Effects of wildlife tourism on white shark associative behaviour

While wildlife tourism may impact the animals it targets, it plays a critical role in public education and conservation awareness. Understanding changes in animal behaviour in response to tourism activities can inform the trade-offs between negative impacts and socioeconomic bene ﬁ ts. There are public claims that cage-diving activities may condition white sharks, Carcharodon carcharias , to interact with boats, and may potentially increasing risk of shark bites. We tracked the ﬁ ne-scale movements of 73 white sharks in relation to cage-diving boats using acoustic telemetry between 2018 and 2022 at Neptune Islands, Australia, to investigate associative behaviour and factors potentially in ﬂ uencing residency and time spent in proximity to the cage-diving boats. White sharks spent gradually less time near cage-diving boats throughout their residency at the tourism site. This behaviour was consistent across individuals, years, sexes and sizes. Sharks, however, resumed their natural behaviours (i.e. initial amount of time near the cage-diving boats) each time they returned to Neptune Islands, suggesting that the observed habituation (i.e. loss of response to the stimulus used to attract sharks) did not last for long periods. These trends support the lack of long-term learnt behaviour of white sharks increasingly interacting with boats. Our results indicate that current management strategies such as regulating the number of days the industry can operate at the site and the amount of food-based attractant used, and reducing the amount of bait consumed can limit associative behaviour between white

