Characterizing Fraser's Dolphin (Lagenodelphis hosei) in the Lesser Antilles: Distribution, Movements, and Co-Occurrence With Other Cetacean Species to Inform Conservation Strategies in the Caribbean

Fraser's dolphin (Lagenodelphis hosei) is one of the least studied dolphin species due to its tropical, offshore distribution and low density. However, it is frequently observed in the Lesser Antilles, where we characterized its distribution and ecology using 4 years of data collected from Grenada to Anguilla. We employed species distribution models, movement analysis, and co-occurrence analysis with other species. Fraser's dolphin was the second most encountered delphinidae species, with confirmed sightings throughout the Lesser Antilles. Depth, slope, distance to canyons, and eastward current velocity best explained the observed distribution, accounting for 22% of the variance. The Caribbean side of the Lesser Antilles represented a continuum of suitable habitat, with resightings of 10 individuals indicating inter-island connectivity from the Grenadines to Guadeloupe (415 km). Notably, Fraser's dolphin exhibited the highest co-occurrence rate (83%) and stood out statistically from other species in co-occurrence frequency and strength, underscoring the ecological significance of interspecies interactions. Overall, Fraser's dolphins in the Lesser Antilles likely represent a single population restricted to the arc, with negligible spatial fragmentation. Our results highlight the regional connectivity and the need for cooperation and harmonization of regulations in the Lesser Antilles to ensure effective conservation of the cetacean community.