fish were caught, was high at 62.5% (Table 7). Stocked Murray cod, which were captured from three of the six sites sampled, were either 1 year old (33%) or 2 years old (67%); 0 year old fish (from the 2013/14 sttockings) were absent (Figure 7a). Yet, as previously suggested, 0 year old marked Murray cod fingerlings stocked into Gunbower Weir were captured at one off the Kow Swamp survey sites (see secction on Kow Swamp). The absence of 0 year old Murray cod in Gunbower Creek, and particularly Gunbower Weir, may have been due to the ability of boat electro-fishing to capture small Murray cod in different habitats. In 2010/11, 20,000 non-marked Murray cod were releeased into Gunbower Creek, but fish formm this stocking (i.e. 3 years old) were not caught during sampling. Between July 2013 to June 2014, the North Central Catchment Management Authority (NCMA) received an environmental water allocation to encourage Murray cod spawning and juvenile development in the Gunbower Creek. Subsequent monitoring between October and December 2013 found several cohorts of Murray cod larvae which suggested that spawning events had occurred (http://www.finterest.com.au/the-story-so-far/murray-cod-spawning-in- gunbower-creek/). Fish from these spawnings were absent in the samples collected in the currrent study.

Figure 7. Gunbower Creek fish survey results. (a) Age of marked and non-marked goldden perch and Murray cod, and length frequency distribution of marked and non-marked golden perch and Murray cod, and fish not analysed. (b) Electro-fishing catch per unit effort (CPUE) from historic Fisheries Victoria surveys between (2006-2007),, Hunt and Gorfine (2012) (2011/12) and the current survey (values representt mean and s.e.).

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 17

Gunbower Creek has been stocked with Murray cod since 2000/01, though in the past 3 seasons, stocking levels have been increased dramatically (3-fold) as part of the Building the Northern Fisheries Project (Appendix III). Some of the large Murray cod caught during the study, which were not analysed, may have been from these stockings. These fish were 642—1,100 in length and 4,250- 19,000 in weight (Appendix V).. One interesting note was the capture of a trout cod (Maccullochella macquariensis) (190 mm TL) that was caught at the top end of Gunbower Creek (below Headworks Road). Although critically endangered, trout cod are occasionally caught in Gunbower Creek, which indicates an expansion of its range in the Murray River (Rehwinkel et al. 2010, Douglas et al. 2012). Earlier surveys of Gunbower creek indicated that the abundance of golden perch and Murray cod was low (Douglas et al. 1998), though more recently Rehwinkel and Sharpe (2009) suggested there was an increase in the abundance of Murray cod in the Gunbower Creek compared to earlier surveys, while Rehwinkel et al. (2010) suggested Murray cod abundance was constant between 2009 and 2010 and that the abundance of golden remained low. Electro-fishing CPUE from both historic (2006/07 and 2011/12) and the current (2013/14) data for both golden perch and Murray cod in the Gunbower Creek were highly variable, but suggested an increase since the last survey in January 2012 (Hunt and Gorfine 2012) (Figure 7b). Although these results, combined with the presence of a high percentage of marked fish, suggest that stocking has had a possible impact on Murray cod abundance in the Gunbower Creek, sample size (10 fish only) was too small to allow any conclusions to be made regarding the contribution of stockings to stocks. Further stockings of this species will need to take into account changes in water management practices being undertaken by the NCMA. For example, providing increased environmental flows and improved connectivity, within the catchment, such as construction of fishways to bypass in-stream barriers (see Stuart and Sharpe 2012), may improve fish abundance naturally.

Key Finding  The contribution of stocking Murray cod to the population in Gunbower Ck is uncertain as the sample size was small and non-marked fish were released.

Kow Swamp Two sites were sampled in Kow swamp, one of which was sampled twice (both day and night) (Appendix I). A total of 37 golden perch and 18 Murray cod were caught, and 35 golden perch and 13 Murray cod were analysed to determine age and the presence of a calcein mark. The percent of stocked fish present in the catch, averaged for all sites at which fish were caught, was 31.6% for golden perch (Table 6) and 46.7% for Murray cod (Table 7). Age and length frequency distribution of marked and non-marked golden perch and Murray cod captured from Kow Swamp are presented in Figure 8a. Eighty seven percent of the marked golden perch captured were 0-year old with the remainder (13%) being 1-year old. These fish were 52-141 mm in length. In the previous survey of Kow Swamp conducted in January 2012 a small number of golden perch between 100 and 450 mm were caught (Hunt and Gorfine 2012). Most (15 of 17 fish) of the 0 and 1 year old fish that caught in the present survey were marked, but there was doubt as to the whether the other two fish were marked or not. For these fish the fluorometer meter registered a signal overload which indicated the fish were marked, but calcein was not detected in the sectioned otoliths. The high number of 0 year old golden perch present was likely due to sampling occurring shortly after these fish were stocked. On the 14 January 2014, 60,000 golden perch were released into Kow Swamp, which was then surveyed 3 weeks later on 5 February 2014. The proportion of captured golden perch that were from stockings of hatchery-bred fish is likely to be under-estimated as many non-marked fish have been released into the lake previously. Two golden perch that were non-marked 3 years old fish were caught during the survey of Kow Swamp. These fish may have been from a stocking of 30,000 non-marked golden perch released into Kow Swamp in 2010/11 (Table 2). Sixteen golden perch >3 years old were caught from Kow swamp during surveys (Appendix V), some of which may have been from stockings undertaken prior to Building the Northern Rivers Project. Golden perch have been stocked into Kow Swamp and Pyramid Creek below Kow Swamp since 2002/03 and 2004/05, respectively (Appendix III). Both 0 and 1 year old stocked (marked) Murray cod were captured, whereas stocked 2 year old fish (from the 2011/12 stocking) were not captured. Of the 13 Murray cod that were aged, 10 were 0 years old, of which 6 were marked with calcein (Appendix VI) even though no Murray cod of this age group were stocked into Kow Swamp in 2013/14 (Table 7). These fish were caught on the 5th February 2014 during sampling of the channel (Taylor Ck) downstream of Dyes Weir and into Kow Swamp (at night). These fish are most likely from a stocking of 80,000 marked Murray cod fingerlings that were released into the Gunbower Weir pool 3 weeks earlier (on 15th January 2014), approximately 9 km upstream. No stockings of Murray cod into Kow Swamp occurred prior to Building the Northern Rivers Project, although Murray cod

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 18

have been stocked into Pyramid Creek below Kow Swamp between 2004/05 and 2012/13 (Apppendix III). Of the three 1 year old Murray cod analysed, one was a stocked fish (Figure 8). Two large Murray cod (890-930 mm in length) were captured in Kow Swamp, which were released. Golden perch and redfin have previously dominated the catch of anglers in Kow Swamp (Huntt et al. 2011). In the current study, the catch was dominated by carp (36%), bony bbream (27%) and then golden perch (11%), but no redfin were captured (Appendix IV). In the January 2012 survey of Kow swamp, carp (77%) and golden peerch (13%) were the most common species caught (Hunt and Gorfine 2012). Electro-fishing CPUE for both golden perch and Murray cod in Kow Swamp have increased since the earlier survey conducted in January 2012 by Hunt and Gorfine (2012), which was attributed mainly to the large number of 0 year old fish that were caught (Figure 8b). These results suggest that the most recent stockings have had a positive impact on the abundance of these species in the swamp. However,, further monitoring will be required to dettermine if the large number of 0- and 1- year classes observed in the current studdy recruit to the recreational fishery.

Key Finding  The contribution of stocking golden perch and Murray cod to the populations in Kow Swaamp is uncertain as sample sizes were small and non-marked fish were released. Results were also confounded by capture of a large numbers of fingerlings shortly after their release.

Figure 8. Kow swamp fish survey results. (a) Age of marked and non-marked golden perch and Murray cod, and length frequency distribution of marked and non-marked golden perch and Murray cod, and fish not analysed. (b) Electro-fishing catch per unit effort (CPUE) from historic surveys (Hunt and Gorfine 2012) and the current survey (values represent mean and s.e.).

Loddon River A total of 100 golden perch were captured at eight sites surveyed in the Loddon River (Table 6), while only 22 Murray cod were captured from five sites (Table 7). Of these, 37 golden perch and 13 Murray cod werre analysed to determine age and the presence of a calcein mark. The percent of stocked fish present, averaged for all sites at which fish were caught, was 38.6% for golden perch and 22.2% for Murray cod. Ten marked 1 and 2 year old golden perch were captured from four sites, whereas just two marked Murray cod were captured from a single site, immediately upstream of the Bridgwater bridge. Age and length frequency distribution of marked and non-marked golden perch and Murray cood captured from the Loddon River are presented in Figure 9a. Golden perch that were analysed were 1-9 years old (111-573 mm TL) (Appendix V). A high percent (59.2%) of golden perch that were analysed and <4 years old were stocked fish (Table 6). All 1 year old fish and 88% of 2 year old fish were stoccked, but all 3 year old fish were not marrkked (Appendix VI). Since all 50,000 golden perch that were released into the Loddon River in 2010/11 were not marked with calcein (Table 2), it is not possible to determine from the current data that the 3 year old fish were from the 2010/11 stocking or wild spawned.

