| 要旨トップ | 目次 | | 日本生態学会第73回全国大会 (2026年3月、京都) 講演要旨 ESJ73 Abstract

一般講演（ポスター発表） P1-365 （Poster presentation）

#### Beyond the camera view: Using sensor data to reveal vessel-related feeding and the diving ecology of humpback whales【A】【E】

*Menghua LV（The University of Tokyo）, Kagari AOKI（Teikyo University of Science）, Patrick J. O. MILLER（University of St Andrews）, Katsufumi SATO（The University of Tokyo）

Herring grounds are characterized by high density of herring and intensive fishing activity, creating a complex ecological context in which fish-eating predators exhibit diverse diving and foraging behaviors. Multiple cetacean species, including humpback whales, have been reported to aggregate around fishing boats and engage in vessel-associated foraging. While multi-sensor biologging data provide continuous measurements of animal movements, interpreting these data in terms of behavioral states remains challenging, particularly in complex environments involving vessels and the presence of other humpback whales and killer whales. Video data offer valuable behavioral context but are typically limited in temporal coverage. Here, we investigated the diving patterns of humpback whales in a Norwegian herring ground by combining sensor-derived dive parameters with video-identified events. Nineteen humpback whales were tagged using suction-cup tags equipped with a sensor logger and video camera in the offshore waters in Norway between 2023 and 2025. Kinematic features derived from sensor data, including acceleration, depth, and body orientation, were clustered, and video-scored events were projected onto the clustered dives to assess associations between specific events and dive patterns. Results from one individual (ID mn23_299a) were presented to illustrate the integration of sensor-derived dive parameters and video-identified events. Results showed that humpback whales exhibited distinct diving patterns when close to fishing vessels compared to when away from vessels. Vessel-related dives were generally shallow (mean maximum depth = 9.30 ± 5.59 m, n = 124 dives) and characterized by higher stroking rates (0.42 ± 0.08 s⁻¹), frequent body posture adjustments, and frequent changes in heading (circular variance = 0.54 ± 0.22), consistent with movements to remain close to vessels during fishing activity. Two distinct vessel-associated foraging patterns were identified: a low-intensity pattern characterized by moderate movement and limited body adjustment, and a high-intensity pattern characterized by drastic movements such as surface lunging and body rolling. In contrast, dives occurring away from vessels also showed multiple patterns, including shallow moving dives (mean maximum depth = 7.69 ± 2.85 m, n = 111 dives) with stable body posture and consistent movement direction, deeper dives (mean maximum depth = 90.51 ± 42.33 m, n = 29 dives) lacking clear lunge signals that may represent search or transit behaviors, and intermediate transition states (mean maximum depth = 17.56 ± 15.57 m, n = 54 dives) positioned between distinct diving patterns, suggesting a behavioral transition.

日本生態学会