Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 1 of 47 1 Inconspicuous, recovering, or northward shift: Status and management of the white shark 2 (Carcharodon carcharias) in Atlantic Canada 3 Bastien, G.1, Barkley, A.1, Chappus, J.1, Heath, V.1, Popov, S.1, Smith, R.1, Tran, T.1, Currier, 4 S.1, Fernandez, D.C.1, Okpara, P.1, Owen, V.1, Franks, B.2,3, Hueter, R.3,4, Madigan, D.J.1, 5 Fischer, C.3, McBride, B.3 and Hussey, N.E.1* 6 7 1 8 Canada 9 2 Integrative Biology, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Marine Science Research Institute, Jacksonville University, 2800 University Blvd N, 10 Jacksonville, FL 32211, USA 11 3 OCEARCH, Park City, Utah, USA 12 4 Center for Shark Research, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, 13 Fl 34236, USA 14 15 16 *Author of correspondence: Nigel E. Hussey. Email: nehussey@uwindsor.ca / Tel: 519 253 3000 17 ext. 4957. 18 19 20 21 22 KEYWORDS: Satellite telemetry; historical observations; species range; range shift; 23 management plan; seasonal site fidelity 1 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 2 of 47 24 Abstract 25 Although white sharks (Carcharodon carcharias) have been considered rare in Atlantic Canada 26 waters, recent sighting records indicate a potentially increasing presence. We combine historical 27 to present sighting data with satellite telemetry tracks of large juvenile/adult white sharks tagged 28 in U.S. (n = 9) and Atlantic Canada waters (n = 17) to show seasonal white shark presence and 29 distribution in Atlantic Canada, returns by individuals over multiple years, and high site fidelity to 30 the region. Telemetry data indicate that white sharks are a more common and consistent occurrence 31 in Canadian waters than previously thought, presenting two potential scenarios: 1) tagging 32 technology is revealing white shark presence that was historically cryptic, and/or 2) a northward 33 range expansion of white sharks in the Northwest Atlantic, potentially due to climate change, 34 population recovery, and/or increasing pinniped prey. Given combined sighting and telemetry data 35 indicate a current need for proactive management of white sharks in Atlantic Canada waters, we 36 propose the basis for a management action plan, addressing conservation priorities, management 37 goals and research incentives while considering the potential for human-shark interactions. 2 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 3 of 47 38 Introduction 39 The distribution and abundance of species are rarely static, but fluctuate through time and space 40 in response to the stochasticity of ecological and environmental conditions and anthropogenic 41 influences (Brown et al. 1996). This is especially true in marine biomes, which are characterized 42 by high habitat connectivity and limited barriers to species dispersal (Macpherson and Duarte 43 1994) and face increasing exploitation rates (Pauly and Zeller 2016). 44 Shifts in species distributions can be inherent life cycle components of an organism as 45 ontogenetic changes in diet and space use (Werner and Gilliam 1984), or modified as a result of 46 environmental changes, disturbances to trophic and community structure, and/or human 47 exploitation (Dunne et al. 2002; Perry et al. 2005; García Molinos et al. 2016). For example, the 48 overfishing and collapse of Atlantic cod (Gadus morhua) in the Northwest Atlantic ultimately led 49 to the expansion of several prey species’ ranges (Mason 2002). In addition, several species 50 distributions have demonstrated marked shifts in response to climate change (Perry et al. 2005; 51 García Molinos et al. 2016). Zooplankton in the North Atlantic and marine fish in the North Sea 52 are shifting rapidly northward in response to rising sea surface temperatures (Beaugrand et al. 53 2009) with the speed and direction of regional climate shifts strongly influencing the direction and 54 magnitude of species’ shifts (Pinsky et al. 2013). However, the impact of these altered species 55 distributions on overall ecosystem function is poorly understood. In order to effectively manage 56 marine species’ and ecosystems, management plans must account for the dynamic nature of our 57 changing oceans and the potential for species’ distribution shifts (Pecl et al. 2017). 58 The white shark (Carcharodon carcharias) is a long-lived, apex predator with globally 59 distributed populations in temperate to tropical waters (Compagno et al. 1997; Huveneers et al. 60 2018). It is considered a highly mobile species that undertakes basin-scale migrations between 3 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 4 of 47 61 near-shore coastal environments and pelagic waters (Bonfil et al. 2005; Jorgensen et al. 2010). The 62 drivers of such mobility are diverse, including movements to aggregate in offshore waters 63 potentially for feeding, mating and gestation (e.g., off the Northeastern Pacific Shared Offshore 64 Foraging Area or ‘white shark café’; Domeier and Nasby-Lucas 2008; and the proposed Northwest 65 Atlantic Shared Foraging Area or NASFA), moving into coastal environments to give birth (e.g., 66 Domeier and Nasby-Lucas 2013), and congregating near prey resources in coastal regions (e.g., 67 seal colonies; Kock et al. 2013). While white sharks are highly mobile, they also display a high 68 degree of homing and seasonal philopatry to known aggregation sites (Domeier and Nasby-Lucas 69 2008; Jorgensen et al. 2010; Anderson et al. 2011; Domeier and Nasby-Lucas 2013). 70 Large mobile predators such as the white shark typically show some level of population 71 connectivity (Bonfil et al. 2005; Taylor and Norris 2010). Mitochondrial DNA analyses, for 72 example, have found some populations to be closely related (e.g., Australia and New Zealand), 73 while others are genetically distinct (e.g., Australia-New Zealand versus South Africa; Pardini et 74 al. 2001; O’Leary et al. 2015). The Atlantic population of white sharks historically included both 75 the South African and the Northwest Atlantic (U.S. and Canada) populations (Andreotti et al. 76 2016). However, mitochondrial and nuclear genetic testing has revealed that Northwest Atlantic 77 and South Africa white sharks are distinct populations, with the Northwest Atlantic population 78 specifically showing signs of a strong genetic bottleneck effect (O’Leary et al. 2015). There is 79 therefore recognized need for proactive management of the North Atlantic white shark population. 80 In Canada, species are managed by the Minister of Environment and Climate Change in 81 partnership with the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) 82 under the framework of the Species at Risk Act (SARA 2002). To be managed and assessed in 83 Canada, a species must be divided into recognizable “designatable units”, defined by COSEWIC 4 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 5 of 47 84 as a “species, subspecies, variety, or geographically or genetically distinct population…where such 85 units are both discrete and evolutionarily significant” (Environment and Climate Change Canada 86 2015). Given previous genetic testing, white sharks observed in Canadian waters are treated here 87 as a designatable unit, distinguishable from the South African population (COSEWIC 2006; 88 O’Leary et al. 2015). While a formal assessment and status report for the Atlantic Canada white 89 shark designatable unit was undertaken more than a decade ago, the species was identified as 90 “endangered”, albeit rare, in Atlantic Canada waters, based on only 34 observations of white sharks 91 off eastern Canada since 1874 (COSEWIC 2006). As a result, no action plan was established. 92 In the current study, we combine available sighting data (historical to present) on white 93 sharks with recent satellite telemetry efforts in U.S. and Atlantic Canada waters to update the 94 current status and distribution of this species in Canadian waters. We identify potential drivers of 95 the occurrence of white sharks in Atlantic Canada and propose avenues of research for improved 96 understanding of regional population dynamics. Finally, under the scenario of a relatively high, 97 and/or potentially increasing presence of white sharks in Canadian waters, we present first 98 considerations for an action plan for this species, given that the last review by COSEWIC was 99 undertaken nearly 15 years ago. 100 101 METHODS 102 Collation of historical to present white shark sightings data in Atlantic Canada. 103 A systematic literature search was conducted to identify all relevant papers on the sighting or 104 occurrence of white sharks in Atlantic Canada using standard academic and web-based search 105 engines. Supplementary files from two key papers (MacPherson & Myers 2009 and Curtis et al. 106 2014) and the COSEWIC white shark assessment (COSEWIC 2006) provided the majority of 5 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 6 of 47 107 historical records up until 1992 (n = 37). A recent report provided updated sightings between 1992 108 and 2016 (n = 23; DFO (2017)). All records were verified against the systematic literature 109 search/internet reports. Associated metadata tied with shark sightings from the three main data 110 sources were standardized and observations ranked in terms of level of confidence in recorded data 111 (i.e., if estimated size of animal was realistic; Supplementary Table S1). Duplication of sightings 112 were checked and removed as necessary. 