Bottlenose dolphin (tursiops truncatus) spatial dispersion and orientation in pods

Bottlenose Dolphins (Tursiops truncatus) are commonly found in the waters of Turneffe Atoll, Belize, where they inhabit areas that vary in physical features. Variables such as water depth, prey abundance, and location are related to the spatial dispersion of bottlenose dolphins. The spatial dispersion (areas within a pod) and orientation (line abreast, parallel, scattered, facing inward) of bottlenose dolphin pods have yet to be examined in relation to pod size, substrate type, and behavioral state. We explore how abiotic and biotic factors may affect bottlenose dolphin movement. Video recordings of free-swimming bottlenose dolphins were taken by drone in Turneffe Atoll, Belize and transformed into a series of screenshots for data extraction. Pod size (3-15), substrate type (boundary, seagrass, mixed), and behavioral state (forage, social, rest, travel) were categorized from the screenshots. Spatial dispersion and orientation were measured in ImageJ and data were averaged per video. Spatial dispersion of dolphin pods was significantly related to pod size, substrate type, and behavioral state (F = 3.375, P < 0.05). Pods were most dispersed when engaged in social activities, suggesting frequent events of separation. When swimming over a mixed substrate, spatial dispersion was also high, potentially indicating a lack of predators or an abundance of non-schooling prey. Small pods (n < 15) showed low spatial dispersion, suggesting a potential defensive strategy against predators. Assessment of dolphin activity researched using non-invasive techniques yield insights to how dolphins use their habitat when exposed to minimal human encroachment.