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Huveneers C, Luo K, Otway NM, Harcourt RG (2009) Assessing the distribution and relative abundance of wobbegong sharks (Orectolobidae) in New South Wales, Australia, using recreational scuba‐divers. Aquatic living resources, Volume 22, Issue 3, pp. 255 to 264.

Access to the published version: http://dx.doi.org/10.1051/alr/2009046

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1 Assessing the distribution and relative abundance of wobbegong sharks 2 (Orectolobidae) in New South Wales, Australia using recreational scuba-divers 3 4 Charlie Huveneers1,2,*, Kehui Luo3, Nick M. Otway4, and Robert G. Harcourt1 5 6 1 Graduate School of the Environment, Macquarie University, Sydney, NSW, 2109, Australia 7 2 School of Biological Sciences, Flinders University, Adelaide, SA, 5043, Australia 8 3 Department of Statistics, Macquarie University, Sydney, NSW, 2109, Australia 9 4 NSW Department of Primary Industries, Port Stephens Fisheries Centre, Taylors Beach Road, Taylors 10 Beach, NSW, 2316, Australia 11 12 * Correspondence to: Dr. Charlie Huveneers, SARDI – Aquatic Sciences, 2 Hamra Avenue, West Beach, 13 South Australia, 5024, Australia, E-mail: [email protected], phone: + 61 8 8207 5302, 14 fax: + 61 8 8207 5481 15 16 Running title: The distribution and abundance of wobbegongs 17 18 Abstract – Wobbegongs are benthic sharks that are commercially targeted in New South 19 Wales (NSW), Australia. Given a dramatic reduction of more than 50% in landed catch in 20 a decade, there is a clear need to ensure that basic ecological data such as distribution and 21 abundance are available for management use. Opportunistic sightings of wobbegongs 22 collected by recreational scuba-divers were used to assess the distribution and relative 23 abundance of wobbegongs in NSW. From July 2003 until January 2005, 304 dives were 24 undertaken by recreational divers and 454 wobbegongs were reported. Larger numbers of 25 wobbegongs were sighted in northern compared to southern NSW. Spotted and ornate 26 wobbegongs were sighted in similar numbers, but species composition was highly 27 variable across locations. Only a few juvenile and newborn spotted wobbegongs were 28 sighted, whereas small ornate wobbegongs were mostly sighted north of central NSW. 29 The latter were possibly the third, cryptic species, the dwarf ornate wobbegong. The 30 paucity of sightings of small wobbegongs suggests that juveniles and newborns are 31 inconspicuous to divers or that small wobbegongs are found in areas not visited by 32 divers. Potential species and size segregation suggest that closing areas to fishing may 33 enable populations to sustain current levels of commercial exploitation. The cost- 34 effectiveness of using recreational scuba-divers to opportunistically collect distribution 35 and relative abundance data was apparent from this study. However, the lack of spatial 36 and temporal homogeneity in diving effort suggests that future studies should consider