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In the current study, many fish under 300 mm were caught (63% of the analysed fish were stocked). Just one golden perch <300 mm was caught during a survey of the Looddon River in December 2011 (Hunt andd Gorfine 2012). The two calceein-marked Murray cod analysed were 2 years old (released in 2011/12), whereas all other analysed Murray cod were either 1 year old or 3 years old and not marked with calcein (Figure 9a) (Appendix VII). It is not possible to determine whether these non-marked fish were wild spawned or stocked fish because all Murrray cod released into the Loddon River in 2010/11 and 2012/13 were not marked with calcein (Table 2). Electro-fishing CPUE for golden perch in the current study was substantially higher than for values estimated from previous surveys of the Loddon River undertaken between 1996 and 2011/12 (Fiigure 9b). In tthe current study the catch was highly variable between sites, with 30 or more fish caught at each of two sites (in the vicinnity of Bridgwater), and just 3 fish being caught at each of two sites (Benjeroop and Fernihurst Weir). Since the Loddon Riiver below Laanecoorie Reservoir has been stocked with golden perch in most seasons since 1987/88 (Appendix III), some of the larger golden perch captured during this study may have been stocked. The increase in electro-fishing CPUE along with a high proportion off calcein-marked golden perch amongst the analysed fish indicates that stocking has contributed to the golden perch population in the Loddon River, particularly around Bridgewater. There was no meaningful difference in electro-fishing CPUE for Murray cod between the curreent study and values estimated from previous surveys conducted in 2005/06 and 2011/12 (Figure 9b). Sections of tthe Loddon River below Laanecoorie Reservoir has been stocked with Murray cod in since 1990/91 (Appendix III). Despite limited assessment of these stockings anecdotal reports suggest positive results. In an earlier study, 48% (12 of 25 ffish) of Murray cod caught from the Lodddon River were identified as stocked fish (Hall and Douglas 2008). In the current study, however, no conclusions can be made regarding the contribution of stocking to Murray cod to populations as the sample size was small (13 fish), fish were caught at a small number of sites surveyed and many of the fish in thhe target age group (<4 years old) may have been stocked fish that were not marked with calcein.

Key Findings  The high percentage of stocked fish present along with an appreciable change in electro--fishing CPUE suggests that golden perch stocking is making a substantiial contribution to the population in the Loddon River.  No conclusions can be made regarding the contribution of stocking to Murray cod to populations as the sample size was small and marked fish were caught in a small number of sites only.

Figure 9. Loddon River fish survey results. (a) Age of marked and non-marked golden pperch and Murray cod, and length frequency distribution of marked and non-marked golden perch and Murray cod, and fish not analysed. (b) Electro-fishing catch per unit effort (CPUE) from historic Fisheries Victoria surveys between (1996 and 2005-2007), Hunt and Gorfine (2012) (2011/12)) and the current survey (values represent mean and s.e.).

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 20

Lake Eildon Fish surveys Murray cod were caught at all seven sites surveyed in Lake Eildon (Table 7). A total of 232 Muurray cod were caught, most (202 fish) were caught along the dam wall and rocky bank southeast of the wall. A total of 150 were analysed to determine age and the presence of a calcein mark. The percent of stocked fish present in the catch across the sites was very high, 98.4% for all fish samples and 99.6% for fish <4 years old (Table 7). Age and length frequency distribution of marked and non-marked Murray cod captured from Lake Eildon are presented in Figure 10a. Murray cod were 101-575 in total length ((mean 262 mm) and 113,770 g in weightt (mean 363 g). No fish were over the minimum legal size of 60 cm, although large fish were not targeted, as they would be older fish without a calcein mark and released anyway. Three years classses from stocked fish were captured, moost were 2 years old (67 fish) and 3 years old (57 fish) (Figure 10b). No 0 year old fish were caught. Electro-fishing CPUE for Murray cod in Lake Eildon was 1.46 ± 0.78 (s.e.) fish/machine min. There is no comparable historic data available to determine if stocking has affected compare electro-fishing CPUE. The gut contents of 39 Murray cod were examined, and prey was found in 25 (64%) fish. Prey items were yabbies (30% of fish), fish (27% of fish), which included smelt and either redfin or roach, insects (23% of fish), including beetles, mayflies and moths, and shrimp (20% of fish). Lake Eildon has been stocked with hatchery-produced Murray cod since 1991/92 (Appendix IIII). Murray cod were also stocked into the Delatite River above Lake Eildon between 1986/87 and 1990/91. In recent years, Lake Eildon has been developing a reputation as a quality Murray cod fishery. Anglers targeting Murray cod are often capturing Murray cod of varying sizes, even exceeding 100 cm in length (e.g. MMcCarthy 2011, Ainsworth 2013). The orrigin of these fish, whether stocked or from natural recruitment, is not known. Thhe presence of a very high percentage of stocked young (1-3 years old) Murray cod in Lake Eildon suggests that these fish will substantially contribute to Murray cod fishery in the lake as the fish reach the legal size in coming years. In 2013/14 (January 2014), 33,500 non-marked Murray cod were released in the areas around Jerusalem Creek, Eildon Dam wall and at the Fraser Boat Ramp, sites which had been stocked with calcein-marked fish in previous years, and were sites surveyed during the current study. Howeveer these fish, which were 0 years old, weere not captured during the surveys. Nevertheless, future surveys assessing the contributing of stocking Murray cod into Lake Eildon will need to consider methods of identifying these non-marked fish in sampled fish, such as growth checkss in otoliths.

Key Finding  Stocked Murray cod have made a significant contribution to the Murray cod population in Lake Eildon.

Figure 10. Lake Eildon fish survey results. (a) Age of marked and non-marked Murray cod, and length frequency distribution of marked and non-marked Murray cod, and fish not analysed. (b) Age frequency distribution of marked and non-marked Murray cod.

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 21

Creel surveys A total of 110 anglers were interviewed during the 2014 creel survey of Lake Eildon. Anglers ffished for between 60 min and 8:15 hrs (mean 3:53 hrs). There were more angleers that used lures (35%) than bait (21%)) while others used both bait and lures. Most anglers were 18-49 years old (75%), and most fished from a boat (73%). Murray cod reepresented 4.7% of the total number of fiish caught by anglers (caught by 2% of anglers), which was more than reported in the 2011 survey when golden perch and Murray cod combined represented just 0.8% of the total number of fish caught by anglers (Pierotti and Hunt 2012) (Figure 11). Redfin perch and trout made up 44% and 33% of the total number of fish caught by anglers, respectivelly. Despite large numbers of small Murray cod being caught by electro-fishing and mesh netting during the current study, the low number of anglers catching tthe species suggested that Murray cod were generally not being targeted by the anglers, or were not being caught. In contrast, there were several anecdotal reports of anglers targeting and catching “reasonable” numbers of small Murray codd during the summer months of 2014. Angler CPUE (fish/angler/hr) for Murray cod ranged from 0.15 to 0.8 (mean = 0.48±0.32s.e). There was little change in the angler CPUE for Murray cod in Lake Eildon between the time when the initial creel survey wwas conducted in 2011 and the 2014 survey (Figure 12).

Figure 11. Change in percent of catch by anglers in Lake Eildon between 2011 and 2014.

Figure 12. Angler catch per unit effort (CPUE) results for Murray cod in Lake Eildon for Murray cod (2011 data from Pierotti and Hunt 2012 and 2014 data from the current study) (values equal mean and s.e.).

In the 2014 survey, on the day when anglers were interviewed, a high proportion of anglers were either “not very” satisfied or “not at all” satisfied with the overall quality of fishing (Figure 13a) Factors affectingg the dissatisfaction level of anglers in the current survey were:  Not catching fish (37% of anglers).  Otheer recreational activities in the area (36% of anglers), especially jet skiing, water skiing and wakeboarding  Weather (25%). This was in stark contrast to the 2011 survey when most angers were either “very” or “quite” satisfied (Figure 13a). More anglers, however, were either “very” or “quite” satisfieed with the quality of fishing over the past 12 months for both the 2014 and 2011 surveys (Figure 13b). A notable channge in the views of anglers since the 20111 survey was the increase in dissatisfaction of not catching fish. In the earlier survey, 17% of anglers were dissatisfied wiith not catching fish and/or catching undersize fish and 10% with blue-green algae (Pierotti and Hunt 2012). Since the 20011 creel survey, the number of times anglers are fishing Lake Eildon per year has decreased slightly (Figure 14). Catch expectations can be a primary driver of angler satisfaction (Arlinghaus 2006). The high level of dissatisfaction of anglers interviewed in 2014 may be due to catch of fish not meeting expectations. Many anglers may be drawn to fishing Lake Eildon as a result of increased publicity about Murray cod stockings and reports of large Murray cod being taken in the lake. The million Murray cod into Lake Eildon has been heavily promoted (http://www.depii.vic.gov.au/fishing-and- hunting/recreational-fishing/fish-stocking/murray-cod-mmillion-lake-eildon, https://www.facebook.com/DEPIFisheries/posts/), and which has been featured in a number off fishing magazines (e.g.

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 22

McCarthy 2011 and Anon 2012, http://www.fishingworrld.com.au/news/murray-cod-stockings-near-million-mark), and on- line angling blogs (e.g. http://www.indepthangler.com..au http://www.fishnet.com.au/forums). Several articles have highlighted Murray cod fishing in the lake; “Fish of 55 to 65cm are increasingly common with a few reports of trophy fish around one metre being landed” (Anon 2012, http://www.fishingworld.com.au/news/murray-cod-stockings-near-million- mark); “Metre plus Murray cod can take some catchinng, but they can also turn up when you least expect them” (Ainsworth 2013). The vast majority of the Murray cod captured during surveys of the lake conducted during this study, were 1-3 years old, hatchery-produced fish, none of which were over the legal size of 60 cm. Angler satisfaction and expectations are likely to change as these fish recruit into the fishery in coming years.

