Response of juvenile lemon sharks, Negaprion brevirostris, to a magnetic barrier simulating a beach net

O’Connell, Craig P.; Abel, Daniel C.; Gruber, Samuel H.; Stroud, Eric M.; Rice, Patrick H.

doi:10.1016/j.ocecoaman.2010.11.006

Cited by 42 publications

(28 citation statements)

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“…These findings suggest that beyond the visual stimuli provided by the columns, the magnetic fields might have enhanced barrier exclusion efficacy, further supporting previous studies on magnetoreception capabilities and magnetic repellent effects on elasmobranchs (Rigg et al, 2009;O'Connell et al, 2010O'Connell et al, , 2011aO'Connell et al, , 2012aO'Connell et al, , 2013a.…”

Section: Bull Sharkssupporting

confidence: 88%

“…Exploiting an elasmobranch's ability to detect magnetic fields, research demonstrates that supernormal magnetic stimuli, such as those produced by permanent magnets, can elicit repellent responses in elasmobranchs (Stoner and Kaimmer, 2008;Rigg et al, 2009;Robbins et al, 2011;O'Connell et al, 2010O'Connell et al, , 2011aO'Connell et al, , 2012aO'Connell et al, , 2013a. Scientists hypothesize that these responses occur due to flux differentials that exist between permanent magnets and geomagnetic fields.…”

Section: Introductionmentioning

confidence: 99%

“…For example, grade C8 barium-ferrite permanent magnets generate an approximate surface magnetic flux of 3850 G, where the geomagnetic flux ranges from 0.25 to 0.65 G. Being several orders of magnitude greater in strength, the novel stimulus produced by the permanent magnets is hypothesized to overstimulate the ampullary system and deter approaching elasmobranchs. To date, numerous studies tested this hypothesis and have produced mixed findings (Stoner and Kaimmer, 2008;Rigg et al, 2009;Robbins et al, 2011;O'Connell et al, 2010O'Connell et al, , 2011aO'Connell et al, , 2012bO'Connell et al, , 2013a. Stoner and Kaimmer (2008) examined the behavior of Pacific halibut (Hippoglossus stenolepis), a teleost, and spiny dogfish (Squalus acanthias), an elasmobranch, in response to neodymium-iron-boride magnets (Nd 2 Fe 14 B).…”

Section: Introductionmentioning

confidence: 99%

“…Besides basic behavioral analyses, several studies were conducted which used permanent magnets for conservation applications to determine their potential to reduce elasmobranch capture in fisheries and beach nets (O'Connell et al, 2011a(O'Connell et al, ,b, 2012a(O'Connell et al, ,b, 2013b. These studies demonstrated that magnetic deterrent responses were species-specific and also were highly correlated with variations in environmental and biological parameters.…”

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 Sharkssupporting

confidence: 88%

Section: Introductionmentioning

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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“…Coastal communities often demand intervention to reduce the risk of further attacks, especially if an unusually high number of incidents have occurred in a short space of time (Curtis et al 2012). A wide range of mitigation measures to decrease the risks of shark attack have been implemented, including short-term targeted shark fishing, long-term deployment of shark-fishing devices such as gillnets or drumlines, use of shark repellents and, more recently, scientific studies to understand better the biology, ecology and behaviour of sharks (Cliff and Dudley 1992;Wetherbee et al 1994;Nel and Peschak 2006;Beschta and Ripple 2009;Cliff and Dudley 2011;O'Connell et al 2011O'Connell et al , 2014Hazin and Afonso 2014). In general, knowledge of apex shark predators remains scarce compared to their terrestrial counterparts (Beschta and Ripple 2009).…”

Section: Seasonal Variability Of Bull and Tiger Shark Presence On Thementioning

confidence: 99%

Seasonal variability of bull and tiger shark presence on the west coast of Reunion Island, western Indian Ocean

Blaison

Jaquemet

Guyomard³

et al. 2015

African Journal of Marine Science

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International audienceA fisheries‑independent survey using longlines and drumlines, and an acoustic telemetry study, revealed that bull sharks Carcharhinus leucas and tiger sharks Galeocerdo cuvier occur throughout the year off the west coast of Reunion Island. The research, which commenced in 2011, was conducted in response to an increase in the rate of shark attacks. Juvenile, subadult and young adult tiger sharks of 111–390 cm total length (TL) were caught in all months except July; the sex ratio was 1:1 (M:F; n = 61). All bull sharks taken, except one (183 cm TL), were mature (205–329 cm TL), with a sex ratio of 0.7:1 (M:F; n = 54), and catches occurred throughout the year except in May and August, with the highest CPUE in September. Presence/absence of a total of 46 tagged tiger sharks and 36 tagged bull sharks was monitored by means of 42 acoustic receivers distributed along the west coast of the island. Tagged tiger sharks were detected in all months, with seasonal variation between sexes. Detections of males remained low throughout the year but with a peak in winter, whereas detections of females were low in May and August only and peaked in summer. Tagged bull sharks of both sexes were more abundant in winter than in summer, with females present year round. The reasons for the apparent differences in seasonality found in longline and drumline catches compared to acoustic monitoring are discussed

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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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Response of juvenile lemon sharks, Negaprion brevirostris, to a magnetic barrier simulating a beach net

Cited by 42 publications

References 28 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

Seasonal variability of bull and tiger shark presence on the west coast of Reunion Island, western Indian Ocean

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

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