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37 incorporating organized surveys and a facilitator, rather than using opportunistic records 38 of sightings. 39 40 Key words: Orectolobus ornatus / Orectolobus maculatus / Orectolobus halei / survey / volunteers 41 42 Introduction 43 Wobbegong sharks (family Orectolobidae) are benthic sharks found in temperate to 44 tropical continental waters of the western Pacific (Compagno, 2001). In Australia, 45 wobbegongs have been commercially targeted in NSW by the Ocean Trap and Line 46 Fishery since 1991 for sale as ‘boneless fillet’ or ‘flake’. Their catch has declined from 47 about 120 tonnes in 1990/1991 to about 55 tonnes in 1999/2000, a decrease of more than 48 50% in a decade (Scandol et al., 2008). Although fishing effort is unknown and this 49 reduction might be due to a decrease in fishing effort, this large decrease in total catches 50 led to wobbegongs being listed as ‘Vulnerable’ in NSW under the World Conservation 51 Union (IUCN) Red List assessment (Cavanagh et al., 2003). Despite their commercial 52 importance, little is known of the current population size and distribution of wobbegongs. 53 Given the decline in landed catch, there is a clear need to ensure that basic ecological 54 data, such as distribution and abundance are available for commercially harvested species 55 to enable ecologically-minded management. Amateurs and volunteers represent a large 56 pool of potentially skilled unpaid labour, and have helped collect and gather data for 57 scientific purposes for centuries (Mims, 1999; Fore et al., 2001). The use of volunteers 58 has rapidly increased (USEPA, 1998) with volunteers used worldwide in many 59 conservation orientated projects to conduct baseline surveys, and to monitor marine 60 (Halusky et al., 1994; Evans et al., 2000; Barrett et al., 2002) and terrestrial organisms 61 (Johnson, 2001; Brandon et al., 2003). Recreational scuba-divers are a specialized type of 62 volunteer that have previously been used to investigate distribution and relative 63 abundance of marine species (e.g. Parker and Bucher, 2000; Otway et al., 2003; Goffredo 64 et al., 2005), and to assess the effects of marine protected areas (MPA) (Barrett et al., 65 2002).

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66 In this study, recreational scuba-divers were asked to collect data to document the 67 distribution and relative abundance of wobbegongs in NSW. Information on species 68 composition and length frequency were also collected. 69 70 Methods 71 The present study was promoted to recreational scuba-divers through scuba-diving and 72 spearfishing magazines, e-mails to dive clubs and shops, and on scuba-diving websites 73 and forums. Any willing recreational diver was able to participate in the study. Training 74 sessions about the project’s aims and methods were provided at diving clubs and shops 75 with the aim of training scuba-divers to identify wobbegong species found in NSW and 76 correctly complete a sighting form printed on waterproof paper. Information requested on 77 the sighting form included the lead diver’s name and address, dive site details (site, 78 nearest major town, date, time, and dive duration) and details on each wobbegong 79 sighting (depth, time, species, estimated total length: 0–50 cm, 50–100 cm, 100–150 cm, 80 150–200 cm, and > 200 cm, and habitat: rock, boulder, sand, and ‘other’ such as corals or 81 algae). An instruction sheet was provided with each form to ensure its correct completion 82 and an identification key with pictures of ornate and spotted wobbegongs was provided 83 on the back of the form to help divers distinguish between the species (using colour 84 pattern and dermal lobe counts). 85 The principal investigator dived with about 20% of the participants to ensure the 86 efficacy of the training sessions. Furthermore, contact between the principal investigator 87 and participating scuba-divers was made at approximately 6-week intervals. Divers were 88 asked to record information on each wobbegong sightings by completing the form during 89 all of their usual dives in NSW, including dives during which no wobbegongs were 90 sighted. 91 At the time the study was conducted, only two species of wobbegongs were known to 92 occur in NSW, the spotted wobbegong Orectolobus maculatus (Bonnaterre, 1788) and 93 the ornate wobbegong O. ornatus (De Vis, 1883). A third species, the large ornate or gulf 94 wobbegong O. halei Whitley, 1940 formerly synonymized with O. ornatus, has since 95 been found to differ from O. ornatus (Huveneers, 2006; Corrigan et al., 2008) (Fig. 1). As 96 the differences between the two species of ornate wobbegongs were unknown at the time