Figure 13. Angler satisfaction of the overall quality of fishing in Lake Eildon. (a) On day of being interviewed. (b) Over the last 12 months. 2011 data from Pierottti and Hunt (2012) and 2014 data from the current study.

Figure 14. Number of times per year anglers fish LLake Eildon in 2011 (Pierotti and Huntt 2012) and 2014 (current study).

Lower Goulburn River The lower Goulburn River is a popular Murray cod fishery. In a survey undertaken in 2008 and 2009 most anglers targeted Murray cod, which reflected their dominance, along with silver perch, in the catch (Brown 2011). Thirteen sites were sampled in the Goulburn River with golden perch being captured at all sites (Table 6) and Murray cod at 12 sites (Table 7). Of the 53 golden perch and 104 Murray cod caught, 22 golden perch and 35 Murray cod were analysed to determine age and the presence of a calcein mark. The percent of stocked fish prresent in the catch across all sites was very low for both golden perch (mean 10%) and Murray cod (mean 11.3%). Stockked golden perch and Murray cod were caught at just one site (Mooroopna) and three sites (Cemetery Bend, Pyke Road and downstream of Shepparton Weir No. 2), respectively. With the exception of Cemetery Bend, these sites corresponded with sites that were stocked with golden perch and Murray cod. The low percentage of marked fish in the Goulburn Riiver may have been due to poor survival oor emigration of stocked fish. The Goulburn River has few barriers impeding movement of fish. Previous studies have shown that golden perch in the Goulburn River move actively, especially during late spring and early summer, and in association with variations in

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 23

river flow (Koster et al. 2012) Tagged golden perch have moved into the Murray River from the Goulburn River during the spawning season (Koster et al. 2012). The small number (2,000) of non-marked golden perch that were released at Loch Garry in late March 2014, after surveys were commpleted, did not affect the results of this sstudy. Age and length frequency distribution of marked and non-marked golden perch and Murray cood captured from the Goulburn River are presented in Figure 15a. Just one marked golden perch was caught, whicch was 1 year old and 98 mm in length. Marked Murray cod were 63-237 mm in length. Five Murray cod that were 0-2 years old were caught. Non-marked golden perch that were analysed covered a board age range from 2-20 years. Larger Murray cod were caught but not analysed (Appendix V). These results are similar to an earlier study that found golden perch in the lower Goulburn River consisted of mainly older (larger fish), and that, despite observing small numbers of golden perch eggs and larvae in the drift in 05/06, 06/07 and 11/12, recruitment from spawning is negligible since young-of year fish were uncommon (Koster et al. 2012).

Figure 15. Lower Goulburn River fish survey results. (a) Age of marked and non-marked golden perch and Murray cod, and length frequency distribution of marked and non-marked golden perch and Murray cod, and fish not analysed. (b) Electro-fishing catch per unit effort (CPUE) from historic Fisheries Victoria surveys and the current survey (values represent mean and s.e.).

There was a large number of non-marked 0 year old Murray cod present, which are presumabbly due to natural spawnings in the Goulburn River, especially between Pyke Road and Shepparton. Murray cod spawn naturally in the lower Goulburn River (Koster et al. 2012). Stocking of the lower Goulburn river with Murray cod hhas occurred in most years since 1996/97 (Appendix III). Stocking of large numbers (+20,000/year) of golden perch into the lower Goulburn commenced in 2006//07, although some smaller stocking occurred in the mid-1990’s (Appendix III). Crook and Koster (2006) and Koster et al. (2012) suggested that since the 1980’s, the abundance of golden perch and Murray cod has increased in the lower Goulburn River. In the present study, electro-fishing CPUE for both golden perch and Murray cod in the Goulburn River has generally increased from the 1990’s, with highest figures being recorded in 2013/14 during this study (Figure 15b). However, sincce there was a very low percentage of stocked fish recorded in the present study, this trend cannot be attributed to stockiings of calcein-marked fish conducted since 2010/11. With a low percent of stocked golden perch and Murray cod present in a small number of sites sampled during the study, these results suggest that stockings of fish undertaken between 2010/11 and 2013/14 are not likely to influence the fishery in the Goulburn River. Since previous studies have shown that the lower Goulburn river supports significant populations of golden perch and Murray cod, which may have increased in abundance since the 1980’s, and that both species spawn naturally in the lower Goulburn River (King et al. 2005, Koster et al. 2012), stocking the lower Goulburn River may not be necessary to maintain the fishery. Golden perch and Murray cod stocks in the lower Goulburn River may be being maintained by natural recruitment from spawnings in the lower reaches of the river and emigration from the Murray River. However, short-term stocking of these species may be appropriate to assist recovery of stocks following fish kills. Discharges of degraded water, such as blackwater events, have caused significance mortalities that have impacted the abundance and recruitment of golden perch and Murray cod in the Goulburn River (Koehn 2005, King et al. 2012, Koster et al. 2012).

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Key Findings  Results suggest that stocking of golden perch is contributing little to the population, which are more likely being supported by immigration and natural recruitment.  Small numbers of stocked Murray cod were caught which are likely to contribute to the population, along with immigration and natural recruitment.

Nagambie Lakes creel survey There were 164 anglers interviewed during the 2013/14 creel survey conducted in the Nagambie Lakes area on the Goulburn River. Anglers fished for between 45 min annd 11 hours (mean 6:48hrs). More anglers fished with bait (57%) than lures (6%) (others used both bait and lures), and more anglers fished from the bank (62%) than from a boat (22%). Most anglers were 18-49 years old (64%). In 2013/14, more anglers were targeting golden perch and Murray cod compared to in 2011/12, which is reflected in the catch (Figure 16). Golden perch and Murray cod represented 47% and 17%, respectively, of the fish caught by anglers, interviewed in 2013/14. These values were substantiaally greater than observed in the 2010/111 creel survey (golden perch = 13%, Murray cod = 7%) (Pierotti and Brown 2012), which suggests that stocking in Nagambie Lakes is having a positive impact on the recreational fishery for these species. Nagambie Lakes has been stocked with golden perch intermittently between 1987/88 and 1993/94, and with both golden perch and Murray cod annually since 2008/09. Many of the golden perch and Murray cod being taken by anglers from the NLS are likely to have origginated from these stockings (Pierotti and Brown 2012). Common carp (23% of catch) and redfin perch (12% of catch) were other commonly caught fish, but these represented a smaller percent of the catch compared to 20111/12 (Figure 16). Angler CPUE (fish/angler/hr) for golden perch (0.11-66.13, Mean = 1.03) was considerably higher than for Murray cod (0.09-1.34, Mean = 0.47). There was no appreciable change in the angler CPUE in Nagambie Lakes between the time when the initial creel survey was conducted in 2010/11 and the 2013/14 survey for either golden perch or Murray cod (Figure 17).

Figure 16. Change in percent of catch by anglers in Nagambie Lakes between 2010/11 and 2013/14. Figure 17. Angler catch per unnit effort (CPUE) results from the Nagambie Lakes for ggolden perch and Murray cod (2010/11 data from Pierottti and Brown (2012) and 2013/14 data from the current study). (values equal mean and s.e.).

Since the 2010/11 creel survey of Nagambie Lakes, there has been a slight increase in the number of anglers that were “very” satisfied with overall quality of fishing on the day the survey and a corresponding decline in the number of anglers that were either “not very” or “not at all” satisfied with overall quality of fishing (Figure 18a). More anglers were satisfied than not satisfied regarding the quality of fishing over the last 12 months (Figure 18b). Factors affecting the dissatisfaction level of anglers included:  Litter (21% of anglers) in the camping areas,, fishing areas and in the water  Otheer recreational activities in the area (21% of anglers), especially jet skiing, water skiing and wakeboarding.

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 Not catching fish (20% of anglers)  Lack of amenities (15% of anglers) such as lack of toilets and rubbish bins  Access for boats and fish, and signage (11% of anglers). A notable change in the views of anglers since the 20010/11 survey has been the increase in diissatisfaction of other recreational activities. In the earlier survey anglers weere dissatisfied with litter and lack of rubbish binds (26%), not catching fish (23%), lack of amenities (16%), other recreational activities (14%) or boat/bank access (13%) (Pierotti and Brown 2012). Since the 2010/11 creel survey, the number of anglers fishing Nagambie Lakes ffrequently (≥ 5 /year) has increased slightly, but the number of anglers fishing Nagambie Lakes infrequently (<5 times/year) has declined (Figure 19).

Figure 18. Angler satisfaction of the overall quality of fishing in the Nagambie Lakes. (a) on day of being interviewed. (b) Over the last 12 months. 2010/11 data from 2012(2012) and 2013/14 data from the current study.

Figure 19. Number of times per year anglers fished in the Nagambie Lakes in 2010/11 (PPierotti and Brown 2012) and 2013/144 (current study).

