nutritional stress?

collecting steller sea lion scat for research

Nutritional stress potentially ties all of the hypothesized reasons for the sea lion decline together. A number of our studies are therefore addressing how changes in the quality or quantity of prey can adversely affect the health or physiology of individual sea lions and alter population size. Such studies help to identify whether Steller sea lions are nutritionally stressed, and whether it is due to a decrease in prey quantity (overfishing), or a decrease in fatty high quality species in the sea lion diet (ecosystem change), or increase the susceptibility to being killed by killer whales (predation), or disease (other factors).  These studies address:

  • Nutritional Stress – What is it and could it have caused the decline in Steller sea lions?
  • Diet Determination―What are sea lions eating and how can it best be determined?
  • Nutrition of Prey – What is the nutritional value of different prey types to sea lions?
  • Energy Needs―How much prey do sea lions need?
  • Effect of Changes in Prey Quantity―How does a change in prey abundance affect sea lions?
  • Effect of Changes in Prey Quality―How does a change in nutritional value of prey affect sea lions?
  • Detecting Nutritional Stress―How can changes in nutritional status be observed in wild sea lions?


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New Technologies
  • Trained Steller sea lions test hypotheses and develop new approaches
Nutritional Stress?
Why did they decline?
We undertake studies to test the leading hypotheses thought to explain the decline of Steller sea lions.
Sea lion biology and ecology
Information about the ecology, biology, physiology, behaviour and population dynamics of sea lions is needed to resolve why sea lions have declined.