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97 of the study, the distribution and relative abundances of the dwarf (O. ornatus) and large 98 (O. halei) ornate wobbegong were combined in this study as ornate wobbegongs. 99 Geographically proximite dive sites (within 100 km of each other) were combined to give 100 a total of nine different sampling locations (Fig. 2). Multiple counts of the same 101 wobbegongs were avoided by avoiding repeated sightings at any one dive site completed 102 on the same day. When multiple counts occurred, the mean number of wobbegongs 103 recorded was used for the analysis. 104 Depth and habitats occupied by the wobbegongs, together with species proportions, 105 were simply described because small sample sizes prevented any further statistical 106 analyses. Due to spatial and temporal heterogeneity in diving effort (Figs. 2 and 3), it was 107 not possible to discern seasonal variations in relative abundance from differences among 108 locations and months. Statistical analyses were, therefore, limited to locations and periods 109 of the year sampled consistently. As a result, the number of wobbegongs sighted at each 110 location was examined for January–February and October–November. Temporal 111 fluctuations in the relative abundance of wobbegongs were only examined for 112 wobbegongs sighted off Sydney with the 19-month study period pooled by month. 113 During data collection dwarf (O. ornatus) and large (O. halei) ornate wobbegong 114 sightings were combined because of unresolved taxonomy. However, these two species 115 differ in their respective maximum total length (110 cm vs. 300 cm) and distribution 116 within NSW (from the NSW/Queensland border to Sydney vs. the whole NSW coast) 117 (Compagno, 2001; Huveneers, 2006). Length frequencies were therefore divided between 118 locations north and south of Sydney to account for the difference in distribution. 119 Estimates of total length were not provided with sufficient regularity to permit statistical 120 analysis. 121 122 Results 123 Sixty-one recreational scuba-divers undertook 304 dives at 142 different dive sites 124 within nine locations along the NSW coast. The locations spanned about 1,280 km from 125 Byron Bay to Eden, and the dives occurred over 19 months from July 2003 to January 126 2005. A total of 454 wobbegongs was recorded over the 304 dives. At least one 127 wobbegong was seen in 140 dives with a maximum of 14 wobbegongs sighted in a single

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128 dive. The diving effort was neither homogenous spatially (Fig. 2) nor temporally (Fig. 3). 129 There was a strong spatial bias with the largest proportion of dives (56%) undertaken off 130 Sydney. Furthermore, a much larger proportion of dives were undertaken between late 131 spring and early autumn with nearly 70% of the dives undertaken in the five months from 132 November 2003 to March 2004. The number of dives per month peaked at about 70 dives 133 in November 2003 (49 of which were off Sydney), after which it decreased to about 8 134 dives per month over the period of April 2004 to January 2005 (Fig. 3). 135 Ornate and spotted wobbegongs were found in depths ranging from 3–30 m (n = 191) 136 and 4–31 m (n = 263), respectively. However, the depth at which wobbegongs were 137 sighted was positively correlated with the maximum depth of the dive (Spearman’s rank

138 correlation: rs: 0.71, p < 0.001) (Fig. 4). Subsequently, any observed depth preference or 139 difference between locations might be an artefact of the maximum depth dived rather 140 than an actual wobbegong depth preference or difference. The predominant habitat 141 observed during the dive differs between the north and south regions. In northern NSW, 142 the rocky habitat was more frequently observed than boulders (~80% vs. 20%), whereas 143 boulders were more commonly found in the southern locations (~60% vs. 35%) (Fig. 5). 144 Wobbegongs were most often sighted underneath rocks (about 45%) and boulders (about 145 25%). Spotted wobbegongs were sighted more frequently on sand patches than ornate 146 wobbegongs (23% and 6%, respectively). 147 As sightings were recorded during recreational dives, dive duration was highly 148 variable (30 to 120 minutes, mean 50 mintues; Fig. 6). Accordingly, abundance as a 149 function of dive time might be expected to be a more accurate reflection of the relative 150 abundance of wobbegongs. However, there was no correlation between the number of

151 wobbegongs recorded and dive duration (Spearman’s rank correlation: rs = 0.015, p > 152 0.05). There were also no correlation between the number of wobbegongs recorded and

153 dive duration in dives undertaken north of Sydney only (Spearman’s rank correlation: rs = 154 0.011, p > 0.05) nor in dives undertaken in or South of Sydney only (Spearman’s rank

155 correlation: rs = 0.007, p > 0.05) (Fig. 6). Therefore, the actual numbers of wobbegong 156 sighted were used for all analyses. 157 Parametric analyses such as ANOVA examining the relative abundances of 158 wobbegong among locations in January–February and October–November were

