Habitat utilisation and movement of black bream (, Munro 1949) in an Australian estuary

Jeremy S. Hindell*, Gregory P. Jenkins and Brent Womersley

* Arthur Rylah Institute, Department of Sustainability and Environment

June 2009

Fisheries Research Report Series No. 41

Black bream tagging

© The State of Victoria, Department of Primary Authorised by the Victorian Government, Industries, 2009. 1 Street, Melbourne This publication is copyright. No part may be Printed by Fisheries Victoria, Queenscliff, reproduced by any process except in accordance Victoria with the provisions of the Copyright Act 1968. Published by the Department of Primary Preferred way to cite this publication: Industries. Hindell, Jenkins and Womersley (2009). Habitat Copies are available from the website: utilisation and movement of black bream www.dpi.vic.gov.au/fishing (Acanthopagrus butcheri, Munro 1949) in an General disclaimer Australian estuary. Fisheries Victoria Research This publication may be of assistance to you but Report Series No. 41. the State of Victoria and its employees do not ISSN 1448‐7373 guarantee that the publication is without flaw of any kind or is wholly appropriate for your ISBN 978‐1‐74217‐691‐8 particular purposes and therefore disclaims all Author Contact Details: liability for any error, loss or other consequence Jeremy Hindell which may arise from you relying on any ARI, DSE information in this publication. PO Box 137, Heidelberg Vic 3084

Black bream tagging ii Executive Summary

Acoustic telemetry was used to document patterns of movement by black bream (Acanthopagrus butcheri) throughout ’s largest estuary, the Lakes. Forty‐four fish were surgically implanted with acoustic transmitters and monitored over 12 months (November 2005 to October 2006). Fish moved throughout the , with some fish moving distances of up to 2600 km, at average speeds of 8.7 km.d‐1 over 12 months. Fish frequently moved among the major estuarine rivers (Tambo, Mitchell and Nicholson Rivers), sometimes moving up to 30 km in a day. Fish use of the rivers, river entrances and lakes varied strongly with the time of year. Fish spent more time in the lakes than rivers in late summer and early autumn, but began to use the rivers more than the lakes at the end of autumn. River use was greatest in early to mid winter then gradually decreased through spring. Fish also spent more time in some rivers than others, with use of their respective entrances peaking during transition phases when fish were moving from the rivers to the lakes and vice versa. Time of the day was a weak predictor of regional patterns of fish use, but during the transitional phases (March through May) fish use of the lakes was greater at night, while use of the rivers was greater during the day. Monthly variation in times spent by fish in particular rivers varied positively with the discharge of freshwater (with a concomitant negative relationship between lakes use and overall river discharge).

Black bream tagging iii

Black bream tagging iv Table of Contents

Executive Summary...... iii

Introduction...... 1

Project Design and Methods ...... 3 Study system...... 3 Selection of study sites and application of acoustic telemetry ...... 3 Tagging fish...... 3 Flow Data ...... 4 Data Analyses...... 4

Results...... 10

Discussion...... 22

Conclusions ...... 24

Acknowledgements...... 25

References ...... 26

Black bream tagging v List of Tables Table 1. Summary of the release date (Date) and location (Location) of tagged fish (Tag ID); fork length (FL, mm) and weight (W, g) of tagged fish; time at liberty (D, days), estimated distance travelled (S, km) and mean rate of movement (km per day) of fish; and, the time (Year and Month) over which spatial information on the movements of individual fish (Tag ID) was collected. See Figure 1 for Release Locations. ** fewer than 20 data points on fish movement so distance parameters not calculated...... 6 Table 2. Summary of probability values of 3‐factor randomised blocks analyses of variance comparing the time (sec.d‐1) spent by fish (F) in different regions (rivers ‐ R, lakes ‐ L, river entrances ‐ E) at different times of the day (T, dawn – 4 am to 8 am, day – 8 am to 4 pm, dusk – 4 pm to 8 pm, night – 8 pm to 4 am). Degrees of freedom shown in subscript. Bold represent significant at P < 0.05...... 12 Table 3. Summary of probability values of 2‐factor randomised blocks analyses of variance and associated planned comparisons of the time (sec.d‐1) spent by fish among rivers, and between the entrance and inside each river (Mitchell entrance – ME, Tambo entrance – TE, Nicholson entrance – NE, Mitchell river – MR, Tambo river – TR, Nicholson river – NR) of the Gippsland Lakes. Degrees of freedom shown in subscript. Bold represent significant at P < 0.05...... 13

Black bream tagging vi List of Figures Figure 1. Map of the Gippsland Lakes showing locations of acoustic receivers, and release locations of fish (NR – Nicholson River, TR, Tambo River, CA – Cunningham Arm, JB – Jones Bay, HL – Hollands Landing)...... 9 Figure 2. Relationship between average speed (km.d‐1) of movement and the length (fork length, mm) of tagged fish...... 14 Figure 3. Examples of typical patterns of use of different regions of the Gippsland Lakes, based on the numbers of times fish were detected (hits), by four individual fish (Fish 1208, 1248, 1217, 1241) over 12 months...... 15 Figure 4. Examples of seasonal patterns of use of different regions of the Gippsland Lakes, based on the numbers of times fish were detected (hits), by fish 1219 over 12 months...... 16 Figure 5. Mean (+ se) time (sec.d ‐1) spent by all fish in each region (entrance , lake , river ) for each month of the study between November 2005 and October 2006...... 17 Figure 6. Mean (+ se) time (sec.d ‐1) spent by all fish in each region (entrance , lake , river ) during each diel period (dawn, day, dusk, night) for each month of the study between November 2005 and October 2006...... 18 Figure 7. Mean (+ se) time (sec.d ‐1) spent by all fish in each region (Mitchell entrance – ME , Tambo entrance – TE , Nicholson entrance – NE , Mitchell river – MR , Tambo river – TR , Nicholson river – NR ) for each month of the study between November 2005 and October 2006... 19 Figure 8. Mean (+ se) time (sec.d ‐1) spent by fish in each region (entrance , lake , river ) through 24 hours during each month between November 2005 and October 2006...... 20 Figure 9. Monthly variability in flow ( ,average Ml.month‐1) and total time (seconds.day‐1) spent by fish ( ) in each of the rivers A) Tambo, B) Nicholson, C) Mitchell, and D) the lakes, and relationship between flows (average ML.month‐1) and total time (sec.d‐1) spent by fish in each of the rivers E) Tambo, F) Nicholson, G) Mitchell, and H) the lakes. Note different Y‐axis scales...... 21

