Longitudinal health and disease monitoring in juvenile Steller sea lions (Eumetopias jubatus) in temporary captivity in Alaska compared with a free-ranging cohort

摘要

From March 2003 to June 2006, 77 juvenile Steller sea lions (Eumetopias jubatus) from the endangered western stock were captured in Resurrection Bay and Prince William Sound, Alaska. Thirtyone were brought into temporary captivity (transient juveniles) for short-term research studies, and 46 were captured, sampled, and released for a control comparison. The groups of wild-caught sea lions were rotated through a quarantine facility. The objectives of this study were to measure exposure to marine and terrestrial mammalian pathogens in temporarily captive Steller sea lions over time, screen for commensal and pathogenic bacteria, and monitor changes in antimicrobial resistance in bacterial isolates. Antibodies to Toxoplasma gondii and Brucella marinus were detected in both free-ranging and transient juveniles. Although an increase in titers to Leptospira spp. and phocine herpesvirus-1 was detected in a small number of sea lions while housed in temporary captivity, none developed evidence of clinical disease. Additionally, exposure was also found to these potential pathogens in the free-ranging control Steller sea lions. There were no significant differences among the variety of bacterial types obtained from, any culture site or animal groups, and antibiotic resistance did not occur in any transient juveniles while in captivity nor in isolates from the free-ranging controls. Results therefore indicated that free-ranging Steller sea lions were not placed at risk for disease following the release of the transient juveniles back into the marine environment.