113 114 Shark capture, handling and satellite tag attachment 115 White sharks were captured by hook-and-line methods consisting of either modified individual 116 drumlines or rod-and-reel with a baited 20/0 zero-offset circle hook, which was crimped to cable 117 leader embedded inside polypropylene rope to minimize damage to the animal. A bite-blocker, 118 consisting of a bamboo cross and/or bullet floats attached to the leader approximately 25 cm from 119 the hook, prevented the bait from being swallowed and ensured the hook was set in the corner of 120 the mouth. For targeting very large sharks (>400 cm TL) a baited 27/0 zero-offset circle hook was 121 used. 122 Once caught, sharks were guided to the research vessel (M/V OCEARCH – 38m length) 123 by a fishing crew operating from an 8.5 m fiberglass boat, using buoys attached to the leader as 124 necessary to maintain the shark swimming near the surface. Each shark was then guided on to a 125 submerged hydraulic platform (capability to lift 34,000 kg) and the lift was raised out of the water, 126 allowing the shark to settle on the platform. The shark was provided with flowing seawater via a 127 PVC tube and mouthpiece, a wet terrycloth towel was placed over the shark’s eyes and gill slits to 128 minimize stress, seawater was poured on the body to keep the skin moist, and a tail rope was 129 attached to limit sudden movements. Morphometric measurements, and collection of samples for 6 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 7 of 47 130 additional projects were then taken while the shark was equipped with satellite and acoustic 131 electronic tags. 132 Smart Position and Temperature (SPOT) satellite tags (Wildlife Computers Ltd, Redmond, 133 Seattle) were attached on the leading edge of the shark’s first dorsal fin by drilling four holes 134 through the fin with a cordless electric drill and attaching the tag with nylon bolts, stainless steel 135 locknuts and plastic spacers. The attachment hardware is designed to retain the tag for its battery 136 life, after which the hardware fails and the tag detaches. In all but one case (Shark ID 25), sharks 137 were large enough to attach a five-year duration SPOT (WC model SPOT-257); shark 25 was 138 outfitted with a one-year SPOT (WC SPOT-258) due to permit restrictions (Table 1). All tags were 139 previously coated with an anti-fouling compound to reduce biofouling of the tags while attached 140 to the animals. 141 Sharks were held on the hydraulic platform for ~15 - 20 minutes. For most of that period 142 sharks rested on their left or right side depending on research procedures, then were turned upright 143 onto their abdomen for SPOT attachment prior to release. Animal condition was monitored 144 throughout the entire period by a marine veterinarian using objective behavioral and physiological 145 criteria. At the conclusion of the protocol the platform was lowered, sharks swam off and post- 146 release behavior was monitored. All activities were undertaken according to DFO Canada, U.S. 147 NOAA, and state and provincial permits throughout the range of the study. All procedures were 148 approved by the Jacksonville University IACUC and/or by IACUCs of individual collaborating 149 organizations. 150 151 Telemetry data processing and analyses. 7 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 8 of 47 152 ARGOS location data derived from SPOT tags were extracted for each white shark that entered 153 Canadian waters, with a focus solely on data that fell within or nearby the Canadian Exclusive 154 Economic Zone (EEZ). Raw location data were first mapped to identify and remove locations that 155 fell on land, and then a speed filter applied to remove unrealistic locations (argosfilter). A swim 156 speed of 5 m/s was assumed for the filter, a liberal estimate, given the maximum swim speed of 157 white sharks is ~2 m/s (Watanabe et al. 2019) and the adopted state-space model (SSM) is intended 158 to control for measurement error. Prior to running the SSM, tag transmission data for each shark 159 were divided into segments based on the time difference between locations to ensure there were 160 no time gaps (i.e., periods without transmissions) > 20 days. Given that white sharks can undergo 161 periods without surfacing, this resulted in multiple tracks for individual sharks in instances where 162 this conditions was met (Supplementary File S1 and Table S2). For white sharks with < 12 163 locations in Canadian waters, data for these individuals were not included in the SSM given it is 164 not informative when based on few data. Raw transmission data, following the initial swim speed 165 filter and removal of land transmissions, were used to document the tracks of these animals. 166 The crawl package was used to fit a continuous-time correlated random walk state-space 167 model (hereafter SSM) to each white shark track, incorporating transmission location error based 168 on ARGOS diagnostic data. The ARGOS ellipse-based ‘location error’ was used when feasible, 169 and Argos ‘location class’ when error was not available. The first step of the SSM predicts the 170 most likely daily locations for each shark based on raw transmission and error data. Given the fact 171 that coastlines in Atlantic Canada are highly complex (i.e. multitude of islands) and the white shark 172 commonly undertakes movements in close proximity to the coast, the second step of the SSM 173 reiterates predicted tracks that cross land masses to circumnavigate the most likely coastal contour 174 that constitutes the shortest distance movement. The final predicted daily locations per individual 8 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 9 of 47 175 were then plotted by month of occurrence in addition to raw transmission data for sharks with <12 176 transmissions to examine the geographical and seasonal extent of white shark occurrence within 177 Atlantic Canada and near the Canadian EEZ. 178 To further visualize the seasonal occurrence of white sharks within Atlantic Canada, the 179 percent days detected in the Canadian EEZ by month was calculated for each individual shark 180 using raw ARGOS locations (excluding those that fell on land or with a 0 or Z ARGOS location 181 class). Raw filtered data were used to allow direct comparisons among all sharks, including those 182 with limited geolocations to run the SSM. Each ‘detection day’ (defined as a day where one or 183 more transmissions with valid locations were received for a shark) that fell within Canada’s EEZ 184 were summed for each individual per month. The total was then converted to a percentage based 185 on the total number of days within that month. For sharks that returned to Canada across multiple 186 years, percent (%) days detected individual-1 by month was calculated as an average across years 187 present. 188 To identify core areas used by white sharks in Atlantic Canada and to provide a visual 189 comparison between historical sightings and telemetry-derived locations, a kernel density plot of 190 the SSM-corrected geolocations was generated using the geoprocessing tool Kernel Density in 191 ArcGIS (ESRI, 2019). Individual geolocations were weighted equally, and the output cell size set 192 to 9.2 km, with a search radius determined by Silverman’s Rule of Thumb. The output density 193 within each cell is a summation of the kernel surfaces that overlap that cell, resulting in higher 194 values where numerous shark geolocations occur. 195 196 RESULTS 197 Historical to present sighting data 9 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 10 of 47 198 A total of 60 historical Atlantic Canada white shark observations from 1872 to 2016 were compiled 199 from the literature. Of the 60 reported observations, 27 were sighted by observers, 26 were caught 200 in fishing gear, and the remaining 7 were inferred from teeth left in fishing gear as well as wounds 201 inflicted on seals and porpoises. 202 The prevailing perspective that white sharks are rare seasonal visitors to Atlantic Canada 203 waters is based on historically infrequent sightings, which occurred every 5 to 10 years (Fig. 1a; 204 McPherson and Myers 2009; Curtis et al. 2014), and inferential data such as slash wounds on seal 205 carcasses, indicating seal predation (Lucas and Natanson 2010). Although a 3- to 950-fold decline 206 in the white shark population within Atlantic Canada waters between any reference year from 207 1874–1988 and 2005 was estimated (McPherson and Myers 2009), recent sighting data suggest an 208 increase in the occurrence of sharks since 2008, with a peak number of individuals recorded in 209 2016 (n = 9; Figure 1a). These sightings data indicate that white shark length (estimated total 210 length; TL) in Atlantic Canada waters ranges from ~2–6 m (mean  SD = 3.95  1 m; Fig. 1c, 211 Supplementary Table S1; unauthenticated lengths excluded) including older juvenile, sub-adult 212 and mature animals. Sightings (n = 29; 48%) peaked in August, indicating seasonality of white 213 shark presence (Fig.1b). In addition, sightings indicate white sharks primarily occur in the Bay of 214 Fundy (n = 28), off the coast of southwest Nova Scotia (n = 15), and off Sable Island (n = 3; Fig. 215 2), with an average of 2 sightings year-1 across years in which sharks were observed (Fig. 1a). 216 Aside from these hotspot areas, sightings of white sharks have occurred as far north as 217 Newfoundland and on the coast of Québec along the St. Lawrence seaway (Fig. 2; McPherson and 218 Myers 2009). 219 220 Satellite telemetry data 10 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 11 of 47 221 Between 2013 and 2019, a total of 18 large juvenile, sub-adult and adult white sharks were 222 equipped with Smart Position or Temperature Transmitting Tags (SPOTs; Wildlife Computers 223 Ltd, Redmond, Seattle) in U.S. Atlantic waters during OCEARCH expeditions (off Massachusetts, 224 n = 11; South Carolina, n = 5; and Florida, n = 2; TL range: 2.5–4.9 m; Table 1). Nine of these 225 sharks (50%) entered Canadian waters with derived geolocations distributed across the majority 226 of coastal and offshore waters within the exclusive economic zone (EEZ) south of Newfoundland 227 (Fig. 3a) and entering the high seas. Tag transmissions in Atlantic Canada occurred predominantly 228 between the months of June and February; seven individuals were present between June and 229 November, three individuals were recorded in December, two sharks in January and one shark in 230 February (Fig 3a,e; Supplementary Table S1). Three individuals returned to Atlantic Canada over 231 two years (Shark ID 5 [male; 3.79m Total Length (TL)]; Fig. 3c, Shark ID 2 [female; 3.84m TL 232 and Shark ID 4 [male; 3.00 m TL]; Supplementary Table S2), while a large female shark (Shark 233 ID 1 [4.42m TL]) returned across three years (Table 1; Supplementary Table S2). 