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Florida manatees (Trichechus manatus latiros-tris) 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 mana-tee sightings (n = 211) and strandings (n = 9) from 1991 to 2012 in North Carolina and Virginia. The goals were to describe spatial and temporal patterns 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. [ABSTRACT FROM AUTHOR]

Data from behavioural observations and acoustic recordings of free-ranging bottlenose dolphins (Tursiops truncatus) were analysed to determine whether signature whistles are produced by wild undisturbed dolphins, and how whistle production varies with activity and group size. The study animals were part of a resident community of bottlenose dolphins near Sarasota, Florida, USA. This community of dolphins provides a unique opportunity for the study of signature-whistle production, since most animals have been recorded during capture-release events since 1975. Three mother-calf pairs and their associates were recorded for a total of 141.25 h between May and August of 1994 and 1995. Whistles of undisturbed dolphins were compared with those recorded from the same individuals during capture-release events. Whistles were conservatively classified into one of four categories: signature, probable signature, upsweep or other. For statistical analyses, signature and probable signature whistles were combined into a 'signature' category; upsweep and other whistles were combined into a 'non-signature' category. Both 'signature' and 'non-signature' whistle frequencies significantly increased as group size increased. There were significant differences in whistle frequencies across activity types: both 'signature' and 'non-signature' whistles were most likely to occur during socializing and least likely to occur during travelling. There were no significant interactions between group size and activity type. Signature and probable signature whistles made up ca. 52% of all whistles produced by these free-ranging bottlenose dolphins.