First insights on the horizontal movements of short-finned pilot whales in the Gulf of Mexico

This study is the first assessment on how short-finned pilot whales (Globicephala macrorhynchus) move within the Gulf of Mexico. In April 2018, seven adult animals were tagged using location-only satellite transmitters in the south-western Gulf (18 degrees 59 ' N and 95 degrees 19 ' W). When tagged, all animals were in a medium-size aggregation that split after a week and followed two routes, indicating that the initial aggregation was consisted of at least two social units. Regardless of the route, short-finned pilot whales moved at a low travel rate (mean = 3.4 km/hr; 50% IC: 1.5-4.8) on the south-western continental shelf-break, between the 500- and 800-m isobaths. The oceanography and hydrographic features of the south-western Gulf's continental shelf-break would favour the aggregation of prey, influencing the low dispersion observed during the transmission period, as well as the co-occurrence of several social units. However, given the relatively short period covered (up to 87 days) and the few animals tagged, the movement patterns described here could vary at longer temporal and spatial scales.