Behavioral modification of visually deprived lemon sharks (Negaprion brevirostris) towards magnetic fields

C. P. O'Connell, T. L. Guttridge, S. H. Gruber, J. Brooks, J. S. Finger, P. He

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The ability of elasmobranchs to orient to weak electromagnetic fields is well documented. Recently, scientists have employed the use of strong electrosensory stimuli, such as permanent magnets, as a means to evaluate the repellent responses of elasmobranchs and assess the utility of these materials for bycatch repellent technologies. However, several studies have produced contrasting results both between and within species. To explain these results, we hypothesized that conditions leading to vision loss (i.e. turbid water) may be a factor affecting electrosensory repellent success. To simulate a visually deprived environment, the nictitating membranes of juvenile lemon sharks (Negaprion brevirostris) were temporarily sutured closed and the behavioral responses of sharks towards a magnetic apparatus were observed in a pen within the shallows of Bimini, Bahamas. Results demonstrate that the magnet-associated behavior of visually deprived sharks significantly differed from control sharks in regard to: (1) avoidance distance, (2) visit quantity prior to first entrance through the magnet zone, and (3) total entrances/total visits. These findings suggest context-dependent switching, where elasmobranchs may exhibit a heightened reliance on their electrosensory system when the extent of their visual range is reduced. These findings also provide insight into favorable environments (e.g. estuary or other coastal ecosystems) and applications (e.g. inshore fisheries and beach nets) that may yield more consistent and successful future implementations of electrosensory repellents for sharks.

Original languageEnglish (US)
Pages (from-to)131-137
Number of pages7
JournalJournal of Experimental Marine Biology and Ecology
StatePublished - Apr 2014

Bibliographical note

Funding Information:
We would first like to thank the Bimini Biological Field Station (BBFS) Foundation for providing support for this research project. In addition, we would like to thank the BBFS staff members and volunteers, such as Lindsay Biermann, Michael Timm, T.J. Ostendorf, Lauren Portner, Kelsey Evans, and Abby Nease for their assistance in specimen capture and experimentation. A special thanks to Dr. John Mandelman, Dr. Gregory Skomal, Dr. Kevin Stokesbury, and Dr. Saang-Yoon Hyun from the University of Massachusetts Dartmouth for assistance in experimental design and manuscript review, and Dr. Jens Krause for reviewing and providing input for this manuscript. Lastly, we would like to thank the University of Massachusetts IACUC and the Bahamas Government for granting the proper permissions to conduct this research. [SS]


  • Beach nets
  • Elasmobranchs
  • Electrosensory repellents
  • Lemon sharks
  • Negaprion brevirostris
  • Permanent magnets


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