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159 prevented because of heterogeneity of variances (Levene’s test: F8,71 = 18.04 , p < 0.001

160 and F5,90 = 4.21 , p < 0.01, respectively). However, non-parametric analyses showed that 161 the number of wobbegong sighted differed significantly among locations in January–

162 February and again in October–November (Kruskal-Wallis: F8 = 39.68, p < 0.001; F6 = 163 26.79, p < 0.001, respectively). During January–February, the number of wobbegong 164 sighted per dive was significantly greater off Byron Bay (6.9 mean, 1.26 s.e.) than off 165 Port Stephens (0.5 mean, 0.5 s.e.), Sydney (0.6 mean, 0.17 s.e.), Batemans Bay (0.5 166 mean, 0.21 s.e.), and Eden (0 mean, 0 s.e.) (Dunnett test: all p < 0.05). The number of 167 wobbegong sighted was also significantly higher in Coffs Harbrour (2.3 mean, 0.47 s.e.) 168 than in Eden (0 mean, 0 s.e.) (Dunnett test: p < 0.05). In October–November, the number 169 of wobbegong sighted in Byron Bay (6.8 mean, 1.4 s.e.) was significantly higher than in 170 Sydney (1.4 mean, 0.3 s.e.) (Dunnett test: p < 0.05) (Fig. 7). 171 Temporal patterns in the relative abundance of wobbegongs off Sydney were also

172 characterized by heterogeneous variances (Levene’s test: F10,163 = 11.47, p < 0.001). In 173 Sydney, there was a significant difference in the number of wobbegong sighted between

174 months (Kruskal-Wallis: F10 = 44.82, p < 0.001). The number of wobbegong observed in 175 November (1.5 mean, 0.27 s.e.) was significantly higher than in March (0.1 mean, 0.7 176 s.e.), May (0 mean, 0 s.e.), June (0 mean, 0 s.e.), July (0 mean, 0 s.e.), August (0.1 mean, 177 0.09 s.e.), October (0 mean, 0 s.e.), and December (0.2 mean, s.e.) (Dunnett test: p < 178 0.001) (Fig. 7). 179 A total of 428 wobbegongs were identified as ornate or spotted wobbegongs. Although 180 the number of ornate wobbegong was similar to the number of spotted wobbegong across 181 the whole NSW coast (199 and 229 respectively, with 26 unidentified sightings), species 182 composition was variable among locations (Fig. 8). For example, Coffs Harbour had 183 approximately equal frequencies of spotted and ornate wobbegongs, whereas ornate 184 wobbegongs were more frequently sighted at South West Rocks, located only 50 km 185 South of Coffs Harbour. Similarly, most of the sharks sighted were ornate wobbegongs in 186 Port Stephens (200 km North of Sydney), whereas the majority of sharks sighted in 187 Sydney were spotted wobbegongs. Species composition also varied temporally in some 188 locations. While sightings in Jervis Bay were mostly of spotted wobbegongs throughout 189 the study period, sightings changed from ornate wobbegongs to spotted wobbegongs in

