The Research Research Analysis Basal Metabolism Resting metabolic rate is determined every three weeks in a dry metabolic chamber, measuring amounts of gas exchange through a respirometer. This data is used to monitor seasonal and developmental changes in energy requirements of the Stellers, which indicates when, at particular times of the year, and at different ages, sea lions may have higher or lower food requirements. Results have shown that energy requirements drop as the animal ages, but also fluctuates seasonally, being higher in the winter and lower in the summer.
Body mass is monitored on a daily basis.
Many of the prey items are of different energy densities, making it important to monitor daily changes in body mass. When fed a lower calorie prey, such as pollock, the sea lions appear unable to maintain body mass. The sea lions are being trained to hold position against a current in a swim mill to measure energetic costs of swimming. The tank is completely covered except for a canopy through which the sea lion's expired gases are collected. By testing the sea lions at various swimming speeds, researchers obtain information on the possible energetic effects of changes in prey location and abundance for wild sea lions.