Black bream tagging vii

Introduction

Understanding patterns of habitat use and (Potter and Hyndes 1999), this potentially movement by fish is critical to the sustainable involves movement among different estuarine management of aquatic resources (Fromentin regions. Næsje et al. (2007) and Kerwath et al. and Powers 2005; Semmens et al. 2007). Spatial (2005) reported that use of South African metrics on connectivity, residency, habitat estuaries by spotted grunter (Pomadasys affinities and behaviour are crucial in the commersonnii) was restricted mainly to the lower development of models for resource 6 km of the study area, while movements by management (Walters and Martell 2004). Recent white stumpnose (Rhabdosargus globiceps) were technological advances have dramatically largely along channels at night (Attwood et al. improved our ability to study the spatial 2007). Taylor et al. (2006) found strong fidelity for behaviour of animals in aquatic environments deeper holes within an estuary by mulloway (Lucas and Baras 2000). Biotelemetry methods (Argyrosomus japonicus), although larger fish provide valuable information on home range ventured outside the holes at night. Hartill et al. size, habitat selection and activity (Heupal et al. (2003) found that snapper (Pagrus auratus) 2006). Observations on the change in behaviour occupied small (100s of metres), discrete areas of animals with environmental disturbance are with a substratum of soft sediment, and made increasingly important for predicting changes in repeated, predictable movements within these resource structure and function with areas. Fewer studies have attempted to environmental perturbations. understand the variability in movements of fish in estuaries in relation to environmental Acoustic telemetry is one of the most widely conditions, such as freshwater inflows. Smith et used methods of documenting behaviour of fish al. (1994) found adult Atlantic salmon (Salmo and invertebrates, and has been used to explore salar) entered rivers in complex and varied ways questions of habitat use, movement and with river discharge, with river entry closely connectivity, and behaviour (Heupal et al. 2006). associated with days when flows had increased Acoustic telemetry has been used to quantify fish since the previous day, but only during periods use of marine protected areas (Parsons et al. 2003; of lower than average seasonal flows. Lindholm 2005; Topping et al. 2005), artificial structures (Girard et al. 2004; Szedlmayer and Black bream (Sparidae, Acanthopagrus butcheri) is Schroepfer 2005) and re‐established aquatic endemic to nearshore coastal areas, rivers and habitat (Hindell 2007). More recently, acoustic estuaries of southern Australia. A. butcheri is techniques have been useful in describing subtle thought to be the only truly estuarine sparid in differences in movement and habitat use Australia, and can tolerate a wide range of between stocked and natural fisheries resources salinities from fresh (around 3‐4) to hypersaline (Taylor et al. 2006), as well as documenting the waters. In most estuaries, however, A. butcheri degree of connectivity among disparate regions are most abundant in areas where salinities range of large estuaries (Gudjonsson et al. 2005; Næsje 15‐25, particularly during the spawning period et al. 2007). A common message from these (late winter to early summer). Little is known studies is that the spatial behaviour of about the movements of A. butcheri. Potter and individuals changes dramatically over different Hyndes (1999) generally considered A. butcheri to temporal scales. Acoustic telemetry can provide be resident within estuaries, completing their more frequent monitoring of fish movement entire lifecycle within a specific estuary. A. patterns, and is beneficial in answering questions butcheri can, however, move considerable on the spatial behaviour of fish compared with distances up and down estuaries (Hindell 2007), traditional fish sampling methods, which and some fish have been found to move among provide only a ‘snap‐shot’ of fish behaviour in estuaries along the coast (Butcher and Ling 1958). time and space. A. butcheri supports valuable recreational and The spatial behaviour of fish in estuaries varies commercial fisheries in the Gippsland Lakes over a range of temporal scales, from localised (Walker et al. 1998), a large estuary in diel movements to seasonal or life‐cycle related southeastern Australia. Historical catch and events (Lucas and Baras 2000). For estuarine effort data from the commercial fishery suggests resident species with wide salinity tolerances that abundances of A. butcheri in the Gippsland

Black bream tagging 1 Lakes vary widely among years (Cashmore recent years and, as freshwater flows to the 2002). Since 2001 there has been a sharp decline Gippsland Lakes have declined, high salinity in catches of A. butcheri in the Gippsland Lakes, waters (> 30) have moved further upstream. and current catches are at historically low levels. Consequently, it has been suggested that A. The reasons for the decline are unknown, but are butcheri may be moving further upstream in thought to relate to recruitment and/or spawning pursuit of lower salinities and, in the process, failure as a consequence of unfavourable spending more time in the rivers than the lakes. environmental conditions. There is some The present study aimed to document broad‐ suggestion, however, that fish abundances may scale patterns of movement by A. butcheri not have declined as seriously as catch figures throughout the Gippsland Lakes and rivers. In suggest, and that lower catches may actually be doing so, the degree to which fish used different an artefact of fish moving upstream and regions of the study area, including the rivers, remaining in the rivers for longer periods of time river entrances and lakes, was quantified with (where they are not accessible to commercial respect to the time of year, time of day, and fishers). Southeastern Australia has been freshwater inputs. impacted by one of the most severe droughts in

Black bream tagging 2 Project Design and Methods

from Lakes Entrance to the western end of Study system McLennans Strait (Fig. 1). Within the Lakes, The present study was done in the Gippsland receivers were located to separate the study area Lakes, southeastern Australia (Fig. 1). The into five broad regions (Fig. 1). Within each of the Gippsland Lakes is a network of temperate Tambo, Nicholson and Mitchell Rivers, receivers coastal lakes, marshes and lagoons covering an were placed upstream to distances of around 15 area of about 600 km2. The Gippsland Lakes has a km from the entrance to the lakes. low (< 30 cm) tidal range, and is connected to the Receivers were attached underwater to available open ocean by an artificial channel that was cut structure (such as woody debris or navigational across the beach at Lakes Entrance to stabilise the piles) with plastic cable ties at depths between 2 water level, create a harbour for fishing boats, and 3 m. Sensitivity analyses showed that and open up the lakes to shipping. acoustic receivers were able to detect acoustic Lake Wellington, Lake King and Lake Victoria transmitters (implanted within fish) at distances are the largest of the lakes in the study area. of up to 400 m in the rivers and 600 m in the There are five major entering the lakes, even during periods when environmental Gippsland Lakes; two in the west (the Avon and variables, such as strong winds (increasing water Latrobe rivers), and three feeding the central turbulence), may interrupt the detection of basin of Lake King (the Mitchell, Nicholson and acoustic signals. Tambo rivers). The Gippsland Lakes are around Three types of data were recorded and stored 70 km long, forming the largest navigable when a tagged fish swam within the range of an network of inland waterways in Australia, and acoustic receiver: 1) number of visits; 2) total time (with associated ) is recognised under of visit and, 3) number of hits. The number of the Ramsar Convention as a site of international visits represents the number of times that a fish importance, supporting rare, endangered and has visited a receiver over the course of the vulnerable plants and animals. study. For example, a fish that is detected at a Rainfall in the Gippsland Lakes region between receiver, moves outside the detection range of a 2000 and 2006 was generally lower than average, receiver, and then returns, would have two visits and subsequent annual discharge of freshwater recorded. The total time of a visit (or visits) over to the Lakes from the five major tributaries (Fig. the course of a study represents the total time 1) was only 66% of the long‐term average elapsed (in seconds) between the initial and final (1344 GL per year versus 2018 GL per year). As a detection for a given visit (and is summed over consequence, salinity in the lower and middle all visits). The number of hits represents the basins of the Gippsland Lakes increased from number of times a given transmitter is detected around 20 to more than 30 within a single visit. For example, if a transmitter (www.vicwaterdata.net/vicwaterdata/home.aspx), is set to transmit once every 30 seconds, and a with a concomitant movement and constriction fish remains in the vicinity of a receiver for 2 of the salt wedge inland along the major minutes, four ‘hits’ will be recorded. tributaries. In the Mitchell, Tambo and Nicholson Rivers, salinities as high as 27‐28 were recorded Tagging fish in surface waters at the most inland incursion of The methods for catching and tagging A. butcheri saltwater. are outlined in detail by Hindell (2007). Briefly, fish for tagging were caught using recreational Selection of study sites and methods. Only lip‐hooked fish were retained for tagging because of the high mortality of fish that application of acoustic telemetry swallow hooks (S. Conron unpublished data). Acoustic receivers (VEMCO, VR2) were used to Fish were tagged at five different locations detect and record information from ultrasonic (69 within the Gippsland Lakes, including outside kHz) signals emitted by acoustic transmitters in the major rivers (Table 1, Fig. 1), to avoid real time. Thirty receivers were placed potential effects of release location on strategically throughout the Gippsland Lakes, movements. Fish were also tagged in a number