Animals react and alter their behaviours in response to human presence.Wildlife tourism, which is the practice of observing wild animals in their natural environments, has increased in popularity over the last decades (Giannecchini, 1993).However, wildlife tourism can negatively impact the species it targets by affecting their diets, reproductive success, foraging intensity, hormonal concentrations, habituation to people and modifications of social systems (Blane & Jaakson, 1994;Fowler, 1999;Lacy & Martins, 2003;Lott & McCoy, 1995;Romero & Wikelski, 2002).The need to ensure long-term sustainable wildlife tourism is important because of its numerous socioeconomic and conservation benefits (Meyer, Apps, et al., 2021;Cisneros-Montemayor et al., 2013;Huveneers et al., 2017).Wildlife tourism can bring tourists a sense of wellbeing and better psychological health (Ballantyne et al., 2011;Curtin, 2009), enhance public education and improve conservation awareness for both target and nontarget species, as well as natural ecosystems more broadly (Apps et al., 2017;Zeppel, 2008).Wildlife tourism contributes to conservation by enhancing environmental knowledge and potentially change negative attitudes and behaviour through interpretive messaging and meaningful, first-hand experiences with wildlife (Ardoin et al., 2015;Zeppel, 2008).On-site benefits, such as increased understanding or emotional responses to wildlife encounters, can lead to off-site benefits including greater environmental awareness, natural area stewardship and philanthropic support for nature conservation (Packer & Ballantyne, 2012;Powell & Ham, 2008).
Shark diving is a popular activity involving a variety of species, from small requiem sharks (Carcharhinus spp.) to the largest fish in the ocean (i.e.whale shark, Rhincodon typus), and occurs across many countries (Gallagher et al., 2015;Huveneers & Robbins, 2014).
Most studies on the impacts of shark tourism are focused on effects at the population level, without delving further into the possible differences among individuals (Brena et al., 2015).Yet, intraspecific variation in large-scale movements or behaviour is increasingly being documented in sharks (Dhellemmes et al., 2020(Dhellemmes et al., , 2021;;Niella, Butcher, et al., 2021;Niella, Smoothey, et al., 2021), suggesting that individuals may not be equally impacted by anthropogenic activities.Therefore, potential intraspecific variations in the response of sharks to wildlife tourism need to be accounted for to determine whether management regulations are sufficient for all individuals interacting with humans, or whether additional management is required, particularly as a key factor in wildlife tourism sustainability and animal welfare is ensuring operators impact relatively few individuals (Higham et al., 2016;Meyer, Apps, et al., 2021).Changes in conditions may also lead to the development of new regulations; thus, continued monitoring of the species involved in wildlife tourism, such as in Neptune Islands, Australia (Niella et al., 2023), can ensure potential changes in their populations are detected.
Given its emblematic nature and reputation as being responsible for the most shark bites on humans (Riley et al., 2022), the white shark, Carcharodon carcharias, is an iconic species globally targeted by tourists (Gallagher & Huveneers, 2018).Cage diving with white sharks is a popular activity, with operations reported in the United States, Canada, Mexico, South Africa, New Zealand and Australia (Huveneers et al., 2017).Cage-diving operators use a variety of stimuli to attract white sharks near divers located inside an in-water metal cage, including olfactory (minced fishes (berley or chum) and tethered bait), visual (e.g.seal decoys) or auditory (e.g.music) cues (Bruce & Bradford, 2013).Previous studies have shown that these sensory stimuli can affect sharks in various ways, such as altering their residency time (Bruce & Bradford, 2013), fine-scale movement, vertical distribution and activity (Huveneers et al., 2013(Huveneers et al., , 2018)), and influence short-term behavioural patterns (Becerril-García et al., 2019).Sharks can make associations and have been found to show learning behaviour similar to other vertebrate groups, including classical conditioning (i.e.increased frequency interacting with people) and habituation (i.e.resuming their natural behaviours when exposed to humans), and to remember training routines using food rewards (Guttridge et al., 2009;Heinrich et al., 2020;Schluessel & Bleckmann, 2012;Vila Pouca et al., 2020).Studies from both Mexico and South Africa found that most individuals show no conditioning to cage-diving boats (Becerril-García, Hoyos-Padilla, et al., 2020;Laroche et al., 2007).During cage-diving activities, white sharks often display behaviour similar to that associated with feeding (Becerril-García et al., 2019), but their raised activity levels due to the presence of tourism operators are not responsible for significantly higher energy budgets (Gooden et al., 2023).In addition, spatial segregation by sex and maturity stage and seasonal presence within their aggregation sites due to changes in environmental conditions may also influence how white sharks interact with the cage-diving boats (Becerril-García, Martínez-Rinc on, et al., 2020).
Learning, or the adaptive modification of behaviour based on experience, is relevant to virtually every aspect of animal ecology (Pearce & Bouton, 2001).For example, insects learn how to navigate towards food sources by identifying and recognizing physical characteristics of their environments (Collett & Zeil, 2018), while chimpanzees, Pan troglodytes, use social learning to improve their use of tools by observing more skilled conspecifics (Yamamoto et al., 2013).Associative learning occurs when a relationship between two events is established, e.g. between direct contact and visual, olfactory or hearing cues (Fr eon & Dagorn, 2000;Lieberman, 1990).Such types of learning have led to public concerns about the potential links between cage-diving activities and risk of shark bites, due to the belief that the use of bait or berley may result in associative learning between boats or humans and food (N.Hancock, personal communication).Whether conditioned behaviour is occurring is also a key factor used to assess the overall sustainability and impact of tourism operations (Mellor, 2017;Meyer, Apps, et al., 2021).A recent assessment of white shark cage diving in South Australia highlighted that conditioning behaviour was possible, a potentially negative impact of the industry, and was identified as a priority for future research (Meyer, Barry, et al., 2021).
Here, we investigated the associative behaviour of white sharks in response to cage-diving activities in Australia, which use olfactory and visual stimuli (i.e.southern bluefin tuna, Thunnus maccoyii, bait and berley) to attract sharks.Using fine-scale positioning from passive acoustic telemetry to track white shark movements over a 5-year period, we assessed whether conditioned or habituation behaviour could be detected in white sharks interacting with cage-diving boats for prolonged periods (i.e.>10 days).We hypothesized that residency and the amount of time white sharks spend in proximity to cage-diving boat should significantly increase over time if sharks make an association between the boats and the food they provide (classical conditioning) but that residency should decrease if sharks become habituated to berley because of the lack of reward (i.e.food) and reduce their response to the food-based stimulus.Our results have direct implications for the management of the white shark cage diving globally and contributes to our understanding of whether white sharks make long-term associations from interacting with tourism operators.Our framework can also be applied to other wildlife tourism industries for which longterm monitoring data are available.

Study Site
The Neptune Islands Group Marine Park (35 16 0 12 00 S, 136 6 0 0 00 E) is the only place where cage diving with white sharks is allowed in Australia.Located approximately 70 km southeast from Port Lincoln, South Australia, it is composed of two island groups, i.e. the North Neptunes and the South Neptunes (Fig. 1a).The South Australian Department for Environment and Water manages the white shark cage-diving industry, and since 2012, it limits the number of commercial tour operators to three vessels (i.e. two that use food-based attractants and one that uses auditory stimuli), maximum number of days operation (i.e. 12 per fortnight) and the amount of food-based attractant that can be used (i.e. 100 kg/day for each of the two operators with berley licenses).Two operators offer day trips (boat size 16 m and 20 m), whereas the third operator organizes 2e4-day liveaboard trips (boat size 32 m).

