Abstract

The health of wildlife species has received growing attention both from a conservation perspective and from the global 'One Health' initiative, which integrates human-, animal-, and ecosystem health sciences. Wildlife health can be impaired by changes in environmental factors, infectious agents, and inherent or congenital defects, all of which can be exacerbated by anthropogenic factors. Florida manatees (Trichechus manatus latirostris) are under significant anthropogenic pressure, and collisions with watercraft and loss of warm-water winter habitat have been identified as the greatest threats to the population.² Over the past several years, conservation partners have captured free-ranging manatees to perform physical exams and collect samples, in order to establish a reference range of data values associated with key health parameters for the species. Collected data include blood values and morphometrical information including fat measurements.^1,3 Additional biological samples have been archived to facilitate future analyses. The skin of captured manatees is thoroughly examined for cold-related lesions given that environmental temperature is an important stressor. In order to determine if parameter values in manatees differ among regions of the state, and to explore the sensitivity of current health parameters, we perform health assessments on manatees in two different winter habitats. The habitats include a complex of artesian springs on Florida's west central coast (Crystal River) and a region along Florida's east central coast where manatees rely on one industrial warm-water effluent and a network of secondary warm-water sites (Brevard County). To date, 180 manatees have been captured and evaluated. Overall, captured manatees appeared healthy and no zoonotic pathogens or other infectious diseases or obvious effects of environmental pollution were detected. Although work is ongoing, a preliminary comparison of manatees between regions revealed more evidence of cold exposure in the east coast group. Interestingly, the only deviation from baseline across the two groups was in December 2010, when manatees captured at both sites (n = 20) demonstrated flat and folded ventrums, indicating poor filling of the gastrointestinal tract. These captures directly preceded record cold December temperatures, and a cold-related unusual mortality event was declared on both central Florida coasts later that month. During such events, necropsies and rescues provide valuable information on regional morbidity and mortality; however, health assessments can contribute to a more complete understanding of associated health issues involved in large scale die-offs and for monitoring population health following major events. For example, health assessments in Crystal River later in winter 2010–2011 showed that body condition appearance was back to baseline in captured manatees. But what are the long term impacts of such a large-scale disturbance to the manatee population beyond immediate high mortality? By continued monitoring of live animal health, in combination with carcass surveillance and rescues, our intent is to identify meaningful changes in manatee health related to known or emerging burdens such as potential loss of warm-water capacity and impacts of human pressures on the environment. For this, a conceptual framework is needed that articulates key objectives to assess baseline manatee health parameters and to timely detect population health concerns.

Acknowledgements

Manatee captures are a tremendous team effort and the authors are very appreciative of the invaluable assistance of our colleagues and volunteers from FWRI, USGS, UF and USFWS. Manatee health assessments were conducted under USFWS research permit issued to USGS #MA-791721.

* Presenting author

Literature Cited

1.  Bonde R, Walsh MT, de Wit M, Garrett A. 2011. Manatee health assessment as a tool for research projects. 19th Biennial Conference on the Biology of Marine Mammals Proceedings, Tampa, FL: P. 37.

2.  Runge MC, Sanders-Reed CA, Langtimm CA, Fonnesbeck CJ. 2007. A quantitative threats analysis for the Florida manatee (Trichechus manatus latirostris). U.S. Geological Survey Open-File Report 2007–1086. 34 pp.

3.  Walsh MT, Bonde R, de Wit M, Beck C, Garrett A, Reid J, Wong AW, Meegan J, Fricott J. 2009. Health assessments in wild manatees (Trichechus manatus latirostris); individual health and restraint monitoring, intervention, and population health parameters of concern. IAAAM 40th Annual Conference Proceedings, San Antonio, TX; Pp.1–2.