Toward acoustically derived population estimates in marine conservation: An application of the spatially-explicit capture-recapture methodology for North Atlantic right whales

Passive acoustics provide a flexible tool for developing understanding of the ecology and behavior of vocalizing marine animals. Yet despite a robust capacity for detecting species presence, our ability to estimate population abundance from acoustics still remains poor. Critically, abundance estimates are precisely what conservation practitioners and policymakers often require. In the current study, we explored the application of acoustic data in the spatially-explicit capture-recapture (SECR) methodology, to evaluate whether acoustics can be used to infer abundance in the endangered North Atlantic right whale. We sub-sampled a year-long acoustic dataset from archival recorders deployed in Massachusetts Bay. Multichannel data were reviewed for the presence of up-calls. A total of 1659 unique up-calls were detected. Estimates of up-call density ranged from zero to 608 (± 70 SE) up-calls/hour. Estimates of daily abundance, when corrected for average calling rate, ranged from 0—69 (± 21 SE) individuals per d...