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190 Coffs Harbour, Forster and Sydney. The differences were not tested statistically due to 191 small sample sizes. 192 Estimates of total length were obtained for 405 wobbegongs. Length frequency 193 differed between species, with large numbers of spotted wobbegongs observed having 194 estimated total lengths of 100–150 cm and 150–200 cm (36% and 33%, respectively). In 195 contrast, ornate wobbegongs showed a greater range in size, with similar proportions of 196 individuals (about 25% in each size class) exhibiting estimated total lengths of 50–100 197 cm, 100–150 cm and 150–200 cm. Very few wobbegongs with estimated total lengths 198 smaller than 50 cm were obsererved (3.7 and 5.5% for ornate and spotted wobbegongs, 199 respectively). When size classes were examined between regions, the frequency of small 200 ornate wobbegongs (<1.5 m) was much lower in the southern (17%) compared to the 201 northern (62%) region (Fig. 9). 202 203 Discussion 204 Wobbegong sightings collected by recreational scuba-divers represent valuable 205 information on the distribution and relative abundance of wobbegongs in NSW. The 206 present study was only possible through the participation of a large number of scuba- 207 divers. A total of 304 dives was undertaken over 550 days, along 1,280 km of coast 208 without incurring substantial cost thanks to the use of volunteers (Darwell and Dulvy, 209 1996; Forster-Smith and Evans, 2003). 210 A major limitation of this study was the lack of consistency in sampling effort across 211 locations and months. When using a network of volunteers without organized survey 212 events, effort is likely to be greater in some areas and at particular seasons. This was the 213 case in our study with 56% of the dives undertaken around Sydney. This bias may be a 214 reflection of human demography as 62% of the NSW population indicated that they lived 215 in Sydney in the 2001 census (ABS 2001 Census). However, numerous other factors 216 including lack of reporting from other locations may have affected the study. 217 Furthermore, recreational divers undertake their sport for pleasure and often choose dive 218 sites that are more enjoyable. Therefore, many sites may not have been dived because of 219 the absence interesting fauna and flora, cold water, exposed conditions and/or general 220 inaccessibility. The repetition of detailed studies at single sites has also been found to

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221 lead to a drop in the level of interest in other studies (Barrett et al., 2002), and this may 222 have led to the temporal decrease in the number of dives and concomitant reduction in the 223 amount of data received. Diver interest was difficult to maintain in the present study as 224 illustrated by a decline in the number of dives after the first summer’s sampling. Colder 225 water in winter and spring further limits the ability to keep a regular program underway 226 throughout the year as interest waned when water and air temperatures fell below 227 comfortable levels. 228 Wobbegongs are cryptic sharks often occupying cracks and crevices (Carraro and 229 Gladstone 2006) and thus, sighting rates may vary according to the proportion of divers’ 230 time actively spent searching for wobbegongs in these habitats. Although the extent to 231 which divers actively searched for wobbegongs could not be quantified, dive duration 232 was recorded as a measure of effort and was not related to sighting success. However, 233 possible biases caused by the different searching skills of divers were assumed to be 234 evenly distributed across locations, and thus, we suggest that the observed trends reflect 235 actual variability in abundance rather than observer bias. 236 The higher percentage of wobbegongs found around rocks and boulders is consistent 237 with earlier reports that wobbegongs prefer topographically complex habitats (Carraro 238 and Gladstone, 2006). We also found a larger number of wobbegong sightings in northern 239 NSW. The larger number of wobbegong sighted in the northern locations might be 240 related to the relatively large proportion of rocky habitat which wobbegongs seem to 241 favour. However, the predominant habitat in southern NSW, boulders which can be 242 similar to rocks for recreational divers, is also a type of habitat that wobbegongs seem to 243 favour. Therefore, the difference observed might instead be due to semantics. Water 244 temperature has also been found to influence chondrichthyan distribution directly and 245 indirectly (Casey and Kohler, 1992; Morrissey and Gruber, 1993; Economakis and Lobel, 246 1998) indicating that wobbegongs in NSW might prefer waters with warmer mean 247 temperatures. Targeted fishing of wobbegongs might have also affected the relative 248 abundance of wobbegongs in NSW. Anecdotal information from divers has suggested 249 that the extensive fishing effort south of Sydney might have depleted local wobbegong 250 populations. Potential for localised depletion is further suggested by the high site fidelity 251 observed in some O. ornatus and O. halei (mis-identified as O. ornatus) individuals

