Reproductive behavior of three mobulid species (Mobula mobular, Mobula thurstoni and Mobula munkiana) in the Southern Gulf of California, Mexico

Abstract We examined the reproductive behavior (courtship and mating) and its seasonality in three mobula species, spinetail, bentfin, and munk’s devil rays ( Mobula mobular, M. thurstoni , and M. munkiana ) in the southwestern Gulf of California, Mexico, using boat surveys (with drones and in-water observation) (n = 69 survey days), spotter planes (n = 428 flights) and citizen science observations (n = 31). We examined whether (1) reproductive grounds existed within the area for any of these species, (2) reproductive behavior followed seasonal patterns and (3) if this behavior was similar among species. We observed reproductive behavior in 221 sessions in 2017 and 2021–2022, for M. mobular (n = 10), M. thurstoni (n = 3), and M. munkiana (n = 208) dispersed along 312 km of the eastern Baja California Peninsula between 4 m to 6.3 km away from the coast. Most events (n = 209) occurred in the La Ventana and Ensenada de Muertos area. Courtship was observed for M. mobular and M. thurstoni and mating for M. munkiana , with reproductive behavior following a seasonal pattern occurring from March to August, with a peak during May. M. munkiana displayed a previously undescribed behavior, the “courtship vortex”, where 122 individuals were observed circling in a clockwise direction for five hours with mating groups joining and leaving the main vortex formation. This study highlights the area of La Ventana and Ensenada de Muertos as a critical habitat for reproductive behavior of three endangered and vulnerable mobulid species.