First abundance estimate for greater Caribbean manatees (Trichechus Manatus Manatus) in Belize

Population status of the Greater Caribbean manatee (Trichechus manatus manatus) is unknown across most of its geographic range, including the western part of the Caribbean in Central America. No statistically derived estimates of abundance are available for this region, but the population appears to be low and possibly stable or declining. To assess abundance and distribution of manatees in Belize, we conducted aerial surveys and estimated abundance by accounting for detection using a framework designed for marine mammals. Using a generalized additive model (GAM), we predicted abundance of manatees in 2014 and 2022 and how it varied across space as a function of spatial habitat covariates. We estimated that in the sampled area (within 500 m of flight path) there were 479 (95% CI: 275–857) manatees in 2014 and 555 (95% CI: 316–998) in 2022. Manatee abundance was higher closer to the coast, freshwater, and shallow waters. These estimates are the first for Greater Caribbean manatees in the western Caribbean Sea that account for sources of error such as observer perception bias, availability bias and spatial variation. Monitoring and assessing the manatee population is important for managers tasked with developing effective strategies to balance the use of marine habitats with biodiversity conservation.