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252 which were recorded within the same area for up to 20 months (Carraro and Gladstone, 253 2006; Huveneers et al., 2006). Fisheries catch reports from the targeted fishery could not 254 be used to investigate potential relationships between wobbegong abundance and fishing 255 pressure due to the lack of data on fishing effort. 256 Only a few small spotted wobbegongs were sighted by divers. Similarly, only a few 257 small ornate wobbegongs were sighted by divers south of Sydney. Sixty-two percent of 258 ornate wobbegongs sighted north of Sydney were smaller than 1.5 m. Orectolobus halei 259 was formerly considered to be the adult specimens of O. ornatus, whereas what is now 260 identified as O. ornatus was previously mistaken for juveniles. It is possible that many of 261 the small ornate wobbegongs north of Sydney were actually adult O. ornatus. The 262 southern limit for O. ornatus is Sydney (Huveneers, 2006), possibly explaining the lack 263 of small ornate wobbegongs in Southern NSW. Small O. halei may therefore be rare 264 along the whole NSW coast. This is supported by data collected from commercial catches 265 in which small juvenile and newborn wobbegongs are only sporadically caught 266 (Huveneers et al., 2007). Wobbegongs in NSW have a size-at-maturity of 175 cm for 267 large ornate, 135 cm for spotted wobbegong and 80 cm for dwarf ornate (Last and 268 Stevens, 2009; Compagno, 2001; Huveneers et al., 2007). Therefore, most sharks sighted 269 might have been large juveniles or mature sharks, whereas small juvenile and young of 270 the year were only sighted in small numbers. However, the observed increase proportion 271 of small wobbegongs in northern NSW might have also been due to an ontogenetic shift 272 in distribution with small wobbegongs preferring the warmer water temperatures in 273 northern NSW. 274 Size segregation of wobbegongs has been reported to occur around Byron Bay by 275 Baker (1998) with populations comprising mainly juvenile ornate wobbegongs (60–100 276 cm total length) and adult spotted wobbegongs. The reclassification of O. ornatus and O. 277 halei by Huveneers (2006) suggests that the proposed size segregation might be 278 erroneous as many of the juvenile ornate wobbegongs may actually be adult O. ornatus. 279 Consequently, the wobbegong population at sites around Byron Bay may simply 280 comprise juvenile and adult dwarf ornate and adult spotted wobbegongs. 281 Newborn and small juvenile wobbegongs were only observed in small numbers in this 282 study and may have been in small cracks and thus, inconspicuous to divers. Alternatively,

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283 juvenile wobbegongs may occur in areas that were not dived. These habitats might not 284 have been explored due to their difficult access (e.g. offshore in deeper waters where it is 285 dangerous for divers to dive or possibly within estuaries where visibility and currents are 286 usually poor for diving) or in areas which are characterized by a lack of ‘interesting’ 287 things to see for divers (e.g. large tracks of seaweed). If these different habitats are 288 important to wobbegongs to ensure that pups and juveniles grow sufficiently to reach 289 maturity and enter the breeding population, then the identification of these areas is an 290 important conservation priority (Heupel et al., 2007). 291 Species composition varied across geographically close locations. This indicates 292 patchiness in the distribution of wobbegong species and may be explained by species- 293 specific site preference. The establishment of suitable sized aquatic reserves or marine 294 parks at those sites where a particular species of wobbegongs is found may help protect 295 the species. If this is the case, studies focusing on the identification of suitable areas and 296 sites would be required. The potential use of specific sites as marine reserves is supported 297 by the long-term residency (i.e. over 2 yr) of individual wobbegongs at a site on the mid- 298 north coast of NSW (Huveneers et al., 2006). 299 The conservation value of using recreational scuba-divers to collect data, albeit 300 opportunistically, is apparent from this study. Although the use of organised survey 301 events with their own limitations was avoided by using recreational dives, the need to 302 ensure the program is executed properly and ensure data quality and homogeneity of 303 survey effort is vital. This requires substantial organisation input at a professional level to 304 facilitate such project. This may be accomplished by using a full-time employee or 305 facilitator. The need for such a skilled facilitator increases the cost of running a volunteer 306 program and highlights the decisions that need to be made by the chief investigators 307 when deciding whether or not to use volunteers. 308 The data provided in the present study are analogous to a pilot study and permitted 309 possible trends to be established at low cost. These results can now be used as a basis for 310 designing cost-effective, randomly-stratified sampling programs involving underwater 311 visuals censuses or other sampling techniques such as baited traps or Baited Remote 312 Underwaer Video Systems (BRUVS) to rigorously quantify the spatial and temporal 313 patterns of relative abundance of the three wobbegong species in NSW waters.

