Effects of the Sharksafe barrier on white shark behavior and its implications for future conservation technologies
Published online on 26. June 2014
Effects of the Sharksafe barrier on white shark (Carcharodon carcharias) behavior and its implications for future conservation technologies
Craig P. O’Connell, Sara Andreotti, Michael Rutzen, Michael Meÿer, Conrad A. Matthee, Pingguo He
ABSTRACT:
The white shark (Carcharodon carcharias) is an apex predator and is a protected species that suffers from several sources of anthropogenic mortality, such as shark nets. Shark nets are devices used to minimize the interaction between beachgoers and potentially dangerous sharks; however, these nets have negatively impacted local and migratory shark populations, in addition to killing substantial quantities of other marine organisms. To address this issue, the present study developed and examined the effects of an alternative technology (the “Sharksafe” barrier) composed of two stimuli: (1) visual-artificial-kelp and (2) electrosensory-magnets, on C. carcharias behavior. Generalized linear mixed effect models were used to test hypotheses pertaining to the effects of treatment type, exposure quantity (i.e. habituation), conspecific density, and water visibility on shark behavior. Analyses based on forty-nine, one-hour trials illustrate that the swim patterns of all sixty-three individual C. carcharias was altered in the presence of the artificial kelp-the procedural control region, and the magnetic kelp-the magnetic region of the barrier (i.e. procedural control and magnetic regions reduced entrance frequency and increased avoidance and pass around frequency). Also, preliminary observations illustrated that the barrier had no observable impact on Cape fur seal (Arctocephalus pusillus pusillus) behavior. The C. carcharias-specific repellency associated with the Sharksafe barrier and the ability of the barrier to withstand harsh environmental conditions warrant future experiments to assess its exclusion capabilities on predatory sharks and possible application to replace shark nets.
Journal of Experimental Marine Biology and Ecology, Volume 460, November 2014, Pages 37–46