Black bream tagging 3 of batches through time (Table 1) to ensure that The placement of double receivers around the adequate numbers of tagged fish were present in entrance to each river, one immediately adjacent the study area over 12 months; the tag to the entrance and the other 600 m upstream, manufacturer only guaranteed 300 days of enabled the separation of time spent by fish in battery power for the acoustic transmitters. the rivers versus the lakes. Detection ranges within the rivers were between 300 and 400 m, so Fish were first anaesthetised to stage III sedation it was always possible to determine if a fish was (Ross and Ross 1999) with Benzocaine (2 g in 10 l swimming downstream toward the entrance or of estuarine water), and the fork length (FL, mm) upstream. To further increase our understanding and weight (g) of each fish was recorded. A of fish use of the entrance region of the rivers, we single, individually‐coded, acoustic transmitter estimated the time spent by fish outside the river (VEMCO V9‐2L coded, random signal delay 20 to but in the immediate vicinity (between 400 and 60 seconds) was inserted into the peritoneal 500 m into the lakes) of the entrance. Overall, the cavity via a 2‐3 cm off‐centre ventral incision in average time required for fish to move between the body‐wall, which was then ‘closed’ with 2 to the entrance receiver and that immediately 3 sutures and ‘sealed’ with Cyanoacrylate upstream was around 3 minutes. Subsequently, adhesive. All fish were also tagged with external four rules were applied in calculating the times anchor tags (T‐bar), which were inserted into the spent by fish in the river versus entrance versus dorsal musculature, adjacent to the dorsal fin. lake regions: (1) all time recorded by fish at the Once tagged, the wound areas of fish were entrance receiver was ‘entrance time’, (2) if a fish, swabbed with antiseptic, and fish were placed in on departing the entrance receiver, was next a square (70 × 70 × 70 cm) holding net in water to detected upstream, the difference between the recover. Once fish were able to maintain balance, departure and arrival times was apportioned they were released close to the point of capture. ‘river time’, (3) if a fish, on departing the entrance receiver, was next detected back at the Flow Data entrance within 3 minutes of departure, the Freshwater input is a significant determinant of difference between departure and arrival times water quality (especially salinity and was apportioned ‘entrance time’ (i.e. the fish temperature) in the Gippsland Lakes. Given the swam just outside the detection range of the salinity preferences of A. butcheri, especially for listing station and then back again within a short spawning, it is possible that freshwater flows time), (4) if a fish, on departing the entrance from the Nicholson, Tambo and Mitchell Rivers receiver, was next detected at a receiver outside may influence fish use of the rivers. Freshwater the river, the difference between departure and discharge (discharge, ML.day‐1) data are arrival times was apportioned ‘lake time’. recorded for each river entering the Gippsland Once the amounts of time spent by fish in each Lakes and are stored at the Victorian Water region (lake, entrance and river) had been Resources Data Warehouse calculated, the data were adjusted by the number (http://www.vicwaterdata.net/vicwaterdata/hom of days that a fish was detected in the last month e.aspx). Daily discharge data over the period of for which it was observed. For example, if a fish the present study were extracted and monthly was not again detected after the 20th day of July, averages calculated. then time data for July were divided by 20. This ensured that the estimates of time for fish were Data Analyses not weighted by differences in the number of The present study provided time‐integrated days in a month (or the number of days for information on the time (seconds) and number of which they were observed in their last month). hits by each tagged fish at each acoustic receiver Subsequently, the principal response variable (n = 30) between November 2005 and October describing fish use of the study area was time 2006. As in Hindell (2007), two broad rules were (seconds) per day. Data were assessed for used to select data for analyses. First, to reduce normality and homogeneity of variance prior to effects of surgery‐induced changes on fish analyses using box plots and plots of residuals behaviour, only data 1 month post fish release (Quinn and Keough 2002). Data that did not meet were used in analyses. Second, fish had to be these assumptions were transformed (Log10) and recorded for at least 3 months within (or leading reassessed. into) the year‐long study; three tagged fish were Variability in time (seconds.day‐1) was initially ‘lost’ 2 months after tagging, so these data were analysed using 3‐factor randomised blocks excluded from further analyses. analyses of variance for each month (November

Black bream tagging 4 2005 to October 2006) separately. Region (Lake, entrances. As above, region (Mitchell entrance – Entrance, River), and Time of day (dawn – 0400 ME, Tambo entrance – TE, Nicholson entrance – to 0800, day – 0800 to 1600, dusk – 1600 to 2000, NE, Mitchell river – MR, Tambo river – TR, night – 2000 to 0400) were treated as fixed Nicholson river – NR) was treated as a fixed factors. Fish were included in the model only as a factor, and fish was again treated as a random random blocking factor. Planned comparisons blocking factor. Planned comparisons were again were used to compare differences in time among used to investigate differences among regions, regions. rivers, river entrances, and rivers and their respective entrances. Regression analyses were Time of day had only a minor influence on used to assess relationships between time (of all patterns of fish use among regions, so a second fish) and average monthly freshwater flows for series of 2‐factor randomised blocks analyses of each river individually (e.g. time spent by all fish variance were done, for each month separately in the Mitchell River versus flow in the Mitchell (as above), to expand the regional comparisons River), as well as time in the lakes versus total among particular rivers and their respective average monthly flows from all three rivers.