234 In 2018, a total of six white sharks were caught and tagged at West Ironbound Island, Nova 235 Scotia, during 17 days of active fishing between 20 September and 9 October (four additional 236 sharks were observed, but were not captured and another was captured, measured, sampled and 237 released without a tag due to permitting restrictions at that time; catch per unit effort [CPUE] = 238 0.0076 sharks hook-hour-1; Supplementary Table S3). In 2019, a total of eleven sharks were 239 captured and tagged at Scatarie Island in Cape Breton (n = 3) and west Ironbound Island (n = 8) 240 during 19 days of active fishing between 14 September and 4 October (five additional sharks were 241 observed, but not captured; estimated CPUE = 0.0084 sharks hook-hour-1; Supplementary Table 242 S3). Sharks captured in Atlantic Canada included both large juveniles, sub-adults and mature 243 animals (TL range: 2.5–4.3 m) and both sexes (6 females and 11 males; Table 1). White shark tag 11 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 12 of 47 244 transmission data over the two-year period were centered around southern Nova Scotia, including 245 the Bay of Fundy (Fig. 3b and accepting the bias associated with animals being captured and 246 tagged in this location). All six white sharks tagged off Nova Scotia in 2018 returned to the region 247 in 2019 (Supplementary Table S2). Sharks demonstrated site fidelity, with shark ID 10 (male; 248 2.74m TL) returning to the southern peninsula of Nova Scotia (Fig 3d), shark ID 12 (female; 4.25m 249 TL) returning to the Bay of Fundy, and shark ID 9 (male; 3.90m TL) detected < 3 km from its 250 original capture location 10.5 months post-release (recorded via pop-off location of a pop-up 251 archival satellite tag [PSAT; Wildlife Computers Ltd, Redmond, Seattle]). When considering only 252 the return year (i.e., removing bias associated with capture/tagging, and the potential for sharks to 253 migrate out of a region post-capture), sharks were present in Atlantic Canada between June and 254 October inclusive, with the highest number of individuals detected in July and August (Fig. 3e). 255 White sharks remained on average 45 ± 47 days (mean ± SD; range: 1 – 119 d; n = 6); however, 256 there was evidence of only two sharks exiting Canadian waters within this timeframe, suggesting 257 this likely does not encompass the entire period sharks were present within Atlantic Canada waters. 258 Combined, U.S. and Canada-tagged white sharks entered and exited the Canadian EEZ via 259 both continental shelf and pelagic waters (Fig. 3a, b). The focal hotspot of white shark occurrence, 260 based on kernel density estimation of interpolated track data, encompassed the coastal region along 261 the southeastern coast of Nova Scotia and extending in to the Bay of Fundy, an area where a large 262 number of historical sightings were recorded (Fig. 2). A secondary hotspot occurred in southern 263 coastal and offshore waters around Newfoundland including the Grand Banks (Fig 2, 3a and 3c). 264 The hotspot for the latter location, however, was influenced by intense tracks of a few individual 265 sharks. 266 12 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 13 of 47 267 DISCUSSION 268 The size range of white sharks, timing of occurrence, and focal areas used in Atlantic 269 Canada expands on initial tagging data presented by Skomal et al. (2017) for sharks tagged off 270 Massachusetts. The recent, increasing trend in sighting data of white sharks in Atlantic Canada 271 also matches that reported in Massachusetts and the US north Atlantic (Skomal et al. 2012; Curtis 272 et al. 2014). The frequency of U.S.-tagged sharks entering Canadian waters, and the successful 273 targeted capture and tagging of multiple white sharks off Nova Scotia over two consecutive years, 274 indicate seasonal, inter-annual presence of white sharks in Canadian waters and higher regional 275 frequency and abundance than previously thought. 276 277 Distribution and population trends of the white shark in the northwest Atlantic 278 Until recently, our understanding of white shark distribution in U.S. Northwest Atlantic waters 279 relied mostly on data collected through opportunistic sightings and catches (Casey and Pratt 1985; 280 Curtis et al. 2014). White shark sightings primarily ranged from New England to Florida in water 281 temperatures between 14–23°C, with most restricted to the continental shelf (<200 m depth; Curtis 282 et al. 2014). Of sightings recorded in the Gulf of Mexico, the majority occurred in winter and 283 spring between January and June (Casey and Pratt 1985; Curtis et al. 2014). This contrasts with 284 sightings in Atlantic Canada, which primarily occur between May and September (Fig. 1b). 285 Collectively, these data suggest that white sharks move to waters off the southeastern U.S., with 286 some moving into the Gulf of Mexico, during the winter and early spring when water temperatures 287 drop below 22°C in the Northwest Atlantic (Adams et al. 1994). These marked seasonal 288 movements have recently been verified using satellite telemetry (n = 31 individuals tagged with 289 PSATs off Cape Cod, Massachusetts and n = 1 off Jacksonville, Florida) (Skomal et al. 2017). 13 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 14 of 47 290 White shark populations in the U.S. North Atlantic are reported to have declined 291 significantly through the 20th century (Baum et al. 2003; but see Burgess et al. 2005). Recent 292 evidence, however, suggests that the population has been recovering since the early 1990s (Curtis 293 et al. 2014), with a 26% increase in shark observations off Massachusetts between 1990 and 2009, 294 corresponding with the recovery of the grey seal (Halichoerus grypus) population (Skomal et al. 295 2012). The population recovery of white sharks off Massachusetts is circumstantially corroborated 296 by the recent increase in Atlantic Canada sightings between 2010–2016 (Fig. 1a). 297 298 Potential scenarios for current white shark occurrence and abundance in Canadian waters 299 The apparent abundance and/or distribution of white sharks in Atlantic Canada (Fig. 2) presents 300 two alternative, but not mutually exclusive, scenarios: 1) white sharks have been historically 301 abundant seasonally in Canadian waters, and recent focused studies and technological advances 302 have allowed for research to demonstrate this; or 2) white shark abundance and/or residency 303 duration in Canadian waters has increased. A northward range expansion could be related to 304 multiple factors, including warming Canadian waters due to climate change, population recovery, 305 and/or increased regional prey abundance. 306 The previously low number of white shark sightings in Atlantic Canada waters could be 307 due to poor or incomplete historical data (Curtis et al. 2014). Lack of sightings may relate to 308 inadequate sampling in certain habitats (remote or difficult to access areas, e.g., offshore waters) 309 or depths (e.g., Skomal et al. 2009), public inability to correctly identify white sharks (e.g., Rankin 310 et al. 2007), or poor environmental conditions that result in low sighting accuracy and 311 observational effort (e.g., Theberge and Dearden 2006; Rankin et al. 2007). In recent years, the 312 general public has become more involved with the scientific community through citizen science 14 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 15 of 47 313 programs (Silvertown 2009; LaRue et al. 2019). These programs are promoting the rapid growth 314 of megafauna sighting datasets with greater spatial coverage (i.e. increased spatio-temporal effort; 315 Devictor et al. 2010; LaRue et al. 2019) for numerous pelagic species (e.g., minke whales, Rankin 316 et al. 2007; and manta rays, O’Malley et al. 2013). In addition, fishing methods have become more 317 efficient over the past three decades (Kennelly and Broadhurst 2002), covering larger areas and 318 increasing in intensity, resulting in higher levels of shark bycatch (Dulvy et al. 2014; Queiroz et 319 al. 2019). Based on compiled shark sightings between 1872 and 2016, “free swimming” sharks 320 were reported more frequently in earlier years, while sharks reported as bycatch were more 321 common in later years (Supplementary Table S3). The ability to track white sharks for multiple 322 years with electronic tagging technology far surpasses the ability to otherwise observe white 323 sharks, which seem to be particularly cryptic in Canadian waters. This presents the possibility that 324 tag-demonstrated yearly aggregations of white sharks in Atlantic Canada may have been occurring 325 over historical timeframes, as confirmed historical sightings date back to 1872. This underscores 326 the importance of telemetry studies, since a large, highly mobile, predatory shark may have been 327 historically abundant in Canadian waters, yet considered ‘rare’ simply due to our inability to 328 observe them. 329 A northward range shift or expansion of habitat use by Atlantic white sharks is also 330 possible, which may be partially explained by climate change. White sharks are most frequently 331 sighted in Canadian waters during summer months (Fig. 1b), when the southerly waters of the U.S. 332 are above the sharks’ preferred temperature range of 14–23°C (Curtis et al. 2014). Climate change 333 is a known driver of marine fish redistributions, particularly in areas experiencing rapidly warming 334 temperatures (Perry et al. 2005; Cheung et al. 2009; Pinsky et al. 2013). In North Atlantic waters, 335 sea surface temperatures have increased by 0.11°C decade-1 (IPCC 2014), triggering changes in 15 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 16 of 47 336 abundance, range, phenology, and body size of local marine fauna (Kavanaugh et al. 2017), and is 337 projected to further increase by 1.4–5.8°C over the next century (Arbic and Brechner Owens 2001; 338 Belkin 2009; Taboada and Anadón 2012; Saba et al. 2016). An increase in Atlantic Canada white 339 shark sightings in recent years may therefore be the result of white sharks seeking cooler northern 340 waters during the warm summer months (Fig. 1a; Day and Fisher 1954; Mollomo 1998; Turnbull 341 and Dion 2012). A white shark distribution shift may also be influenced indirectly by climate 342 change due to shifts in prey abundance in response to changing water temperatures (Robinson et 343 al. 2009). 344 Such effects of climate change on predator distribution ranges have been well documented. 