Challenges of using passive acoustic monitoring for marine mammals during anthropogenic activities.

Abstract

Monitoring the presence of marine mammals in the vicinity of an anthropogenic activity using passive sonar can greatly improve detection rates by visual monitoring, and it is the only way to detect marine mammals at large distances during nighttime monitoring. Therefore, passive acoustic monitoring (PAM) is sometimes required by regulatory agencies as a mean to supplement visual monitoring during anthropogenic activities that may potentially adversely affect marine mammals. However, there are many critical aspects that need to be taken into consideration when prescribing PAM to support mitigation measures. These challenges include (1) training for shipboard observers to operate and maintain sophisticated PAM hardware and software; (2) proper design of PAM system that works well during industrial operations (such as seismic vessels); (3) reliable bearing and ranging of calling of animals, thus providing basis for mitigation measures; and (4) the affordability of PAM system to small businesses. This presentation provides a comprehensive analysis on the above aspects that are essential for marine mammal passive acoustic monitoring during anthropogenic activities, and highlights future needs to improve and expands PAM as a standard technique to support mitigation measures to reduce anthropogenic impacts.