Black bream tagging 5 Table 1. Summary of the release date (Date) and location (Location) of tagged fish (Tag ID); fork length (FL, mm) and weight (W, g) of tagged fish; time at liberty (D, days), estimated distance travelled (S, km) and mean rate of movement (km per day) of fish; and, the time (Year and Month) over which spatial information on the movements of individual fish (Tag ID) was collected. See Figure 1 for Release Locations. ** fewer than 20 data points on fish movement so distance parameters not calculated.

2005 2006

Tag ID Date Location FL W D S Rate Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

90 November 2005 Nicholson River 255 367 306 837.3 2.7

91 November 2005 Nicholson River 245 331 197 215.9 1.1

93 November 2005 Nicholson River 260 371 131 143 1.1

94 November 2005 Nicholson River 255 324 234 151 0.6

95 November 2005 Nicholson River 260 408 183 1282 7.0

96 November 2005 Nicholson River 255 347 198 729 3.7

97 November 2005 Nicholson River 275 425 207 388 1.9

98 November 2005 Nicholson River 270 424 326 513.4 1.6

99 November 2005 Nicholson River 265 403 330 1405.3 4.3

1205 December 2004 Nicholson River 243 309 314 195.1 0.6

1206 December 2004 Nicholson River 324 740 361 634.1 1.8

1207 December 2004 Nicholson River 227 257 337 1405 4.2

1208 December 2004 Nicholson River 213 208 342 515.9 1.5

1209 December 2004 Jones Bay 215 230 327 530.9 1.6

1211 December 2004 Nicholson River 309 668 359 539.6 1.5

1213 December 2004 Tambo River 235 264 216 974.9 4.5

1214 December 2004 Tambo River 209 192 344 463.6 1.3

Black bream tagging 6 1217 December 2004 Nicholson River 225 244 336 1819.5 5.4

1219 March 2005 Tambo River 360 920 344 2463.1 7.2

1220 March 2005 Tambo River 250 292 ** ** **

1224 March 2005 Tambo River 260 350 72 408.7 5.7

1225 March 2005 Tambo River 240 291 317 1544.9 4.9

1228 March 2005 Tambo River 260 325 336 470.9 1.4

1229 November 2005 Nicholson River 270 428 329 331.4 1.0

1230 October 2005 Hollands Landing 255 405 ** ** **

1231 March 2005 Tambo River 240 305 306 2656.9 8.7

1232 October 2005 Hollands Landing 230 282 ** ** **

1234 October 2005 Hollands Landing 245 327 318 99.3 0.3

1235 October 2005 Hollands Landing 260 466 ** ** **

1237 October 2005 Hollands Landing 400 1932 ** ** **

1240 October 2005 Hollands Landing 240 301 190 59.9 0.3

1241 October 2005 Hollands Landing 245 362 298 575.5 1.9

1242 October 2005 Hollands Landing 305 640 340 214.4 0.6

1243 August 2005 Cunningham arm 225 216 ** ** **

1245 August 2005 Cunningham arm 225 237 ** ** **

1248 August 2005 Cunningham arm 200 173 208 66.7 0.3

1249 December 2004 Jones Bay 213 210 361 1760.1 4.9

1250 December 2004 Jones Bay 195 165 197 741.8 3.7

1251 December 2004 Nicholson River 211 192 81 258.8 3.2

1252 December 2004 Nicholson River 215 216 87 326.8 3.7

1254 December 2004 Jones Bay 210 200 ** ** **

Black bream tagging 7 1255 December 2004 Nicholson River 225 241 335 240.5 0.7

1258 December 2004 Jones Bay 203 185 ** ** **

1260 December 2004 Nicholson River 224 241 ** ** **

TOTAL NUMBER OF FISH DETECTED.MONTH-1 35 42 41 39 35 35 32 30 24 23 22 17

Black bream tagging 8 Figure 1. Map of the Gippsland Lakes showing locations of acoustic receivers, and release locations of fish (NR – Nicholson River, TR, Tambo River, CA – Cunningham Arm, JB – Jones Bay, HL – Hollands Landing).

Nicholson R. Tambo R. TR Mitchell R. NR

JB Lake King

CA Lakes Entrance

ria to ictor V ke HL LakLa N

10 0 10 Kilometers

Black bream tagging 9 Results

All fish analysed in the present study survived similar but greater than river entrances (Figs. 5 & surgery and were detected for more than 4 6). In May, fish began to spend slightly more months post release. Most fish (54%) moved time in the rivers than the lakes and there was relatively large distances (> 300 km, Table 1) little difference in fish use of the river entrances during the present study, and there was little and the lakes. Between June and October there evidence of residency in a single river of the was a significant increase in the time that fish Gippsland Lakes (Table 1). Fish moved regularly spent in the rivers, with the difference between among the Tambo, Nicholson and Mitchell the rivers and lakes peaking in June, July and Rivers at an average speed (across all fish) of 2.8 August (Figs. 5 & 6). In September and October, km.day‐1. Some fish were estimated to have fish were again spending similar periods of time moved distances in excess of 2600 km while at in the lakes and river entrances. liberty, at an average speed of 8.7 km.day‐1 (e.g. Patterns of fish use in the study area also varied Fish 1231, Table 1); rates of movement for other at finer spatial scales with different rivers and fish were as low as 0.6 km.day‐1 (e.g. Fish 1205, their respective entrances (Table 3, Fig. 7). In Table 1). There was no discernable relationship November and December, fish spent more time between the average speed of movement by fish in the Nicholson than Mitchell or Tambo Rivers, and fish length (Regression; df = 1,32; R2 = 0.006; and there was little difference among the P = 0.667; Fig. 2); fish length and weight were entrances to these rivers (Table 3, Fig. 7). As fish strongly correlated (n = 44; Pearson correlation use of the rivers decreased through January, coefficient = 0.915; Bartlett Chi‐square = 75.374, P February and March, fish were spending similar < 0.001). amounts of time in all three rivers and their Release location had some influence on where respective entrances. In April and June, fish use fish were likely to move. Fish released in of the Mitchell and Tambo Rivers increased, as Cunningham Arm or at Hollands Landing were did fish use of their respective entrances. Fish use found to use the Tambo, Nicholson and Mitchell of the entrance regions of all rivers started to Rivers despite the relatively large (up to 30 km) decline significantly in June, with fish again distances separating release and river locations spending similar periods of time in all three (Fig. 3). Time spent by these fish in these rivers rivers, and fish use of the entrances ceased for the was less than that spent by fish released either Nicholson and Tambo Rivers in July. Between directly into these rivers, or in the lake adjacent August and October, fish use of the entrances to the river entrances (i.e. Jones Bay). Fish increased again, and fish were generally released in a particular river did not remain in spending more time in the Mitchell and that river permanently (Fig. 3); most fish moved Nicholson Rivers compared with the Tambo into a different river (or into the lake from the River. river) to that of their release location within days The time spent by fish in the lakes was strongly of tagging. influenced by fish that were released furthest The degree to which fish used the river versus from the rivers, which rarely used the rivers in lake components of the Gippsland Lakes differed the north‐central regions of the Gippsland Lakes strongly among months (Table 2 , Figs. 4 to 6), (Fish 1230, 1232‐1248, Table 1). To better assess and varied in subtle ways with time of day (Fig. the subtle diel variability, hour‐to‐hour 6). Fish spent more time in the rivers than the variability in time spent in the different regions lakes, and least time around the river entrances of the study area (entrance, river, lake) was in November and December (2005). January plotted without ‘lake‐based’ fish (Fig. 8). The marked a period of transition, when the use of exclusion of these fish did not increase the lakes and rivers was similar, although fish use of overall times that fish spent in the rivers, but river entrances remained low (Figs. 5 & 6). In reduced the difference between rivers and lakes February and March, fish spent more time in the for the periods when fish were previously lakes than the rivers, with fish use of the river associated more strongly with the lakes entrances still around half that of the lakes (Figs. (February to April). Figure 8 also demonstrated 5 & 6). April was another period of transition, much stronger diel effects from February to May. when fish use of the rivers and lakes was again Fish use of the rivers and lakes was the same in