345 For example, sightings of the striped dolphin (Stenella coeruleoalba) off northwest Scotland have 346 doubled since 1998 as a result of a northward movement, replacing the historically dominant 347 white-beaked dolphin in the region (MacLeod et al. 2005; MacLeod 2009). Similarly, the gray 348 whale (Eschrichtius robustus) was recently recorded in the Mediterranean Sea (Scheinin et al. 349 2011). Marine ectotherms, such as demersal fish assemblages of cod, anglerfish, and snake blenny 350 are also experiencing northward range shifts (Perry et al. 2005), while climate-driven alterations 351 in migratory routes and spatial distribution have been noted in regional endotherms such as the 352 Atlantic bluefin tuna (Thunnus thynnus) (e.g. Robinson et al. 2009). In the Northeast Atlantic, 353 killer whales (Orcinus orca) have moved northward from the Norwegian Sea into Arctic waters in 354 pursuit of northward shifting prey (Moore and Huntington 2008). It is plausible that Atlantic white 355 sharks may be responding to similar prey distribution shifts driven by climate change. 356 The apparent increase in white sharks in Atlantic Canada waters could also result from 357 either a population recovery due to effective conservation measures in the U.S. and/or a response 358 to increasing prey abundance, i.e. driven by recovering seal populations (Bowen et al. 2003). Four 16 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 17 of 47 359 species of seal are commonly found in eastern Canadian waters, all documented prey of white 360 sharks. Two species of seal are resident year-round: the harbour seal (Phoca vitulina) and the grey 361 seal (Dubé et al. 2003). The harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) 362 are migratory and can be found in eastern Canada waters from December to May (Lucas et al. 363 2003; Dubé et al. 2003). The two resident seal populations, harbour and grey seals, have both 364 experienced population growth and recovery in recent decades. 365 White shark predation on harbour seals in the Maritimes has been reported, particularly 366 around Sable Island, Nova Scotia (Boulva and McLaren 1979; Brodie and Beck 1983), with 367 predation typically intensifying during the late summer and early autumn months (Boulva and 368 McLaren 1979). Historically, the harbour seal population in the region has fluctuated through time, 369 though the overall trend indicates an increase in population from 1949 to present (Hammill and 370 Stenson 2000; DFO 2016). Following the termination of a harbour seal hunt and bounty program, 371 which was in place until the early 1970s (DFO 2016), abundance of seals increased from ~23,000 372 in the 1990s to ~32,000 in 1996 (Hammill and Stenson 2000). A more recent 2010 minimum 373 estimate of the total population, including all ages, is between ~8,000–12,000 individuals on Sable 374 Island, ~4,000–5,000 in the Gulf and estuary of the St. Lawrence, and ~4,000–7,000 in the Bay of 375 Fundy (Hammill et al. 2010); DFO currently estimates there to be ~20,000–30,000 harbour seals 376 in Atlantic Canada (DFO 2016). While sightings of sharks actively preying on harbour seals are 377 still relatively rare (Day and Fisher 1954; Turnbull and Dion 2012), there has been a noted increase 378 in harbour seal carcasses and an increase in seals with wounds (Lucas and Stobo 2000; Lucas and 379 Natanson 2010). The grey seal, an important prey species for white sharks off Massachusetts, has 380 experienced exponential population growth since 1960, from ~13,000 to 410,000 in 2010 (Skomal 381 et al. 2012). A 2014 population modelling study based on survey data of the northwest Atlantic 17 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 18 of 47 382 grey seal populations on Sable Island, coastal Nova Scotia, and the Gulf of St. Lawrence during 383 the breeding season found that there has been a continuous increase in population size over time, 384 with an estimated current total population of ~505,000 (Hammill et al. 2014). 385 Marine apex predators such as killer whales have been documented to increase the 386 probability of calving in response to prey abundance (Ward et al. 2009). It is therefore possible 387 that with greater prey availability, white sharks are experiencing a similar increase in fecundity 388 and survival rates. An increase in shark sightings in Atlantic Canada due to an increase in the local 389 seal population would mirror that observed in Massachusetts (Skomal et al. 2012). 390 391 Proposed Action Plan for White Shark Conservation and Management in Atlantic Canada 392 White sharks have not been considered a species in need of active management in Canada 393 (COSEWIC 2006). However, historical to present sightings and recent telemetry data presented 394 here demonstrate a substantial, regional and seasonally consistent white shark presence in Atlantic 395 Canada. We recommend a precautionary approach to develop a management plan for white sharks 396 in Atlantic Canada, one that considers adaptive conservation measures in the face of climate 397 change (Pecl et al. 2017), identifies knowledge gaps and research priorities, and assesses current 398 legislation protecting this species. Successful management of the white shark will balance public 399 opinions on its presence and conservation in Atlantic Canada to ensure responsible approaches to 400 human-shark interactions and anticipate the potential for human-shark conflicts (Simpfendorfer et 401 al. 2011; Christie et al. 2017). We outline a proposed action plan that includes the following 402 components; (1) prioritizing improved public awareness and education of white shark conservation 403 issues and perception of the species; (2) quantifying multi-year distribution, seasonality, 404 population size, and environmental health of white sharks in Atlantic Canada through focused 18 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 19 of 47 405 research efforts; (3) promoting/enforcing responsible fisheries management practices; and (4) 406 establishing relevant protective legislation in Canadian EEZ waters with consideration of the need 407 for marine protected areas relevant to white shark core habitat use and identifying shark-human 408 interaction hotspots (Table 2). 409 410 1. Prioritizing public awareness 411 The public perception of white sharks is often negative due to attacks on humans and anti-shark 412 media, leading to reduced support for conservation actions (Muter et al. 2013; Bornatowski et al. 413 2019). In terms of fatal shark attacks on humans when the species of shark can be identified, white 414 sharks are responsible for the most fatalities (ISAF 2018). This may lead to support for lethal 415 measures for shark control following serious human-shark interactions (Pepin-Neff and Wynter 416 2018). In Australia, however, there has been overwhelming public support for non-lethal measures 417 of shark control following campaigns to educate the public of conservation issues and potential 418 actions to mitigate conflicts (Pepin-Neff and Wynter 2018). Therefore, increased education is 419 necessary to raise public awareness for shark conservation and to foster positive public shark 420 perceptions in Canada (Simpfendorfer et al. 2011; O’Bryhim and Parsons 2015). Following recent 421 lessons learned in Cape Cod as a result of direct human-white shark interactions, it will be prudent 422 to both implement more stringent public safety measures in identified hotspots (e.g. increased life 423 guard presence, relevant first aid training, beach medical response supplies and signage and safety 424 protocols) and to consider technology-based shark mitigation measures (see Woods Hole Group 425 2019 for detailed recommendations). 426 427 2. Quantifying population distribution and size 19 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 20 of 47 428 Current distribution and abundance data for the white shark in Canadian waters 429 inadequately represents its true range and seasonality, as it is based primarily on data collected 430 through rudimentary sighting techniques (Curtis et al. 2014). Telemetric approaches (i.e. satellite, 431 acoustic and biologging tags) can provide accurate, continuous location data on the spatial and 432 temporal distribution of white sharks in Canadian waters, allowing researchers to more accurately 433 determine movement behaviors, monitor change and predict future patterns (Bonfil et al. 2005; 434 Hussey et al. 2015), and also to assess survivorship rates and population size (Block et al. 2019; 435 Lees et al. In revision). The use of PSATs with integrated pressure/temperature sensors deployed 436 on four Canadian white sharks to date as part of the OCEARCH program will provide diving 437 profiles of individuals, with associated ambient temperature data, to understand the vertical 438 thermal regimes encountered. These data will further our understanding of the physiology and 439 ecological role of this species in Canadian waters and complement current efforts underway by 440 DFO to derive PSAT data for this species (two tags deployed to date). Overall, movement data 441 (e.g. increased sample size and long-term monitoring) and advanced techniques (e.g. kernel 442 density estimators that account for autocorrelation; Fleming and Calabrese (2016)) will build on 443 these initial findings to allow continued assessment of hotspot regions (vertical and horizontal) 444 that can be managed in a sustainable manner for both shark and human needs (Heupel et al. 2015). 445 Specifically, with increasing white shark abundance, these data will highlight coastal regions 446 where there is the potential for high human-shark conflict and allow experts to assess the current 447 status of marine protected or conservation areas and if considered necessary designate new areas 448 appropriate for white shark management. Consideration of new conservation or marine protected 449 areas, however, must involve consultation with all stakeholders that could be potentially impacted. 450 In addition, studies of the environmental health of white sharks in Atlantic Canada are required to 20 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 21 of 47 451 assess population fitness and resilience to ongoing climate change and environmental threats such 452 as marine pollution. Understanding the ecological role of this apex predator species, through 453 improved knowledge of predator-prey interactions (via direct observation and biotelemetry 454 techniques such as biologging) and the application of chemical tracers (e.g. stable isotopes and 455 fatty acids) to document diet and trophic shifts will be needed for accurate ecosystem assessment 456 and management. National and provincial funding for focused white shark research from research 457 council, government, and non-government sectors should be prioritized to address knowledge gaps 458 and to enhance conservation and management efforts. 