Seasonal variation in nutrient composition of Alaskan walleye pollock (Theragra chalcogramma) and its effect on the nutritional status of Steller sea lions (Eumetopias jubatus) ...

• Main Author: Azana, Cynthia Dy Prieto
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Theragra chalcogramma; Alaska
• Online Access: https://dx.doi.org/10.14288/1.0074850; https://doi.library.ubc.ca/10.14288/1.0074850

Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska declined since the late 1970s. Their population decline might be related to a shift in their diet from fatty, high-calorie fishes such as herring (Clupea pallasi) to low energy density fish such as walleye pollock (Theragara chalcogrammd). I compared the nutritional value of herring with pollock and explored seasonal changes in the nutrient content of pollock. I also compared the nutritional status of three captive Steller sea lions fed pollock and herring. Herring was a more concentrated in dietary lipid (p<0.001) and energy source (p<0.001) than pollock. The protein of herring was also higher in digestibility (p=0.015) than pollock protein, which could indicate that even if ingested energy was equal in both diets, absorbed energy for body functions may be reduced when pollock is eaten. There was little difference in the protein quality of pollock and herring with the exception that valine was more abundant in herring (p=0.004). The energy ...