Effects of the Sharksafe barrier on white shark (Carcharodon carcharias) behavior and its implications for future conservation technologies

O’Connell, Craig P.; Andreotti, Sara; Rutzen, Michael; Meÿer, Michael A.; Matthee, Conrad A.; He, Pingguo

doi:10.1016/j.jembe.2014.06.004

Cited by 17 publications

(19 citation statements)

References 37 publications

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“…Comparable to previous studies, C. leucas behavior was significantly altered in relation to both the magnetic and procedural control regions (O'Connell et al, 2013b(O'Connell et al, , 2014. In O'Connell et al (2014), white sharks (Carcharodon carcharias) never entered through procedural control and magnetic regions of the Sharksafe barrier.…”

Section: Bull Sharkscontrasting

confidence: 65%

“…Similarly, in O'Connell et al (2013b), C. leucas were observed to swim around magnetic and procedural control regions of a barrier; however unlike the present study and O'Connell et al (2014), entrance behaviors through procedural control and magnetically-treated barrier regions did occur. In the present study and in O'Connell et al (2014), there were two and three rows of alternating columns, respectively, whereas in the previous study (O'Connell et al, 2013b), only one row of columns was deployed. Therefore, the added visual stimulus provided by increased column quantity may have been sufficient to elicit these behavioral differences and may have maximized overall barrier effectiveness.…”

Section: Bull Sharkscontrasting

confidence: 52%

“…In O'Connell et al (2014), white sharks (Carcharodon carcharias) never entered through procedural control and magnetic regions of the Sharksafe barrier. Similarly, in O'Connell et al (2013b), C. leucas were observed to swim around magnetic and procedural control regions of a barrier; however unlike the present study and O'Connell et al (2014), entrance behaviors through procedural control and magnetically-treated barrier regions did occur. In the present study and in O'Connell et al (2014), there were two and three rows of alternating columns, respectively, whereas in the previous study (O'Connell et al, 2013b), only one row of columns was deployed.…”

Section: Bull Sharksmentioning

confidence: 99%

“…However, although beach nets are successful at reducing this conflict, substantial and localized elasmobranch mortality occurs (Dudley, 1997;Dudley and Cliff, 1993;Dudley and Gribble, 1999) in addition to non-target species mortality (Gribble et al, 1998). To address this mortality and using the findings from previous beach net-associated magnetic repellent analyses (O'Connell et al, 2012a(O'Connell et al, , 2013a, an eco-friendly conservation technology, known as the Sharksafe barrier, was developed (O'Connell et al, 2014). This barrier contains two key stimuli:…”

Section: Introductionmentioning

confidence: 99%

“…Using this technology, a previous study demonstrated that swimming patterns of all interacting Carcharodon carcharias significantly changed in the presence of the barrier and that the barrier can withstand heavy seas (exceeding 4 m), is cost-effective, does not require electrical input, and requires little maintenance since barium-ferrite magnets do not degrade in seawater. However, this experiment (O'Connell et al, 2014) only evaluated changes in shark swim patterns, not whether the technology could be used to exclude sharks which is integral to understanding the utility of this technology as an alternative to beach nets. Furthermore, observations could not be conducted in low visibility conditions (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Bull shark ( Carcharhinus leucas ) exclusion properties of the sharksafe barrier and behavioral validation using the ARIS technology

O’Connell

Hyun

Rillahan

et al. 2014

Global Ecology and Conservation

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a b s t r a c tMagnetic deterrents have recently been employed to assess their ability to reduce elasmobranch mortality in beach nets. With previous studies exhibiting promise, the present study examined the ability of a magnetic barrier technology, known as the Sharksafe Barrier, to exclude bull sharks (Carcharhinus leucas) from bait, and how behavioral interactions may change with variations in environmental and biological factors. Generalized linear mixed model analyses based on 114, 30-min trials illustrate that all interacting C. leucas were successfully excluded from baited procedural control and magnetic regions (i.e. zero entrances through either region). Avoidance and pass around frequencies significantly differed from the control region and were based on situational context. To enhance behavioral analysis techniques, an Adaptive Resolution Imaging Sonar (ARIS) was employed which revealed that C. leucas distance from and swim speed associated with the magnetic barrier region were significantly greater than those associated with the procedural control region. This study demonstrates the Sharksafe barrier's effectiveness in excluding C. leucas from baited regions, regardless of variations in biological and/or environmental parameters. While other bather protection systems (e.g. beach nets and drumlines) continue to be used, this study exhibits promise that the Sharksafe barrier can be an eco-friendly alternative to beach nets.