Calcein marking Detection method Three methods were used to detect the calcein in sampled fish, visualisation with a torch in the field (torch method), fluorometer, aand visualisation in sectioned otoliths (otolith method). The torch method gave a substantially higher percentage of marked golden perch overall (86%) compared to the otolith method (26%) (Appendix IV). Percent marked values for the torch method were higher than for the otolith method by 7-89% for all age classes of golden perch except for 1 year old fish in which the percent marked value was lower by 35% (Figure 20) (Appendix VII). This study was not expecting to find calcein in fish >3 years old as golden perch were not marked wiith calcein prior to 2010/11, yet the torch method indiccated that 89% of golden perch >3 years old were marked (Figure 20). Differences between the torch method and otolith method for different ages of Murray cod ranged from 3% to 21% (Figure 20). These results indicated that the torch method was not effective in detecting the presence of calcein as there were many false positive (torch method detected a mark when otolith method did not) and false negative (otolith method detected a mark when torch method did not) readings. When compared to the otolith method, 59% and 48% of torch readinngs for golden perch and

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Murray cod, respectively, were false positives, and 73% and 13% of torch readings for golden perch and Murray cod, respectively, were false negative.

Figure 20. Percent of marked golden perch and Murray cod for different year classes determined visualisation with a torch in the field (torch method) and visualisation in sectioned otoliths (otolith meethod). Values in brackets represent difference in percent determined from each method for each year class.

Variations in fluorometer readings for different age classes of marked and non-marked golden perch and Murray cod are presented in Append VII. These data show that, on average, readings in marked fish (golden perch = 403, Murray cod = 390) were higher than in non-marked fish (golden perch = 290, Murray cod = 156). However, in both species, fluorometer readings from marked and non-marked (as determined from sectioned ottooliths) fish were highly variable and overlapped to the point where there was no clear distinction between marked and non-marked fish (Figure 21). This trend was more or less reflected in fish of diifferent age classes. In Murray cod, at leeast, fluorometer readings >550 suggest fish are marked, but at lower readings distinguishing marked and non-marked fish is not possible. Signal overload readings on the fluorometer, which were reccorded in 42 fish (mostly 0 year old), was a clear indicator that fish were marked, though a small number of apparently non-marked fish also exhibited signal overrload readings (Figure 21). These fish may reflect an error in visualising a calcein mark in sectioned otoliths. Fluorometer readings varied greatly between river catchments for both marked and non-marked golden perch and Murray cod. For example, the fluorometer readings in non-marked Loddon River golden perch and Murray cod were 209 ± 27 s.e. and 29 ± 13 s.e., respectively, whereas the readings in non-marked golden perch and Murray cod from the lower Goulburn river were 534 ± 79 s.e. and 227 ± 799 s.e, respectively. These results indicate that there are considerable geographical variations in natural background fluorescence, which may be affectting separation of marked and non-marked fish by fluorometry.

Effect of fish age Since the callcein marking protocol was changed between 2010/11 and 2011/12 to reduce fish mortalities associated with marking (see Methods section), and to explore the duurability of the calcein mark over time, changes in the intensity of the calcein mark in different age classes of fish was examined. The intensity of the calcein mark in sectioned otoliths was greater for both older golden perch and older Murray cod (i.e. marked earlier) (Figure 22a). Fluuorometer readings of marked fish reflected a similar pattern with readings being higher in older fish. Baumgartner ett al. (2012) also demonstrated that mark intensity in Murray cod was greater in fish exposed to higher salt concentrations. These results suggest that variations in marking protocols employed each year may affect the intensity of the calcein mark. Not only has the protocol changed since 2010/11, but the supplier of calcein has also changed and fishh released as part of this study were marked at different locations (hatcheries) bby different operators.

Key finding  The torch and fluorometer methods for detecting calcein in live fish are unreliable.

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Figure 21. Frequency distribution of fluorometer readings from marked and non-marked, (a) golden perch and (b) Murray cod.

Figure 22. Intensity of calcein mark in golden percch and Murray cod marked in differentt seasons (diferenet age classes). (a) Intensity of mark in sectioned otoliths. (b) Fluorometer readings from marked fish. (values = mean ± s.e.).

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Conclusions

This study has shown that stocking has a resulted in highly variable impacts of the receiving populations. This was demonstrated by the proportion of tagged fish present in analysed fish, from 11% for golden perch and Murray cod in the lower Goulburn River to 99.4% for Murray cod in Lake Eildon) (Table 6 and Table 7), and changes in electro-fishing CPUE over time. There are numerous examples in the literature where stock enhancement programs have failed (e.g. Moran et al. 1991, Lintermans 2013), made no discernable impact (e.g. Saltveit 2006, Lintermans 2013) or been highly successful (e.g. Lorenzen 2008, Koehn et al. 2013, Lintermans 2013). Hunt et al. (2010) showed that stocking golden perch substantially augmented fish populations in three lakes where natural recruitment is very low. Conversely, stocking Murray cod into the Kerang Lakes were inconclusive, as their abundance remained low and insufficient fish were caught to determine if stocking boosted the angler catch (Hunt et al. 2011). Stocking is unlikely to be effective when natural recruitment matches carrying capacity of the environment (Lorenzen et al. 2001). Generally, stocking effectiveness will vary from site to site and season to season. The effectiveness of stock enhancement of, for example, culture-based fisheries varies widely between locations with high mortality of stocked fish is frequently a key limitation (Lorenzen et al. 2001). Good survival of released fish at one site in one season is no guarantee that the same result will be obtained in other stockings. Success may affected by a number of variables, including but not limited to:  Stocking density and ecological carrying capacity of the receiving environment  Age and size of fish at stocking  Condition and health of fish  Genetic factors  Presence and amount of suitable habitat, food, competitors and predators at release sites  Timing of stocking relative to above factors  Release methods (Wahl et al. 1995, Li 1999, Brown and Day 2002). Results in the present study are consistent with a similar study being undertaken in NSW, where stocking has also had variable results. “Calcein marked Murray cod comprised 0%-94% of the age-specific population in impoundments and 7%-15% in rivers. Calcein marked golden perch comprised 23%-98% in impoundments, and 9%-14% in rivers” (Forbes et al. 2014). These results, and results from the current study, indicate that stocked fish may have a greater impact on populations and fisheries in large artificial lakes and impoundments, such as Lake Eildon, than in open rivers systems where populations are more likely to be influenced by natural recruitment, emigration and immigration and environmental conditions. The results in the present study should be interpreted with much caution due to a numbers of reasons including, small sample sizes in some waters, variations in electro-fishing efficiency and non-marked fish being released into some waters in some years. Sampling in each waterbody was undertaken over a short period at one time, which provides a ”snapshot” only. In some cases, samples sizes of caught fish were very small, which limits assessment of results. This was the case for the Gunbower Creek for both species (<20 fish for each species), and Campaspe River and Kow Swamp for Murray cod (<20 fish for each water). The absence of stocked fish in small catches does not necessarily mean that they are absent from the population. In other cases there is strong evidence that stocking fish is contributing to populations. This study used electro-fishing CPUE to compare gross changes in catch rate of fish at different times from selected waters. Electro-fishing is a common and well-established sampling method in freshwaters (Cowx and Lamarque 1990). This approach has been used previously, but results should be interpreted with considerable caution as aggregation of data at large temporal scales has the potential to confound analysis of spatial variations in fish assemblages (Crook and Koster 2006). Further, a range of environmental, biological and technical factors can affect electro-fishing capture efficiency, including conductivity, turbidity, water depth, water flow, habitat type, wave action, size and species of fish, machine settings and operator experience (Zalewski and Cowx 1990, Bayley and Austen 2002). Lyon et al. (2014) identified a number of these factors that affected the capture efficiency of native fish and concluded that “variation in capture probability in large lowland rivers results in additional uncertainty when estimating population size or relative abundance”. A large number of fish were released into the study sites, especially in 2010/11 that were not marked with calcein at the time of these release. These included all fish stocked into the Campaspe River, Kow Swamp, Loddon river, and

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Gunbower Creek in 2010/11, Murray cod stocked into the Loddon River in 2012/13 and 90% of Murray cod stocked into Lake Eildon in 2013/14. Consequently, estimates of the proportion of stocked fish present in samples may be underestimates for these waters. At the commencement of the stocking initiative in 2010, there was no expectation that there would be follow-up evaluation of these stockings, and that fish were marked with calcein only where there was a specific request made to Fisheries Victoria management and DEPI Snobs creek staff to do so, such as by external clients that were monitoring fisheries in specific rivers (eg Arthur Rylah Institute, Heidelberg). A proportion of fish older than 3 may also have been stocked as all water bodies surveyed in the current study have been stocked with non- marked fish prior to 2010 (Appendix III). In order to assess the contribution of stock enhancement programs to fish populations in the wild and recreational fisheries a reliable method is required to distinguish stocked fish from wild fish. Calcein marking has been widely promoted as a reliable method of distinguishing hatchery-produced fish from wild fish (e.g. Barwick et al. 2014). Importantly, the mark can be detected on live fish which mean that fish do not have to be killed (Crook et al. 2007). However, our study showed that field detection methods for calcein are unreliable. The use of a torch gave a high proportion of false positive and false negative readings and fluorometer readings in marked fish were highly variable and over-lapped with readings from non-tagged fish. Consequently, there is a need for on-going review of non-destructive methods for discriminating hatchery-bred fish from wild fish. The more promising option is application of genetic marks (microsatellites and single nucleotide polymorphisms), which are intrinsic, permanent, can be recovered from finclips of live fish, and which can provide additional information about populations that cannot be inferred from traditional tags (Schwartz et al. 2007, Denson et al. 2012, Darden et al. 2013). In some rivers stocked year classes were absent in the sampled fish. In most cases sample sizes in each year class were too small to evaluate differences in survival between years. The one exception to this was Lake Eildon, where mostly 2 and 3 year old stocked Murray cod were caught whereas a smaller number of 1 year and no 0 year old fish were caught (Appendix VI). Stocking of native fish over multiple years, rather than in a once only event, has been promoted to build up a structured population, increase genetic diversity and to overcome unseasonal or unpredictable (catastrophic) events impacting on survival (Douglas et al. 1994). The effective of this approach was demonstrated in the decade-long Ovens River trout cod stocking program in which fish stocked in 2003 and 2004 were more common than fish stocked in other years, indicating a higher rate of survival for the fish released in these years (Lyon et al. 2012).

