An automated approach for detection and classification of toothed whales in Hawai'i marine protected areas

Passive acoustic monitoring is an effective technique for studying cetacean presence within marine protected areas (MPAs). The Hawaiian archipelago is home to 18 species of resident toothed whales, but little is known regarding the spatio-temporal variability of false killer whales (Pseudorca crassidens—FKW) and short-finned pilot whales (Globicephala macrorhynchus) across Hawai‘i MPAs. Bottom-moored recorders were deployed inside and outside the Hawaiian Islands Humpback Whale National Marine Sanctuary and Papahānaumokuākea Marine National Monument through SanctSound and Pacific Islands Fisheries Science Center. High Frequency Acoustic Recording Packages (HARPs) and SoundTraps (200 kHz/48 kHz SR, respectively) deployed between 2018 and 2022, allowed leveraging of long-term datasets. Data used in this study include 27 deployments across 11 sites, encompassing >187 months of data. Here, we describe an automated approach for species classification which is challenging given the high spectral overlap in whistle features and acoustic masking during humpback whale season. PAMGuard detectors were used to detect whistles, clicks, and burst pulses. Features were extracted using PAMpal and species classified using BANTER models and confirmed from a Hawaiian Islands Ecosystem Assessment Survey annotated dataset. Acoustic monitoring provides vital information about the value of MPAs and a better understanding of endangered insular FKW habitat use.