Ethical Note
This project was carried out under the Department for Environment and Water permit number Q26292.Tagging was undertaken under Flinders University ethics approval number E398 and E464e17.White sharks were not captured or handled during this study, and the tagging procedures described below are minimally intrusive for these animals (Niella et al., 2022).

Shark Tagging
Acoustic transmitters (Innovasea V16-6H; random interval of 70e150 s) were tethered to a Domeier umbrella dart head using a 100e150 mm long stainless wire trace (1.6 mm diameter) and implanted in the dorsal musculature of sharks using a modified spear gun.Biases in residency estimates can be introduced by targeting specific sharks (e.g.sharks may be more likely to remain in the Neptune Islands) or due to temporal variations in residency (e.g.sharks may be more likely to remain in Neptune Islands during weaning of long-nosed fur seals, Arctocephalus forsteri).To minimize the potential impacts of these biases, we tagged sharks randomly throughout the monitoring period.At tagging, we estimated shark size (May et al., 2019) and recorded the sex whenever possible.We tagged 174 white sharks (180e450 cm total length; mean ¼ 340 cm), including 49 females (180e450 cm total length; mean ¼ 349 cm), 102 males (200e450 cm total length; mean ¼ 338 cm) and 23 individuals of unknown sex (260e450 cm total length; mean ¼ 333 cm) at the North and South Neptune Islands between 14 September 2013 and 28 June 2022 during the monitoring period (Supplementary Table S1).

Acoustic Telemetry Design
We deployed 15 acoustic receivers (Innovasea VR2AR) off the North Neptune Islands in August 2018: eight on the northern side and seven on the southern side (Fig. 1b).These receivers were deployed in a gridded array, with overlapping detection ranges (i.e.~300 m apart) determined by in situ testing.In this approach, the internal clock of each receiver was synchronized within the array, thus allowing the fine-scale position of sharks to be calculated using the time differences between the same acoustic detection captured by multiple receivers (Espinoza et al., 2011).Time synchronization of receivers and calculation of fine-scale positions were performed in the Fathom Position software (version 2.0.3;Innovasea, Boston, MA, U.S.A.).All other analyses were performed in the R software (version 4.3.1;R Core Team, 2023).
Physical and environmental factors are known to impact receiver performance, detection range and positional accuracy (Aspillaga et al., 2019;Huveneers et al., 2016;Smith, 2013).Therefore, we performed positional error corrections separately for each side of the North Neptune Islands (Fig. 1b).These consisted in using linear regressions between the measured horizontal positional errors (HPE m ) of the synchronization transmitters contained within each VR2AR receiver, with the corresponding values or error sensitivity (HPE s ), to obtain the equations representative of the fine-scale positional errors on each side of the North Neptune Islands (Appendix, Fig. A1).We then used these equations to calculate the location errors for each shark fine-scale position based on its corresponding HPE s values (Appendix, Fig. A2).Positions were found to be more accurate at the southern side (minimum error ¼ 8.9 m) compared to the northern side (minimum error ¼ 32.5 m), and all the positions with errors >40 m (i.e.only <1% from all shark fine-scale positions) were excluded from the analyses.All shark locations recorded on the same day of tagging were removed from the data set to avoid any bias from postrelease behaviour, although such an effect is expected to be minimal from white sharks tagged in this area (Niella et al., 2022).We retained 82 305 fine-scale positions from 73 white sharks (42% from all sharks tagged since 2013) after this initial processing (Appendix, Fig. A2), including seven sharks tagged before the deployment of the fine-scale acoustic receivers in 2018 (one in 2014 and six in 2017), with individuals (females ¼ 21, males ¼ 41, unknown sex ¼ 11) ranging between 240 and 450 cm (mean ¼ 334 cm) total length (Appendix, Fig. A3).

