Reproductive behavior, seasonality, and distribution of three devil ray species (Mobula mobular, M. thurstoni, and M. munkiana) in the Southern Gulf of California, Mexico

Abstract

We examined the reproductive behavior (courtship and mating), seasonality and its distribution in three Mobula species, spinetail, bentfin, and Munk’s devil rays (M. mobular, M. thurstoni, and M. munkiana) in the southwestern Gulf of California, Mexico, using boat surveys (with drone and in-water observations) (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) whether reproductive behavior followed seasonal patterns, and (3) if this behavior was similar among all mobula rays. We observed reproductive behavior in 221 events 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 and 6.3 km away from the coast. Most events (n = 209) occurred in the La Ventana and Ensenada de Muertos areas. Courtship was observed for M. mobular and M. thurstoni and a copulation attempt for M. munkiana, with reproductive behavior following a seasonal pattern occurring from March to August, with a peak during May (81.9% of the events). Mobula munkiana displayed previously undescribed behaviors, such as the “piggyback leaps” as a pre-copulatory position and the “courtship vortex”, where 122 individuals were observed circling in a clockwise direction for 5 h with courtship groups joining and leaving the main vortex formation. This study highlights the areas of La Ventana and Ensenada de Muertos as critical habitats for reproductive behavior of two endangered and one vulnerable devil ray species.

First records of Mobula hypostoma (Bancroft, 1831), Atlantic Pygmy Devil Ray, (Myliobatiformes, Mobulidae) and other devil rays in shallow waters of the Republic of the Congo, Gulf of Guinea (West Africa)

“…Devil rays are challenging to observe and study in their natural environment, and there are relatively few locations around the world where they are easily approached (e.g. Thorrold et al 2014;Palacios et al 2023). The devil rays are poorly documented in much of the eastern tropical Atlantic (ETA), which extends along the west coast of Africa from Mauritania to Angola and includes the Gulf of Guinea.…”