Black bream tagging 10 February regardless of diel period. In March, For the Nicholson and Mitchell Rivers, there there was a trend for fish to use the lakes more were significant positive linear relationships than the rivers between 7 pm and 7 am, and for between the average time spent by fish in a river fish use to be similar between the rivers and and the average monthly flows (Mitchell River; lakes between 7am and 7 pm. In April and May, df = 1,8; R2 = 0.407, P = 0.047: Nicholson River; df fish use of the lake and entrance regions was = 1,10; R2 = 0.704, P = 0.001: Figs. 9 F & G). The always lower than that in the rivers, but, time spent by fish in the lakes varied negatively especially for the entrance, decreased markedly with the total average flows from the Nicholson, between 7 am and 7 pm (Fig. 8). Mitchell and Tambo Rivers (df = 1,10; R2 = 0.704, P = 0.001; Fig. 9 H), but average monthly flows in The time spent by fish in each of the rivers and the Tambo River were a weak predictor of time the lakes was compared with mean freshwater used by fish (df = 1,10; R2 = 0.205, P = 0.098; Fig. 9 discharge for each river respectively at monthly E). intervals over the entire study period. The increase in times spent by A. butcheri in each of the Tambo, Nicholson and Mitchell Rivers always occurred before peaks in freshwater flow (Fig. 9 A‐C). Fish use of the lakes peaked in February and March, corresponding with the lowest flows, while highest flows (collectively) into the lakes corresponded with the movement of fish into the rivers (Fig. 9 D).

Black bream tagging 11 Table 2. Summary of probability values of 3‐factor randomised blocks analyses of variance comparing the time (sec.d‐1) spent by fish (F) in different regions (rivers ‐ R, lakes ‐ L, river entrances ‐ E) at different times of the day (T, dawn – 4 am to 8 am, day – 8 am to 4 pm, dusk – 4 pm to 8 pm, night – 8 pm to 4 am). Degrees of freedom shown in subscript. Bold represent significant at P < 0.05.

2005 2006

Source Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

Region (R) 0.0022,68 <0.0012,82 0.0022,80 <0.0012,76 0.0012,68 0.0052,68 0.0222,66 <0.0012,58 <0.0012,46 <0.0012,44 0.0012,42 0.0262,32

E = R <0.0011,68 <0.0011,82 0.0041,80 0.0141,76 0.2061,68 0.0041,68 0.0061,66 <0.0011,58 <0.0011,46 <0.0011,44 <0.0011,42 0.0011,32

E = L 0.0191,68 0.0031,82 0.0011,80 <0.0011,76 <0.0011,68 0.0051,68 0.1361,66 0.0781,58 0.2331,46 0.1091,44 0.4711,42 0.4871,32

R = L 0.2101,68 0.1321,82 0.6421,80 0.0601,76 0.0111,68 0.9041,68 0.1851,66 <0.0011,58 <0.0011,46 0.0021,44 0.0021,42 0.0041,32

Time of day (T) <0.0013,102 0.2353,123 0.1653,120 0.3013,114 0.1003,102 0.0043,102 0.7173,99 0.0983,87 0.0533,69 0.0023,66 0.3583,63 0.3533,48

Fish (F) <0.00134,204 <0.00141,246 <0.00140,240 <0.00138,228 <0.00134,204 <0.00134,204 <0.00133,198 <0.00129,174 <0.00123,138 <0.00122,132 <0.00121,126 <0.00116,96

T × R 0.0026,204 0.0776,246 0.2356,240 0.2936,228 0.2336,204 <0.0016,204 0.1626,198 0.0346,174 0.1926,138 0.0016,132 0.1876,126 0.6006,96

F × R <0.00168,204 <0.00182,246 <0.00180,240 <0.00176,228 <0.00168,204 <0.00168,204 <0.00166,198 <0.00158,174 <0.00146,138 <0.00144,132 <0.00142,126 <0.00132,96

F × T <0.001102,204 0.005123,246 0.254120,240 <0.001114,228 0.072102,204 0.009102,204 <0.00199,198 0.01187,174 0.45369,138 <0.00166,132 0.00163,126 0.11148,96

Black bream tagging 12 Table 3. Summary of probability values of 2‐factor randomised blocks analyses of variance and associated planned comparisons of the time (sec.d‐1) spent by fish among rivers, and between the entrance and inside each river (Mitchell entrance – ME, Tambo entrance – TE, Nicholson entrance – NE, Mitchell river – MR, Tambo river – TR, Nicholson river – NR) of the Gippsland Lakes. Degrees of freedom shown in subscript. Bold represent significant at P < 0.05.