Monitoring of Cage-diving Activities
Since 2012, a monitoring programme requires all cage-diving operators to record their arrival and departure time, anchoring locations (Appendix, Fig. A3) and number of sharks sighted using a mobile phone application (Nazimi et al., 2018).A total of 1714 cagediving locations were recorded at the Neptune Islands between 16 November 2018 and 25 July 2022 (Appendix, Fig. A4).We included only North Neptunes locations that were within the range of the fine-scale acoustic array (86.3%) in the analyses.We also removed from the analysis days on which the only operator present had used acoustic attractant (2.3%) as our study focused on white shark response to food-based attractant.
We then used daily times of cage-diving start (i.e.arrival at North Neptunes) and stop (i.e.departure from North Neptunes) to further standardize the data set of fine-scale shark locations.We only retained shark positions recorded during days and times when at least one cage-diving operator was present at North Neptunes and calculated their distances to cage-diving boats.When multiple boats were present at North Neptunes, we calculated each shark distance in relation to all boats present and used the shortest one, to account for white sharks moving between different boat anchoring locations.We then used the distribution of all white shark positions in relation to cage-diving boats to classify shark distances into three categories using a breakpoint analysis with the 'strucchange' R package (Zeileis et al., 2003).This approach uses multiple linear regression models to identify the optimal breakpoint values in a numerical distribution.Using this approach, we categorized white shark locations as (1) near (0e43.2m), (2) medium (43.2e601.1 m) and ( 3) far (>601.1 m) (Fig. 2).We also considered analysing whether shark arrival times were affected by cage-diving boats and whether sharks increasingly anticipated the arrival time of the boats.However, while one company arrived at the Neptune Islands at approximately the same time each day of operation, the other operator's arrival time varied extensively, ranging from 0700 to 1200 hours, and the operator frequently stayed at the tourism site overnight.However, cage-diving activities are mostly limited to daytime hours, with only infrequent charters continuing to bait during a few hours after sunset.Additionally, white sharks were also often detected throughout the night (27.4% of all detections; Appendix, Fig. A5), making it impossible to discern a specific arrival time.

Defining Visit Events
We calculated the elapsed time difference (in days) between consecutive positions for each white shark to identify visit events.Following our previous study, detection intervals longer than 15 days can be used as a good proxy to determine whether a white shark has left the Neptune Islands region (Niella et al., 2023).To investigate whether smaller temporal windows would affect our results (i.e.temporal autocorrelation), we conducted a sensitivity analysis by comparing the model outputs using this 15-day break size (i.e.where consecutive detections exceeding 15 days were considered new visit events) to the smaller break size of 5 days used previously (Bruce & Bradford, 2013).While a 5-day break provided significantly smaller mean residency values (7 days) compared to a 15-day break (14 days) (ANOVA: P < 0.001), most sharks had residency values <30 days independent of the break size used (Appendix, Fig. A6).In addition, we ran the models using both break sizes (see below) and obtained similar outcomes (Appendix, Fig. A7) and percentages of deviance explained (5-day ¼ 14.6%; 15day ¼ 15.6%).Therefore, we used the validated break size of 15 days (Niella et al., 2023) for the residency analysis.

Modelling Approach
Since most sharks (54 individuals, 74%) had residency times less than 30 days, we further restricted our data set to the first 30 days for each new visit to the North Neptunes.The response variable was the daily percentage of time spent in each of the three distance categories.We used generalized linear mixed models (GLMM) to investigate the influence of different sets of temporal and biological variables on the percentage of time spent in each distance category, using binomial families of error distribution.All temporal and biological models included the categorical variables shark identity (ID), visit event and year as random effects.For the temporal model (ran using both 5-day and 15-day breaks; Appendix, Fig. A7), the candidate predictors consisted in the interaction between the distance category (categorical: near, medium, far) and days since arrival at North Neptunes (continuous: 1e30) and the daily number of hours that cage-diving boats spent at the site.The biological models were calculated independently for each distance category, and the candidate predictors consisted in the interactions between the variables sex (categorical: male, female; individuals of unknown sex were removed) and days since arrival in the North Neptunes, and another interaction between the variables sex and total length (continuous: 240e450 cm total length).
Since the previous analyses were limited to the first 30 days when sharks were present at the North Neptunes, we further inspected potential long-term changes in visit duration using another approach.During the study period, white sharks returned to the North Neptunes a maximum of 10 times (i.e.maximum number of visits).Thus, we used their respective residency values to build a matrix, with one column for each visit event (i.e.1e10) per shark, which we then centre-scaled.Since previous studies suggested intraindividual variation in residency times of white sharks (Niella et al., 2023;Schilds et al., 2019), we first investigated intraindividual differences in residency times.We used a clustering analysis with the 'factoextra' R package (Kassambara & Mundt, 2020) to identify groups of sharks with similar residency times.We then assessed whether residency changed over time for each cluster of sharks using linear regression models.All models were visually inspected for normal residual distributions.

