2001 Marine Mammal Conference Abstracts

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.