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Recommendations

This study has shown that some stocked fish survived in all waters that were stocked, however, the percentage contribution of the stocked fish to fish populations is highly variable. While the vast majority (98.4%) of Murray cod caught Lake Eildon were stocked fish, values in other waters were either substantially less or inconclusive due to numbers of reasons including, small sample sizes in some waters, variations in electro-fishing efficiency and non-marked fish being released into some waters in some years. Creel surveys conducted in Nagambie Lakes and Lake Eildon provided valuable information on changes in anglers’ perception of the native fish fisheries and targeted species in these waters. While there is evidence of changes in satisfaction levels of anglers since earlier creel surveys were undertaken, further changes are expected to occur as fished stocked over the last three years enter the fishery, especially for Murray cod in Lake Eildon. Many of the fish that were stocked during these initiatives have yet to entered the recreational fishery. In order to assess the contribution of stocked fish to the fishery, further monitoring of these stocked water within the next two years will need to be undertaken. This is especially the case for Lake Eildon where the stocked fish represent a high proportion of the fish captured. A concurrent creel survey in Lake Eildon should be undertaken to evaluate changes in angler perceptions as these fish enter the fishery. This reports represents a retrospective evaluation of three majors stocking initiates, which came out of funding made available in 2013/14, after the initiatives commenced. A well-designed monitoring and evaluation program needs to be designed and implemented at the commencement of such programs to fully assess their effectiveness, benefits and returns at their conclusion. Characteristics of such a program, as described by Hughes (Hughes 2014, should include a clearly stated objectives or questions, a statistical study design sufficient for answering those questions, an appropriate geographic framework, standard sampling methods so that observed differences are not confounded by methodological differences, quantitative indicators with known precision to maximize explanatory power and public reporting of survey results. This study and others (e.g. Hunt et al. 2011), have suggested that stocking has been more effective in lakes than rivers. A review of stocking plans for native fish to take into account habitat type is required. The years or years by site that have proven to have successful stockings need to be investigated, to see if these conditions are suitable for other potential stocking sites. This study has questioned the value of marking fish with calcein. Since field detection methods are unreliable, fish will need to be destroyed to conclusively determine if a mark is present. Consequently, there is a need to review methods of marking hatchery –bred fish for identification purposes. Several options may be considered depending on the desired outcome, including use of barium, otolith chemistry and genetic tags. This review should include a cost –benefit analysis that takes into account both the cost of marking as well as the cost of recovery of the mark from live and dead fish.

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 31

golden perch Water Investment Presence of Distribution of Abundance of Contribution of Comments over stocked fish2 stocked fish3 fish4 stocked fish to 4 seasons1 wild stocks Campaspe R. Low High Moderate 0 Likely Current project supports past studies suggesting that regular ($84,536) stocking is maintaining the golden perch population. Presence of marked fish may be underestimated due to non-marked fish being released. All marked fish from 2011/12 stocking only. No Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014native Victoria: in stockings fish Monitoring appreciable change in electro-fishing CPUE. Lower Goulburn R. Low ?+ Low 0 Unlikely Results suggest that stocking is contributing little to the ($34,444) population, which is more likely being supported by immigration and natural recruitment. Sample size was too small for assessment and marked fish caught at small number of surveyed sites only. Gunbower Ck Nil Not stocked. Golden perch captured during surveys, but no marked fish present. Kow Swamp Moderate Moderate Moderate +1 Inconclusive The contribution of stocking to the population is uncertain as ($66,322) sample size was too small for assessment and non-marked fish were released. Results were confounded by most marked fish

32 being from the 2013/14 stocking that were captured 3 weeks

after release. These fish also inflated the CPUE. Loddon R. Moderate Moderate Moderate +1 Likely The high percentage of stocked fish present along with an

($110,600) appreciable change in electro-fishing CPUE suggests that golden 

Recreational Fishing Grants Program Grants Fishing Recreational perch stocking is making a substantial contribution to the population. Presence of marked fish may be underestimated due to non-marked fish being released. 1. Investment: Number of fingerlings stocked between 2010/11 and 2013/14 multiplied by median value (exc. GST) of fingerlings purchased between 2010/11 and 2013/14. Golden perch: $0.25-$0.308/fish (median $0.286/fish). Murray cod: $0.6-$0.72/fish (median $0.62/fish). An additional $0.03/fish was added for calcein marking. Low = < $50,000. Moderate = $50,000 - $150,000. High = $150,000 - $300,000. Very High = > $300,000. 2. Presence: Proportion of analysed fish that were stocked where number of fish analysed was >30 fish. Nil = No marked fish detected. ?+ = Marked fish present but sample size <30 fish. Low = Marked fish <25% of fish analysed. Moderate = Marked fish 25-50% of fish analysed. High = Marked fish 50-75% of fish analysed. Very High = Marked fish >75% of fish analysed. 3. Distribution: Number of sites surveyed where stocked fish present. Low = Present at <1/3 of sites. Moderate = Present at 1/3 - 2/3 of sites. High = Present at >2/3 of sites. Very High = present in all sites. 4. Abundance: Change in electro-fishing CPUE compared to historic data. -1 = Substantial decline (CPUE more than halved). 0 = No/minimal change (CPUE less than halved or CPUE less than doubled). +1 substantial increase ( CPUE more than doubled). ? = No historic data available for comparison.

Murray cod Water Investment Presence of Distribution of Abundance of Contribution of Comments over stocked fish2 stocked fish3 fish4 stocked fish to 4 seasons1 wild stocks Campaspe R. Moderate ?+ Low 0 Unlikely The sample size (10 fish) was too small to assess the ($77,805) contribution of stockings to the population. Marked fish caught in small number of surveyed sites only. No appreciable change in electro-fishing CPUE.

Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014native Victoria: in stockings fish Monitoring Lake Eildon Very High Very High Very High ? Yes Stocked Murray cod have made a significant contribution to the ($770,900) Murray cod population. Marked fish were caught at all sites surveyed. Most fish (98.4%) analysed were stocked fish. Marked fish caught at all sites surveyed. Most fish (89%) released in 2013/14 were not marked, but this year class was not present in fish samples. Lower Goulburn R. Moderate Low Low 0 Likely Small numbers of stocked fish were caught which are likely to ($86,125) contribute to the population, along with immigration and natural recruitment. Marked fish caught in small number of surveyed sites only. Gunbower Ck High ?+ Moderate 0 Inconclusive The contribution of stocking to the population is uncertain as the ($169,779) sample size was too small for assessment and non-marked fish

33 were released. Electro-fishing CPUE greater than for 2012

survey, but no appreciable change when historic data considered. +

Kow Swamp Moderate ? Moderate +1 Inconclusive The contribution of stocking to the population is uncertain as  ($130,000) sample size too small for assessment and non-marked fish were Recreational Fishing Grants Program Grants Fishing Recreational released. Results confounded as most marked Murray cod caught were thought to be fish that moved from Gunbower Ck to Kow Swamp (released 3 weeks before the survey occurred). Loddon R. Moderate ?+ Low 0 Unlikely No conclusions can be made regarding the contribution of ($139,425) stocking Murray cod to the population as the sample size was small and marked fish were caught in a small number of sites only. Presence of marked fish may be underestimated due to non-marked fish being released. 1. Investment: Number of fingerlings stocked between 2010/11 and 2013/14 multiplied by median value (exc. GST) of fingerlings purchased between 2010/11 and 2013/14. Golden perch: $0.25-$0.308/fish (median $0.286/fish). Murray cod: $0.6-$0.72/fish (median $0.62/fish). An additional $0.03/fish was added for calcein marking. Low = < $50,000. Moderate = $50,000 - $150,000. High = $150,000 - $300,000. Very High = > $300,000. 2. Presence: Proportion of analysed fish that were stocked where number of fish analysed was >30 fish. Nil = No marked fish detected. ?+ = Marked fish present but sample size <30 fish. Low = Marked fish <25% of fish analysed. Moderate = Marked fish 25-50% of fish analysed. High = Marked fish 50-75% of fish analysed. Very High = Marked fish >75% of fish analysed.

3. Distribution: Number of sites surveyed where stocked fish present. Low = Present at <1/3 of sites. Moderate = Present at 1/3 - 2/3 of sites. High = Present at >2/3 of sites. Very High = present in all sites. 4. Abundance: Change in electro-fishing CPUE compared to historic data. -1 = Substantial decline (CPUE more than halved). 0 = No/minimal change (CPUE less than halved or CPUE less than doubled). +1 substantial increase ( CPUE more than doubled). ? = No historic data available for comparison.

Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014native Victoria: in stockings fish Monitoring 34



Recreational Fishing Grants Program Grants Fishing Recreational

Acknowledgements

This project was funded through the Victorian Government to improve recreational fishing in Victoria through revenue from Recreational Fishing Licences. The authors wish to thank the following organisations and people. Mr Anthony Forster and Mr John Douglas (Fisheries Victoria) for developing and instigating the projects. Andrew Pickworth, John Mahoney and Lauren Dodd from the Arthur Rylah Institute provided technical support during field surveys. Kyne Krusic-Golub (Fish Ageing Services Pty Ltd. Portarlington, Victoria) processed and analysed otoliths to determine age and the presence of a calcein mark. Ewan McLean provided information on fish stockings in the study sites. Stephen Vidler provided details on calcein protocols used by Fisheries Victoria. This project was conducted under the Animal Ethics Application No. 0072, “Fish population surveys” (Department of Primary Industries, Fish Animal Ethics Committee).

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 35

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Capture efficiency of a boat electrofisher. Transactions of the American Fisheries Society 131 (3): 435-451. Brown, C. and Day, R.L. (2002). The future of stock enhancements: lessons for hatchery practice from conservation biology. Fish and Fisheries 3 (2): 79-94. Brown, P. (2011). Lower Goulburn River Angler Survey 2008-2009. Fisheries Victoria Research Report Series No. 40. Cowx, I.G. and Lamarque, P. eds. (1990). Fishing with Electricity. Applications in Freshwater Fisheries Management. Fishing News Books. 248 pp. Crook, D.A. and Koster, W.M. (2006). Temporal change in fish assemblages in the lower Goulburn River, south-eastern Australia: comment on Pollino et al.(2004). Marine and Freshwater Research 57 (3): 303-308. Crook, D.A., O'Mahony, D., Gillanders, B.M., Munro, A.R. and Sanger, A.C. (2007). Production of external fluorescent marks on golden perch fingerlings through osmotic induction marking with alizarin red S. 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In: Freshwater Fisheries in Victoria - Today and Tomorrow. Symposium Proceedings (Cadwallader, P. ed.), pp. 21-38. Department of Conservation and Natural Resources, Melbourne. Hall, K. and Douglas, J. (2008). Campaspe and Loddon Rivers Murray cod Stock Assessment. Fisheries Victoria Assessment Report No. 54. Hughes, B. (2014). Monitoring: Garbage In Yields Garbage Out. Fisheries 39:6, 243-243 (6): 243 & 287. Humphries, P. (2005). Spawning time and early life history of Murray cod, Maccullochella peelii (Mitchell) in an Australian river. Environmental Biology of Fishes 72 (4): 393-407. Humphries, P., Brown, P., Douglas, J., Pickworth, A., Strongman, R., Hall, K. and Serafini, L. (2008). Flow-related patterns in abundance and composition of the fish fauna of a degraded Australian lowland river Freshwater Biology 53 (4): 789-813. Humphries, P. and Lake, P. (2000). Fish larvae and the management of regulated rivers. Regulated Rivers: Research & Management 16 (5): 421-432. Hunt, T., Green, C.P. and Brown, P. (2011). Evaluation of past and new stocking practices for recreational fisheries in the Kerang Lakes (Project number: R06/07/01). Recreational Fishing Grants Program Research Report. Department of Primary Industries Fisheries Victoria.

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Hunt, T.L., Allen, M.S., Douglas, J. and Gason, A. (2010). Evaluation of a sport fish stocking program in lakes of the southern Murray-darling basin, Australia. North American Journal of Fisheries Management 30 (3): 805-811. Hunt, T.L. and Gorfine, H. (2012). Northern Rivers Native Fisheries Assessment. Fisheries Victoria. Technical Report Series No. 167. Department of Primary Industries, Queenscliff. 11 pp. King, A.J., Crook, D.A., Koster, W.M., Mahoney, J. and Tonkin, Z. (2005). Comparison of larval fish drift in the Lower Goulburn and mid-Murray Rivers. Ecological Management & Restoration 6 (2): 136-139. King, A.J., Tonkin, Z. and Lieshcke, J. (2012). Short-term effects of a prolonged blackwater event on aquatic fauna in the Murray River, Australia: considerations for future events. Marine and Freshwater Research 63: 576-586. Koehn, J.D. (2005). The loss of valuable Murray cod in fish kills: a science and management perspective. In: Management of Murray cod in the Murray-Darling Basin. Statement, recommendations and supporting papers (Workshop held in Canberra, 3-4 June 2004) (Lintermans, M. and Phillips, B. eds.), pp. 73-82. Murray-Darling Basin Commission, Canberra. Koehn, J.D., Lintermans, M., Lyon, J.P., Ingram, B.A., Gilligan, D.M., Todd, C.R. and Douglas, J.W. (2013). Recovery of the endangered trout cod Maccullochella macquariensis: What have we achieved in more than 25 years? Marine and Freshwater Research 64: 822–837. Koehn, J.D., McKenzie, J.A., O'Mahony, D.J., Nicol, S.J., O'Connor, J.P. and O'Connor, W.G. (2009). Movements of Murray cod (Maccullochella peelii peelii) in a large Australian lowland river. Ecology of Freshwater Fish 18 (4): 594- 602. Koster, W., Crook, D., Dawson, D. and Moloney, P. (2012). Status of fish populations in the lower Goulburn River (2003- 2012). 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Lorenzen, K., Amarasinghe, U.S., Bartley, D.M., Bell, J.D., Bilio, M., de Silva, S.S., Garaway, C.J., Hartmann, W.D., Kapetsky, J.M., Laleye, P., Moreau, J., Sugunan, V.V. and Swar, D.B. (2001). Strategic review of enhancements and culture-based fisheries. In: Aquaculture in the Third Millennium. Technical Proceedings of the Conference on Aquaculture in the Third Millennium, Bangkok, Thailand, 20-25 February 2000 (Subasinghe, R.P., Bueno, P., Phillips, M.J., Hough, C. and McGladdery, S.E. eds.), pp. 221-237. Lyon, J.P., Bird, T., Nicol, S., Kearns, J., O’Mahony, J., Todd, C.R., Cowx, I.G., Bradshaw, C.J. and Jech, J.M. (2014). Efficiency of electrofishing in turbid lowland rivers: implications for measuring temporal change in fish populations. Canadian Journal of Fisheries and Aquatic Sciences 71 (6): 878-886. Lyon, J.P., Todd, C., Nicol, S.J., McDonald, A., Stoessel, D., Ingram, B.A., Barker, R.J. and Bradshaw, C.J.A. (2012). Reintroduction success of threatened Australian trout cod (Maccullochella macquariensis) based on growth and reproduction. Marine and Freshwater Research 63: 598-605. McCarthy, A. (2011). The rise and rise of Lake Eildon. In Victoria Fishing Monthly, Vol. January. Fishing Monthly Magazines. Moran, P., Pendas, A., Garcia‐Vazquez, E. and Izquierdo, J. (1991). Failure of a stocking policy, of hatchery reared brown trout, Salmo trutta L., in Asturias, Spain, detected using LDH-5* as a genetic marker. Journal of Fish Biology 39 (sA): 117-121. Pierotti, K.A. and Brown, P. (2012). Nagambie Lakes Fisheries Assessment – Collecting baseline data three years after stocking. Fisheries Victoria Research Report Series No. 53. Pierotti, K.A. and Hunt, T.L. (2012). Lake Eildon Fisheries Assessment – Angler catch and perception. . Fisheries Victoria Research Report Series No. 52. Pollock, K.H., Jones, C.M. and Brown, T.L. (1994). Angler survey methods and their applications in fisheries management. American Fisheries Society Special Publication No. 25. American Fisheries Society, Bethesda, MD. Rehwinkel, R. and Sharpe, C. (2009). Gunbower Forest Fish monitoring Surveys 2008/2009. A MDFRC Report prepared for the North Central Catchment Management Authority by The Murray-Darling Freshwater Research Centre. 57 pp. Rehwinkel, R., Sharpe, C. and Wallace, T. (2010). Gunbower Forest Fish Monitoring Surveys: Autumn 2010. Final Report prepared for the North Central Catchment Management Authority. MDFRC Publication 21/2010. Murray- Darling Freshwater Research Centre. 56 pp. Reynolds, L.F. (1983). Migration Patterns of Five Fish Species in the Murray-Darling River System. Australian Journal of Marine and Freshwater Research 34: 857-871.