RESULTS
Between 2018 and 2022, 64 white sharks (88% of the sharks detected) were detected when cage-diving activities were taking place (Fig. 3a), while nine sharks (12%) were detected only when cage-diving boats were absent from the North Neptunes.From the sharks detected during cage-diving activities, 28 (44%) were present in the North Neptunes in multiple years and for up to 4 years (Fig. 3a).Cage-diving activities most often began between 0900 and 1000 hours (Fig. 3b) and stopped between 1500 and 1600 hours (Fig. 3c), which corresponded to the arrival and departure times of the consistent operator.However, on days when boats were present, most white shark locations occurred between 1300 and 1400 hours (Fig. 3d).On days when cage-diving boats were absent from the North Neptunes, white shark locations peaked around 0800 hours and between 1600 and 1700 hours (Fig. 3e).

Trends in Shark Movements in Relation to Cage-diving Boats
The interaction between the distance to the cage-diving boats and days since shark arrival at North Neptunes significantly influenced the daily proportions of time sharks spent in each distance category (Table 1).The proportion of time white sharks spent within the near and far distance categories significantly decreased over time, while the proportion of time white sharks spent within the medium category increased (Fig. 4, Appendix, Fig. A7).These proportions became significantly different ~10 days after sharks arrived at North Neptunes (Fig. 4, Appendix, Fig. A7).These trends were consistent across sharks, visit events and years (Table 1).However, the number of hours that cage-diving boats spent at the Neptune Islands did not affect the daily proportions of time sharks spent in each distance category (Table 1).The biological GLMMs including the effects of shark size and sex further revealed that the proportion of time spent in each distance category was not significantly influenced by any of these variables (Table 2).

