Diving Behavior and Fine-Scale Kinematics of Free-Ranging Risso's Dolphins Foraging in Shallow and Deep-Water Habitats

摘要: Air-breathing marine predators must balance the conflicting demands of oxygen conservation during breath-hold and cost diving locomotion to capture prey. However, it remains poorly understood how modulate foraging performance when feeding at different depths in response changes prey distribution type. Here, we used high-resolution multi-sensor tags attached Risso’s dolphins (Grampus griseus) concurrent surveys quantify their over a range types. Dolphins (N=33) foraged shallow deep habitats [seabed less or more than 560m, respectively] within habitat, vertically stratified features occurring several aggregation levels. Generalized linear mixed-effects models indicated that dive kinematics were driven by depth rather habitat. Bottom-phase duration number buzzes (attempts prey) per increased with depth. In dives, gliding for >50% descent adopted higher pitch angles both ascents, which was likely reduce energetic longer transits. This lower transit counteracted record highest vertical swim speeds, rolling maneuvers stroke rates depth, together 4-fold increase inter-buzz interval, suggesting costs pursuing handling compared shallow-water feeding. spite effort managed keep estimated overall metabolic rate comparable across indicates adjustments swimming modes may enable energy deeper dives. If think surface as central place where divers return breathe, our data match predictions foragers should quality items greater distances. These forage efficiently from near-shore benthic communities depth-stratified scattering layers, enabling them maximize fitness.