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315 Acknowledgements 316 The authors would like to thank all divers who helped gathering information during 317 the study and in particular S. Newson and S. Walsh who sent the most forms back and 318 have helped with their insights on the scuba-diving community in Australia. Wobbegong 319 illustrations were provided by S. Corrigan and drawn by L. Marshall of Stickfigurefish 320 (www.stickfigurefish.com). S. Allen, M. Braccini, W. Robbins and P. Rogers are thanked 321 for their constructive comments helping to greatly improve earlier versions of this 322 manuscript. Charlie Huveneers was supported by an international Macquarie University 323 Research Scholarship. Financial support by the Graduate School of the Environment, 324 Department of Primary Industries (NSW) and the Australian Geographic Society was 325 provided for sample collection. This study was undertaken under the NSW DPI permit 326 number PO03/0057 and a Macquarie University Ethics Committee approval number 327 2003/011. 328

329 References

330 Baker M.A., 1998, The population structure of Orectolobidae sharks, Orectolobus 331 ornatus and O. maculatus in Byron Bay, NSW. Lismore, Australia, School of 332 Resource Science and Management, Southern Cross University, pp. 51. 333 Barrett N., Edgar G., Morton A., 2002, Monitoring of Tasmanian inshore reef 334 ecosystems. An assessment of the potential for volunteer monitoring programs and 335 summary of changes within the Maria Island Marine Reserve from 1992–2001. 336 Technical Report Series. Hobart, Tasmania, Australia, Tasmanian Aquaculture & 337 Fisheries Institute, University of Tasmania, pp. 50. 338 Brandon A., Spyreas G., Molano-Flores B., Carroll C., Ellis J., 2003, Can Volunteers 339 Provide Reliable Data for Forest Vegetation Surveys? Nature Areas Journal 23, 254– 340 262. 341 Carraro R., Gladstone W., 2006, Habitat preference and site fidelity of the ornate 342 wobbegong shark (Orectolobus ornatus) on rocky reefs of New South Wales. Pac Sci 343 60, 207–224. 344 Casey J.G., Kohler N.E., 1992, Tagging Studies on the Shortfin Mako Shark (Isurus 345 oxyrinchus) in the Western North Atlantic. Aust J Mar Freshw Res 43, 45–60. 346 Cavanagh R., Kyne P., Fowler S.L., Musick J.A., Bennett M.B., 2003, The conservation 347 status of Australasian chondrichthyans. Report of the IUCN Shark Specialist Group

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Figure captions

Figure 1. Illustrations of (A) Orectolobus ornatus, (B) O. halei, and (C) O. maculates (not to scale).

Figure 2. Map of New South Wales coast showing ‘locations’ where dives were undertaken. Number of dives undertaken at each location is indicated in parenthesis.

Figure 3. Diving effort throughout NSW during the 19-month study period.

Figure 4. Maximum diving depths and depths of wobbegong sightings against locations. Black circles are mean maximum dive depth ± standard deviation; white circles are depth at which wobbegongs were sighted at each location.

Figure 5. Proportion of predominant observed habitat during a dive across locations.

Figure 6. Relationship between the number of wobbegongs sighted and dive duration. ‘n’ indicates the number of dives with dive duration provided. The discrepancy between the total number of dives (304) and ‘n’ (299) is due to five dives for which dive duration was not provided by divers. Circles indicate dives undertaken north of Sydney; triangles indicate dives undertaken in or South of Sydney.