Source November December January February March April May June July August September October

Region <0.0016,204 <0.0016,246 <0.0016,240 <0.0016,228 <0.0016,204 <0.0016,204 <0.0016,186 <0.0016,174 0.0026,138 0.0046,132 0.0376,126 0.0046,96

ME = MR 0.9181,204 0.4871,246 0.3351,240 0.3401,228 0.7831,204 0.2591,204 0.3841,186 0.0051,174 0.3021,138 0.1341,132 0.3651,126 0.8871,96

NE = NR 0.0081,204 <0.0011,246 0.0491,240 0.1721,228 0.3361,204 0.4891,204 0.5541,186 0.0521,174 0.0021,138 0.0191,132 0.0181,126 0.0161,96

TE = TR 0.3351,204 0.1311,246 0.4721,240 0.5391,228 0.8031,204 0.1311,204 0.1141,186 0.0281,174 0.0531,138 0.2131,132 0.6101,126 0.6411,96

TE = ME 0.6981,204 0.8351,246 0.3281,240 0.5291,228 0.3051,204 0.2561,204 0.0071,186 0.0311,174 0.0991,138 0.6351,132 0.8331,126 0.0541,96

TE = NE 0.5761,204 0.5481,246 0.8891,240 0.7721,228 0.4941,204 0.4541,204 0.8091,186 0.9221,174 1.0001,138 0.7051,132 0.5681,126 0.8561,96

ME = NE 0.8631,204 0.6951,246 0.4021,240 0.3581,228 0.7321,204 0.0601,204 0.0131,186 0.2581,174 0.0991,138 0.3941,132 0.4351,126 0.0801,96

MR = NR 0.0071,204 0.0011,246 0.8651,240 0.6121,228 0.7311,204 0.0211,204 0.0061,186 0.0451,174 0.6691,138 0.9921,132 0.4851,126 0.5961,96

MR = TR 0.6351,204 0.5421,246 0.2211,240 0.3321,228 0.2931,204 0.4511,204 0.0431,186 0.0981,174 0.4561,138 0.4651,132 0.5441,126 0.1061,96

NR = TR 0.0251,204 0.0071,246 0.1641,240 0.6431,228 0.1631,204 0.1171,204 0.4531,186 0.7231,174 0.2421,138 0.4581,132 0.1931,126 0.0331,96

Fish 0.00134,204 0.02441,246 0.03740,240 0.38338,228 0.27934,204 0.40034,204 0.35631,186 0.98629,174 0.99023,138 0.94122,132 0.11821,126 0.60316,96

Black bream tagging 13 Figure 2. Relationship between average speed (km.d‐1) of movement and the length (fork length, mm) of tagged fish.

10 9 8 7 6 5 4 3 2 1 Average speed (km.day-1) 0 0 100 200 300 400 500 Length of fish (Fork Length, mm)

Black bream tagging 14 Figure 3. Examples of typical patterns of use of different regions of the Gippsland Lakes, based on the numbers of times fish were detected (hits), by four individual fish (Fish 1208, 1248, 1217, 1241) over 12 months.

Fish 1208 Fish 1248 Nicholson R. Nicholson R. Tambo R. Tambo R.

Mitchell R. Mitchell R.

Lake King Lake King

Lakes Entrance Lakes Entrance ria rriiaa to ttoo c icc Vi ViV ke kkee La LLaa N N

10010Kilometers 10010Kilometers

Fish 1217 Fish 1241 Nicholson R. Tambo R. Nicholson R. Tambo R.

Mitchell R. Mitchell R.

Lake King Lake King

Lakes Entrance Lakes Entrance Lakes Entrance a riia ria tto to ic ic VVi V ke ke La La

N N

10 0 10 Kilometers 10 0 10 Kilometers

Black bream tagging 15 Figure 4. Examples of seasonal patterns of use of different regions of the Gippsland Lakes, based on the numbers of times fish were detected (hits), by fish 1219 over 12 months.

Summer Autumn Nicholson R. Tambo R. Nicholson R. Tambo R.

Mitchell R. Mitchell R.

Lake King Lake King

Lakes Entrance Lakes Entrance

ria riia toor to ic icct V V ke ke Laake akea L N L N

10 0 10 Kilometers 10 0 10 Kilometers

Winter Spring Nicholson R. Tambo R. Nicholson R. Tambo R.

Mitchell R. Mitchell R.

Lake King Lake King

Lakes Entrance Lakes Entrance

iaia or ia cctt oorir Vi ctct V Vi ke e Lakea k L Lakea N N

10 0 10 Kilomet er s 10 0 10 Kilometers

Black bream tagging 16 Figure 5. Mean (+ se) time (sec.d ‐1) spent by all fish in each region (entrance , lake , river ) for each month of the study between November 2005 and October 2006.

80000

-1 70000

60000

50000

40000

30000

20000

10000 Time (seconds).day 0 ND J F M A M J J A S O

2005 2006

Year and Month

Black bream tagging 17 Figure 6. Mean (+ se) time (sec.d ‐1) spent by all fish in each region (entrance , lake , river ) during each diel period (dawn, day, dusk, night) for each month of the study between November 2005 and October 2006.

5 November December January 4 3 2 1 5 February March April 4 3

(x+1) transformed) (x+1) 2 10 1

5 May June July 4 3 2 1

5 August September October 4 3 2 Time (seconds) per day (log day per (seconds) Time 1 0 Dawn Day Dusk Night Dawn Day Dusk Night Dawn Day Dusk Night Times of the day

Black bream tagging 18 Figure 7. Mean (+ se) time (sec.d ‐1) spent by all fish in each region (Mitchell entrance – ME , Tambo entrance – TE , Nicholson entrance – NE , Mitchell river – MR , Tambo river – TR , Nicholson river – NR ) for each month of the study between November 2005 and October 2006.

5.0 4.5 November December 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 5.0 4.5 January February 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 5.0 4.5 March April 4.0 3.5 3.0 2.5 2.0 (x+1) transformed)(x+1) 1.5 10 1.0 0.5 0.0 5.0 4.5 May June 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 5.0 4.5 July August 4.0 3.5

Time (seconds) per day (Log 3.0 2.5 2.0 1.5 1.0 0.5 0.0 5.0 4.5 September October 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 M-E N-E T-E M-R N-R T-R M-E N-E T-E M-R N-R T-R Region

Black bream tagging 19 Figure 8. Mean (+ se) time (sec.d ‐1) spent by fish in each region (entrance , lake , river ) through 24 hours during each month between November 2005 and October 2006.

4500 4000 November 2005 December 2005 January 2006 3500 3000 2500 2000 1500 1000 500 4500 4000 February 2006 March 2006 April 2006 3500 3000 2500 2000 1500 1000 500 4500 4000 May 2006 June 2006 July 2006 3500 3000 2500 Time (seconds.day-1) Time 2000 1500 1000 500 4500 4000 August 2006 September 2006 October 2006 3500 3000 2500 2000 1500 1000 500 0 1 3 5 7 9 11 13 15 17 19 21 23 1 3 5 7 9 11131517192123 1357911131517192123

Hour of the day (24 hour clock)

Black bream tagging 20 Figure 9. Monthly variability in flow ( ,average Ml.month‐1) and total time (seconds.day‐1) spent by fish ( ) in each of the rivers A) Tambo, B) Nicholson, C) Mitchell, and D) the lakes, and relationship between flows (average ML.month‐1) and total time (sec.d‐1) spent by fish in each of the rivers E) Tambo, F) Nicholson, G) Mitchell, and H) the lakes. Note different Y‐axis scales.

