Core habitat use of an apex predator in a complex marine landscape

Jewell, Oliver J. D.; Wcisel, Michelle A.; Towner, Alison V.; Chivell, Wilfred; Merwe, Lize van der; Bester, Marthán N

doi:10.3354/meps10814

Cited by 17 publications

(29 citation statements)

References 51 publications

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“…For example, movement analysis of a smaller number of acoustically tracked white sharks in Gansbaai identified core areas of habitat use but was not able to detect switching behaviours or differences in movements between the sexes (Jewell et al . ). Of course, movements by marine predators will also include a vertical component and we did not measure swimming depths.…”

Section: Discussionmentioning

confidence: 97%

“…; Jewell et al . ). Geographic locations were recorded every 5 min, and surface predation events or attempts were noted during the track.…”

Section: Methodsmentioning

confidence: 97%

“…; Martin, Rossmo & Hammerschlag ; Jewell et al . ). Pinnipeds are primarily ambushed at the surface although previous studies have not quantified if the sharks were performing ARS or patrolling behaviour before the attack (e.g.…”

Section: Introductionmentioning

confidence: 97%

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Sex‐specific and individual preferences for hunting strategies in white sharks

et al. 2016

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Summary Fine‐scale predator movements may be driven by many factors including sex, habitat and distribution of resources. There may also be individual preferences for certain movement strategies within a population which can be hard to quantify. Within top predators, movements are also going to be directly related to the mode of hunting, for example sit‐and‐wait or actively searching for prey. Although there is mounting evidence that different hunting modes can cause opposing trophic cascades, there has been little focus on the modes used by top predators, especially those in the marine environment. Adult white sharks (Carcharhodon carcharias) are well known to forage on marine mammal prey, particularly pinnipeds. Sharks primarily ambush pinnipeds on the surface, but there has been less focus on the strategies they use to encounter prey. We applied mixed hidden Markov models to acoustic tracking data of white sharks in a coastal aggregation area in order to quantify changing movement states (area‐restricted searching (ARS) vs. patrolling) and the factors that influenced them. Individuals were re‐tracked over multiple days throughout a month to see whether state‐switching dynamics varied or if individuals preferred certain movement strategies. Sharks were more likely to use ARS movements in the morning and during periods of chumming by ecotourism operators. Furthermore, the proportion of time individuals spent in the two different states and the state‐switching frequency, differed between the sexes and between individuals. Predation attempts/success on pinnipeds were observed for sharks in both ARS and patrolling movement states and within all random effects groupings. Therefore, white sharks can use both a ‘sit‐and‐wait’ (ARS) and ‘active searching’ (patrolling) movements to ambush pinniped prey on the surface. White sharks demonstrate individual preferences for fine‐scale movement patterns, which may be related to their use of different hunting modes. Marine top predators are generally assumed to use only one type of hunting mode, but we show that there may be a mix within populations. As such, individual variability should be considered when modelling behavioural effects of predators on prey species.

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Section: Discussionmentioning

confidence: 97%

“…; Jewell et al . ). Geographic locations were recorded every 5 min, and surface predation events or attempts were noted during the track.…”

Section: Methodsmentioning

confidence: 97%

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Sex‐specific and individual preferences for hunting strategies in white sharks

et al. 2016

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“…A similar result was obtained for adult fur seals in “shark alley” at Geyser Rock, Gaansbaai which avoided resting and playing in the deep open water habitat during winter when white shark presence was high (Jewell et al . ).…”

Section: Discussionmentioning

confidence: 97%

“…It would be of interest to see whether artificial spatial refuges ( e.g., a kelp forest, artificial rocky outcrop with a shallow patch) placed in the deep water within the danger zone at Seal Island would attract fur seals ( sensu Jewell et al . ) and hence result in a change in space use to reduce encounters with predators (for examples of such experiments see Hochman and Kotler , Stankowich and Coss , Morgan and Fernández‐Juricic ).…”

Section: Discussionmentioning

confidence: 99%

Behavior of Cape fur seals (Arctocephalus pusillus pusillus) in response to spatial variation in white shark (Carcharodon carcharias) predation risk

Vos

O’Riain

Meÿer³

et al. 2015

Marine Mammal Science

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Foraging and predation risk are often separated at rookeries of marine central place foragers, thus offering an opportunity to gain insight into how predator‐avoidance shapes the behavior of prey. Here we compare the behavior of Cape fur seals (Arctocephalus pusillus pusillus) at two island rookeries with and without white shark (Carcharodon carcharias) predations, and assess seal behavior in relation to marked spatiotemporal variation in risk at the high‐risk site (Seal Island, South Africa). Our results show that seal behavior at the two sites is comparatively similar in summer, when predation risk is low at both sites, but not in winter. Compared to seals at the “low‐risk” site, seals at Seal Island avoided deep‐water habitat around the island at high risk times and restricted their use of this habitat in favor of safe, shallow waters when engaging in social and thermoregulatory behaviors. Seals increased their frequency of jostling, porpoising, and diving when moving through the danger zone and seals in groups were safer than single individuals. Overall, our results suggest that seal behavior around the high‐risk site is strongly affected by predation risk, and show this rookery to be an excellent predator‐prey system at which to evaluate long‐standing ecological hypotheses.

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Diverse habitats shape the movement ecology of a top marine predator, the white shark Carcharodon carcharias

Jewell,

Chapple,

Jorgensen

et al. 2024

Ecosphere

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An animal's movement is influenced by a plethora of internal and external factors, leading to individual‐ and habitat‐specific movement characteristics. This plasticity is thought to allow individuals to exploit diverse environments efficiently. We tested whether the movement characteristics of white sharks Carcharodon carcharias differ across ontogeny and among habitats along the coast of Central California. In doing so, we elucidate how changes in internal state (physiological changes coinciding with body size) and external environments (differing seascapes and/or diel phases) shape the movement of this globally distributed predator. Twenty‐one white sharks, from small juveniles to large adults, were equipped with motion‐sensitive biologging tags at four contrasting seascapes: two islands, a headland, and an inshore cove. From multisensor biologging data, 20 metrics characterizing movement (i.e., depth use, vertical velocities, activity, turning rates, and bursting events) were derived and subjected to multivariate analyses. Movement characteristics were most different across seascapes, followed by ontogeny and diel phase. Juvenile sharks, which were only encountered at the cove, displayed the most distinct movement characteristics. Sharks at this seascape remained close to the shore traveling over smaller areas, shallower depth ranges, and with lower levels of tail beat frequencies, when corrected for size, than sub‐adult and adult sharks tagged elsewhere. Distinct tortuous daytime versus linear nighttime horizontal movements were recorded from sharks at island seascapes but not from those at the headland or inshore cove. At the offshore islands, the linear nighttime swimming patterns coincided with repeated dives to and from deeper water. The availability of prey and access to deeper water are likely drivers of the differences in movement characteristics described, with varying demographics of pinniped prey found at the subadult and adult aggregation areas and juvenile sharks being piscivorous and their habitat neither adjacent to pinniped haul out areas nor deeper water. This study demonstrates plasticity in the movements of a top predator, which adapts its routine to suit the habitat it forages within.

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Core habitat use of an apex predator in a complex marine landscape

Cited by 17 publications

References 51 publications

Sex‐specific and individual preferences for hunting strategies in white sharks

Sex‐specific and individual preferences for hunting strategies in white sharks

Behavior of Cape fur seals (Arctocephalus pusillus pusillus) in response to spatial variation in white shark (Carcharodon carcharias) predation risk

Diverse habitats shape the movement ecology of a top marine predator, the white shark Carcharodon carcharias

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