Bottlenose dolphins may use certain areas in their home range for specific activities such as feeding, socializing, and traveling. Knowledge of habitat use patterns can be important for dolphin conservation. While dolphin habitat use has been studied extensively in Sarasota Bay, Florida and a few other sites, information on habitat use in other areas is limited. The focus of my recently completed dissertation was to examine habitat use by a previously unstudied bottlenose dolphin community in Roanoke Sound, North Carolina. This area is inhabited by a seasonal community of dolphins but it is uncertain as to why they come to this area.
We applied hot spot analyses to determine if dolphins used specific areas more frequently than others. The activities of the dolphin groups, including feeding, milling, socializing and traveling, were also analyzed to determine how dolphins used these areas. We found hot spots used primarily for feeding and traveling.
Another objective of my dissertation research was to compare hot spot results between transect surveys and opportunistic surveys conducted from a local wildlife ecotour boat. Transect surveys cover a standardized route to survey an area, but these surveys can be expensive, and it can be difficult to obtain large sample sizes. Data may be collected more easily from opportunistic surveys, but the wildlife ecotour boat did not survey all of Roanoke Sound consistently, and unequal survey coverage may introduce spatial bias into dolphin sighting data. We found differences between transect hot spots and opportunistic hot spots, suggesting that spatial bias can influence hot spot results. This comparison identified a limitation of spatially-biased opportunistic data, and this limitation should be considered for future analyses of dolphin distribution using data collected opportunistically.
This article appeared on page 20 of the 2017 SDRP Annual Report, Nicks n Notches.