25000 A 160 E 140 20000 120 15000 100 80 10000 60 5000 40 20 0 5000 10000 15000 20000 25000 35000 180 30000 B 160 F 140 25000

120 Ml.month-1) (average Flow ) 20000

-1 100 15000 80 10000 60 40 5000 20 0 5000 100001500020000250003000035000 35000 2500 30000 C G 2000 25000 20000 1500

Time (totalseconds.day 15000 1000 10000 500 5000 0 5000 100001500020000250003000035000 60000 2500 D H 50000 2000 40000 1500 30000 1000 20000 10000 500 0 NDJ FMAM JASO J 10000 20000 30000 40000 50000 60000 Month Time (total seconds.day-1)

Black bream tagging 21 Discussion

This is the first study to document and interpret In the present study, patterns of use of the rivers, broad‐scale patterns of movement and river entrances and lakes depended strongly on swimming speed for a resident estuarine species the time of year. Fish were generally spending (Acanthopagrus butcheri), with respect to seasons, more time in the lakes than the rivers in summer times of the day and freshwater flows. Fish and were also moving more widely in the lakes moved throughout the study area, sometimes region of the study area at this time. Autumn moving up to 30 km in a day. Most movements (March‐May) represented a transition time for by fish were confined to the riverine regions of the movement of fish into the rivers. Fish the study area with the lakes serving as a residency time in the rivers peaked in early to thoroughfare among rivers. River and lake use mid winter, when fish were spending high varied strongly through time and with proportions of time in the most upstream freshwater flows. While the present study regions, before gradually beginning to move confirmed the status of A. butcheri as an back into the lakes during spring. These general ‘estuarine resident’, it also demonstrated the patterns of movement are consistent with the highly transient nature of this species and its movement of fish into the upper, salt‐wedge ability to undertake sub‐daily movements over dominated regions of the estuaries where 10s of kms among smaller estuarine tributaries. haloclines of 17 and 20 support productive zones for the survival of eggs and larvae. Throughout Several Acanthopagrus butcheri in the present the present study, freshwater discharge to the study demonstrated their propensity for rivers was at historically low levels because of an sustained and rapid movements, in some cases extended period (up to 6 years, 2001 to 2007) of travelling at > 6 km.day‐1 and covering distances drought, and salinities appropriate for spawning > 2000 km.year‐1. Some fish displayed these were restricted to the uppermost regions of the patterns of movement by moving 20 to 30 km major tributaries (such as the Nicholson, Tambo through the study area, but most fish achieved and Mitchell Rivers). these distances moving only among the rivers in the north‐central region of the Gippsland Lakes. While there was a clear movement of fish into the As in Næsje et al. (2007), there was no significant upper reaches of rivers in winter, there was also relationship between the area of estuary used a brief period in summer when river flows and the length of fish, with fish size being a poor increased (due to localised heavy rain in the predictor of movement behaviour. The rates of catchments) and fish use of the rivers increased. movement observed in the present study of 0.3 to The movement of fish into the rivers at this time 8.7 km.day‐1 were lower than those of estuarine was unlikely to be for spawning, as most species such as mulloway (Argyrosomus spawning is restricted to the July‐November japonicus), which travelled up to 16 km.day‐1 period, with a peak in October (Butcher 1945). (Taylor et al. 2006), but greater than those of the Reasons for the fish moving from the lakes into white stumpnose (Rhabdosargus globiceps) in the rivers at this time are unclear. Estuarine fish South Africa, which travelled ≈ 1.5 km.day‐1 may move into lower salinity water to feed (Kerwath et al. 2005; Attwood et al. 2007). The and/or remove parasites, however, this is purely overall distances moved by A. butcheri in this speculative, and further research is required to study were significantly greater than those address these hypotheses. observed for a related species (Pagrus auratus, Diel periods can be strong determinants of fish Sparidae) in estuarine and marine water in New movement and spatial behaviour. Hartill et al. Zealand, that generally had small home ranges in (2003) found that Pagrus auratus remained in the vicinity of 100s of m in diameter (Hartill et al. relatively small home ranges during the day, but 2003; Pittman and McAlpine 2003), and also moved out of the main channel onto surrounding greater than sparids such as Rhabdosargus shallow banks at night. Smith and Smith (1997) globiceps and Chrysoblephus laticeps, which found up‐estuary movements and penetration of travelled up to 16 and 4 km in estuarine and non‐tidal regions by Atlantic salmon were more marine waters of South Africa, respectively likely to occur at night. For most of the present (Attwood et al. 2007; Kerwath et al. 2007). study, there were no clear differences between night‐day patterns of movement or use of the

Black bream tagging 22 river versus lakes. Between February and May, by Hindell (2007) has identified movements of A. however, fish use of the rivers, river entrances butcheri out of estuarine tributaries at night, and lakes varied with the time of day. In probably for foraging. Patterns of movement February, there was no difference in time spent observed in the present study support these in the lakes versus river, regardless of the time of earlier observations, and could be interpreted as day. In March, there was a trend for fish to spend moving from the rivers to the lakes to forage at more time in the lakes than the river, except for a night, and then returning to the rivers in the day brief period between 7 and 11 am, when fish use to shelter within large woody debris (Hindell of the rivers and lakes was similar. In April and 2007). May there were clear increases in the time spent The present study clearly demonstrates that, over by fish in the rivers between 6 am and 6 pm, with 12 months, A. butcheri spent, on average, twice as a peak around midday; there were also subtle much time in the rivers of the Gippsland Lakes increases in fish use of the river entrances and than the lakes per se, with a small amount of lakes at night during these month. Previous work time spent around the river entrances.

Black bream tagging 23 Conclusions

The present study has demonstrated the value of Links with habitat are ambiguous, and depend acoustic telemetry in documenting the movement on the time of day, season, provision of patterns of A. butcheri in the Gippsland Lakes. freshwater flows, and the . Flows had a Fish survived surgery, the acoustic tags lasted for weak effect on fish movement in the present at least 300 days on most occasions, and fish study, although the work was done during a appeared to move in a natural way throughout period of drought, so larger scale flow events the system. may be required to stimulate fish movement. The primary question of how “much time do fish Future work needs to expand the spatial extent of spend in the rivers versus the lakes” has been listening stations to western regions of the quantified at monthly time intervals over 1 year. system, increase the number of tagged fish in the Fish spend up to 70% of their time in the rivers system, and be of sufficient duration so as to during winter, but increase the time spent in the coincide with one or more flood events. lakes during late summer and early autumn.

Fish were not resident within a particular tributary, and moved extensively and often among all 3 riverine systems in the vicinity of Lake King. It is not clear, however, whether fish move to the major tributary systems in the western‐most area of the system.

