Indicators of individual and population health in the Vancouver island Marmot (Marmota Vancouverensis)

The Vancouver Island Marmot (Marmota vancouverensis) is an endangered rodent endemic to the mountains of Vancouver Island, British Columbia, Canada. Following population declines in the 1980s and 1990s, an intensive captive breeding and reintroduction program was initiated involving three Canadian zoos and a purpose-built, subalpine facility on Vancouver Island. From 1997 to 2017, 660 marmots were associated with the captive program, including 63 wild-born individuals captured for breeding and 597 marmots born and weaned in captivity. Reintroductions began in 2003 and by 2017 a total of 501 marmots had been released. Although this significantly increased the wild population from its low point in 2003, conservation of the Vancouver Island Marmot (VIM) continues to involve intensive ex situ management, reintroductions, and translocations. Health and disease surveillence is fundamental to the success of conservation programs like the marmot recovery project. This thesis builds upon our understanding of VIM health by describing and evaluating select health parameters, to determine baseline characteristics for VIM under its different treatments (wild, captive and captive-release) and to identify potential risk factors that may influence the health of the marmot’s population and its capacity to achieve recovery objectives. The analysis involved data that was collected between 1992 and 2016, and included 1,106 VIM blood profiles, 3,174 physical examinations, 140 post mortem examinations and 533 field mortality records. VIM hematology and serum biochemistry reference ranges were calculated as a baseline metric and were qualitatively comparable to published values for other rodent species. Leukogram and protein values were found to have potential utility as a quantitative measure for comparing VIM management groups. There were significant differences in the clinical and pathological data collected from captive and free-ranging (captive-release and wild) marmots. Captives could be monitored with greater intensity and to an older age, due to increased longevity. A host of clinical and pathological disorders were described in captive marmots, including age-related, management-related, and congenital problems. There was a paucity of health conditions identified in free-ranging VIM and this could be due to a fundamental lack of disease, or limited opportunities to conduct post mortem examinations or evaluate compromised individuals in the field. The analysis did not identify any specific infectious agents that represented a generalized population threat to VIM. Cardiomyopathy and neoplasia, which occurred in older individuals, were the most consequential health complications for captive marmots. Implantation of abdominal radio-transmitters was not found to impact marmot health and was important for identifying mortalities in the field. The first wild hibernation represented a time of significant mortality for VIM released from captivity. However, reintroduced marmots that survived their first year in the wild were comparable to their wild-born counterparts with respect to hibernation success and clinical presentation. Predators continued to represent a major cause of mortality for free-ranging marmots. In the absence of other identified health threats, predation and reduced hibernation success of captive-release marmots appear to be significant factors limiting the health and potential recovery of the in situ population.