Understanding how marine vertebrates move throughout the oceans is critical to effectively protecting and managing these species. Mantas are no exception, and are perhaps one of the most poorly studied marine species on the planet. Using archival satellite tags, which provide satellite-transmitted location estimates from data collected during a tag deployment, researchers from Scripps Institution of Oceanography are finally beginning to understand the movements of these elusive and mysterious creatures. Below you can find some of the first results of tagging mantas at two field sites in Pacific Mexico: Bahia de Banderas, on the mainland, and the offshore Revillagigedo Islands. So far, the tagging data indicates that there is no connectivity between mantas tagged at the islands (in blues) and those tagged on the mainland (in greens), meaning that mantas do not travel between these sites. However, mantas from both locations made north-south movements during the same seasons, spent extensive amounts of time in deep-water pelagic zones, and made some monumental deep dives. These tagged mantas showed a high degree of site affinity, suggesting that mantas may form local subpopulations rather than being the prolific oceanic wanderers once assumed. Explore the data to see how these mantas moved around over the 6-month deployments, and what their daily maximum depths were. Stay tuned for more tag data this winter!

Conclusions

Understanding how mantas in Pacific Mexico, and elsewhere in the world, move around and use ocean habitats allows researchers to identify critical habitats and make recommendations for management. If these tagging results are upheld by other research methods such as stable isotope analysis and genetic analyses, it will indicate that small subpopulations of manta rays exist perhaps all over the world, which are subject to local-scale pressures from fisheries and bycatch and therefore are best managed at a local or regional scale.

Tagging an Oceanic Manta from Josh Stewart on Vimeo.