Abstract: Florida manatees (Trichechus manatus latirostris) are known to range north into the U.S. mid-Atlantic during warmer summer and fall months. However, rapid cooling of water temperatures in the fall can be detrimental to their survival in this region. This study reports upon all known manatee sightings (n = 211) and strandings (n = 9) from 1991 to 2012 in North Carolina and Virginia. The goals were to describe spatial and temporal pat-terns of manatee habitat use and mortality and relate those patterns to seasonal water temperatures, and to develop a finer-scale understanding of environmental temperatures across the region by deploying temperature data loggers at multiple sites throughout inland and coastal waterways. Although sightings were opportunistically gathered and, thus, not corrected for effort, they reveal a consistent picture of manatee presence in the mid-Atlantic. In both states, sightings were most common from June to October when water temperatures were above 20° C. Sightings in North Carolina were most common in the Intracoastal Waterway (27%), and in rivers and creeks (46%) in Virginia. Fine-scale temperature data collected throughout the region demonstrated highly variable, declining water temperatures in late fall, with temperatures dropping by as much as 1.35° C/d. Manatee sightings decreased precipitously with water temperature in November, while strandings increased. The results of this study demonstrate that manatees are predictably found in North Carolina and Virginia throughout the late spring, summer, and fall. These data can be used to plan future education and outreach, monitoring, regulatory actions, and habitat protection measures for this endangered species in this region.
Key Words: mid-Atlantic, habitat, strandings, Florida manatee, Trichechus manatus latirostris
Document Type: Research article
DOI: 10.1578/AM.40.2.2014.126
Page Numbers: 126-138