Temporary Captivity as a Research Tool: Comprehensive Study of Wild Pinnipeds Under Controlled Conditions

Abstract: A new approach to the study of free-ranging, endangered western stock Steller sea lions (Eumetopias jubatus) was implemented at the Alaska SeaLife Center in Seward, Alaska. Groups of up to four juvenile (n = 16) Steller sea lions were held in temporary quarantine for research periods of up to three months. Hematological and blood chemistry parameters were collected at the beginning and end of captivity and compared to free-ranging juvenile controls to determine if animals in temporary captivity can provide accurate physiological data representative of their wild counterparts. Free-ranging pups and juveniles were compared for hematological differences related to developmental stage. Overall, temporarily captive animals did not differ from free-ranging juveniles. Seven of 17 blood parameters measured changed significantly during captivity, likely as a function of a regular schedule and low-impact nutritional studies (e.g., increased mass, cholesterol, total protein, and globulins). A decrease in white blood cells during the study period (10.4 ± 0.59 to 7.9 ± 0.33 m/mm3) to levels lower than that of free-ranging animals (10.7 ± 0.40 m/mm3) indicated a drop in overall stress during captivity despite research and handling procedures. Calcium increased with captivity duration, suggesting that physiological changes can begin in even limited time frames. Eight parameters related to immune status and diet differed significantly between juveniles and pups from the same geographical region. A strategy that combines the benefits of an extended research design with temporary holding of free-ranging animals is proposed as an alternative to traditional field methods for some types of focused physiological studies.

Key Words: Steller sea lion, Eumetopias jubatus, temporary captivity, blood panel

Document Type: Research article

DOI: 10.1578/AM.32.1.2006.58

Page Numbers: 58-65

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