Update on the spatial-temporal distribution and natural history of the killer whale (Orcinus orca) in the Caribbean Sea
Jaime Bola?os-Jim?nez, Jolanda Luksenburg, Angiolina Henriquez, Laurent Bouveret, Grisel Rodr?guez Ferrer, Eric Angel Ramos
The killer whale is a cosmopolitan species distributed worldwide. Extensive studies have revealed that, in different parts of the world, the killer whale tends to form communities of reproductively-isolated prey specialists and that phylogenetic relationship among different types of communities are complex. There has been an increase in published reports on killer whales from tropical and subtropical regions in recent years. The recent description of a previously unidentified tropical ecotype of the killer whale in the Eastern Tropical Pacific highlights the importance of contributing to the growing knowledge of killer whales in tropical waters. In this paper, we build on our previous work to update the knowledge on the spatial-temporal distribution and natural history on the killer whale in the Caribbean Sea. We collected 332 records from the literature, biodiversity platforms, internet (social networks and video hosting websites), and citizen-based initiatives. Records included sightings (89 %), takes (2 %) and strandings (9 %). The origin of the records included research projects/activities (49 %), citizen-based initiatives (39 %), occasional takes (9 %), and the whaling industry (3 %). Most records (76 %) were concentrated on the Eastern Caribbean (39 %) and the Greater Antilles (37 %), with only 17 % and 7 % for the southern and western Caribbean, respectively. Killer whales were recorded during all the months of the year, with the highest numbers in August (n = 35) and April (n = 34), and the lowest in February and September (n = 11 each), and we found no differences in the median of records by month. Records were more common during the warmer seasons (n = 84 and 88 for spring and summer, respectively) than during the colder months (n = 56 and 57 for fall and winter, respectively, but we found no differences in the median of records by season (Hc = 1.82, p = 0.56). The presence of solitary individuals was recorded in 25.9% of occasions. Minimum group size averaged 4.1 (± 3.7 S.D., range: 1-25 n = 306). We found no differences between average group size of killer whales in the Caribbean Sea and average group size in Hawaii (t = -0.12, p = 0.90), Perú (t = -0.26, p = 0.79; and t = -0.38, p = 0.70, respectively) and Mexico-Eastern Tropical Pacific (t = -0.53, p = 0.59), respectively. We found difference in average group size between killer whales from the Caribbean Sea and West Africa (t = -2.19, p = 0.03). Our updated database of killer whale records supports their regular and widespread occurrence throughout the Caribbean Sea. Limited study and their probable low densities limit our ability to predict if and where they regularly occur in most regions. More detailed, systematic surveys are necessary to document the offshore distribution, relative abundance, habitat preference and prey preference of killer whales in the Caribbean region. Future work should also include more detailed efforts to document the potential presence of tropical ecotype(s) in the Caribbean Sea and, if such an ecotype exists, to describe its behavioral ecology.