459 460 3. Promoting responsible fisheries 461 Recreational and commercial fishing can negatively impact marine organisms at all trophic levels 462 (Pauly et al. 1998; Cooke and Cowx 2004; Pauly and Zeller 2016). Sharks are particularly 463 susceptible to fisheries exploitation due to late ages of maturity, slow growth rates, and low 464 fecundity (Morgan and Burgess 2007; Dulvy et al. 2014), with estimated catch rates (including 465 bycatch) often exceeding rebound rates and contributing to population declines (Worm et al. 2013). 466 Certain fishing gears result in increased susceptibility of accidental capture of larger individuals, 467 particularly pelagic longlines (Oliver et al. 2015; Queiroz et al. 2019). While white sharks are not 468 a species typically considered at risk of high bycatch in commercial fisheries (but see Baum et al. 469 2003), accurate data to assess this are not available. Following a precautionary approach, it will be 470 advisable for managers to work closely with the fishing industry to establish protocols for 471 accurately reporting white shark bycatch (e.g., location, date, basic data on size and sex) (Glass et 472 al. 2015). Moreover, given the increasing presence of white sharks in Atlantic Canada, it would 473 seem prudent to consider options for modifying fisheries gear to limit white shark bycatch, and to 21 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 22 of 47 474 establish handling and release protocols to minimize mortality if encountered. Continuing work 475 on mitigating shark bycatch in Atlantic Canada waters following initial trials (Godin et al. 2013) 476 is required for other large pelagic species (e.g. blue [Prionace glauca], shortfin mako [Isurus 477 oxyrinchus] and porbeagle [Lamna nasus]) as well as white sharks. For recreational fisheries, 478 targeting of the species should not be allowed in either recreational or commercial fisheries, though 479 incidental catch-and-release may occur. 480 481 4. Relevant species protective legislation and protected areas 482 The responsible management of white sharks in Atlantic Canada is the obligation of several 483 regulatory bodies. These include international agencies and treaties such as the International Union 484 for Conservation of Nature (IUCN), the Northwest Atlantic Fisheries Organization (NAFO), 485 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), 486 Convention on Biological Diversity (CBD), and Convention on Migratory Species of Wild 487 Animals (CMS). At the federal level in Canada, the Committee on the Status of Endangered 488 Wildlife in Canada (COSEWIC), Species at Risk Act (SARA), Department of Fisheries and 489 Oceans (DFO), Environment and Climate Change Canada (ECCC), and the Canadian Endangered 490 Species Conservation Council are responsible for regulations governing wildlife. In addition, non- 491 governmental organizations, such as the National Resources Defense Council (NRDC), World 492 Wildlife Fund (WWF), Wildlife Conservation Society (WCS) and Sharks of the Atlantic Research 493 and Conservation Centre (SHARCC) could play key roles advocating for the management of white 494 sharks during the public consultation in the COSEWIC and SARA listing process. OCEARCH, a 495 U.S.-based nonprofit research and education organization, has already made significant inroads in 496 outreach to the Canadian public through two expeditions to Nova Scotia in 2018-2019 during 22 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 23 of 47 497 which people were able to visit the research vessel and speak with staff over scientific activities 498 underway. In addition, OCEARCH provides open access to resulting white shark satellite tracks 499 through their website (www.ocearch.org) and OCEARCH Tracker free app for smartphones. 500 Effective communication and collaboration among all stakeholders will be essential to ensure the 501 successful implementation of a proactive management strategy for white sharks in Atlantic 502 Canada. 503 The current state of regulations and associated legislation for white sharks in Canadian 504 waters is limited. In the early 2000s, CITES listed the white shark in Appendix II, which requires 505 close monitoring of trade in meat and by-products (e.g. fins, jaws). In U.S. federal waters, white 506 sharks are on the “prohibited” species list and cannot be retained, although there are no regulations 507 against 508 www.fisheries.noaa.gov). While the IUCN and DFO consider the white shark vulnerable (Rigby 509 et al. 2019) and endangered in Atlantic Canada waters (COSEWIC 2006), respectively, currently 510 no federal or provincial laws directly protect this species (COSEWIC 2006). This contrasts with 511 the Pacific population of white sharks that have limited protection, with laws preventing hook- 512 and-line fisheries from keeping any sharks except spiny dogfish (Squalus acanthias; COSEWIC 513 2006). Considering the consistent seasonal occurrence of white sharks in Atlantic Canada 514 demonstrated here, exploration of effective and preemptive management of this species beyond 515 current legislation with relevant stakeholders is a necessity. Quantifying white shark spatial 516 overlap with current marine conservation areas and identifying risk areas based on proximity of 517 white sharks to recreational and commercial human population centers and core water usage areas 518 will also be necessary to sustainably manage this iconic species. targeting the species in catch-and-release 519 23 recreational fisheries (see Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 24 of 47 520 Conclusion 521 Sighting and satellite telemetry data indicate a potential recent increase, and apparent seasonal 522 abundance, of white sharks in Atlantic Canada. This presents new challenges to manage this 523 species and mitigate potential detrimental effects resulting from unintended shark-human 524 interactions. The rebuilding of the white shark population off Massachusetts (Skomal et al. 2012) 525 and the recent shark attack in Cape Cod, which negatively shifted local public opinion of white 526 sharks, emphasize the importance of a clear action plan and need for both data and education to 527 limit negative interactions and promote awareness and conservation. This will need to be a 528 coordinated and collaborative effort that includes researchers, policy makers, non-governmental 529 organizations and the general public. Actions recommended here will ensure adequate protection 530 for white sharks and their associated ecosystems, given their role as a top predator and their current 531 SARA listing of “endangered” in Atlantic Canada waters (COSEWIC 2006). Whether the 532 consistent seasonal presence of white sharks in Canadian waters had previously gone unknown or 533 is a result of population recovery, a northward shift related to increasing ocean temperatures, 534 and/or increased abundance of marine mammal prey requires further investigation. 535 536 Acknowledgements 537 This manuscript represents the first publication (No. 1) of the Hussey Special Topics Graduate 538 Class at the University of Windsor. Anna and Alina Hussey are thanked for their unquestioning 539 support over the years. In addition, we express sincere gratitude to all OCEARCH team members 540 for their assistance with capture/tagging and sampling operations in Atlantic Canada waters and 541 for making this work possible. 24 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 25 of 47 542 References 543 Adams, D. H., Mitchell, M. E., and Parsons, G. R. (1994). Seasonal occurrence of the white 544 shark, Carcharodon carcharias, in waters off the Florida west coast, with notes on its life 545 history. Marine Fisheries Review, 56(4), 24–28. 546 Anderson, S. D., Chapple, T. K., Jorgensen, S. J., Klimley, A. P., and Block, B. A. (2011). Long- 547 term individual identification and site fidelity of white sharks, Carcharodon carcharias, off 548 California using dorsal fins. Marine Biology, 158(6), 1233–1237. 549 https://doi.org/10.1007/s00227-011-1643-5 550 Andreotti, S., Rutzen, M., van der Walt, S., Von der Heyden, S., Henriques, R., Meÿer, M., 551 Oosthuizen, H., and Matthee, C. (2016). An integrated mark-recapture and genetic approach 552 to estimate the population size of white sharks in South Africa. Marine Ecology Progress 553 Series, 552, 241–253. https://doi.org/10.3354/meps11744 554 Arbic, B. K., and Brechner Owens, W. (2001). Climatic warming of Atlantic intermediate 555 waters. Journal of Climate, 14(20), 4091–4108. https://doi.org/10.1175/1520- 556 0442(2001)014<4091:CWOAIW>2.0.CO;2 557 Baum, J. K., Myers, R. A., Kehler, D. G., Worm, B., Harley, S. J., and Doherty, P. A. (2003). 558 Collapse and conservation of shark populations in the Northwest Atlantic. Science, 559 299(5605), 389–392. https://doi.org/10.1126/science.1079777 560 Beaugrand, G., Luczak, C., and Edwards, M. (2009). Rapid biogeographical plankton shifts in 561 the North Atlantic ocean. Global Change Biology, 15(7), 1790–1803. 562 https://doi.org/10.1111/j.1365-2486.2009.01848.x 563 564 Belkin, I. M. (2009). Rapid warming of large marine ecosystems. Progress in Oceanography, 81(1–4), 207–213. https://doi.org/10.1016/j.pocean.2009.04.011 25 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 26 of 47 565 Block, B. A., Whitlock, R., Schallert, R. J., Wilson, S., Stokesbury, M. J. W., Castleton, M., and 566 Boustany, A. (2019). Estimating natural mortality of Atlantic bluefin tuna using acoustic 567 telemetry. Scientific Reports, 9(1), 4918. https://doi.org/10.1038/s41598-019-40065-z 568 Bonfil, R., Meÿer, M., Scholl, M. C., Johnson, R., O’Brien, S., Oosthuizen, H., Swanson, S., 569 Kotze, D., and Paterson, M. (2005). Transoceanic migration, spatial dynamics, and 570 population linkages of white sharks. Science, 310(5745), 100–103. 571 https://doi.org/10.1126/science.1114898 572 Bornatowski, H., Hussey, N. E., Sampaio, C. L. S., and Barreto, R. R. P. (2019). Geographic bias 573 in the media reporting of aquatic versus terrestrial human predator conflicts and its 574 conservation implications. Perspectives in Ecology and Conservation, 17(1), 32–35. 575 https://doi.org/10.1016/J.PECON.2018.12.004 576 Boulva, J., and McLaren, I. A. (1979). Biology of the harbor seal Phoca vitulina in eastern 577 Canada. Bulletin of the Fisheries Research Board of Canada, 200. http://www.dfo- 578 mpo.gc.ca/library/919.pdf 579 Bowen, W. D., McMillan, J., and Mohn, R. (2003). Sustained exponential population growth of 580 grey seals at Sable Island, Nova Scotia. ICES Journal of Marine Science, 60(6), 1265–1274. 