Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour.
Personal shark deterrents offer the potential of a non-lethal solution to protect individuals from negative interactions with sharks, but the claims of effectiveness of most deterrents are based on theory rather than robust testing of the devices themselves. Therefore, there is a clear need for thor...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2019-01-01
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| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0212851 |
| _version_ | 1818588168241283072 |
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| author | Channing A Egeberg Ryan M Kempster Nathan S Hart Laura Ryan Lucille Chapuis Caroline C Kerr Carl Schmidt Enrico Gennari Kara E Yopak Shaun P Collin |
| author_facet | Channing A Egeberg Ryan M Kempster Nathan S Hart Laura Ryan Lucille Chapuis Caroline C Kerr Carl Schmidt Enrico Gennari Kara E Yopak Shaun P Collin |
| author_sort | Channing A Egeberg |
| collection | DOAJ |
| description | Personal shark deterrents offer the potential of a non-lethal solution to protect individuals from negative interactions with sharks, but the claims of effectiveness of most deterrents are based on theory rather than robust testing of the devices themselves. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with information on their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between Carcharodon carcharias (white sharks) and a baited target in the presence of a commercially available electric anklet shark deterrent, the Electronic Shark Defense System (ESDS). The stereo-camera system enabled accurate assessment of the behavioural responses of C. carcharias when approaching an ESDS. We found that the ESDS had limited meaningful effect on the behaviour of C. carcharias, with no significant reduction in the proportion of sharks interacting with the bait in the presence of the active device. At close proximity (< 15.5 cm), the active ESDS did show a significant reduction in the number of sharks biting the bait, but this was countered by an increase in other, less aggressive, interactions. The ESDS discharged at a frequency of 7.8 Hz every 5.1 s for 2.5 s, followed by an inactive interval of 2.6 s. As a result, many sharks may have encountered the device in its inactive state, resulting in a reduced behavioural response. Consequently, decreasing the inactive interval between pulses may improve the overall effectiveness of the device, but this would not improve the effective deterrent range of the device, which is primarily a factor of the voltage gradient rather than the stimulus frequency. In conclusion, given the very short effective range of the ESDS and its unreliable deterrent effect, combined with the fact that shark-bite incidents are very rare, it is unlikely that the current device would significantly reduce the risk of a negative interaction with C. carcharias. |
| first_indexed | 2024-12-16T09:20:28Z |
| format | Article |
| id | doaj.art-0a54d877618d4e19921d4fa0bb820204 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-16T09:20:28Z |
| publishDate | 2019-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-0a54d877618d4e19921d4fa0bb8202042022-12-21T22:36:47ZengPublic Library of Science (PLoS)PLoS ONE1932-62032019-01-01143e021285110.1371/journal.pone.0212851Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour.Channing A EgebergRyan M KempsterNathan S HartLaura RyanLucille ChapuisCaroline C KerrCarl SchmidtEnrico GennariKara E YopakShaun P CollinPersonal shark deterrents offer the potential of a non-lethal solution to protect individuals from negative interactions with sharks, but the claims of effectiveness of most deterrents are based on theory rather than robust testing of the devices themselves. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with information on their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between Carcharodon carcharias (white sharks) and a baited target in the presence of a commercially available electric anklet shark deterrent, the Electronic Shark Defense System (ESDS). The stereo-camera system enabled accurate assessment of the behavioural responses of C. carcharias when approaching an ESDS. We found that the ESDS had limited meaningful effect on the behaviour of C. carcharias, with no significant reduction in the proportion of sharks interacting with the bait in the presence of the active device. At close proximity (< 15.5 cm), the active ESDS did show a significant reduction in the number of sharks biting the bait, but this was countered by an increase in other, less aggressive, interactions. The ESDS discharged at a frequency of 7.8 Hz every 5.1 s for 2.5 s, followed by an inactive interval of 2.6 s. As a result, many sharks may have encountered the device in its inactive state, resulting in a reduced behavioural response. Consequently, decreasing the inactive interval between pulses may improve the overall effectiveness of the device, but this would not improve the effective deterrent range of the device, which is primarily a factor of the voltage gradient rather than the stimulus frequency. In conclusion, given the very short effective range of the ESDS and its unreliable deterrent effect, combined with the fact that shark-bite incidents are very rare, it is unlikely that the current device would significantly reduce the risk of a negative interaction with C. carcharias.https://doi.org/10.1371/journal.pone.0212851 |
| spellingShingle | Channing A Egeberg Ryan M Kempster Nathan S Hart Laura Ryan Lucille Chapuis Caroline C Kerr Carl Schmidt Enrico Gennari Kara E Yopak Shaun P Collin Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour. PLoS ONE |
| title | Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour. |
| title_full | Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour. |
| title_fullStr | Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour. |
| title_full_unstemmed | Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour. |
| title_short | Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour. |
| title_sort | not all electric shark deterrents are made equal effects of a commercial electric anklet deterrent on white shark behaviour |
| url | https://doi.org/10.1371/journal.pone.0212851 |
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