Insular and mainland interconnectivity in the movements of oceanic manta rays (Mobula birostris) off Mexico in the Eastern Tropical Pacific

The oceanic manta ray (Mobula birostris) is the largest batoid. The species is distributed circumglobally in tropical and subtropical seas around offshore islands and seamounts where upwelled waters are present with high productivity. They inhabit the waters of the Eastern Tropical Pacific, with known aggregations around the Revillagigedo Archipelago (RA), and in Bahia de Banderas (BB), along the western edge of the Mexican mainland. Manta rays from the Archipelago and Bahia de Banderas were identified by their unique color markings, in photographs collected by citizen scientists and researchers, and/or coded acoustic beacons detected by autonomous monitors deployed at sites mentioned below. Here we report the movements of 22 individuals that moved between RA and several aggregation sites over 21 years: BB, Bahía de Navidad (BN), and the Gulf of California (GC). Two manta rays moved from Isla Cerralvo in the southern GC to RA over periods of 3.0 and 3.3 years (y). Seventeen mantas moved back and forth between RA and the mainland over periods ranging from 0.1 to 15.3 years. The longest manta transit was from RA to Bahía de Navidad on the western coast of Mexico, traversing approximately 560 km. Findings suggest that the three populations constitute a metapopulation, with connectivity between the three locations. Resulting from the scarcity of past biological research conducted in RA and GC, we introduce some information from telemetry monitoring and significant observational data from the author’s long-term field research.