What Is It about Food? Examining Possible Mechanisms with Captive Steller Sea Lions

Changes in the quality or quantity of food can have a dramatic effect on the population status of wild animals. Unfortunately, it is difficult to assess (or define) whether nutritional stress is a contributing factor to the decline of any particular species. The “nutritional quality” of a diet to an animal is a complex matter to assess given the range of components that can influence its value. The effects of different diets on animal health are equally complex, and are particularly difficult to assess in large, wild animals. Research by the North Pacific Universities Marine Mammal Research Consortium with captive Steller sea lions is evaluating the possible mechanisms by which dietary changes might adversely affect the nutritional or health status of individual animals, and ultimately the population as a whole. The research investigates the three potential proximate mechanisms by which changes in diet might impact Steller sea lions: a decrease in energy intake, a decrease in the intake of some essential element, and the over-consumption of an element detrimental to sea lion health.