Changes in Visit Duration Over Time
Sharks were grouped into three significant clusters in relation to their residency time in the North Neptunes (Fig. 5a; total deviance explained ¼ 91.8%).Because cluster 3 included only one individual (unknown sex and 370 cm total length) with a single visit of 106 days to the North Neptunes (Fig. 5b), we only applied the linear regression models to sharks from clusters 1 and 2. Sharks from cluster 1 made more visits to the North, but their residency times were usually shorter (mean ± SD ¼ 7.9 ± 11.7 days) than those of sharks from cluster 2 (29.4 ± 34.2 days).Linear regressions revealed that residency times did not differ across visits for sharks from cluster 1 (P ¼ 0.969) or cluster 2 (P ¼ 0.996).
hypothesis of white sharks increasing residency and time in proximity to cage-diving operators.Instead, white sharks showed evidence of habituation, reducing the amount of time spent close to cage-diving operators within 10 days of being at the tourism site.This habituation and reduction in behavioural response to bait and berley was consistent across shark sizes and sexes and was not influenced by the daily amount of time that cage-diving boats spent at the Neptune Islands.
The learning abilities of sharks are varied and range from the ability to solve complex spatial cognitive and discrimination tasks (Aronson et al., 1967;Fuss et al., 2014;Graeber & Ebbesson, 1972)    We included the interactions between sex (F ¼ female; M ¼ male) and days since shark arrival at the Neptune Island (Days) and between sex and total length (TL) in the model as well as the random effect of shark identity (Shark ID), visit event (Visit) and tracking year (Year).We also show the corresponding estimate, standard error, z value and P value for each model variable., 1995;Papastamatiou et al., 2011;Schluessel & Bleckmann, 2005, 2012).Sharks have also been shown to quickly associate various sensory cues (e.g.artificial sounds, smell of natural preys) with food rewards (Heinrich et al., 2020(Heinrich et al., , 2022;;Vila Pouca & Brown, 2018) and engage in social learning (Guttridge et al., 2013;Vila Pouca et al., 2020).Given their learning abilities, and the general capability of animals to make associations when provided with food (e.g. through instrumental, classical or operant conditioning; Wise, 2006), there have been concerns about white sharks learning to associate cage-diving boats with the smell of, or access to, natural prey (e.g.bait and berley used to attract white sharks).However, neither of our hypotheses indicating associative behaviours were supported.This lack of conditioning was observed across all individuals tracked in our study and is likely due to management regulations preventing cage-diving operators to feed white sharks intentionally and limiting the amount of food-based attractant used (cdn.environment.sa.gov.au/marine-parks/docs/white-shark-tour-licensing-policy-gen.pdf;accessed on 4 September 2023).These regulations limit the magnitude (i.e.amount) and frequency (i.e.number of positive trials) of the potential reward (i.e.bait consumed), which influence learning rates (Heinrich et al., 2020;Lauer & Estes, 1955;Muzio et al., 1992).Although white sharks can consume baits when operators are unable to detect rapidly approaching sharks, the bait is most often retracted in time, preventing white sharks accessing food cued by scent.The frequent lack of food rewards and the sharks' inability to access the source of the scents that attracted them to the cagediving boats likely explain why associative behaviour was not observed.It also explains why white sharks spent less time near boats throughout their residency: their response to olfactory cues decreases when they are unable to fulfil the expected energy gain from food that they can sense but are unable to acquire, whereas their energy expenditure increases during bursts of acceleration when attempting to consume bait offered by the cage diving operators (Gooden et al., 2023;Huveneers et al., 2018).
The sustainability and viability of wildlife tourism relies on consistent interactions with tourists while ensuring minimal detrimental impacts to the population targeted by the tourism industry.Feeding of wildlife (either intentionally or unintentionally) is often used to improve visitor experience (Higham, 2012;Meyer, Barry, et al., 2021) but can affect the target animals through changes in natural behaviour, such as increased vigilance behaviour of redcrowned crane, Grus japonensis (Li et al., 2017), predation risk of fish (Patroni et al., 2018) and injuries in bottlenose dolphins (Christiansen et al., 2016).Sharks also modify their behaviour in response to the presence of wildlife tourists when food rewards are used, by reducing their arrival times and increasing their residency times at operation sites (Brunnschweiler & Barnett, 2013;Johnson & Kock, 2006) and interacting with tourism operators more often (Legaspi et al., 2020).While cage-diving activities do affect the behaviour of white sharks in the Neptune Islands in the short term (Huveneers et al., 2018), they have not been found to significantly affect white shark physiology or diet (Meyer et al., 2019).Our results provide further evidence of the sustainability of the cagediving activities in this region, since all sharks resumed their natural behaviour of investigating the tourism boats on each new visit to the Neptune Islands.
Studies from other regions have found that white sharks mostly show no conditioning to cage-diving boats (Becerril-García, Hoyos-Padilla, et al., 2020;Laroche et al., 2007).However, there is evidence of short-term effects, such as some individuals being more likely to interact with the bait than others (Becerril-García et al., 2019;Laroche et al., 2007) and localized increases in activity levels (Gooden et al., 2023;Huveneers et al., 2018).The rapid recovery of white shark natural behaviours (i.e.time spent in proximity to boats returns to normal at the start of each visit) shows that any habituated behaviour is also of short term and restricted to the current residency period.As most white sharks are either transients (detected only for a few days) or temporary residents to the Neptune Islands, with a mean residency of ~12 days (Niella et al., 2023), the impact that the cage-diving industry might have on the behaviour of white sharks is, therefore, minimal and the habituation to the olfactory cue used to attract sharks to boats is of short term (i.e.disappears shortly after sharks leave the tourism site).White sharks spent more time within medium distances (i.e. between 43.2 and 601.1 m) to cage-diving boats through time, suggesting that they did not completely lose interest in the boats or leave the Neptune Islands, but instead, might monitor the boats from a distance (i.e.opportunistic behaviour).
Extrinsic components, such as exposure level, individual experience and environmental context, affect intraspecific variations in animal behaviour (Harding et al., 2019).We purposely tagged individuals with different behaviours (i.e. more or less likely to interact with cage-diving boats) and expected to find some level of intraspecific variation.Indeed, evidence of intraspecific variation in movement patterns has often been documented and may be driven by a range of factors, including individual personality or behavioural syndromes (Milles et al., 2020).Such intraspecific variation has previously been observed in the residency times of white sharks at tourism sites and in relation to their behaviour during cage-diving tourism activities (Becerril-García, Hoyos-Padilla, et al., 2020;Becerril-García, Martínez-Rinc on, et al., 2020).In our study, we observed intraspecific variation in relation to residence time only, while trends in the amount of time spent in proximity to cagediving boats were consistent across individuals, sexes and sizes.This suggests that no white sharks obtained sufficient rewards for classical conditioning to occur and that all sharks were equally likely to show some habituation.However, the relatively small size range of sharks visiting the Neptune Islands (63% of sharks are 3e4 m total length, although smaller and larger sharks do occur) may preclude our ability to test for the effect of size on behaviour.
Cage diving is a valuable tourism activity, both economically (e.g. the South Australian white shark cage-diving industry is worth ~$15 million annually; Huveneers et al., 2017) and socially (engaging hundreds of thousands of people each year; Apps et al., 2018), that can dispel negative myths around white sharks and raise public awareness towards conservation of this vulnerable species (Apps et al., 2017;Gallagher & Huveneers, 2018;Rigby et al., 2019).A previous expansion of the cage-diving industry at the Neptune Islands after 2007 was responsible for increased white shark residency time from a mean of ~10 days in 2001e2002 to ~23 days in 2009e2011 and altered white shark distribution around the Neptune Islands (Bruce & Bradford, 2013;Huveneers et al., 2013).Following changes in practices since 2012, white shark residency in this region has returned to the level prior to the 2007 increase in cage-diving activity (Niella et al., 2022(Niella et al., , 2023)).Therefore, the current management policies, which include limiting the number of operators, days of activity and amount of food-based attractant, can be considered an efficient strategy to reduce the impacts of the cage-diving industry (Niella et al., 2023).These actions may also explain the lack of long-term conditioning of sharks to cage-diving boats, further supporting the suitability of current management practices and the sustainability and acceptability of the industry overall, given the minimal and short-term impacts on animal welfare.In addition, our results should appease public concerns that cage-diving activities may condition white sharks to interact with boats and people more often, thus potentially increasing risk of shark bites.Here, we provide empirical evidence that white sharks quickly become habituated to tourism boats, and therefore, that this tourism activity is unlikely to be responsible for increased risk.

