HABITAT USE OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) IN THE BELIZE BARRIER REEF LAGOON

Peterson, Heidi

Habitat use and behavior of bottlenose dolphins (Tursiops truncatus) were studied in a subtropical coastal lagoon. Boat-based surveys were conducted from February 1999 to November 2000. Despite the relatively low density of dolphins (0.36 sightings/hour), dolphins were present throughout the year. Seasonal sighting frequencies were independent of tidal state (X2 = 4.586, df = 3, n = 169, 0.10 < p 0.25) and tidal current (X2 = 0.349, df = 1, n =169, 0.50 < p < 0.75).

Log-likelihood ratio contingency analysis indicated that dolphin sightings were concentrated in small, protected channels between mangrove cayes (G = 41.542, df = 2, n = 63, p <0.001). Dolphin sightings were lowest in offshore areas, (G = 42.738, df = 2, p <0.001), lee of the cayes during the dry season and lee of the reef during the wet season (G = 47.607, df = 3, p < 0.001). High frequencies of foraging behavior alone (54.9%) and in combination with travel and social behavior (86.3%)indicate that the area is used as a foraging ground. The high proportion of calves (14.1% of dolphins seen during the dry season and 19.2% during the wet season) suggests additional use as a nursery area. Mangrove channels, with their close proximity to seagrass beds and patch corals, provide important habitat for bottlenose dolphins in this subtropical lagoon habitat.