581 https://doi.org/10.1016/S1054-3139(03)00147-4 582 Brodie, P., and Beck, B. (1983). Predation by sharks on the grey seal (Halichoerus grypus) in 583 eastern Canada. Canadian Journal of Fisheries and Aquatic Sciences, 40(3), 267–271. 584 https://doi.org/10.1139/f83-040 585 Brown, J. H., Stevens, G. C., and Kaufman, D. M. (1996). The geographic range: Size, shape, 586 boundaries, and internal structure. Annual Review of Ecology and Systematics, 27(1), 597– 587 623. https://doi.org/10.1146/annurev.ecolsys.27.1.597 26 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 27 of 47 588 Burgess, G. H., Beerkircher, L. R., Cailliet, G. M., Carlson, J. K., Cortés, E., Goldman, K. J., 589 Grubbs, R. D., Musick, J. A., Musyl, M. K., and Simpfendorfer, C. A. (2005). Is the 590 collapse of shark populations in the northwest Atlantic Ocean and Gulf of Mexico real? 591 Fisheries, 30(10), 19–26. https://doi.org/10.1577/1548-8446(2005)30[19:ITCOSP]2.0.CO;2 592 Casey, J. G., and Pratt, H. L. (1985). Distribution of the white shark, Carcharodon carcharias, in 593 the western North Atlantic. Memoirs of the Southern California Academy of Sciences, 9, 2– 594 14. 595 Cheung, W. W. L., Lam, V. W. Y., Sarmiento, J. L., Kearney, K., Watson, R., and Pauly, D. 596 (2009). Projecting global marine biodiversity impacts under climate change scenarios. Fish 597 and Fisheries, 10(3), 235–251. https://doi.org/10.1111/j.1467-2979.2008.00315.x 598 Christie, P., Bennett, N. J., Gray, N. J., Aulani Wilhelm, T., Lewis, N., Parks, J., Ban, N. C., 599 Gruby, R. L., Gordon, L., Day, J., Taei, S., and Friedlander, A. M. (2017). Why people 600 matter in ocean governance: Incorporating human dimensions into large-scale marine 601 protected areas. Marine Policy, 84, 273–284. 602 https://doi.org/10.1016/J.MARPOL.2017.08.002 603 Compagno, L. J. V, Marks, M. A., and Fergusson, I. K. (1997). Threatened fishes of the world: 604 Carcharodon carcharias (Linnaeus, 1758) (Lamnidae). Environmental Biology of Fishes, 605 50(1), 61–62. https://doi.org/10.1023/A:1007308406137 606 Cooke, S. J., and Cowx, I. G. (2004). The role of recreational fishing in global fish crises. 607 BioScience, 54(9), 857–859. https://doi.org/10.1641/0006- 608 3568(2004)054[0857:TRORFI]2.0.CO;2 609 610 COSEWIC. (2006). COSEWIC assessment and status report on the white shark Carcharodon carcharias (Atlantic and Pacific populations) in Canada (p. vii + 31). Retrieved from 27 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 28 of 47 611 612 COSEWIC website: www.sararegistry.gc.ca/status/status_e.cfm Curtis, T. H., McCandless, C. T., Carlson, J. K., Skomal, G. B., Kohler, N. E., Natanson, L. J., 613 Burgess, G. H., Hoey, J. J., and Pratt Jr, H. L. (2014). Seasonal distribution and historic 614 trends in abundance of white sharks, Carcharodon carcharias, in the western North Atlantic 615 ocean. PLoS ONE, 9(6), e99240. https://doi.org/10.1371/journal.pone.0099240 616 617 618 Day, L. R., and Fisher, H. D. (1954). Notes on the great white shark, Carcharodon carcharias, in Canadian Atlantic waters. Copeia, 4, 295. https://doi.org/10.2307/1440049 Devictor, V., Whittaker, R. J., and Beltrame, C. (2010). Beyond scarcity: citizen science 619 programmes as useful tools for conservation biogeography. Diversity and Distributions, 620 16(3), 354–362. https://doi.org/10.1111/j.1472-4642.2009.00615.x 621 622 623 DFO. (2016). Seal species. Retrieved April 26, 2019 from Fisheries and Oceans Canada website: http://www.dfo-mpo.gc.ca/fm-gp/seal-phoque/seal-species-eng.htm DFO. (2017). Evaluation of scope for harm for white shark (Carcharodon carcharias) in 624 Atlantic Canada. Canadian. Retrieved April 26, 2019 from Fisheries and Oceans Canada 625 website: https://waves-vagues.dfo-mpo.gc.ca/Library/40625436.pdf 626 Domeier, M., and Nasby-Lucas, N. (2008). Migration patterns of white sharks Carcharodon 627 carcharias tagged at Guadalupe Island, Mexico, and identification of an eastern Pacific 628 shared offshore foraging area. Marine Ecology Progress Series, 370, 221–237. 629 https://www.int-res.com/abstracts/meps/v370/p221-237/ 630 Domeier, M., and Nasby-Lucas, N. (2013). Two-year migration of adult female white sharks 631 (Carcharodon carcharias) reveals widely separated nursery areas and conservation concerns. 632 Animal Biotelemetry, 1(1), 2. https://doi.org/10.1186/2050-3385-1-2 633 Dubé, Y., Hammill, M. O., and Barrette, C. (2003). Pup development and timing of pupping in 28 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 29 of 47 634 harbour seals (Phoca vitulina) in the St. Lawrence River estuary, Canada. Canadian Journal 635 of Zoology, 81(2), 188–194. https://doi.org/10.1139/z02-231 636 Dulvy, N. K., Fowler, S. L., Musick, J. A., Cavanagh, R. D., Kyne, P. M., Harrison, L. R., 637 Carlson, J. K., Davidson, L. N., Fordham, S. V, Francis, M. P., Pollock, C. M., 638 Simpfendorfer, C. A., Burgess, G. H., Carpenter, K. E., Compagno, L. J., Ebert, D. A., 639 Gibson, C., Heupel, M. R., Livingstone, S. R., … White, W. T. (2014). Extinction risk and 640 conservation of the world’s sharks and rays. ELife, 3, e00590–e00590. 641 https://doi.org/10.7554/eLife.00590 642 Dunne, J. A., Williams, R. J., and Martinez, N. D. (2002). Network structure and biodiversity 643 loss in food webs: Robustness increases with connectance. Ecology Letters, 5(4), 558–567. 644 https://doi.org/10.1046/j.1461-0248.2002.00354.x 645 Environment and Climate Change Canada. (2015). COSEWIC guidelines for recognizing 646 designatable units. Retrieved August 21, 2019 from Government of Canada website: 647 https://www.canada.ca/en/environment-climate-change/services/committee-status- 648 endangered-wildlife/guidelines-recognizing-designatable-units.html 649 650 Flanders Marine Institute (2020). MarineRegions.org. Available from www.marineregions.org. [accessed 01 May 2020]. 651 Fleming, C.H. and Calabrese, J.M. (2016) A new kernel density estimator for accurate home- 652 range and species-range area estimation. Methods in Ecology and Evolution, 8, 571-579. 653 García Molinos, J., Halpern, B. S., Schoeman, D. S., Brown, C. J., Kiessling, W., Moore, P. J., 654 Pandolfi, J. M., Poloczanska, E. S., Richardson, A. J., and Burrows, M. T. (2016). Climate 655 velocity and the future global redistribution of marine biodiversity. Nature Climate Change, 656 6(1), 83–88. https://doi.org/10.1038/nclimate2769 29 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 30 of 47 657 658 659 GEBCO Compilation Group (2020). GEBCO 2020 Grid. doi:10.5285/a29c5465-b138-234d-e0536c86abc040b9. Glass, C. W., Eayrs, S., and Cournane, J. M. (2015). Bycatch reduction devices: Development, 660 adoption and implementation? In G. H. Kruse, H. C. An, J. DiCosimo, C. A. Eischens, G. S. 661 Gislason, D. N. McBride, C. S. Rose, & C. E. Siddon (Eds.), Fisheries Bycatch: Global 662 Issues and Creative Solutions (pp. 79–98). https://doi.org/10.4027/fbgics.2015.05 663 Godin, A. C., Wimmer, T., Wang, J. H., and Worm, B. (2013). No effect from rare-earth metal 664 deterrent on shark bycatch in a commercial pelagic longline trial. Fisheries Research, 143, 665 131–135. https://doi.org/10.1016/J.FISHRES.2013.01.020 666 GSHHG (2017) A global self-consistent, hierarchical, high-resolution shoreline database by 667 Wessel, P. and Smith W.HF. Available from https://www.soest.hawaii.edu/pwessel/gshhg/. 668 [accessed 01 May 2020]. 669 Hammill, M. O., Bowen, W. D., and Sjare, B. (2010). Status of harbour seals (Phoca vitulina) in 670 Atlantic Canada. NAMMCO Scientific Publications, 8, 175–189. 671 https://doi.org/10.7557/3.2684 672 Hammill, M. O., den Heyer, C. E., and Bowen, W. D. (2014). Grey seal population trends in 673 Canadian waters, 1960-2014. DFO Canadian Science Advisory Secretariat, 674 Res.Doc(2014/037), iv + 44p. https://waves-vagues.dfo-mpo.gc.ca/Library/360467.pdf 675 Hammill, M. O., and Stenson, G. B. (2000). Estimated prey consumption by harp seals (Phoca 676 groenlandica), hooded seals (Cystophora cristata), grey seals (Halichoerus grypus) and 677 harbour seals (Phoca vitulina) in Atlantic Canada. Journal of Northwest Atlantic Fishery 678 Science, 26, 1–23. https://doi.org/10.2960/J.v26.a1 679 Heupel, M. R., Simpfendorfer, C. A., Espinoza, M., Smoothey, A. F., Tobin, A., and Peddemors, 30 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 31 of 47 680 V. (2015). Conservation challenges of sharks with continental scale migrations. Frontiers in 681 Marine Science, 2, 1–7. https://www.frontiersin.org/article/10.3389/fmars.2015.00012 682 Hussey, N. E., Kessel, S. T., Aarestrup, K., Cooke, S. J., Cowley, P. D., Fisk, A. T., Harcourt, R. 683 G., Holland, K. N., Iverson, S. J., Kocik, J. F., Mills Flemming, J. E., and Whoriskey, F. G. 684 (2015). Aquatic animal telemetry: A panoramic window into the underwater world. Science, 685 348(6240). https://doi.org/10.1126/science.1255642 686 Huveneers, C., Apps, K., Becerril-García, E. E., Bruce, B., Butcher, P. A., Carlisle, A. B., 687 Chapple, T. K., Christiansen, H. M., Cliff, G., Curtis, T. H., Daly-Engel, T. S., Dewar, H., 688 Dicken, M. L., Domeier, M. L., Duffy, C. A. J., Ford, R., Francis, M. P., French, G. C. A., 689 Galván-Magaña, F., … Werry, J. M. (2018). Future research directions on the “elusive” 690 white shark. Frontiers in Marine Science, 5, 1–15. https://doi.org/10.3389/fmars.2018.00455 691 IPCC. (2014). Climate change 2014: Synthesis report. Contribution of working groups I, II and 692 III to the fifth assessment report of the intergovernmental panel on Climate Change [Core 693 writing team, R.K. Pachauri and L.A. Meyer (eds.)]