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Section: Bull Sharkscontrasting

confidence: 65%

Section: Bull Sharkscontrasting

confidence: 52%

Section: Bull Sharksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bull shark ( Carcharhinus leucas ) exclusion properties of the sharksafe barrier and behavioral validation using the ARIS technology

O’Connell

Hyun

Rillahan

et al. 2014

Global Ecology and Conservation

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Testing the exclusion capabilities and durability of the Sharksafe Barrier to determine its viability as an eco‐friendly alternative to current shark culling methodologies

O’Connell¹,

Andreotti

Rutzen³

et al. 2017

Aquatic Conservation

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1. Following a shark attack, local governments often rapidly respond by implementing indiscriminate shark culls. These culls have been demonstrated to have substantial localized and adverse effects on a variety of marine organisms, and therefore there is an increasing need for an ecofriendly alternative that maximizes both beachgoer and marine organismal safety.2. In response to such culls, the novel magnetic barrier technology, the Sharksafe Barrier was developed and rigorously tested on a variety of sharks implicated in shark attacks (e.g. bull sharks -Carcharhinus leucas and white sharks -Carcharodon carcharias). Although these studies exhibited promise in shark swim pattern manipulation and C. leucas exclusion, research was lacking in assessing if the technology could serve as an alternative to shark nets, or more specifically, if it could exclude motivated C. carcharias from bait.3. Using a 13 m × 13 m square exclusion zone, this study aimed to test the C. carcharias exclusion capabilities of the Sharksafe Barrier while additionally assessing the long-term structural integrity of the system. 4. After 34 trials and approximately 255 hours of total video collected over two years, data illustrate that all interacting C. carcharias were successfully excluded from the baited Sharksafe Barrier region, whereas teleosts and other small elasmobranch species were not. In addition, the long-term deployment potential of this barrier system held promise owing to its ability to withstand harsh environmental conditions. 5. Therefore, with the successful exclusion of a second large shark species, C. carcharias, from a baited region, continued long-term research and implementation of this system at other locations should be considered to assess its viability and overall success as a bather and shark protection system.

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Evaluating the effects of a SharkSafe Barrier™ shoreline deployment on bull shark (Carcharhinus leucas) behaviour

O’Connell

Gressle²,

Crews

et al. 2021

Aquatic Conservation

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1. Beach nets and drumlines are lethal devices that are used to minimize the interaction between potentially dangerous sharks and beachgoers. Mortality to these large shark species as a result of these lethal measures has led to the development of non-invasive technologies that may minimize the risks of rare encounters with beachgoers while simultaneously protecting vulnerable sharks and other marine species.2. One such technology is the SharkSafe Barrier™, which uses visual and magnetic stimuli to non-invasively deter sharks from a designated area. Previous experiments using this technology were performed on a small scale (e.g. 13 m Â 13 m), with an attempt made to extrapolate the results to a larger scale application without actual large-scale deployments and experimentation.3. The present study examined whether a large-scale SharkSafe Barrier™ shoreline deployment could successfully exclude the bull shark (Carcharhinus leucas) from acoustic and olfactory cues and evaluated whether the technology could serve as a less invasive replacement to current culling practices.4. Generalized linear mixed-model analyses based on 59 trials illustrate that C. leucas swimming behaviour (i.e. avoidances, entrances, and pass arounds) significantly differed between the control (i.e. unmanipulated area) and the experimental (i.e. SharkSafe Barrier™) regions. Unlike previous small-scale experiments, 10 of 16 sharks repeatedly penetrated the barrier and swam in an accelerated manner once within the experimental barrier region.5. The present findings raise concerns that the size of the previous experimental areas may have been insufficient to provide a realistic representation of barrier efficacy for large-scale deployments. With continued shark-culling measures in various locations, a non-invasive and eco-friendly alternative is needed, but substantial modifications to the current Sharksafe barrier design or an entirely new eco-friendly approach are needed as the barrier in its present state does not reliably deter large and potentially dangerous sharks from a large-scale area.

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Effects of the Sharksafe barrier on white shark (Carcharodon carcharias) behavior and its implications for future conservation technologies

Cited by 17 publications

References 37 publications

Bull shark ( Carcharhinus leucas ) exclusion properties of the sharksafe barrier and behavioral validation using the ARIS technology

Bull shark ( Carcharhinus leucas ) exclusion properties of the sharksafe barrier and behavioral validation using the ARIS technology

Testing the exclusion capabilities and durability of the Sharksafe Barrier to determine its viability as an eco‐friendly alternative to current shark culling methodologies

Evaluating the effects of a SharkSafe Barrier™ shoreline deployment on bull shark (Carcharhinus leucas) behaviour

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