Black bream tagging 24 Acknowledgements

JH thanks B. McKenzie for his assistance driving boats and advice on fisheries ecology in the Gippsland Lakes, and members of the Nicholson Angling Club for their help catching fish for tagging. A. King and J. Koehn provided valuable comments on earlier drafts of the manuscript. The care and use of fish in the present study complies with all relevant local animal welfare laws, guidelines and policies, and the relevant approval for this study was granted through a Department of Primary Industries Animal Ethics Committee.

Black bream tagging 25 References

Attwood, C. G., Cowley, P. D., Kerwath, S. auratus, Sparidae) in an estuarine E., Næsje, T. F., Økland, F., and environment. Marine and Freshwater Thorstad, E. B. (2007). First tracking Research 54, 931‐940. of white stumpnose Rhabdosargus Heupal, M., Semmens, J., and Hobday, A. globiceps (Sparidae) in a South (2006). Automated acoustic tracking African marine protected area. of aquatic animals: scales, design African Journal of Marine Science 29, and deployment of listening station 147‐151. arrays. Marine & Freshwater Research Butcher, A. (1945). Conservation of the 57, 1‐13. bream fishery. Fisheries and Game Hindell, J. (2007). Determining patterns of Department, Victorian State use by black bream (Sparidae, Government, Report No. 1, Acanthopagrus butcheri, Munro 1949) Melbourne. of re‐established habitat in a Butcher, A., and Ling, J. (1958). Bream southeastern Australian estuary. tagging experiments in East Journal of Fish Biology 71, 1331–1346. Gippsland during April and May Kerwath, S. E., Gotz, A., Attwood, C. G., 1944. Fisheries and Wildlife Cowley, P. D., and Sauer, W. H. H. Department, Report No. 17. (2007). Movement pattern and home Cashmore, S. (2002). Biology and population range of Roman Chrysoblephus dynamics of black bream, laticeps. African Journal of Marine Acanthopagrus butcheri, in the Science 29, 93‐103. Gippsland Lakes and the Kerwath, S. E., Gotz, A., Cowley, P. D., implications for management of this Sauer, W. H. H., and Attwood, C. fishery M. App. Sci. Thesis, (2005). A telemetry experiment on Australian Maritime College. spotted grunter Pomadasys Fromentin, J., and Powers, J. (2005). Atlantic commersonnii in an African estuary. bluefin tuna: population dynamics, African Journal of Marine Science 27, ecology, fisheries and management. 389‐394. Fish and Fisheries 6, 281‐306. Lindholm, J. (2005). Acoustic tracking of Girard, C., Benhamou, S., and Dagorn, L. marine fishes: Implications for the (2004). FAD: Fish Aggregating design of marine protected areas. Device or Fish Attracting Device? A Marine Technology Society Journal 39, new analysis of yellowfin tuna 7‐9. movements around floating objects. Lucas, M. C., and Baras, E. (2000). Methods Animal Behaviour 67, 319‐326. for studying spatial behaviour of Gudjonsson, S., Jonsson, I. R., and freshwater fishes in the natural Antonsson, T. (2005). Migration of environment. Fish and Fisheries 1, Atlantic salmon, Salmo salar, smolt 283‐316. through the estuary area of River Næsje, T. F., Childs, A. R., Cowley, P. D., Ellidaar in Iceland. Environmental Potts, W. M., Thorstad, E. B., and Biology of Fishes 74, 291‐296. Økland, F. (2007). Movements of Hartill, B. W., Morrison, M. A., Smith, M. D., undersized spotted grunter Boubee, J., and Parsons, D. M. (Pomadasys commersonnii) in the (2003). Diurnal and tidal Great Fish Estuary, South Africa: movements of snapper (Pagrus Implications for fisheries

Black bream tagging 26 management. Hydrobiologia 582, 25‐ adult Atlantic salmon. Journal of Fish 34. Biology 45, 953‐960. Parsons, D., Babcock, R., Hankin, R., Willis, Smith, I., and Smith, G. (1997). Tidal and T., Aitken, J., OʹDor, R., and Jackson, diel timing of river entry by adult G. (2003). Snapper Pagrus auratus Atlantic salmon returning to the (Sparidae) home range dynamics: Aberdeenshire Dee, Scotland. acoustic tagging studies in a marine Journal of Fish Biology 50, 463‐474. reserve. Marine Ecology Progress Szedlmayer, S. T., and Schroepfer, R. L. Series 262, 253‐265. (2005). Long‐term residence of red Pittman, S. J., and McAlpine, C. A. (2003). snapper on artificial reefs in the Movements of marine fish and northeastern Gulf of Mexico. decapod crustaceans: Process, Transactions of the American Fisheries theory and application. Advances in Society 134, 315‐325. Marine Biology 44, 205‐294. Taylor, M. D., Laffan, S. D., Fielder, D. S., Potter, I. C., and Hyndes, G. A. (1999). and Suthers, I. M. (2006). Key Characteristics of the ichthyofaunas habitat and home range of of southwestern Australian mulloway Argyrosomus japonicus in a estuaries, including comparisons south‐east Australian estuary: with holarctic estuaries and Finding the estuarine niche to estuaries elsewhere in temperate optimise stocking. Marine Ecology Australia: A review. Australian Progress Series 328, 237‐247. Journal of Ecology 24, 395‐421. Topping, D. T., Lowe, C. G., and Caselle, J. Quinn, G., and Keough, M. (2002). E. (2005). Home range and habitat ʹExperimental design and data utilization of adult California analysis for biologists.ʹ (Cambridge sheephead, Semicossyphus pulcher University Press: Cambridge.) (Labridae), in a temperate no‐take marine reserve. Marine Biology 147, Ross, L., and Ross, B. (1999). ʹAnaesthetic 301‐311. and sedative techniques for fish ‐ 2nd ed.ʹ (Blackwell Science: Oxford.) Walker, S., Sporcic, M., and Coutin, P. (1998). Development of an Semmens, J. M., Pecl, G. T., Gillanders, B. environment‐recruitment model for M., Waluda, C. M., Shea, E. K., black bream : a case study for Jouffre, D., Ichii, T., Zumholz, K., estuarine fisheries management Katugin, O. N., Leporati, S. C., and Marine and Freshwater Resources Shaw, P. W. (2007). Approaches to Institiute, Queenscliff, Victoria. . resolving cephalopod movement and migration patterns. Reviews in Walters, C., and Martell, S. (2004). ʹFisheries Fish Biology and Fisheries 17, 401‐423. Ecology and Management ʹ (Princeton University Press: Smith, G., Smith, I., and Armstrong, S. Princeton.) (1994). The relationship between river flow and entry to the Aberdeenshire dee by returning

Black bream tagging 27