. https://doi.org/10.1046/j.1365- 694 2559.2002.1340a.x 695 ISAF. (2018). International shark attack file. Species implicated in attacks. Retrieved October 696 31, 2019 from Florida Museum website: https://www.floridamuseum.ufl.edu/shark- 697 attacks/factors/species-implicated/ 698 Jorgensen, S. J., Reeb, C. A., Chapple, T. K., Anderson, S., Perle, C., Van Sommeran, S. R., 699 Fritz-Cope, C., Brown, A. C., Klimley, A. P., and Block, B. A. (2010). Philopatry and 700 migration of Pacific white sharks. Proceedings of the Royal Society B: Biological Sciences, 701 277(1682), 679–688. https://doi.org/10.1098/rspb.2009.1155 702 Kavanaugh, M. T., Rheuban, J. E., Luis, K. M. A., and Doney, S. C. (2017). Thirty-three years of 31 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 32 of 47 703 ocean benthic warming along the U.S. northeast continental shelf and slope: Patterns, 704 drivers, and ecological consequences. Journal of Geophysical Research: Oceans, 122, 9399– 705 9414. https://doi.org/10.1002/2017JC012953 706 Kennelly, S. J., and Broadhurst, M. K. (2002). By-catch begone: changes in the philosophy of 707 fishing technology. Fish and Fisheries, 3(4), 340–355. https://doi.org/10.1046/j.1467- 708 2979.2002.00090.x 709 Kock, A., O’Riain, M. J., Mauff, K., Meÿer, M., Kotze, D., and Griffiths, C. (2013). Residency, 710 habitat use and sexual segregation of white wharks, Carcharodon carcharias in False Bay, 711 South Africa. PLoS ONE, 8(1), e55048. https://doi.org/10.1371/journal.pone.0055048 712 LaRue, M. A., Ainley, D. G., Pennycook, J., Stamatiou, K., Salas, L., Nur, N., Stammerjohn, S., 713 and Barrington, L. (2019). Engaging ‘the crowd’ in remote sensing to learn about habitat 714 affinity of the Weddell seal in Antarctica [online]. Remote Sensing in Ecology and 715 Conservation. https://doi.org/10.1002/rse2.124 716 717 Lees, K, MacNeil, M.A., Hedges, K.H. and Hussey, N.E. (In review) Estimating demographic parameters for fisheries management using acoustic telemerty. Fish and Fisheries. 718 Lucas, Z. N., Daoust, P. Y., Conboy, G., and Brimacombe, M. (2003). Health status of harp seals 719 (Phoca groenlandica) and hooded seals (Cystophora cristata) on Sable Island, Nova Scotia, 720 Canada, concurrent with their expanding range. Journal of Wildlife Diseases, 39(1), 16–28. 721 https://doi.org/10.7589/0090-3558-39.1.16 722 Lucas, Z. N., and Natanson, L. J. (2010). Two shark species involved in predation on seals at 723 Sable Island, Nova Scotia, Canada. Proceedings of the Nova Scotian Institute of Science, 724 45(2), 64–88. http://hdl.handle.net/10222/71006 725 Lucas, Z. N., and Stobo, W. T. (2000). Shark-inflicted mortality on a population of harbour seals 32 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 33 of 47 726 (Phoca vitulina) at Sable Island, Nova Scotia. Journal of Zoology, 252(3), 405–414. 727 https://doi.org/10.1111/j.1469-7998.2000.tb00636.x 728 MacLeod, C. D. (2009). Global climate change, range changes and potential implications for the 729 conservation of marine cetaceans: a review and synthesis. Endangered Species Research, 730 7(2), 125–136. https://www.int-res.com/abstracts/esr/v7/n2/p125-136/ 731 MacLeod, C. D., Bannon, S. M., Pierce, G. J., Schweder, C., Learmonth, J. A., Herman, J. S., 732 and Reid, R. J. (2005). Climate change and the cetacean community of north-west Scotland. 733 Biological Conservation, 124(4), 477–483. https://doi.org/10.1016/J.BIOCON.2005.02.004 734 Macpherson, E., and Duarte, C. M. (1994). Patterns in species richness, size, and latitudinal 735 range of east Atlantic fishes. Ecography, 17(3), 242–248. 736 http://www.jstor.org/stable/3683049 737 738 739 Mason, F. (2002). The Newfoundland cod stock collapse: A review and analysis of social factors. Electronic Green Journal, 1(17). https://escholarship.org/uc/item/19p7z78s McPherson, J. M., and Myers, R. A. (2009). How to infer population trends in sparse data: 740 Examples with opportunistic sighting records for great white sharks. Diversity and 741 Distributions, 15(5), 880–890. https://doi.org/10.1111/j.1472-4642.2009.00596.x 742 Mollomo, P. (1998). The white shark in Maine and Canadian Atlantic waters. Northeastern 743 744 Naturalist, 5(3), 207–214. https://doi.org/10.2307/3858620 Moore, S. E., and Huntington, H. P. (2008). Artic marine mammals and climate change: Impacts 745 and resilience. Ecological Applications, 18(sp2), S157–S165. https://doi.org/10.1890/06- 746 0571.1 747 748 Morgan, A., and Burgess, G. H. (2007). At-vessel fishing ormtality for six species of sharks caught in the northwest Atlantic and Gulf of Mexico. Gulf and Caribbean Research, 19(2), 33 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 34 of 47 749 750 123–129. https://doi.org/10.18785/gcr.1902.15 Muter, B. A., Gore, M. L., Gledhill, K. S., Lamont, C., and Huveneers, C. (2013). Australian and 751 U.S. news media portrayal of sharks and their conservation. Conservation Biology, 27(1), 752 187–196. https://doi.org/10.1111/j.1523-1739.2012.01952.x 753 O’Bryhim, J. R., and Parsons, E. C. M. (2015). Increased knowledge about sharks increases 754 public concern about their conservation. Marine Policy, 56, 43–47. 755 https://doi.org/10.1016/J.MARPOL.2015.02.007 756 O’Leary, S. J., Feldheim, K. A., Fields, A. T., Natanson, L. J., Wintner, S., Hussey, N., Shivji, 757 M. S., and Chapman, D. D. (2015). Genetic diversity of white sharks, Carcharodon 758 carcharias, in the northwest Atlantic and southern Africa. Journal of Heredity, 106(3), 258– 759 265. https://doi.org/10.1093/jhered/esv001 760 O’Malley, M. P., Lee-Brooks, K., and Medd, H. B. (2013). The global economic impact of 761 manta ray watching tourism. PLoS ONE, 8(5), e65051. 762 https://doi.org/10.1371/journal.pone.0065051 763 Oliver, S., Braccini, M., Newman, S. J., and Harvey, E. S. (2015). Global patterns in the bycatch 764 of sharks and rays. Marine Policy, 54, 86–97. 765 https://doi.org/10.1016/J.MARPOL.2014.12.017 766 Pardini, A. T., Jones, C. S., Noble, L. R., Kreiser, B., Malcolm, H., Bruce, B. D., Stevens, J. D., 767 Cliff, G., Scholl, M. C., Francis, M., Duffy, C. A. J., and Martin, A. P. (2001). Sex-biased 768 dispersal of great white sharks. Nature, 412(6843), 139–140. 769 https://doi.org/10.1038/35084125 770 Pauly, D., Christensen, V., Dalsgaard, J., Froese, R., and Torres, F. (1998). Fishing down marine 771 food webs. Science, 279(5352), 860–863. https://doi.org/10.1126/science.279.5352.860 34 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 35 of 47 772 Pauly, D., and Zeller, D. (2016). Catch reconstructions reveal that global marine fisheries catches 773 are higher than reported and declining. Nature Communications, 7(1), 10244. 774 https://doi.org/10.1038/ncomms10244 775 Pecl, G. T., Araújo, M. B., Bell, J. D., Blanchard, J., Bonebrake, T. C., Chen, I. C., Clark, T. D., 776 Colwell, R. K., Danielsen, F., Evengård, B., Falconi, L., Ferrier, S., Frusher, S., Garcia, R. 777 A., Griffis, R. B., Hobday, A. J., Janion-Scheepers, C., Jarzyna, M. A., Jennings, S., … 778 Williams, S. E. (2017). Biodiversity redistribution under climate change: Impacts on 779 ecosystems and human well-being. Science, 355(6332), eaai9214. 780 https://doi.org/10.1126/science.aai9214 781 Pepin-Neff, C. L., and Wynter, T. (2018). Reducing fear to influence policy preferences: An 782 experiment with sharks and beach safety policy options. Marine Policy, 88, 222–229. 783 https://doi.org/10.1016/J.MARPOL.2017.11.023 784 Perry, A. L., Low, P. J., Ellis, J. R., and Reynolds, J. D. (2005). Climate change and distribution 785 shifts in marine fishes. Science, 308(5730), 1912–1915. 786 https://doi.org/10.1126/science.1111322 787 Pinsky, M. L., Worm, B., Fogarty, M. J., Sarmiento, J. L., and Levin, S. A. (2013). Marine taxa 788 track local climate velocities. Science, 341(6151), 1239–1242. 789 https://doi.org/10.1126/science.1239352 790 Queiroz, N., Humphries, N. E., Couto, A., Vedor, M., da Costa, I., Sequeira, A. M. M., 791 Mucientes, G., Santos, A. M., Abascal, F. J., Abercrombie, D. L., Abrantes, K., Acuña- 792 Marrero, D., Afonso, A. S., Afonso, P., Anders, D., Araujo, G., Arauz, R., Bach, P., Barnett, 793 A., … Sims, D. W. (2019). Global spatial risk assessment of sharks under the footprint of 794 fisheries. Nature, 572(7770), 461–466. https://doi.org/10.1038/s41586-019-1444-4 35 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 36 of 47 795 Rankin, S., Norris, T. F., Smultea, M. A., Oedekoven, C., Zoidis, A. M., Silva, E., and Rivers, J. 796 (2007). A visual sighting and acoustic detections of minke whales, Balaenoptera 797 acutorostrata (Cetacea: Balaenopteridae), in nearshore Hawaiian waters. Pacific Science, 798 61(3), 395–398. https://doi.org/10.2984/1534-6188(2007)61[395:AVSAAD]2.0.CO 799 Rigby, C. L., Barreto, R., Carlson, J., Fernando, D., Fordham, S., Francis, M. P., Herman, K., 800 Jabado, R. W., Liu, K. M., Lowe, C. G., Marshall, A., Pacoureau, N., Romanov, E., 801 Sherley, R. B., and Winker, H. (2019). Carcharodon carcharias. The IUCN Red List of 802 Threatened Species 2019: e.T3855A2878674. https://doi.org/10.2305/IUCN.UK.2019- 803 3.RLTS.T3855A2878674.en. 804 Robinson, R. A., Crick, H. Q. P., Learmonth, J. A., Maclean, I. M. D., Thomas, C. D., Bairlein, 805 F., Forchhammer, M. C., Francis, C. M., Gill, J. A., Godley, B. J., Harwood, J., Hays, G. C., 806 Huntley, B., Hutson, A. M., Pierce, G. J., Rehfisch, M. M., Sims, D. W., Santos, B. M., 807 Sparks, T. H., … Visser, M. E. (2009). Travelling through a warming world: climate change 808 and migratory species. Endangered Species Research, 7(2), 87–99. http://www.int- 809 res.com/abstracts/esr/v7/n2/p87-99/ 810 Saba, V. S., Griffies, S. M., Anderson, W. G., Winton, M., Alexander, M. A., Delworth, T. L., 811 Hare, J. A., Harrison, M. J., Rosati, A., Vecchi, G. A., and Zhang, R. (2016). Enhanced 812 warming of the Northwest Atlantic ocean under climate change. Journal of Geophysical 813 Research: Oceans, 121(1), 118–132. https://doi.org/10.1002/2015JC011346 814 815 816 817 SARA. (2002). SARA Species at Risk Act. S.C. 2002, c. 29. https://lawslois.justice.gc.ca/eng/acts/S-15.3/page-1.html#h-434501 Scheinin, A. P., Kerem, D., MacLeod, C. D., Gazo, M., Chicote, C. A., and Castellote, M. (2011). Gray whale (Eschrichtius robustus) in the Mediterranean Sea: anomalous event or 36 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 37 of 47 818 early sign of climate-driven distribution change? Marine Biodiversity Records, 4, e28. 819 https://doi.org/10.1017/S1755267211000042 820 821 822 Silvertown, J. (2009). A new dawn for citizen science. Trends in Ecology & Evolution, 24(9), 467–471. https://doi.org/10.1016/J.TREE.2009.03.017 Simpfendorfer, C. A., Heupel, M. R., White, W. T., and Dulvy, N. K. (2011). The importance of 823 research and public opinion to conservation management of sharks and rays: a synthesis. 