Development and Application of Marine Mammal Density Estimation Methods for Directional and Omnidirectional Hydrophones
Estimates of the population density of marine mammals in an area and the change in population over space and time are critical inputs for managing the interactions of human activity and mammal populations. Visual surveys from boats, shore stations, and aircraft have served as the basis for most population estimates currently used by managers. However, these survey methods are generally only performed in good weather conditions and require many trained observers. These factors make visual surveys expensive and reduce the temporal and spatial coverage of population estimates. Passive acoustic monitoring (PAM) data, which can be collected night-and-day, in all weather conditions and year-round, are a cost-effective alternative to visual data. JASCO has data sets and ongoing data collection programs whose results that contain the vocalizations of numerous marine mammal species that are of high concern to regulators and the public, including right, blue and sei whales on the east coast and southern resident killer whales on the west coast of Canada. Converting the acoustic detections into estimates of the population density would greatly enhance the conservation value of the data sets.