Behavioral biology of marine mammal deterrents: A review and prospectus

Marine mammal depredation of fisheries is a concern from a scientific, management, and conservation perspective. This conflict has prompted the development of non-lethal deterrents, a management technique that uses aversive stimuli to elicit avoidance. Animals are expected to be sensitive to cues of danger to avoid sources of mortality. Deterrents capitalize on behavioral mechanisms such as threat detection, assessment and learning. A deterrent must create enough risk, or cost, that it overcomes the heightened foraging benefits of depredation. Theoretically, effective deterrence relies on altering the relative costs and benefits to the individual depredator by creating a perceived risk associated with human resources. Here we discuss the underlying behavioral basis of how deterrents generate avoidance. We review deterrents applied to marine mammals to mitigate conflict with fisheries and suggest that fear conditioning could be useful in this context. This is discussed in the context of some potential management concerns of application of non-lethal deterrents in the wild.