824 Marine and Freshwater Research, 62(6), 518–527. https://doi.org/10.1071/MF11086 825 Skomal, G. B., Braun, C. D., Chisholm, J. H., and Thorrold, S. R. (2017). Movements of the 826 white shark Carcharodon carcharias in the north Atlantic ocean. Marine Ecology Progress 827 Series, 580, 1–16. https://www.int-res.com/abstracts/meps/v580/p1-16/ 828 Skomal, G. B., Chisholm, J., and Correia, S. J. (2012). Implications of increasing pinniped 829 populations on the diet and abundance of white sharks off the coast of Massachusetts. In M. 830 L. Domeier (Ed.), Global Perspectives on the Biology and Life History of the White Shark 831 (pp. 405–417). https://doi.org/10.1201/b11532-31 832 Skomal, G. B., Zeeman, S. I., Chisholm, J. H., Summers, E. L., Walsh, H. J., McMahon, K. W., 833 and Thorrold, S. R. (2009). Transequatorial migrations by basking sharks in the western 834 Atlantic Ocean. Current Biology, 19(12), 1019–1022. 835 https://doi.org/10.1016/J.CUB.2009.04.019 836 Taboada, F. G., and Anadón, R. (2012). Patterns of change in sea surface temperature in the 837 north Atlantic during the last three decades: beyond mean trends. Climatic Change, 115(2), 838 419–431. https://doi.org/10.1007/s10584-012-0485-6 839 840 Taylor, C. M., and Norris, D. R. (2010). Population dynamics in migratory networks. Theoretical Ecology, 3(2), 65–73. https://doi.org/10.1007/s12080-009-0054-4 37 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 38 of 47 841 Theberge, M. M., and Dearden, P. (2006). Detecting a decline in whale shark Rhincodon typus 842 sightings in the Andaman Sea, Thailand, using ecotourist operator-collected data. Oryx, 843 40(3), 337–342. https://doi.org/10.1017/S0030605306000998 844 Turnbull, S. D., and Dion, D. (2012). White shark (Carcharodon carcharias) attack on a harbor 845 porpoise (Phocaena phocaena) in the Bay of Fundy, Canada. Northeastern Naturalist, 846 19(4), 705–707. http://www.jstor.org/stable/41810156 847 Ward, E. J., Holmes, E. E., and Balcomb, K. C. (2009). Quantifying the effects of prey 848 abundance on killer whale reproduction. Journal of Applied Ecology, 46(3), 632–640. 849 https://doi.org/10.1111/j.1365-2664.2009.01647.x 850 Watanabe, Y. Y., Payne, N. L., Semmens, J. M., Fox, A., and Huveneers, C. (2019). Swimming 851 strategies and energetics of endothermic white sharks during foraging. Journal of 852 Experimental Biology. https://doi.org/10.1242/jeb.185603 853 Werner, E. E., and Gilliam, J. F. (1984). The ontogenetic niche and species interactions in size- 854 structured populations. Annual Review of Ecology and Systematics, 15(1), 393–425. 855 https://doi.org/10.1146/annurev.es.15.110184.002141 856 Woods Hole Group. (2019). Outer Cape shark mitigation alternatives analysis: Evaluating 857 strategies to support regional decision making and public safety efforts. 858 https://static1.squarespace.com/static/525d3c81e4b04f0184097802/t/5da65f622f46d156f89 859 461c9/1571184493060/Shark_Mitigation_Alternatives_Analysis_Technical_Report_10112 860 019.pdf 861 Worm, B., Davis, B., Kettemer, L., Ward-Paige, C. A., Chapman, D., Heithaus, M. R., Kessel, S. 862 T., and Gruber, S. H. (2013). Global catches, exploitation rates, and rebuilding options for 863 sharks. Marine Policy, 40, 194–204. https://doi.org/10.1016/J.MARPOL.2012.12.034 38 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 39 of 47 864 39 Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 40 of 47 FIGURES: Figure 1. Synthesis of historical to present white shark sightings in Atlantic Canada. (A) Counts and cumulative white shark sightings in Atlantic Canada waters from 1872–2016 (n = 60 total sightings). (B) Monthly distribution of white shark sightings in Atlantic Canada (total n = 55; unreliable records excluded). (C) Length distribution of white sharks sighted in Atlantic Canada (n = 38; includes only sharks with verified length information). See Supplementary file S1 and Table S1 for details on data. Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 41 of 47 Figure 2. Distribution and hotspots of white sharks in Atlantic Canada waters derived from sightings and telemetry data. Circles show historical to present distribution of white shark sightings in Atlantic Canada waters from 1872 to 2016 (colored by year of sighting). Sightings include visual observations of animals in water (n = 27), capture in fishing gear (n = 26) and teeth in fishing gear/wounds on marine mammals (n = 7). Underlying map indicates high core area use of all satellite-tracked white sharks tagged in US and Atlantic Canada waters to date, based on kernel density estimation. Hashed area demarcates the Canadian Economic Exclusive Zone (EEZ; Flanders Marine Institute 2020). Map created in ArcGIS (ESRI 2020) using bathymetry and derived contour lines from GEBCO Compilation Group (2020) and shorelines from GSHHG (2017). Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 42 of 47 Figure 3. Spatial-temporal distribution of all white sharks equipped with SPOT satellite transmitters recorded in Atlantic Canada waters. (A) Satellite tracks of nine white sharks tagged in U.S. waters that entered Atlantic Canada (n = 9), (B) Satellite tracks of 17 white sharks Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 43 of 47 tagged in Canadian waters in 2018 (n = 6) and 2019 (n = 11). (C) tracks of Hilton (tagged in US waters) and (D) Cabot (tagged in Atlantic Canada waters) that exited and returned to Canadian waters over a two-year period. All locations are those estimated using a continuous time correlated random walk state-space model with the exception of the 2018 track for Cabot (shown as triangles in D), which shows geolocated positions due to the limited sample size (See Methods) (E) Number of days that transmissions were received each month (calculated as a percentage; days month-1) for each individual white shark present in Atlantic Canada waters (labelled by those tagged in both US and Canadian waters). Hashed area demarcates the Canadian Economic Exclusive Zone (EEZ; Flanders Marine Institute 2020). Map created in ArcGIS (ESRI 2020) using bathymetry and derived contour lines from GEBCO Compilation Group (2020) and shorelines from GSHHG (2017). Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 44 of 47 Table 1: Metadata for all white sharks equipped with SPOT satellite transmitters that entered or were tagged in Atlantic Canada waters. ID is the assigned identification number, latitude and longitude indicate the exact location of tagging, TL is total length in meters, F and M refer to female and male, respectively. Name ID Tag Date Latitude Longitude TL Sex Capture location & (m) Country Lydia 1 2013-03-03 30.39 -81.38 4.42 F Florida, USA Betsy 2 2013-08-13 41.69 -70.30 3.84 F Massachusetts, USA Katharine 3 2013-08-20 41.69 -70.30 4.32 F Massachusetts, USA George 4 2016-10-07 41.49 -69.98 3.00 M Massachusetts, USA Hilton 5 2017-03-03 32.09 -80.57 3.79 M South Carolina, USA Savannah 6 2017-03-05 32.23 -80.63 2.60 F South Carolina, USA Nova 7 2018-09-24 44.23 -64.28 3.41 M Nova Scotia, Canada Jefferson 8 2018-09-24 44.23 -64.28 3.86 M Nova Scotia, Canada Hal 9 2018-09-29 44.23 -64.28 3.90 M Nova Scotia, Canada Cabot 10 2018-10-05 44.23 -64.28 2.74 M Nova Scotia, Canada Jane 11 2018-10-08 44.23 -64.28 2.86 F Nova Scotia, Canada Luna 12 2018-10-08 44.23 -64.28 4.25 F Nova Scotia, Canada Helena 13 2019-02-22 32.06 -80.42 3.79 F South Carolina, USA Brunswick 14 2019-02-26 32.00 -80.59 2.66 M South Carolina, USA Caroline 15 2019-02-26 32.00 -80.59 3.88 F South Carolina, USA Sydney 16 2019-09-15 46.02 -59.68 3.71 M Nova Scotia, Canada Murdoch 17 2019-09-16 46.00 -59.68 3.93 M Nova Scotia, Canada Unama’ki 18 2019-09-20 46.02 -59.68 4.33 F Nova Scotia, Canada Caper 19 2019-09-26 46.04 -59.69 2.50 F Nova Scotia, Canada Bluenose 20 2019-09-29 44.23 -64.28 3.53 F Nova Scotia, Canada Ferg 21 2019-09-30 44.23 -64.29 3.32 M Nova Scotia, Canada Shaw 22 2019-10-01 44.23 -64.29 2.88 M Nova Scotia, Canada Scotia 23 2019-10-01 44.23 -64.28 3.13 F Nova Scotia, Canada Ironbound 24 2019-10-03 44.23 -64.29 3.46 M Nova Scotia, Canada Teazer 25 2019-10-03 44.23 -64.29 3.13 M Nova Scotia, Canada Vimy 26 2019-10-04 44.23 -64.28 3.63 M Nova Scotia, Canada Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 45 of 47 Table 2. Outline of Atlantic Canada white shark (Carcharodon carcharias) management priorities and conservation goals. Objective 1: Positive Action 1: Enhance social media presence of white shark science public awareness and underway and associated researchers/organizations perception of white sharks Action 2: Promote balanced white shark coverage in Canadian broadcasting and news media Action 3: Increase white shark public education programs (targeting schools, general public, and specifically recreational and commercial water users, e.g., surfers and fishers) Objective 2: Improved Action 1: Identify seasonal/yearly movement and migration scientific knowledge patterns in Canadian waters Action 2: Long-term monitoring to determine the stability of identified “hotspot” habitat in Atlantic Canada and quantify associated environmental and prey resources Action 3: Estimate population size and survivorship parameters Action 4: Derive health and condition data to monitor population status Action 5: Determine ecological role to facilitate ecosystem level management Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 46 of 47 Objective 3: Responsible Action 1: Limit shark bycatch in commercial fisheries and proactive fisheries maintain a zero landings limit for all fisheries management Action 2: Prohibit targeting of white sharks in recreational and commercial fisheries Action 3: Invest in active research and trials to support gear modification to reduce shark bycatch and development of best handling practices for releasing large sharks Action 4: Improve reporting of bycatch by fisheries (location, size, weight, sex) Action 5: Ensure ban on trade of white shark products is enforced Objective 4: Appropriate Action 1: Coordinate re-evaluation of white shark status and legislation and enact required species legislation with broad stakeholder consideration of human- involvement shark conflict Action 2: Assess variation in spatial distribution of white sharks relative to current marine protected/conservation area network, and modify, expand, or create new conservation/protected areas and associated legal frameworks to include white shark-specific criteria Can. J. Fish. Aquat. Sci. Downloaded from www.nrcresearchpress.com by Paul Withers on 07/07/20 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record. Page 47 of 47 Action 3: Determine proximity of white shark occurrence to human coastal settlements, prime areas used by recreational water users, and overlap with fisheries Action 4: Assign potential risk in human-shark conflict areas, ensure awareness of general public and implement public safety measures