Foraging efficiency is a product of balancing aerobic activity using on-board oxygen stores, anaerobic activity after oxygen stores are depleted and dive productivity in volume of prey captured. This relationship between calories expended and calories gained can be put more simply as:
While longer dives may increase the volume of prey captured, they can also result in more anaerobic activity and a longer recovery time, delaying subsequent foraging dives. Data on fish capture, stroke performance, time, depth, and oxygen consumption, has been collected from Weddell seals in Antarctica over 4 field seasons. These variables correlate to energetic cost and will allow me to measure the efficiency of their foraging dives as well as better understand the physiological trade-offs involved.