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Ryan, T. and O'Mahony, J. (2005). Movement of golden perch and Murray cod in the Nagambie Lakes System. Department of Sustainability and Environment, Arthur Rylah Institute for Environmental Research, Hiedelberg. 45 pp. Saltveit, S. (2006). The effects of stocking Atlantic salmon, Salmo salar, in a Norwegian regulated river. Fisheries Management and Ecology 13 (3): 197-205. Schwartz, M.K., Luikart, G. and Waples, R.S. (2007). Genetic monitoring as a promising tool for conservation and management. Trends in Ecology & Evolution 22 (1): 25-33. Stuart, I. and Sharpe, C. (2012). Monitoring and assessment of Gunbower and Thompson’s weir fishways. Wahl, D.H., Stein, R.A. and DeVries, D.R. (1995). An ecological framework for evaluating the success and effects of stocked fishes. In American Fisheries Society Symposium, Vol. 15, pp. 176-189. Zalewski, M. and Cowx, I.G. (1990). Factors affecting efficiency of electric fishing. In: Fishing With Electricity. Applications in Freshwater Fisheries Management (Cowx, I.G. and Lamarque, P. eds.), pp. 89-111. Fishing News Books, Blackwell Scientific Publications, Ltd. , Oxford

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 38

Appendix I. Sites surveyed and environmental data

Waterbody Location Date Sample Sample Gear EL Conductivity Turbidity Temperature pH Dissolved reach width type* Machine (µs/cm) (NTU) (oC) oxygen (m) (mm) seconds (mg/L) Campaspe R. Upstream of Ayson's Reserve, 6/02/14 3000 45 EL 2153 483 11.4 22.1 8.01 4.47 Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014native Victoria: in stockings fish Monitoring northeast of Elmore Upstream of the Campaspe Weir, 5/02/14 3500 45 EL 2100 508 16.4 20.9 7.83 4.72 northeast of Elmore Around boat launch site off 7/02/14 1250 45 EL 1341 495 17.3 23.1 7.11 4.57 private property English's bridge to 500 metres 4/02/14 500 30 EL 1464 432 12.8 21.1 7.77 6.59 upstream, Goornong. Rochester Rail Bridge, Rochester. 3/02/14 3500 25 EL 3614 661 15 29 6.83 3.96 Barnadown Rd Reserve, 4/02/14 800 25 EL 1771 432 13 22 7.7 7.5 Barnadown. Campaspe Street, Elmore. 5/02/14 4000 30 EL 3900 459 16 25.6 7.8 5.32

39 Goulburn R. Cable Hole 7/03/14 EL 1800 42 21.3 20.4 6 9.3

Cemetary Bend 3/03/14 EL 1740 105 25.1 25.1 6.6 7.7

downstream Shepparton Wr No 2 4/03/14 EL 1800 79 17.1 27.3 6.2 6.8 

Recreational Fishing Grants Program Grants Fishing Recreational Kotupna 11/03/14 EL 1800 66 26.3 26 6.6 6.92 Loch Garry 5/03/14 EL 1800 Mooroopna 13/03/14 EL 1200 Murphy Road 12/03/14 EL 1800 Pogues Road 6/03/14 EL 1800 Pyke Road 4/03/14 EL 1800 Shepparton Causeway 5/03/14 EL 1800 62 19.8 24.2 6.3 8 Upstream McCoys Bridge 6/03/14 EL 1800 Yambuna 12/03/14 EL 1800 69 34.4 26.2 6.6 7.1 * EL = electro-fishing. MN = mesh nets

Waterbody Location Date Sample Sample Gear EL Conductivity Turbidity Temperature pH Dissolved reach width type* Machine (µs/cm) (NTU) (oC) oxygen (m) (mm) seconds (mg/L) Gunbower Ck Downstream Cohuna weir 23/01/14 600 35 EL 818 66 41.4 24.7 6.81 6.02 Upstream Koondrook Weir. 22/01/14 3000 45 EL 4481 70 49.6 26 6.84 5.04 Headworks to cable across river 21/01/14 1200 40 EL 1002 61 41.6 26.6 7.05 5.21 downstream. National Channel road crossing 21/01/14 2000 40 EL 2947 61 41.6 26.6 7.05 5.21 Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014native Victoria: in stockings fish Monitoring Spences bridge 21/01/14 1800 45 EL 3401 61 32.2 26.4 6.7 5.39 Thompsons Wr to National channel 20/01/14 1200 45 EL 2551 61 32.2 26.4 6.7 5.39 pipes Kow Swamp Channel downstream Dyes Weir and into 5/02/14 1000 EL 1500 86 25.2 21.6 7.43 7.04 Kow Swamp Channel downstream Dyes Weir and into 5/02/14 1000 EL 1273 86 25.2 21.6 7.43 7.04 Kow Swamp at night Kow Swamp and Box Ck channel 5/02/14 1200 EL 2215 86 252 21.6 7.43 7.04 Lake Eildon Bonnie Doon area 18/02/14 EL 1400 44 4.1 23.8 6.35 7.59 Bonnie Doon to Peppin point area 17/02/14 1715 EL/MN (1‐6”) 1620 44 4.1 23.8 6.35 7.59 Fraser National Park area 18 & 20 /02/14 EL/MN (2‐6”) 2000 44 4.1 23.8 6.35 7.59 40

Jerusalem Ck and Big River arm 24‐25/02/14 EL/MN (1‐6”) 2000 44 4.1 23.8 6.35 7.59 Jerusalem Ck area 26/02/14 MN (3‐6") 44 4.1 23.8 6.35 7.59



Lake Eildon dam wall 18/02/14 EL 2000 44 4.1 23.8 6.35 7.59 Recreational Fishing Grants Program Grants Fishing Recreational Lake Eildon dam wall and rocky bank 25 & 27/02/14 EL/MN (3‐6") 2000 44 4.1 23.8 6.35 7.59 southeast of wall Loddon R. Baringhup Road via Baringhup 3/02/14 1170 40 EL 1555 448 8.9 22.5 7.92 6.63 Caravan Park. Downstream Laanecoorie Res. 3/02/14 2200 45 EL 2271 Benjeroop. 6/02/14 2800 25 EL 2300 157 184 24 7.26 5.5 Fernihurst Weir 4/02/14 700 60 EL 1711 185 66.9 23.8 7.27 5.89 Murray Valley Highway Bridge 22/01/14 1200 17 EL 2145 627 2.5 22.2 7.38 3.58 Serpentine Weir 4/02/14 950 17 EL 2130 1029 120.9 23.5 7.54 4.3 Sweeneys Lane, Bridgewater 23/01/14 1350 40 EL 3211 963 252 24.6 7.43 5.96 Bridgewater bridge 24/01/14 1100 40 EL 1716 980 11.7 24.1 7.71 6 * EL = electro-fishing. MN = mesh nets (mesh sizes)

Appendix II. Creel Survey questionnaire

Lake Eildon Creel Survey Date: ______Interviewer:______Page ______of ______Day Type (tick one): Saturday □ Sunday □ Public Holiday □ Weekday □ Angler No.

Interview time (24 hr clock) ______:______h ______:______h 1. 2010/11 2. 2014 1. 2010/11 2. 2014 Have you been interviewed before? 3. Both 4. No 3. Both 4. No

Interview Location

Fishing start time (or shift start if earlier?) ______:______h ______:______h

Finish time or estimate (24 hr clock) ______:______h ______:______h Interview type (End time ) (E =Estimated if not finished fishing or C =Completed if 1. E 2. C 1. E 2. C finished)? CATCH DURING THIS SHIFT: RF = redfin, MC = Murray cod, GP = golden perch, RT = rainbow trout, BT = brown trout, CC = carp, RO = roach Sp1 Sp2 Sp1 Sp2

What Species caught Sp3 Sp4 Sp3 Sp4 Number each species caught Sp1 n= Sp2 n= Sp3 n= Sp4 n= Sp1 n= Sp2 n= Number each species returned Sp3 n= Sp4 n= Reason for release U size, S sportfishing, B over bag limit, T tagged fish Target species (list code or ‘any’) Preferred target species ranking MC__ RF__ GP__ RT__ BT__ CC_ MC__ RF__ GP__ RT__ BT_ CC_ How highly do you rank Murray cod? (1=highest) 1 2 3 4 5 1 2 3 4 5 Boat or Bank (circle) 1. Boat 2. Bank 3. Both 1. Boat 2. Bank 3. Both Main Method (circle) 1. Bait 2. Lure 3. Both 1. Bait 2. Lure 3. Both How important on a scale of 1-5 is each of the following factors to you as a motivation to go fishing… (1 = extremely important, 2 = slightly important, 3 = don’t mind, 4 = somewhat unimportant, 5 = totally unimportant)

Local to where I live Local to where I live Good access/facilities Good access/facilities Good chance of catching target fish Good chance of catching target fish What is your motivation/reason for fishing at Attractive, clean environment Attractive, clean environment Lake Eildon today Solitude Solitude Heard it’s been stocked Heard it’s been stocked Other: Other:

How satisfied are you with the overall quality of the 1. Very 2. Quite 3. Unsure 1. Very 2. Quite 3. Unsure fishing today at Lake Eildon? (circle) 4. Not very 5. Not at all 4. Not very 5. Not at all How satisfied are you with the overall quality of the 1. Very 2. Quite 3. Unsure 1. Very 2. Quite 3. Unsure fishing over the last 12 months at Lake Eildon? (circle) 4. Not very 5. Not at all 4. Not very 5. Not at all How many times a year do you fish Lake Eildon? 1. <5 2. 5-14 3. >15 1. <5 2. 5-14 3. >15 How many days a year do you go fishing? (circle) 1. <5 2. 5-14 3. >15 1. <5 2. 5-14 3. >15 Age Bracket (circle years) 1.<18 2.18-49 3.50-69 4. >70 1.<18 2.18-4 3.50-69 4.>70 What is your home postcode?

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 41

What, if anything, detracts from your satisfaction in your fishing experience at Lake Eildon?

What would improve your satisfaction in your fishing experience at Lake Eildon?

The following questions relate to the economic cost of your fishing trip. Are you OK if we continue?

How many anglers are there in your group today that are actively fishing?

Is fishing at Lake Eildon the sole purpose of your trip today?

Are you visiting any other sites on this trip? If so, what are they?

How much time will you spend travelling to and from

(return) Lake Eildon on this trip? (Hours and minutes)

How long will you stay at Lake Eildon on this trip?

