RESULTS 



IDENTIFICATION AND DETECTION 



The ability to identify the animal species sighted during aerial surveys was 

 important to the results and quality of the Pilot Study. On occasion conditions were 

 encountered which prevented positive identification of the species or exact composition 

 of mixed groups. In such cases the most detailed identifications available were recorded 

 and analyzed. In some cases identifications were possible at a later time due to 

 increased sightings and incorporation of other data not available at the time of the 

 sighting. On the basis of all data available, probabilistic identifications can be made and 

 the sum of all observations considered in evaluating occurrence, abundance, and 

 movements. For example, tentative groupings such as unidentified dark tern were not 

 necessarily a single species but instead were those animals for which more specific data 

 were unavailable. Dark terns were likely to be black terns, sooty terns, or bridled terns 

 and the availability of tentative data allowed consideration of the total number of 

 possible black, sooty, or bridled tern records. 



Mammals 



The identification of mammals from an airplane depended upon a number of 

 factors. The behavior, size, and coloration of individual species were critical in making 

 precise identifications. Most species can be readily identified if viewed from the proper 

 angle or vantage point. Most of the animals popularly termed dolphins are similar in 

 body shape and size but differ in head shape, behavior, and subtle aspects of coloration. 

 Bottlenose dolphins were distinctive but not all dolphins were adequately observed to 

 differentiate the bottlenose from other species. Dolphins of the genus Stenella were 

 quite similar and consequently difficult to identify to species in all cases. However, 

 because of the paucity of information on the ecology, movements, and behavior of this 

 genus, all data were considered to be of potential value. Three Stenella species were 

 identified: spotted dolphin, striped dolphin, and spinner dolphin; although the last species 

 was identified tentatively and only once. 



Dolphin groups containing 20 to 150 animals were often sighted over large 

 distances whereas individuals or small groups were seldom seen except near the transect 

 line or immediately perpendicular to the plane's position. Because large groups presented 

 more visual cues, most could be identified. In contrast, individuals and small groups were 

 less likely to be viewed adequately for identification of species. Thus, the number of 

 sightings of unidentified dolphin groups probably represented a small percentage of the 

 total number of dolphins relative to the number of identified individuals and groups. 



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