Factors Affecting Energy Expenditure in a Declining Fur Seal Population
Understanding energy balance in animals can inform wildlife conservation efforts that ensure survival and reproductive success. In this study, researchers investigated the effect of diving behavior, diet, and season on field metabolic rates and foraging success of lactating northern fur seals (Callorhinus ursinus) from the Pribilof Islands in the Bering Sea.
Since the 1990’s, the population of northern fur seals has declined by half for reasons that are still unknown. Field metabolic rate measurements obtained in this study shed light on the effort that fur seal mothers expend on finding food and how energy needs are changing at the critical time of pup provisioning and growth.
Results indicate that females are working hard to find food and that they likely have limited capacity to further increase foraging effort in response to environmental changes. These high metabolic rates mean that a female expends on herself a considerable amount of the energy she gains from foraging, thereby reducing the amount of energy she has to invest in lactation. These results provide indirect support for the hypothesis that food limitation may be contributing to the poor growth observed in this declining population.
Citation
McHuron, E.A., Sterling, J.T., Costa, D. P., and Goebel, M.E. (2019). Factors affecting energy expenditure in a declining fur seal population. Conservation Physiology. http://doi.org/10.1093/conphys/coz103
