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The coastal waters off Southern California are feeding grounds for a variety of baleen whale species including blue whales, fin whales, and humpback whales. The feeding grounds overlap with highly used shipping lanes in the Santa Barbara Channel (SBC), increasing the risk of ship-whale interactions. In November 2019, a buoy equipped with a digital acoustic monitoring (DMON) instrument was deployed in the SBC and has been actively recording sounds and transmitting detection information in near real time since then. Data are transmitted in fifteen-minute summary periods of detected pitch tracks, which are reviewed by an analyst onshore for blue, fin, and humpback whale calls. Humpback whales were the most prolific callers, with detection rates reaching 80% of daily summary periods, whereas fin and blue whales rarely exceeded 20%. Baleen whale detections were low in late fall, with humpback whale detections increasing throughout winter and in spring and blue whale detections peaking during the summer. As part of the Benioff Ocean Initiative project to reduce whale strikes, these data are combined with visual surveys in the SBC and habitat models to produce a whale presence metric. This metric can be used by regional stakeholders to guide policy decisions and enhance conservation efforts.

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