Figure 1 .
Figure 1.Location of (a) Neptune Islands at the coast of South Australia (SA), showing (b) the deployment arrays of the fine-scale acoustic receivers (black circles) in the northern and southern sides of the North Neptunes between September 2018 and July 2022.

Figure 2 .
Figure 2. Distribution of white shark fine-scale minimum distances to the cage-diving boats including their respective distance categories (colour bar) identified by the breakpoint analyses (dashed lines).

FrequencyFigure 3 .
Figure 3. Distribution of (a) white shark fine-scale positions coloured by individual identity (Shark ID) and cage-diving anchoring locations in the North Neptunes between 2018 and 2022.Frequency distributions of position hour for (b) cage-diving start, (c) cage-diving stop, (d) shark locations when boats were present and (e) shark locations when boats were not present.
to the ability to use different orientation strategies and spatial memory systems to navigate during migration(Clermont et al.,

Figure 4 .
Figure4.Generalized linear mixed model of daily proportions of white shark location estimates in relation to cage-diving boats, including the interaction between distance to cagediving boat (Near, Medium, Far) and days since shark arrival at the North Neptunes.The vertical dashed lines and shaded areas represent significant changes in the proportion of time and the 95% confidence intervals, respectively.

Figure 5 .
Figure 5. Cluster analyses of shark residency time as a function of visit events, including (a) significant shark clusters and (b) distributions of residency times as a function of the clusters identified.Median values are indicated by the bold horizontal bar; the lower and upper ranges of the box are the first and third quartiles; whiskers represent the minimum and maximum values.

Figure A3 .
Figure A3.Yearly size distribution of all white sharks tagged between 2014 and 2022 per sex category (Female, Male, Unknown) and detected in the fine-scale array during the present study.

Figure A4 .Figure A7 .
Figure A4.Map of all 1714 cage-diving boats using food-based attractant anchoring positions at North and South Neptunes between 16 November 2018 and 25 July 2022.The red square delimits the area covered by the acoustic receiver array in the North Neptunes, which was used to standardize the cage-diving boat locations during the study period.

Figure A6 .
Figure A6.Differences in distribution of white shark residency times using 5-and 15-day break sizes.Dashed lines and numbers represent mean residency times with each corresponding break size.

Table 1
Temporal generalized linear mixed model of daily proportions of time spent in each distance category in relation to cage-diving boats

Table 2
Biological generalized linear mixed models of daily proportions of time spent in each distance category