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Background The Gulf of Mexico (GOM) is a semi-enclosed sea where the waters of the United States, Mexico and Cuba converge. Al least 21 species of cetaceans inhabit it. The only mysticete (baleen whale) is found in the northeast (U.S. waters). The distribution of the 20 species of odontocetes (toothed cetaceans) is well understood in U.S. waters, but practically unknown in Mexican and Cuban waters. In this study we used sighting data from several odontocete species to construct habitat suitability maps in order to identify geographical regions suitable for high diversity throughout the GOM. Methods Historical datasets of georeferenced sightings from across the GOM were used to implement the maximum entropy algorithm (MaxEnt) to model the habitat suitability of each species. Five environmental predictors were used, selected for their influence over the occurrence of cetaceans: two oceanographic predictors (sea surface temperature and chlorophyll-a concentration), and three bathymetric predictors (depth, slope, and distance to 200-m isobath). A spatial approach based on the habitat suitability maps was used to identify the suitable regions. Results Only 12 species were modeled, which were the ones with the minimum sample size required. The models performed well, showing good discriminatory power and slight overfitting. Overall, depth, minimum sea surface temperature, and bottom slope were the most contributing predictor in the models. High suitability areas of 10 species were located on the continental slope, and four suitable regions were identified: (1) the Mississippi Canyon and the Louisiana-Texas slope in the northern GOM, (2) the west Florida slope in the east-northeastern GOM, (3) the Rio Grande slope in the west-northwestern GOM, and (4) the Tamaulipas-Veracruz slope in the west-southwestern GOM. Conclusions We were able to detect four geographic regions in the GOM where a high diversity of odontocetes is expected, all located on the continental slope. Although the methodology to identify them (spatial overlap) is a very conservative approach, it is useful for conservation and management purposes. The paucity of data did not allow all species to be modeled, which highlights the importance of establishing transboundary monitoring programs.

El golfo de California es uno de los ecosistemas marinos más productivos del planeta. Es un sistema eutrófico con una producción fitoplanctónica (PF) integrada de >1 g C m-2 día-1 y en algunos lugares >4 g C m-2 día-1 (Álvarez-Borrego y Nutrient input from the Colorado River to the northern Gulf of California is not required to maintain a productive pelagic ecosystem El aporte de nutrientes del río Colorado al norte del golfo de California no se requiere para mantener un ecosistema pelágico productivo

Pilot whales (Globicephala spp.) are social marine top predators that forage primarily on squid, but also on mesopelagic fish (Beasley et al., 2019;Mintzer et al., 2008). These deep-diving delphinids can travel hundreds of kilometres in relatively short periods (Baird et al., 2016) and in several locations exhibit seasonal inshoreoffshore movements related to prey availability (Alves et al., 2019;de Stephanis et al., 2008). Given their long displacement and deepdiving capacities, obtaining data on their movements often exceeded the logistical capabilities using traditional observational methods. Recently, new technologies, such as satellite telemetry, have allowed the acquisition of information on the ecology of pilot whales, showing a variety of behaviours, ranging from localized movements to large-scale displacements associated with foraging opportunities (e.g. Thorne et al., 2017), and have also provided a valuable insight on their social structure (e.g. Bloch et al., 2002). The short-finned pilot whale (Globicephala macrorhynchus) is distributed in tropical and warm waters worldwide (Olson, 2018), including semi-enclosed seas such as the Gulf of Mexico, where it is found year-round (Würsig, 2017). The Gulf of Mexico is the ninth largest body of water in the world, and it is connected to the Atlantic Ocean by the Straits of Florida and to the Caribbean Sea through the Yucatan Channel. It is delimited to the north and northwest by the United States, to the west and south by Mexico, and to the east by Cuba, converging the Exclusive Economic Zones (EEZ) of these countries.Currently, it is unknown whether the short-finned pilot whales of the Gulf of Mexico are from a different population of those in the Northwest Atlantic, and it is not clear if there is more than one stock

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