(days and nights)

For each category listed on this card (SHOW CARD 1), can you provide an estimate of the cost associated with that category for your ENTIRE fishing trip to the Lake

Eildon and provide a guess of the proportion of the cost which you would attribute to the fishing component of the trip. (may need to prompt)

If the costs of your trip had increased by 50%, would you still be planning to come to the Lake Eildon for recreational fishing? If the costs of your trip had increased by 20%, would you still be planning to come to the Lake Eildon for recreational fishing? If the costs of your trip had increased by 10%, would you still be planning to come to the Lake Eildon for recreational fishing?

1. retired/pensioner 2. employed 3. self-employed What is your occupational status? 4. unemployed 5. student 6. other

Do you have any comments you would like to make?

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 42

Card 1: Estimate cost for return trip and percentage relating to fishing and fishing at Lake Eildon

Category Cost $ % Cost related to fishing Lake Eildon

Fuel for motor vehicle $ ______.00 ____.0 %

Fuel for boat $ ______.00 ____.0 %

Tackle $ ______.00 ____.0 %

Bait $ ______.00 ____.0 %

Other equipment $ ______.00 ____.0 %

Accommodation $ ______.00 ____.0 %

Food and drink $ ______.00 ____.0 %

Other (specify) ______$ ______.00 ____.0 %

Other (specify) ______$ ______.00 ____.0 %

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 43

Appendix III. Fish stocking history

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 44

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grannts Program 45

Appendix IV. Species and number of fish observed in each waterbody during surveys

Waterbody

Lower Fish group Name Scientific name Campaspe Gunbower Kow Lake Loddon Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014 native Victoria: in stockings fish Monitoring Goulburn TOTAL River Creek Swamp Eildon River River

Large-bodied Brown trout Salmo trutta 2 2

Carp Cyprinus carpio 286 94 265 122 222 419 1,408

Golden perch Macquaria ambigua 44 50 18 37 37 100 286

Murray cod Maccullochella peelii 16 104 18 18 252 22 430

Redfin perch Perca fluviatilis 2 5 638 760 1,405

Silver perch Bidyanus bidyanus 1 4 6 26 3 40 46

Trout cod Maccullochella macquariensis 4 1 5

Medium-bodied Bony herring Nematalosa erebi 1 91 6 98

 Goldfish Carassius auratus 27 68 29 44 146 314 Recreational Fishing Grants Program Grants Fishing Recreational Roach Rutilus rutilus 409 409

Small-bodied Australian smelt Retropinna semoni 491 166 1,680 16 7,885 7,972 18,210

Carp gudgeons Hypseleotris spp. 2 308 12 96 418

Eastern gambusia Gambusis holbrooki 350 332 682

Flat-headed gudgeon Philypnodon grandiceps 67 1 147 531 746

Murray-Darling rainbowfish Melanotaenia fluviatilis 30 22 1 90 143

Craterocephalus Un-specked hardyhead 390 390 stercusmuscarum fulvus TOTAL 907 485 3,132 340 9,648 10,477 24,989

Appendix V: Age, total length and weight of golden perch and Murray cod captured during surveys

Waterbody Golden perch Murray cod

Monitoring fish stockings in Victoria: 2014 native fish surveys fish 2014 native Victoria: in stockings fish Monitoring Age (years old) Tot. length (mm) Weight (g) Age (years old) Tot. length (mm) Weight (g) Range Mean Range mean Range Mean Range Mean Range Mean Range Mean

Aged fish Campaspe R. 2-18 5.5 194-555 366 104-3,230 993 1-2 1.1 102-335 156 11-533 85

Lower Goulburn R. 1-20 7.1 98-507 350 13-2,392 850 0-8 2.3 36-565 259 1-2,500 484

Gunbower Ck 2-8 4.4 345-545 444 1-2 1.6 181-404 313

Kow Swamp 0-7 2.6 52-469 239 20-1,726 945 0-1 0.2 41-217 90 22-128 65

Lake Eildon 1-4 2.3 101-575 277 11-3,770 438

Loddon R. 1-9 3.6 111-537 317 32-3,024 1,528 1-3 1.3 171-482 231 70-90 80 47

Overall 0-20 4.4 52-555 327 13-3,230 958 0-8 2 36-757 257 1-3,770 419



Recreational Fishing Grants Program Grants Fishing Recreational Non-aged fish Campaspe R. 306-486 356 449-2,148 828 635-810 722 4,320-7,781 5,663

Lower Goulburn R. 360-540 441 725-2,913 1,450 50-800 359 2-7,780 1,130

Gunbower Ck 642-1,100 774 4,250-19,000 8,640

Kow Swamp 470 470 890-930 910 11,500-15,000 13,250

Lake Eildon 136-550 354 688-820 754 120-368 233 20-594 170

Loddon R. 212-611 360 350-1,730 1,126 710-970 880 9,800-13,700 12,167

Overall 136-611 378 350-2,913 1,239 50-1,100 345 2-19,000 1,598

ALL FISH 52-611 351 13-3,230 1,074 36-1,100 293 1-19,000 907

N.B. Age is for fish that were analysed only. All larger (> 600 mm) golden perch (n=1) Murray cod (n=30) and when abundances were greater than 10 within the bin range were released.

Appendix VI: Percent of fish in each age bracket that were marked

Waterbody Species Season Calcein- Age Number Percent stocked marked (years old) of fish marked analysed (%) Campaspe R. Golden perch Not stocked Not stocked 0 0 2012/13 Yes 1 0 2011/12 Yes 2 12 83.3 2010/11 No 3 5 ? >3 16 N/A Sum 33 Murray cod 2013/14 Yes 0 0 2012/13 Yes 1 9 100 2011/12 Yes 2 1 100 Not stocked Not stocked 3 0 >3 0 Sum 10 Lake Eildon Murray cod 2013/14 9.5% marked 0 0 2012/13 Yes 1 23 91.3 2011/12 Yes 2 68 98.5 2010/11 Yes 3 57 100 >3 2 N/A Sum 150 Lower Goulburn R. Golden perch Not stocked Not stocked 0 0 2012/13 Yes 1 1 100 2011/12 Yes 2 1 0 2010/11 Yes 3 2 0 >3 15 N/A Sum 19 Murray cod 2013/14 Yes 0 9 11.1 2012/13 Yes 1 6 33.3 2011/12 Yes 2 10 20.0 Not stocked Not stocked 3 0 >3 10 N/A Sum 35 Gunbower Ck Golden perch Not stocked Not stocked 0 0 Not stocked Not stocked 1 0 Not stocked Not stocked 2 1 0 Not stocked Not stocked 3 0 >3 13 N/A Sum 14 Murray cod 2013/14 Yes 0 0 2012/13 Yes 1 5 60.0 2011/12 Yes 2 7 85.7 2010/11 No 3 0 >3 0 Sum 12

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 48

Waterbody Species Season Calcein- Age Number Percent stocked marked (years old) of fish marked analysed (%)

Kow Swamp Golden perch 2013/14 Yes 0 14 92.9 2012/13 Yes 1 3 66.7 2011/12 Yes 2 0 2010/11 No 3 2 ? >3 16 N/A Sum 35 Murray cod Not stocked Not stocked 0 10 60.0 2012/13 Yes 1 3 33.3 2011/12 Yes 2 0 Not stocked Not stocked 3 0 >3 0 Sum 13 Loddon R. Golden perch 2013/14 Yes 0 0 2012/13 Yes 1 3 100 2011/12 Yes 2 8 87.5 2010/11 No 3 12 ? >3 14 N/A Sum 37 Murray cod 2013/14 Yes 0 0 2012/13 No 1 10 ? 2011/12 Yes 2 2 100 2010/11 No 3 1 ? >3 0 Sum 13

Monitoring fish stockings in Victoria: 2014 native fish surveys  Recreational Fishing Grants Program 49

Appendix VII: Detection of calcein in golden perch and Murray cod using different methods

Table 1. Percent of different age classes of golden perch and Murray cod marked using different detection methods

Detection Fish age Golden perch Murray cod method (years old) No. fish Percent No. fish Percent analysed marked (%) analysed marked (%) Torch (in field) 0 14 100 12 58 1 4 50 26 31 2 20 90 11 82 3 17 71 13 92 >3 36 89 0 Overall 91 86 62 58

Sectioned otolith 0 14 93 19 37 1 7 86 57 28 2 22 77 88 89 3 21 0 58 98 >3 74 0 12 0 Overall 138 26 234 76

Table 2. Fluorometer measurements recorded in different age classes of golden perch identified as being marked and non-marked using sectioned otoliths

Otolith Fish age Golden perch Murray cod marked/ (years No. fish Mean Range No. with No. fish Mean Range No. with not old) analysed signal analysed signal marked overload overload Not 0 1 - 1 12 5 0-30 5 marked 1 1 - 1 20 79 0-267 0 2 5 148 43-246 0 10 206 76-418 0 3 21 141 30-313 0 1 98 98 0 >3 73 342 53-1,152 0 12 336 26-574 0 Overall 101 290 30-1,152 2 55 156 0-574 5

Marked 0 13 - - 13 7 608 608 6 1 4 255 118-569 0 36 135 0-803 0 2 17 440 49-1,369 1 78 420 43-1,338 8 3 0 - - - 57 525 66-1,286 7 >3 0 - - - 0 - - - Overall 34 403 49-1,369 14 178 390 0-1,338 21

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