Collisions with ships and entanglement in fishing gear have been identified as major sources of mortality. Passive acoustic monitoring is a tool that could provide information required for effective management action. The aim of the Workshop was to evaluate the technical feasibility of passive acoustic monitoring to provide information on North Atlantic right whale distribution, at appropriate spatial and temporal scales, that could be used to develop measures to reduce anthropogenic mortality. There are a number of well established technologies for acoustic sensors and signal processing. However, some of the proposed mitigation measures may require considerable development, in order to detect right whales at locations far from shore, process the acoustic data automatically in real-time, and transmit information ashore so that management decisions can be made in a timely manner.
Right whales make a variety of vocalizations.
Recent studies indicate that the vocal behavior of North Atlantic, North Pacific and southern right whales are similar. Results of studies, in which passive acoustic and visual data have been collected simultaneously, indicate that passive acoustic systems can reliably detect the presence of right whales. Vocalization rates of North Atlantic right whales are highly variable and individuals have been known to remain silent for several hours. Oceanographic conditions in some North Atlantic right whale habitats are generally not optimal for acoustic propagation. Nevertheless, North Atlantic right whale vocalizations have been consistently detected at ranges of several miles and ranges of up to 13 nautical miles have been reported.