Abstract
Baseline data on the distribution and occurrence of marine mammals are needed to better understand their role in marine ecosystems and to protect them from the negative impacts of climate change and human activity. Here, we report the results of vessel-based surveys to document marine mammals throughout the territorial waters of Belize in the Western Caribbean Sea. In 2016 and 2017, 543 km of transects (85 h of survey effort) aboard a 14-m catamaran resulted in 17 sightings of four species of marine mammal: inshore and offshore bottlenose dolphins Tursiops truncatus, Atlantic spotted dolphins Stenella frontalis, pantropical spotted dolphins Stenella attenuata, and Antillean manatees Trichechus manatus manatus. Coastal manatees and bottlenose dolphins were found in shallow waters and all other species exclusively in deep waters east of the Mesoamerican Barrier Reef System. These preliminary findings suggest there is a low density of marine mammals in the offshore habitats of Belize. Future studies should employ vessel-based distance sampling techniques and passive acoustic monitoring to reliably track the occurrence of marine mammals in this region and assess their distribution and abundance.