A Novel Method to Infer Harbor Porpoise Foraging Behavior From Acoustic Data: A Comparative Assessment Against Established Techniques

ABSTRACT

Assessing foraging behavior of harbor porpoise ( Phocoena phocoena ) from acoustic data has become increasingly common. Yet, a wide range of analytical methods is currently used, often without formal evaluation of their comparability. This lack of cross‐method validation limits the ability to compare findings across studies and interpret differences in reported foraging activity. This study addressed this challenge by providing a systematic comparative evaluation of acoustic foraging detection methods, while introducing a novel refinement, the Search Buzz Foraging Identification (SBFI) method. We aimed to quantify the degree of similarity of the SBFI method alongside four established methods that use acoustic data and more specifically inter‐click intervals to identify foraging behavior. All methodologies were applied to the same F‐POD dataset collected at two locations for a full year. Comparability among methods was evaluated using correlation, distance, and trend analyses to assess agreement in relative patterns, absolute magnitude, and temporal dynamics. Most methods indicated strong agreement in relative foraging patterns and temporal trends; however, differences in magnitude and context‐dependent biases emerged under specific spatial or seasonal conditions, suggesting methods are not completely interchangeable. The SBFI method showed strong correlation with several existing methods while providing a comprehensive and accessible framework for identifying foraging behavior. This study gives a systemic overview of existing foraging metrics and provides a basis for improved comparability and interpretation of acoustic‐based foraging studies.