Figure 7. Comparison of the mean number (± SE) of wobbegongs sighted per dive over the 19-month study period (pooled over 12 months) and among locations. Numbers above mean indicate the number of dives undertaken at each location during that month.

Figure 8. Percentages of ornate (black) and spotted (grey) wobbegong species sighted at each location over the 19-month study period (pooled by month). Numbers above bar denote the number of individuals at each location in that month.

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Figure 9. Size frequency of ornate (black) and spotted (grey) wobbegongs sighted in the northern and southern regions. Numbers above bar indicate the number of wobbegongs for which length was estimated. Lenghts from 261 and 144 wobbegongs were estimated in the northern and southern region, respectively.

15 ALR-800

16 ALR-800

Byron Bay (26)

New South Wales –30° Coffs Harbour (22) South West Rocks (8)

Forster (4) –32° Port Stephens (16)

Sydney (174) Jervis Bay (32) –34°

Batemans Bay (16) N 400 km –36° Eden (6)

148° 150° 152°

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10 Number of dives per month . 0 JASONDJFMAMJJASONDJ 2003 2004 2005

18 ALR-800

20 Depth (m)

0 Eden Forster Sydney Byron Bay Jervis Bay Coffs Harbour Port Stephens Batemans Bay South West Rocks

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100% rock boulder 80% sand other 60% unknown 40%

20%

y a our b ster n Bay or phens Eden o F Sydney vis B yr st Rocks te B ffs Har e Jer W Co th Port S Batemans Bay Sou

20 ALR-800

16 n = 299 14

g sighted 10

2 Number of wobbegon Number 0 0 20 40 60 80 100 120 Dive duration (minutes)

21 ALR-800

12 2 7 7 Byron Bay 10 9 26 dives 8 6 4 1 2 0 12 10 Coffs Harbour 8 22 dives 6 1 6 3 5 3 4 4 2 0 12 6 South West Rocks 10 8 dives 8 2 6 4 2 0 12 10 Forster 8 2 4 dives 6 4 2 2 0 12 10 Port Stephens 16 dives 8 6 9 4 2 2 3 2 0 12 10 Sydney 8 174 dives 6

Number of wobbegongs sighted per per dive sighted of wobbegongs Number 4 49 7 23 7 2 22 651311 5 26 0 12 10 Jervis Bay 8 32 dives 2 6 6 9 4 3 5 2 5 2 0 12 10 Batemans Bay 8 16 dives 6 4 6 2 5 2 1 2 0 12 10 Merimbula/Eden 6 dives 8 6 4 2 411 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 22 ALR-800

2 100 17 Byron Bay 80 154 wobbegongs 60 28 25 21 20 21 17 40 20 3 0 100 Coffs Harbour 4 8 80 3 9 43 wobbegongs 3 60 4 2 3 40 1 3 20 1 2 0 7 100 South West Rocks 80 26 43 wobbegongs 60 40 10 20 0 100 3 6 Forster 80 9 wobbegongs 60 40 20 0 1 1 100 18 Port Stephens 80 22 wobbegongs 60 40 20 Frequency of wobbegongsFrequency sighted (%) 2 0 100 3 Sydney 87 wobbegongs 80 39 6 3 60 8 6 4 2 40 16 20 0 4 100 Jervis Bay 5 6 80 19 64 wobbegongs 2 9 3 60 6 2 40 1 5 20 1 1 0 1 100 Batemans Bay 80 6 wobbegongs 3 60 2 40 20 0 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

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50 Ornate wobbegong 47 Spotted wobbegong 40 76 86 42 54 27 30

20 16 32 5 7 10 12 1 Frequency of wobbegongs sighted (%) sighted of wobbegongs Frequency 0 300 300 ≥ ≥ 20–49.9 50–99.9 20–49.9 50–99.9 100–149.9 150–199.9 200–299.9 100–149.9 150–199.9 200–299.9 North South Wobbegong size (cm)